How Soy Affects Hormones and Health

Soy contains phytoestrogens or “plant-estrogens,” which sounds bad but by out-competing estradiol, phytoestrogens can have a beneficial anti-estrogen effect in women of reproductive age.

That’s why soy and other phytoestrogens can make periods lighter and improve estrogen excess symptoms such as PMS and heavy periods. 

Food-based phytoestrogens have long been part of the human diet, so we’re adapted to them. They help to protect and buffer estrogen receptors and promote the healthy metabolism or detoxification of stronger estrogen metabolites. They may even reduce the risk of breast cancer.

👉 Tip: Phytoestrogens are naturally present in many foods including legumes, nuts, seeds, oats, peanuts, cashews, garlic, cabbage, fennel, apples, coffee, beer, dairy, and even meat. Phytoestrogens are a big part of why seeds are beneficial for women’s health.

High-dose soy or soy as a supplement can stop periods or impair fertility because of its strong anti-estrogen effect. Conversely, soy can have a detrimental pro-estrogen effect in men and children.

The other hormonal effects of soy are that it can 1) prevent the healthy uptake of iodine and therefore contribute to breast pain and other premenstrual symptoms, and 2) reduce thyroid hormone by downregulating thyroid peroxidase. Thyroid suppression is less likely to be a problem if there is sufficient iodine intake.

Non-hormonal problems with soy

There’s more to soy than phytoestrogens. For example, industrially grown soy is heavily sprayed with pesticides. Soy is a common food sensitivity so can be a problem for immune conditions like endometriosis and soybean oil is high in omega 6 fatty acids which can be inflammatory.

Most of those negative effects are associated with industrially processed soy. Moderate amounts of traditionally fermented soy such as tempeh, miso, tamari (good soy sauce), and natto are beneficial not only for their anti-estrogen effect but also because they’re a valuable source of vitamin K2.

Bottom line, you can enjoy a moderate amount of tofu and soy sauce and rest assured that it’s fine for hormones.

Ask me in the comments.

152 thoughts on “How Soy Affects Hormones and Health”

  1. Hi Lara thanks for the article.
    I drink soy milk with a tablespoon of black dog powder everyday. And I ovulate super late i.e cycle day 30 >
    Is there a connection? Thanks

    Reply
  2. I’m 16 years old and for the past 2 months I have been drinking soy milk everyday in hopes of it producing more estrogen in my body so my boobs can grow bigger. I’ve read that soy increases estrogen in the body, is this true? I haven’t gotten my period since i started drinking soy milk so I’m starting to get worried.

    Reply
    • Soy generally has an anti-estrogen effect in women. It will not increase breast size and could cause you to lose your period.

      Reply
  3. Hi Lara, would skincare cremes in a base of soybean oil cause estrogen dominance? I
    began to notice uncommon changes in my my when I began a new skincare routine and discovered it has alot of soy in the formulations
    Thank you for your insight.

    Reply
  4. Thoughts on an organic soy mince? I understand it’s refined and therefore not ideal. Not only for a woman, but for a female child and male adult?

    Reply
  5. Oh no. I thought I’d try soy milk a few times a week to lighten my period and now it’s arrived on time without spotting for a whole week prior but even heavier with big clots . No soy for me . I hope it’s lighter tomorrow . I have been VERY stressed lately though.
    🙁

    Reply
    • I can’t see where to add a new comment . I know u get a lot of questions on all blog posts so I’m happy to have a stranger answer this . I have 2 questions.

      1- My 2 year old is given tofu once a week at childcare . Is this ok? I panicked when I saw it on the menu.

      2- I’ve tried all of your recommendations in all of your books so far for pms mood swings/depression and anxiety and insomnia mostly when pms time and not had any luck over the years so I just started drinking 1 cup of non gmo soy milk daily since about half way through my cycle so far only 5 days and not expecting my period until around the 2nd of next month . I’m hoping maybe the soy milk will help? Or will it ruin everything else? I’m 38 I have clear skin and had no trouble conceiving at age 35 Even with heavy consumption of dairy which I also completely quit for a while this year which didn’t help With the pms moods , never had cramps anyway And my cycles are very regular just heavy.
      Can it help to take iodine to prevent soy messing with hormones?
      Thanks

      Reply
  6. Hi! Just discovered you’re website and I’m stoked to get answers!
    I have terrible reactions to soy. I have heavy, clotty periods and had a large fibroid (it is gone as of a month or so ago due to an herbal tincture). But still when I eat anything with soy in it, I have terrible mood swings and spotting. If I’m on my period, I have horrible cramping and hemorrhaging with clots. You said it helps with estrogen management, but I thought it was because I was estrogen dominant, but could it be because of a different problem?

    Reply
  7. i’m 43 years old and my period for past 1 year has been quite regular but lesser in volume. I started a non gmo soy genistein supplement 1 month ago..and its almost 30 days from my last cycle, but there’s no sign of any menses or pms feeling. Why is this? Does genistein supplement delays period? what supplements should i take to ensure my menses is more regular every month? pls reply to my email [email protected].

    Reply
  8. I am reading in your book about cutting out cow’s milk as a way to help with PMS and perimenopause. However, we are working on increasing my probiotic foods, so I am eating yogurt and aged cheese. Genetic testing shows I am not sensitive to dairy but am to gluten, so I am gluten free. If I do switch my milk to soy milk since it is fermented and has probiotics, will it have any ill effects on my PMS or Perimenopause issues?

    Reply
  9. Hi Lara!
    I’m nursing and my baby is sensitive to dairy so I’ve been taking soy cream in my coffee every morning. I imagine this is one of the more dangerous amounts of soy, as you mentioned.
    Can I continue until I notice symptoms that may be pointing to trouble, like breast tenderness? Or should I proactively limit my intake?

    Reply
  10. I saw here that a lot of people could have PCO’s post pill. And I saw that you say that insulin resistance causes PCO’s in some people. But in my researches, insulin is totally correlated with hormonal acne and hormonal imbalance (because can improve the testosterone levels and all that stuffy), which can causes acne, alopecia, hisurtism. Even if I don’t have insulin resistance, an low carb diet or paleo (In Brazil we say low carb – but I mean, eating less refined carbs, eating the good carbs and the one it has fiber on it, eating low glicemyc fruits), is not going to help to pass trough this post pill acne? I’m confusing in this question.
    I don’t know if I have PCO’s (I’m 50% sure that I don’t have or I had an PCO’s post pill) but I notice when once I was dealing with acne that high carb foods was getting this worst

    Reply
  11. Hello, do you know the latest on phytoestrogens and Brest cancer risk for women who have had Hormone receptor positive breast cancer in the past ?

    Reply
  12. Hi Lara,
    I’ve had hypothalamic amennorhea for around 8 years now. I’m 30 years old. I’ve been put on Femoston 2/10 by my doctor to up my estrogen levels which contains 2mg oestradiol. Sometimes I get with withdrawal bleeds at the end of each pack, with are often quite light and only last a few days. Sometimes I don’t get a bleed at all, which concerns me.

    I consume around 100-300ml of soya milk per day and between 100 – 400 g of soya yoghurt per day. I occasionally eat tofu. Is this too much soy and do you think it’s negatively impacting my cycles and causing me not to have a withdrawal bleed?

    Thanks,
    Jess

    Reply
  13. my day 3 estradiol is so low in menopause level, so i am taking some soy isoflavones, hoping to boost estrogen lever and minimize the peri symptom, is this a good idea

    Reply
  14. I am 48 still have regular period , but my day 3 estradiol level is so low, in the menopause zone , so I am taking soy isoflavones, hoping to increase estrogen level, is this a good idea?

    also I believe take certain amount of tofu on a daily basis should not do any harm to your body, after all it is part of the regular diet of women in several asian countries

    Reply
    • I support the consumption of moderate soy intake as food but I recommend against any kind of concentrated soy supplement.

      Reply
      • Hi Lara, what would you define as a “moderate soy intake as food”? I’m vegan so tofu is a big part of my diet. Any studies you could point me to?

        Reply
  15. Lara, is 2 cups soy milk every day with chai tea too much?? I sometimes get certified organic not sure if this helps.

    Reply
  16. What about a lean female athlete doing high levels of intense physical activity, very light periods, small breasts, prone to some facial hair? Would this be more of a low estrogen picture, where soy could help raise estrogen before a period to relieve PMS?

    Reply
    • Soy can never directly raise estrogen in a woman of reproductive age because soy is so much weaker than estradiol that it will always have a mild anti-estrogen effect.
      That said, there is some evidence that low-dose phytoestrogens can help to promote ovulation in women with PCOS, in which case it could have an indirect benefit.

      Ovulation is the way to raise estrogen.

      Reply
  17. I would like your input on the potential benefits of edamame beans. Would they be a good source of phytoestrogens? I am 49 years old and have a lot of histamine problems (lots of double mutations of the HNMT genes, as well as chronic infections in the CNS after a tick bite) which seem to flare around ovulation and prior to menstruation (which I ascribe to high estrogen around those times).

    I am at a loss at how to increase HMNT / clear histamine in the CNS though natural ways, apart eating a low-histamine diet. I’ve recently started taking calcium d-glucarate. And also put a drop of Lugul’s 5% iodine on my skin daily.

    Reply
  18. Hi Lara,

    Interesting read. So I have been allergic to soy since I was about 4 (I get a rash on my wrist and hands about 30 min after eating soy). I try to avoid it but I still sometimes accidentally eat it and I do buy things with soy lecitin because my reaction is much more minor and it is hard to avoid. I am 23 and have always had irregular periods. They are long, heavy and random. I go 2, 4, 6 months without a period. I also have cystic acne which I believe is hormonal.

    Do you think that my soy allergy and my still eating soy sometimes has anything to do with my hormonal imbalance? Could cutting out all soy completely actually help me? Or do you think they are not related for me since I probably consume less soy than most people?

    Thank you!

    Reply
  19. Does breathing in soy from soy candles have the same negative affect on hormones? I am looking into the best options for making candles and I have found that 100% organic soy wax would be a good option, but I didn’t know if that soy would affect hormones.

    Reply
  20. I have amenorrhea for a year already but I love fermented soybeans so much. I have been told not to eat any soy products because it will mess up my already messed-up hormones. So my question is am I still able to eat fermented soybeans? If so, how much should I consume on a daily or weekly basis in order not to have it mess up my hormones?

    Best regards

    Reply
  21. Hi again, sorry for all the questions!… but I just had a thought, perhaps the ground flax seed and milk thistle (been taking daily for years) might not be helping with ovulation if the level of phytoestrogens is enough to have an ANTI-estrogen effect, in a similar way to soy. Or perhaps i’m over thinking it. Love to hear your thoughts!

    Reply
    • Yes, the phytoestrogens of flaxseeds are also anti-estrogen, but I think you’d have to be eating quite a lot for it to suppress ovulation.

      Reply
  22. Ok thanks Lara. I should be on the wait-list but will check again with Lisa and pop down to see you once you’re all set up and running 🙂

    Reply
  23. Wow this is the best news!! I am not in Chch but I will come down or if you are doing skype consults that would be perfect. What is the best way to contact you about it?

    Reply
    • I’m not offering distance consults, but you’re welcome to come down, if you want to. You can reach my assistant Lisa via the email link on my blog. Or ring her on (03) 974 9200. At this stage, she’s just making a wait-list until we get the appointment booking system up and running.

      Reply
  24. Wow thank you SO much Lara for your response. So encouraging to hear – thank you!!!! I look forward to meeting you in NZ when you start seeing clients here, if i’m not recovered by then 🙂

    Reply
    • actually, I found a Christchurch consulting room and will start seeing patients on Fri, 20 Sept. Are you in Christchurch?

      Reply
  25. Hi Lara, I have had HA for about 12 years (i’m 30 now). I have followed the steps in your book and the ‘No Period, Now What’ protocol (half in for 7 months and all in for 3 months). I have CM and sore, swollen boobs etc each month (on the same day) + similar symptoms again 14 days after but still no period. Over 4.5 months LH increased from 1.6 to 4.7IU/L and FSH from 4.5 to 6.9IU/L. Oestrogen still <44 pmol/L. I read that soy isoflavones can 'kick start' ovulation by increasing estrogen? …but having read your post above I am confused and not sure if I should try it or not. Any advice would be SO helpful!! Thanks 🙂

    Reply
    • From the sound of it, I suspect you’re really close to ovulating. I doubt you need soy or anything else to help kick-start things.

      In theory, if you were to use soy, it would be for its ANTI-estrogen effect. Which would mean doing five days or so of very high-dose soy to suppress both FSH and estrogen, and then stopping it suddenly to cause a rebound effect. Similar to how drugs like letrozole work. But honestly, I would not recommend that. I’ve never prescribed soy that way.

      Reply
    • Hi Erika,

      Hope you don’t mind me jumping in here! I just wanted to say that I am also 30 and have had HA for around 8 years. I would love to know what you did to increase LH and FSH 🙂

      Reply
  26. I’m confused. I am low in estrogen, Perimenopausal, and I was wanting to use a phytoestrogen cream to help boost my estrogen levels. But your article states that it competes with our own estrogen and may have anti estrogenic effects. Is this just soy? Because I’m wanting to use a red clover cream.

    Thank you

    Reply
    • If you are still having cycles, then you have more estrogen than you think. And phytoestrogens will have an anti-estrogen effect.

      Reply
  27. Hi
    I have noticed that when I eat soya like quorn sausages or soya alternative to meat products I start bleeding a little for a few days afterwards. It has happened a handful of times… I am 39? What could this mean?

    Reply
  28. Hi Lara! I have a question about soy milk vs oat milk. My milk of choice for my capuccino in the morning is Oaty’s oatmilk because of the flavour and no dairy. However a friend will not drink oatmilk and prefer soy milk because of gluten and the reason she stopped consuming gluten is because she learned it affected her thyroids. My question is: doesnt soy milk affect your thyroid hormones as well? In the thyroid debate…what is a better alternative between oat and soymilk?

    Reply
  29. Hi Laura. Two of my favorite skin products have soy. Soy lecithin and soybean oil. They’re organic from eminence organic. If I am trying to reduce my estrogen dominance, are these safe to use? I read somewhere that the phytoestrogens are not in the fat of the soybean, but I trust your call way better than one random internet articles.

    Reply
  30. What about flax seeds and milk thistle seeds that also contain phytoestrogens? Are they safe to consume daily? How much is too much? Thank you for all your posts. I love your blog.

    Reply
  31. Hi Lara,

    My problem is my acne, I stopped the pill more than 1 year and half ago, and I still sufer with hormonal acne. I am vegetarian, I dont consume dairy and very little sugar. I started suplementing with magnesium and zinc about 5 months ago and It did improve my acne and now after so long time with completly irregular periods it started to come whitin around 42 days. But I still have acne and it bothers me soooo much, kills my self steem. I am considering take DIM. Do you also think soy could be related to acne, since I eat at least on serving of organic tofu daily?
    (I am 25 and I took pill for 6 years.)

    Hoppefully you can give me some light , thank you!!!!

    Reply
  32. Do you have any references to support your statement “Soy’s anti-estrogen effect is so strong that too much soy can stop periods and impair fertility. ” Or can you provide the data from your clinic? Something perhaps like a graph of soy consumption versus period status… Thanks!

    Reply
    • There’s this paper: Adult Ovarian Function Can Be Affected by High Levels of Soy
      They state: “…consuming soy protein in excess (>100 mg soy isoflavones/d) can lead to reduced ovarian function as determined by lower circulating levels of hormones, with the most prevalent finding being lowered gonadotropin levels. This is particularly true in premenopausal women during their reproductive years when these decreases could have the greatest effect.”

      Reply
      • I don’t know… I came upon your site when searching for answer to confirm my suspicions. Of late I’ve been having irregularity in my periods where it had gone missing for many months. I started adding soy milk regularly into my diet and now my periods are back and regular? But reading your article, it’s stating the exact opposite of my n=1 experience. Am I an anomaly or soy isoflavones affect bodies differently as every one of us is unique?

        Reply
        • Yes, I think soy treats our bodies differently. I took soy protein powder recommended by my friend almost everyday few years ago and it totally mess my period. My cycle’s regular but during that whole month of consumption, my period doesn’t came at all. I thought maybe I was stress or anything but my period still hasn’t came the next month of consuming. After I made few readings on the internet, I stopped consume it right away. My period was back on track but I don’t know if the same culprit turns my period cycle to be irregular until today. I wish I could turn back time. I still find it weird cause it doesn’t give negative effect to my friend..

          Reply
  33. Dear Lara, I’m must say I’m a bit confused and I hope you can help me. So, is it right that if I have high heels of estragen then soy consumption might lower that estragen, but if I have low levels, soy consumption might raise those levels? Also, I wonder if you have any research supporting your claims, last thing I read was an overview of several studies showing that soy consumption have no effect at all on hormone levels? Unless you eat like three kilos a day. I really don’t know what to believe. Best, Josefine

    Reply
  34. Hi Lara
    I am trying to conceive after a missed miscarriage in august, i am trying to improve my lifestyle and diet, i thought i was improving my diet by eating fruit seeds and soya yogurt in the afternoon instead of junk food, but now I’m wondering if its doing more damage than good

    Many Thanks

    Erin

    Reply
  35. So, would it be ok to try a cup of organic,non GMO soy milk daily if you are post menopause and having mild hot flashes and insomnia? Would that help a low estrogen, post menopause woman? Would ground flax or black cohosh be better for that? I’m looking for a natural phytoestrogen food that will help alleviate some mild post menopause symptoms. It would seem quality soy would help this particular group,but not if it furthers lowering estrogen? Im confused.

    Reply
    • Yes, it should be fine to try some soy in that situation, as long as thyroid is okay (keeping in mind that soy can suppress thyroid). But I find a better solution for menopausal symptoms is magnesium + taurine and adaptogen herbs like ashwagandha. Natural progesterone can also be helpful. I discuss in Chapter 10 of my new book.

      Reply
  36. Wow thanks so much for clearing up my confusion with soy and phytoestrogens Laura! I have been avoiding soy because I am oestrogen dominant (perimenopausal). I also thought my daily coffe was upping my risk for breast cancer but apparently not! (Yay!) I have fibrocystic breasts, so a serving or two of fermented soy per week will help with that and PMS? I hope so!

    Reply
  37. Hi Dr. Lara. I have a soy protein question for you. I have been using Herbalife for breakfast and lunch meal replacement. It is a soy based protein meal replacement. I have lost 22 lbs using Herbalife. Anyway, I have PCOS and hirsutism. My periods are pretty regular (within a few days). I am wondering if I should be concerned with using this product because of the soy? What are your thoughts? I’d love to hear back from you about this. Thank you.

    Reply
  38. I am using bio-identical compounded estrogen compounded for me. Here lately I am full of inflammation and terrible heat in my muscles and deep pain in my legs and hips. My doses were upped three months ago. What do you think of bio-identical hormones? I had a radical hysterectomy three years ago and began the HRT last October. Any suggestions?

    Reply
  39. Thanks so much for your article. I stopped consuming soy about a year ago. i was a heavy soy consumer until I had 3 different tests that showed somewhat high TSH, and low thyroid function. Not long after I stopped soy, I started getting HEAVY periods. So, I’m going to try tofu every now and then while maintaining my iodine levels, and see what happens. Gee, I hope this works. I’m also taking Red Raspberry and Maca.

    Reply
  40. Hi, I appreciate your very informative article. It’s a bit of a challenge to figure out how much soy is “too much.” I’m post-menopausal by a few years. I’m doing a vegan diet for a few weeks to support a friend doing the same, and as a bit of an experiment. Vegan doesn’t mean a lot of change to my diet–almond milk in my oatmeal (nice!) and coffee (blech) instead of half-and-half, and tofu in place of eggs and fish. Legumes were already a big part of my diet.

    I’m talking about three ounces a day (at most) of non-gmo organic soy tofu. Is this enough to mess with my hormones? I take a number of antidepressants and medications to prevent migraines, and I’m in a very nice, comfortable place in my post-menopausal life. I also have very high cholesterol.

    P.S. I’ll try soy milk “cream” in my coffee next. It may be that the lack of a decent substitute for half-and-half will tank my vegan diet 🙂

    Reply
  41. Another important factor which hardly anybody knows is Soy features one of the most powerful Bowman Birk’s inhibitor, it is a substance which inhibit Protease enzyme from digesting protein. Soy’s Bowman Birk’s inhibitor interfere Trypsin enzyme from doing it’s job. Trypsin which is a Protease enzyme produced by the pancreas, not only function as dietary protein digestor, but also reabsorbed by the small intestine and circulate in our blood stream to scavenge for Cancer cells.

    Please look into the work of Dr. Nicholas Gonzalez, he provides the most thorough and complete explanation about Cancer. And surprisingly his theory does not negate other theories, but rather provide a unifying factor.

    Reply
  42. So many Soy studies are secretly funded by Soy industry. I’m always skeptical how and why a bean which 50 years ago nobody in the West knows about, grew 5 folds in just 60-70 years. Ask your European grandmas if she grew up in 1940s eating soy? And today, Soy being pushed down every Westerners throat?

    I am a Chinese man, the idea of Asians eat alot of soy is a myth! Whenever western media telling you Soy is consumed in large amount in Asia, what they don’t tell you is, we consume the fermented form ie. Soy sauce, Tempeh, Miso, Natto (with occasional tofu). If you don’t believe me, GO travel to Asia and check out the menu in Restaurants. Tofu is rarely featured in Asian dish! Unless if you go to vegetarian Buddhist restaurants.

    Traditionally Tofu as always been a food for Celibate Buddhist monks because of it’s estrogenic effect which reduce sexual libido in (celibate) men. In fact Soy food did not become food for common Asian folks until Seventh Day Adventists missionaries came over to China and promoted Soy as food for the common folks.

    Reply
  43. I think people need to be careful and skeptical when reading about Soy and Cancer studies. So many Soy studies are secretly funded by Soy industry. I’m always skeptical how and why a bean which 50 years ago nobody in the West knows about, grew 5 folds in just 60-70 years. Ask your European grandmas if she grew up in 1940s eating soy? And why today, Soy being pushed down every Westerners throat?

    First of all, I am a Chinese man, the idea of Asians eat alot of soy is a myth! Whenever western media told you that Soy is consumed in large amount in Asia, what they don’t tell you is, we consume the fermented soy such as Soy sauce, Tempeh, Miso, Natto (with occasional tofu). If you don’t believe me, GO travel to Asia and check out the menu in Restaurants. Tofu is rarely featured in Asian dish! Unless if you go to vegetarian Buddhist restaurants.

    Reply
  44. So I was diagnosed with 98% confidence I was in menopause…… Fast forward 11 months 22 days and who shows up knocking at my door…… None other than infamous Aunt Flo…… And she kept reappearing sporadically, like I’d “spot her” every few months…… Until recently she’s been here 2 months in a row….. I finally looked at a product I’ve been using….. A “body dew”, lotion/oil. The first ingredient is soybean oil……. Do you think absorbing this into my skin is causing Aunt Flos return?

    Reply
  45. Hi, I just became a Vegan this month and have been having a large amount of Tofu with meals. I say I have ate Tofu about 4 days a week.

    I didn’t not know Soy was harmful until my boyfriend sent me an article.

    I have gotten my first period since becoming Vegan and I am now on my 9th day. The first 4 days were extremely light. Almost as if it wasn’t a period. And after that they were heavy (Which is the norm for me). Also, I have had ZERO cramps (Except today, my 9th day, I have experienced a little) which is completely out the norm. I am used to terrible cramps each period where I have to take 3 pills every 3hrs.

    How long will my period last? I have already called by Gyno nurse because I am very concerned now. She said if it is still here next week to call back. 🙁

    Reply
    • It’s good your period pain is gone. That’s because you’ve stopped having dairy. Please see my post: What Dairy Does to Periods.

      The new symptom of spotting could be due to several different things. It could just be an adjustment, and your cycle will go back to normal. Or it could be that soy has suppressed your thyroid somewhat. As I explain in my book, premenstrual spotting is a common symptom of underactive thyroid.

      Generally, I do not recommend a vegan diet primarily because it is deficient in zinc, which is essential for hormones and health. Please see my post: 7 Ways Zinc Rescues Hormones.

      Reply
      • A vegan diet is deficient in zinc? Where did you get your medical degree? I’m presuming at an American medical school with the usual 4 hours of nutrition. A vegan diet does not make you deficient in zinc. Educate yourself. You sound stupid.

        Reply
        • Legumes and seeds provide some zinc but nearly as much as you can get from red meat and oysters. I test my patients for zinc and find that almost all vegans require a zinc supplement.

          Reply
          • I also have read that phytates in legumes might nhibit the absorption of zinc and other minerals

  46. Hi Lara,
    I ate a lot of soy during 1,5 years after becoming a vegetarian. And during this time I started having a lot of pain during my menstruation, sooo much more than ever before. I heard somewhere that soy could effect estrogen and decided to stop and see if there were a difference. Two weeks after I stopped I had ny period, and there was no pain. Just the normal feeling I used to have before soy. I have also tried eating soy just to compare, and then the pain is back.
    About 4-5 months after I stopped soy I started getting light menopause like problems, getting dry and very sensitive down there. After trying to deal with the problems I found that it could be problems related to lowered estrogen levels. So now I am trying to find my way in how to make it all balanced again… This is how I came across your site, thank you for all the info! And if you happen to have any advice on what to do after soy might have messed up estrogen levels I would be so grateful.
    Kind regards,
    Anna
    Sweden

    Reply
    • Anna,

      Were you able to fix your estrogen levels? I’ve been pregnant/breastfeeding for the last 8 years and it is taking its toll, especially as I am 37 now. I was experiencing low estrogen type symptoms as you descibed, (being dry and sensitive down there). I tried nongmo soy milk as a solution and my period is over a week late despite nearly a year of regularity. I’m stopping the soy milk, but wondering what to try to balance out the feelings of dryness!

      If you have a solution that worked for you, I’d love to hear it.

      Michelle

      Reply
  47. Hello Lara,

    I’ve missed my periods for the very first time. I’ve been consuming a lot of soy crisps lately, and taking quite a few vitamins. I’m unsure what is to be blamed, and if this is to be considered serious. I’m getting the usual symptoms though.

    Thanks in advance.

    Reply
  48. This is so so interesting…as I’ve upped my soy intake over the last couple of years and my periods have gone 🙁 i put it down to weightloss and over exercising but i realise now that soy might play a part in it.
    if i were to take soy out of my diet now Lara, how long would it take for my period to return? does this mean that I’m not producing eggs, or just no releasing them? thanks!

    Reply
  49. I would really love to know what the thoughts on bonsoy are? Is it considered ‘safe’ if you are trying to conceive.. I am not talking about a litre a day, more in tea and coffee?

    Reply
    • As I explain in the article, soy can suppress estrogen, and a high amount can impair fertility. But it all depends on the dose. Do you mean a splash in coffee and tea, or a daily latte (flat white) made with soy milk?

      Reply
  50. Hi Lara,

    I took melatonin for 2 months after moving across a 12 hour timezone difference. I took too much, before realizing that it was affecting my cycle and suppressing my estrogen. My cycle became very long, with long periods, and mega low-estrogen side effects (hot flashes, no ovulation shown in bbt readings, whack moods and insomnia). I stopped taking it 4 months ago and my cycle is still off (it had been regular for several years). I’m in my late 20s. Can I eat a bunch of organic soy to counteract this low estrogen?

    Reply
    • The effect of the melatonin should wear off fairly quickly, and your goal is to reestablish ovulation, not boost estrogen. Please see my Estrogen Deficiency post.
      Also, as I explain in the post soy has an anti-estrogen effect, so it won’t help you.

      Reply
  51. Hello there.. such an informative site. My sister drank soy milk during her period and the period won’t stop, now is the 10th day. And she normally had it for 7 days.

    So could there be any relation between soy milk and the 10 days period? She is really worried that she crys please help.
    I’LL BE THANKFUL

    Reply
  52. It actually does the opposite. I have high levels of estrogen and it makes me sick and start my cycle. Because of it, I avoid soy.

    Reply
    • Same here! I vomit insane on the first day of my cycle! I have since I was a teenager. Only recently worked it out from cutting it out a few years back. Sometime it may be in a dish or something I have out! But I avoid it 2 weeks before my cycle. I am glad I am not the only one…

      Reply
  53. I just came across your blog, wow so much good information! I have previously struggled with low progesterone/high estrogen. I am starting up my periods again after breastfeeding (it took 15 months post partum for it return) and am noticing long & irregular cycles (30-40 days) and heavy/long periods. I do have quite a bit of soy (probably a cup a day in my 2 coffees). I am thinking it would be beneficial to give it up? (Side note I am hoping to get pregnant again in the near future).

    Reply
  54. I just discovered your blog, sorry to be responding now. I’ve had saliva and blood tests both done and in each my estrogen was high and progesterone was low. I’ve been using vitex for almost two years (which I’ve read isn’t ideal length) and at first it helped tremendously with basic pms moodiness and breast tenderness, but never affected my horrific menstrual cramping. I drank soy milk a few times a week in my early and mid 20s, and then stopped when I heard about its estrogen-like affects. 6 years later, I’m having the most painful periods I’ve ever had, and spotting for 3-5 days beforehand, way worse than ever in my early and mid 20s.
    I’m also now on an organic, dairy free, sugar free, gluten free, corn free, soy free, pescetarian diet (most plastics eliminated, too). I’m almost terrified because of pain to experiment with soy or more phytoestrogens in general, my natural dr wants me to up flax seed intake dramatically to help estrogen to travel out of bowel and not be reabsorbed, but I’m really afraid of anything that might cause more pain. Was on BC for only 6 months about a decade ago, never been pregnant. I recently had it confirmed via ultrasound that I do not have endometriosis, no fibroids or long-term cysts (a single follicular cyst was noted) to blame the debilitating pain on. PCOS hasn’t been 100% ruled out based on blood tests but I have no physical symptoms and am quite slender. My mom had estrogen and progesterone dependent breast cancer, so I’m especially afraid to up phytoestrogens. I’m also taking DIM, calcium d-glucarate, and 3 grams of fish oil every day.
    All this to say, after reading your post I’m remembering about a year ago I opted for a soy latte for the first time in literally years, and my period came two weeks early about 48 hours later. My period NEVER comes early (or late), I’m always like clock work. In my mind that solidified my no soy rule, but after reading your post, I’m reflecting on how less painful that early period was compared to how they usually are. Do you think there’s any correlation with the lack of pain and consuming the soy? (I’m sure the soy itself was junk form, it was from Starbucks and certainly not organic or fermented.) Sorry for the long post, I’ve just not considered it in this way before.

    Reply
    • Hi Julieanne. Dairy is the biggest factor in period pain. You say you’re dairy-free. Does that include all yoghurt, cheese, milky coffees etc?

      Reply
    • julieanne, it sounds like you could have endometriosis. There is absolutely no way an ultrasound could determine if you have endometriosis. That’s ridiculous that a doctor would tell you that. Endometriosis can only be determined by laparoscopy; it cannot be seen via ultrasound. If you are having incredibly painful periods and spotting before your period, that’s a red flag for endometriosis. I have endometriosis and along with diet changes, the only thing that really helps with the pain is progesterone cream used on days 6 to 26.

      Reply
    • i have been eating organic edamame every day for about 4 months, for a vegan source of protein. I’m 24 and have been on the pill since i was 17. Last month, i never got my period. I went off the pill this past month, and now this month again i have missed my period. Could this be due to the soy? I am thinking I should cut it out of my diet completely. I am worried I’ve messed myself up 🙁 Is this reversible if I stop eating it? What should I do? Thanks!

      Reply
  55. Hello Lara,

    I know this is an older post, but I experience a very interesting situation between periods and soy. I have had a long history of going months without having a period then it would randomly come about. After keeping track of the food I was eating the week before, I finally found a connection– soy! I decided to test it, and after multiple duplications, I have found that if I eat anything like half of a cup of edamame or tofu (and as long as I haven’t had my period in the last few weeks), I will instantly have my period within two days of the soy. Even after skipping a few months, one bowl of edamame beans and two days later, there it is. I am a biology major, and still puzzled by this. Any ideas for what would be causing this?

    Reply
    • You say you go long stretches with no period. Do you experience symptoms of estrogen deficiency? If you are low estrogen when you’re amenorrheic, then soy will be estrogenic for you, and could be enough to trigger an anovulatory bleed.

      Reply
  56. Is Soya milk ok to drink if you are worried about PCOS and fertility issues? Do you have any knowledge on PCOS? I have polycystic ovaries but not the syndrome yet and I really suffer with depression and mood change approximately two weeks before I bleed. My cycle is never the same length. I also have digestion issues. I survive as I enjoy a healthy diet and exercise but I know about it as soon as I go off course and this can lead to stress, neck and shoulder pain and depression. I am a completely different person during these two weeks and my thoughts are not my own. Sounds like the syndrome without being overweight to me but doctors have always sent me away with no suggestions or help at all. I had an ovarian cyst when I was younger but this was a dermoid cyst.
    I’m having IVF now

    Reply
    • I’m cautious with soy if there are fertility issues. But dairy can be a problem too as I discuss in my dairy post. I’ve written extensively about PCOS. Please see my ‘4 types of PCOS’ post and Chapter 7 of my book.

      Reply
  57. Really appreciate the light shed on soy needed for different phases of life like post-menopausal vs pre.
    Also helpful to note the “net effect” of soy in relation to the estrogen levels in the body.

    What are your thoughts on sprouted soy-bean products (like this:

    ? Are they also bad for PCOS patients? or may they be consumed once or twice a week?

    Reply
  58. I used to drink soy in early 20’s then for about 8 years I stopped. My pmt has always been bad, howerever had gone off scale now at 34 years of age, so I decided to give soy a try again. And honestly…by my 2nd cycle. My pmt symptoms I swear are 70% better.
    I’m utterly convinced it makes a difference to me.

    Reply
  59. My daughter is 14.5 years of age and has not started menstruating. I started at 13, as did my husbands sisters, but his mother, a country girl, started at age 16! We are vegetarian (but she went vegan 🙁 about 5 monts ago). We eat a wide range of protein sources, including a lot of legumes but also tofu at lunchtime about 3 – 4 days a week. My daughter is still growing and grew about 3 inches in the past 9 -11 months. I’ve noted a mild vit D and B12 defiency about 3 months ago and started her on supps of both. Her iron is low normal and she sporadically takes a supp of this as well. I have a half-sister from my father’s second marriage who didn’t start her period, started putting on weight and turned out to have a pituitary adenoma requiring a transphenoidal resection. She’s been on hormones since. That’s the only thing that concerns me as my daughter is otherwise very healthy and active with good energy levels and generally a very happy, productive kid. Breasts are now beyond buds and she has some zits/mild acne over the past 9 months. Any thoughts?

    Valerie

    Reply
    • Some girls don’t start periods till 16, but I recommend checking with your doctor. If nothing else, just to put your mind at ease (just don’t let her prescribe the Pill!). I wouldn’t expect tofu four times per week to be a problem. You might want to think about a zinc supplement. In my experience, zinc in the nutrient most commonly deficient in vegetarians, and zinc is essential for periods. It’s also really helpful for acne.

      Reply
  60. Thank’s for that post Lara! You really cleared up allot of misconceptions I had about soy. I was under the impression it would contribute to my estrogen dominant problem. I have been avoiding it for years, but for a 34 year old with fibroids and heavy periods that last up to 14 days, maybe it can help me. I’ve been on a mission the last 5 years to try and regulate my horrible periods and I am so happy I found your website! Thanks for all you do!

    Reply
  61. When I started going through perimenopause in my early 40s, I had hot flashes to beat the band. At the time, I wasn’t interested in hormone therapy of any kind, but I did drink soy milk. Not because I thought it would help me with hot flashes, but because I liked the taste of it. I learned it also knocked out my hot flashes.

    I tested my theory by abstaining for a few days and sure enough, the hot flashes came back with a vengeance. I began blogging about perimenopause and have recommended it to readers who ask for non-hormonal solutions to hot flashes.

    I’ve read a lot of studies on it and as I’m sure you know, there is no consensus on it’s effectiveness among the medical professionals. Some studies are adamant it doesn’t work. Others say it does. Other say this and that. I’m one of those “do what works for you” kind of people. If it doesn’t help, don’t use it. If it does, do it.

    I understand that not all soy is created equal or even healthy. But, your article covers it pretty well. . Personally, I think it can be helpful for *some* women. Others, not so much.

    I love your blog!!

    Reply
  62. I’ve found that soy seems to have a negative effect on my PMS symptoms, I get extreme breast tenderness starting 2 weeks before my period and awful mood swings. I’ve now cut out soy and I’m glad to say that this month my more extreme symptoms have only really manifested in the last couple of days before my period and seem much less severe than they are some months. I would be interested to know your thoughts on managing PMS as its been becoming a real issue for me in the last few years.

    Reply
      • Thank you! I don’t have a soy allergy. I was just told by my doctor not to eat soy because of my thyroid. I don’t consume any other soy (that I know of).

        I like using the fruity herbal teas to make Jell-O with my Great Lakes gelatin.

        Reply
  63. I was diagnosed with PCOS about 5 years ago with irregular periods (2-3 times a year) after going off BC. I had blood work done which confirmed the hormone imbalance. I self treated, as my western doctor had very little suggestions.
    Things I did-
    1.Avoided ALL SOY – i realized that after living in asia for long periods of time, as a vegetarian, the soy intake really negatively affected my hormones. and when i say ALL soy i mean, i looked at every package of everything I ate and if there was any trace, i eliminated it from my diet.
    2. started making adrenal supporting soups like this one : https://www.kitchendoctor.com/recipes/blackbean_soup.php
    3. Around the time that I should be menstruating I would drink hot parsley water for 3-4 days in a row (it’s a natural period inducer)
    4. I changed my sleep pattern, where I was in bed by 9pm (religiously) with no technology for about an hour before, only reading with a small light on — sleep pattern greatly affects the endocrine system & allows for hormone production.
    5. I practiced lots of yin yoga — legs up the wall (avoided any other inversions)
    6. I got Miranda Grey’s Red Moon book & started to track myself according to the moon & I did her womb blessing meditations (still do).
    7. Cut out all refined sugars & any animal products because I felt that in order to re-regulate my hormones, I needed to be strict in not allowing any other hormones into my body.
    8. Regular acupuncture & Qi gong practice.
    When I finally started menstruating again, I became quite ill. I ended up menstruating for 64 days straight, with lots of hemorrhaging along the road. I think my body needed to over compensate for the misdirection it had been under. Once that completed — now I’m three years strong of regular charted menstruation — also charted with the lunar cycle.

    I have done extensive research into finding the above solutions (for me, obviously everyone is different) and I’m sorry I didn’t have your blog back then when I was doing this. The information you present is not only really clear but it’s 100% true with my personal findings and easily synthesizes the important points i had to find over man many articles.

    I hope my above helps anyone who is struggling a bit to re-regulate themselves. If i can say one thing, it’s that you DEFINITELY can do it. It just takes patience & commitment.

    x
    m

    Reply
  64. Hi Lara,

    This question isn’t related to soy, but I wasn’t sure which thread to ask it in. I have a copper IUD that I’m getting removed next week. I’ll be starting to try for baby #2 but was wondering how many cycles I should wait before TTC? I’m most concerned about the effects of copper on future pregnancies. I have been taking zinc and magnesium regularly for about 6 months now and have no signs of copper toxicity. Any insight would be much appreciated! My naturopath didn’t really know but said to wait a few months because it was a foreign object in my body, my GP said I can try right away. Conflicting opinions! Thank you.

    Reply
    • Hi Meagan,
      You should be able to start to try right away. Maybe give it one cycle. One period to shed that month’s uterine lining and build a new one.

      Reply
  65. When I was a heavy soy milk drinker, I had the worst acne. It’s occasionally still an issue if I get some soy lecithin in chocolate, so I either make my own (super easy) or find soy-free ones …even Woolworths Select Dark choc is soy free 🙂 (78%)

    Reply
  66. Hi Lara, I’m not having dairy at the moment due to autoimmune/lactose intolerance and have thyroid issues. I drink almond milk in my cereal at home but miss my coffee when I’m out occasionally. Do you think it’s okay to drink a soy milk coffee, say 2-3 x week?

    Reply
  67. How much millk of bon soy a 4 year old child could have every day, as the child is diary intolerance and we replace it with soy milk andcashew milk? Thank you.

    Reply
    • With a child that young, I would stick with cashew milk or almond milk or coconut milk. (Or even no milk. We really don’t need milk for anything apart from convenience and enjoyment.)

      You could also look at goat or sheep products as they are usually well-tolerated. (see my reply to Marina’s comment).

      Reply
  68. Hi Lara,
    If dairy and soy are both not that great for children, then where should they get their recommended daily doze of calcium from? There are so many publications to say that calcium is essential for teeth and bones, but would eating broccoli and other vegetables give them enough of it?

    Reply
    • Great question. First of all, dairy can be ok for children. It depends on the child, and it depends on the dairy. The big problem with dairy is A1 casein, which can be mucus-forming, immune disruptive and inflammatory. It’s not like that for every person. I discuss A1 dairy in my A1 milk post, and I explain the signs to watch for (signs that A1 dairy is a problem): Recurring ear infections, tonsillitis, chronic stuffy nose.

      A2 dairy (goat, sheep, and Jersey) does not have A1 casein, and is fine for most people. A2 dairy has lots of calcium.

      Other calcium foods are: salmon (with bones), almonds, tahini, broccoli and other steamed greens.

      Finally, soy milk only has calcium because it is fortified with calcium. You can just has easily give a child calcium-fortified rice milk or coconut milk.

      Reply
      • Well, it’s easier to say this but when you have a child with food sensitivities and very narrow food choices due to the child not wanted to try new things, since we got get rid of diary products which gave so much chronic constipation to the child, and we introduce soy milk the things are huge better then before! I just want to say that no e of diary products are good for some people. Good luck with your work!

        Reply
  69. Hi Lara.. I LOVE natto miso and have a big tablespoon every day. I thought this would be great for my bones, but should I rethink that seeing I have thyroid issues? kind regards from Cazz

    Reply
    • Hi Cazz, That small amount of soy is completely fine for thyroid. I’m only concerned if women are having a large soy latte every day.

      Reply
      • Hi Lara. Interesting blog! Thanks for clearing all of that up! I was excited to learn that there’s a new oral contraceptive pill available which contains plant-sourced oestrogens. Patented as Zoely. I feel bringing natural ingredients into our medicine is a good step forward, as synthetic drugs are quite toxic to the body. What are your thoughts on Zoely?

        Reply
        • I’m sorry to be the bearer of bad news, but Zoely is no better than your average birth control pill.
          What matters is not the ultimate source of the synthetic steroid (all synthetic steroids are sourced from wild yam or soy precursors). What matters is the actual hormone. Zoely is touted as better because it contains bioidentical estradiol (human-identical estrogen), which is a step up (basically that makes it only as good as some types of HRT or hormone replacement). But Zoely’s progestin is nomegestrol which is a non-bioidentical nasty synthetic progesterone that is no better than any other pill.
          Also, Zoely still works by suppressing ovulation, which is the main problem with the pill. I discuss these issues about the pill in my book Period Repair Manual.

          Reply
    • I believe that Bonsoy is made from the whole bean, so it’s certainly better than some brands of soy milk (which are made from processed soy flour).

      The amount of soy that you should have all depends on whether you have hormonal problems such as thyroid or a lack of periods.

      Reply
  70. Hi Lara, I have replaced my milk in my daily coffee with soya milk, as too much processed dairy plays havoc with my skin. But will that soya play on my PMT? Thanks Jo

    Reply
    • Because soy reduces estrogen, it is usually beneficial for PMS.

      Don’t let a fear of soy drive you back to normal dairy (which as you say, is bad for acne). In the big picture, I have found inflammatory dairy products to be a much bigger problem for hormones than soy. (Dairy is not inflammatory for everyone. I discuss dairy in my A1 milk post.)

      Reply
      • Tried almond milk with coffee and its bitter. Otherwise welcome it.
        So half a cup of soy milk in a latte is better than milk? Trouble is that even though I buy the A2 milk for home, the cafes don’t use it. Not the A2 brand anyway.
        Long black topped up with soy milk I guess.

        Reply
  71. Interesting article.
    I have read a lot about women taking soy isoflavones at the beginning of there cycle to help shorten the follicular phase and bring on ovulation. PArticularly for women with low estrogen levels, long and irregular cycles – what are your thoughts on this?
    Thanks

    Reply
    • Interesting. I wouldn’t have thought that would work at all. My experience is that soy dramatically lengthens the follicular phase.

      Reply
      • If you have a short cycle (23days) would it help? I like soy milk but drink one that is organic and made from whole soybeans. I really like the taste of it?

        Reply
        • Generally, soy does lengthen the follicular phase, so yes, it might help, but be careful it doesn’t suppress ovulation. Are you confident that you ovulate every month? Watch that you continue to do so.

          Reply
  72. it’s crazy to think that most doctors, at least in US, recommend soy to women…especially those that have PCOS…thank you for your post.

    Reply
    • The real problem with GMO crops is that they’re designed to be used with high levels of pesticides. For example,”Round Up Ready” soy is paired with the pesticide Atrazine, which is an endocrine disruptor.

      Reply
      • Actually, all the GMO crops are to feed the animals, not humans. If you don’t want to eat GMO soy, DONT! There are heaps of no GMO soys out there… Simple.

        Reply
        • Jimmy, I’m curious where you get your information from? I am in the US and 95% of soy is completely genetically modified and in the human food supply. Where are these heaps of alternatives you speak of?

          Reply

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