Antibiotics: Disaster for Hormones

prescriptionAccording to a 2011 study in Nature, antibiotics disrupt the metabolic hormones leptin and ghrelin. That effect lasts for at least one year and results in significant weight gain. In another 2012 study, researchers found that British children exposed to antibiotics early in life are more likely to become overweight later in life.

Antibiotics promote thyroid disease, menstrual disorders, and estrogen dominance. Even a few courses of antibiotics can increase the risk of breast cancer by 150 percent.  

Antibiotics are a life-saving miracle, but they’re also not great for our hormonal system. Why? Because they disrupt our healthy gut bacteria.

From a hormonal perspective, gut bacteria are supposed to:

  • Activate thyroid hormone T4 into its active form T3, and prevent autoimmune thyroid disease.
  • Reduce inflammation, which improves the sensitivity of leptin and insulin receptors.
  • Enhance absorption of magnesium, which is essential for progesterone production.
  • Produce vitamin B12 which is essential for the production of the neurotransmitter dopamine, and the methylation of estrogen.
  • Escort estrogen metabolites from the body.
  • Support the neurotransmitter GABA and reduce anxiety.

Save the antibiotics for the saving of lives

Antibiotics are a miracle. They save lives, and that is what they are for: Treatment of life-threatening infections. They’re not for feeling a bit better when you have a chest cold.  In addition to their bacteria-killing properties, many antibiotics have a slight anti-inflammatory effect, which is why people often feel better when they take them. But there are plenty of other ways to feel better including zinc, fluids and rest.

Taking antibiotics when they’re not needed damages the health of our nervous system, immune system and hormonal balance. Furthermore, it promotes antibiotic-resistance.

Choose antibiotic-free meat

Factory-farmed meat can contain a large amount of antibiotic residue (from the antibiotics given to the animals). Choose animal products that are “antibiotic-free”.

Lara Briden, women's health doctor and period revolutionary

13 thoughts on “Antibiotics: Disaster for Hormones”

  1. .hi – I’ve been on anti biotics – metronidazole and penicillin – for about a week, starting the day my peroid was due…still waiting for period nearly 2 weeks later – do you have any insight into this? Hard to find clear info…lots of denial of what seems to be a lot of anecdotal supporting evidence..

  2. Hi is there a way to fix hormones after extensive antiniotic therapy? I have massive hormone problems and developed a lot of lumps in my breasts (im 30) getting it checked out soon. Please is there a wayto reverse this and get healthy again

  3. Dear Lara,

    I have a big and urgent problem and hope you can help me. I come from reading your book, it arrived safely in Germany. I had, during the last months, tidied up my hormon system. Postmenopausal already with 46, my perioid stopped at 39, premature.
    For the last few days I have had an increasingly aching stomach. My gyn yesterday found in the ultrasound a sactosalpinx on the right. It is already big and swollen and full of water. She says there is no other way than surgery, it won’t recover itself.
    For finding the reason for all that I remembered that in April I was in vacation with a guy I thought of relationship material. But he is a guy who fucks around and he said, last year (???) he had an infection with chlamydia!!! Now I think I got them from him and before surgery first the infection has to be gone, right? So today my doctor started a urine test for chlamydia and gave me antibiotics, Moxifloxacin. I haven’t taken the first dose so far because I would like to know first if you see any other way. After tidying up my hormons and my gut I don’t really want to take antibiotics but it’s clear the inflammation in the tube has to be reduced before it can destroy uterus and ovaries, too. Do I have a choice and if yes, which? Is this one of the 3 or 4 times in lifetime you have to take antibiotics?
    I would be very happy for a fast answer because I have to do something as soon as possible…

    Thank you so much for you big help

    Maren <3

      • Dear Lara,

        I am still desperate… I read you take new patients from Sydney in November 2017. Unfortionately I am in Bonn, Germany… Can I book you for a paid skype councelling?

        Why am I desperate:
        The German school medidal gyns tell me I have to do a salpingectomy for my sactosalpinx. I am very sceptical. I can’t imagine that you can remove an organ without having hormonal after-effects. What I found is this video of a doctor who speaks clearly of a following progesterone failure with consequently following higher cancer risk (low progesterone in ralation to estrogen):

        As I already said I am in a much too young age postmenopausal. It was so difficult to get a balance and a good feeling by sports, organic food, removing endocrine disruptors, fasting (which removed the hot flushes), micronized progesterone as cream and also estriol cream against dry vulva skin. I can’t imagine at all to destroy that all by removing an organ!!! There is a big NO inside of me.

        The doctors now tell me it won’t heal itself (What about another fasting? Is there something else I can do?). And they say if it stays as it is it might lead later to tube cancer which is a very dangerous kind of cancer. So better remove tube and cancer risk, they say. (What about the new cancer risk for other organs when my hormones are finally unballanced??? And a removed organ is removed, there ist NO way of healing anymore!!!)

        I am really desperate with the feeling to face cancer and death each way I go.

        Is there a third way? How can I heal my tube? Is there a way and which? And how much time (approx.) will it need, just to know how much patience I need?

        Thank you a lot!!! And if you like please give me a date for a paid councelling. I can also send you the ultrasound pics.


  4. Dear Lara,

    This week I got adult chickenpox. I am 26 years old now. It seems to go away fine besides the general weakness – thanks to my sugar, dairy and gluten free diet. Just that I got some worse spots on my face, doctor prescribed me antibiotic cream to apply and prevent the infection. I am expecting my period this week and I feel my immune system is very week. What supplements would you recommend after dealing with adult chickenpox so my hormonal system would be back on track.

    Thank you very much,


  5. Hi! I am very fascinated by your article. I was just put on a high does of antibiotic because the Dr. Thought I had strep-throat. Turned out after taking this medication for 7 days I did not have strep. I have been battling stomach issues for life, after prolong antibiotic use for reoccurring bladder infections for over 3 yrs.
    I have been following the Diet in Dr. Mullin’s book “the gut balance Revolution” but as soon as I went on the antibiotic my cravings for sugar came back. I know I need to start this diet all over again but I was wondering how to I rebalance my intestines to help reverse the damage caused by the antibiotics? I also have 1/2 of my thyroid and take Armour Thyroid daily.

    Until I read your article I never knew the damages that the antibiotic caused. I knew some of my problems were cause by them but this article was very helpful to me.
    I think I may be battling an overgrowth of bacteria in the small intestines and I have been taking oregano oil and garlic tablets as well as Primal Defense. Do you have any other suggestions to help with this? I had the hydrogen breath test done several years ago and still seem to have the same symptoms as then.
    I know I gave a lot of information. If you are able to help it would be greatly appreciated!

  6. There have been some papers published claiming that in order to develop a Herpes lesion (facial or genital), there must be sufficient fungus present on the skin. The sore does not contain any infective virus particles and is the body’s attempt to purge its waste products. Some researchers claim the fungus provides a suitable environment for a sore to erupt and without sufficient fungus levels, there would not be a sore. There are also some claims that the Pill destroys “good” bacteria. Balanced levels of good bacteria are essential for controlling fungus and other yeast/candida levels in and on the body. Is it possible the Pill is destroying the good bacteria, which in turn is allowing the fungus to reproduce uncontrollably and therefore a suitable environment for a sore is created? There are many effective herb combinations that support the immune system, cleanse the blood, have their own antiviral properties and control fungus/yeast – Google herbal herpes treatment or similar and there are many interesting articles and reports.

  7. Hi!

    I really love your website. It has been tremendously helpful and information. So my question for you is that I rarely take antiobiotics, but I have been taking antivirals on and off due to cold sores that started appearing when I went back on birth control pill. I am one of those many people that developed hair loss (permanent) after going off bc pills and, being scared, went back on. I am intending to wean off of bc pills soon, but am curious what your take is on antiviral medication? I noticed that 2-3 days after I take them, my hair lies lifelessly flat against my scalp and the roots feel very sore and achy. I have read reports online that people’s cold sores tend to go away once they stop taking birth control pills, which makes me suspect that the fake hormones trigger the virus. I am thinking antivirals cause the same problems as antibiotics?

  8. Hi Lara, just stumbled on your blog and I am so happy I did. It is fantastic.

    I am going for a 2 1/2 week holiday to Vietnam in a few weeks from today. My doctor has prescribed 6 weeks of the antibiotic doxycyclon for prevention of malaria as it will be the rear end of the rainy season when I am in Vietnam.

    I HATE taking antibiotics. They really mess with my digestion which has never been quite right anyway.

    Is this one of the cases where you think I should take the antibiotics? What would you do in the same situation? Any advice would be great.

    Thank you!!!

    • Hi Alex, that’s a tricky one. 🙂 It would be irresponsible of me to advise yes or no in a public forum like this.
      I have personally traveled to Vietnam in October/November and I did not worry about malaria, but then I was in urban areas. You’re probably more at risk from Dengue, for which there is no prevention, unfortunately. I recommend that you try to obtain some real numbers about the malaria risk. How likely is malaria in that region that you plan to visit? And use that number to weigh the costs and benefits. Certainly, in a high risk area like parts of Africa, I think that it’s worth taking the antibiotics. Knowing also that the antibiotics are not a guarantee.
      As vulnerable human creatures in the world, we cannot avoid all risk. We have to minimise risk in the most logical, sensible way that we can, and then take our chances.


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