In women, too much testosterone can cause insulin resistance and abdominal weight gain.
That’s why androgen excess is the main driver of weight gain with polycystic ovary syndrome (PCOS), menopause, and some types of birth control.
PCOS
The link between testosterone and insulin resistance is most clear with the hormonal condition PCOS, in which high androgens cause insulin resistance and impair ovulation. Impaired ovulation, in turn, causes low progesterone, which, in turn, robs the system of progesterone’s beneficial anti-androgen feedback. The result is even more high androgens and insulin resistance, creating a vicious cycle I describe in my peer-reviewed paper.
Treatment with natural progesterone can break the cycle by lowering androgens, improving insulin sensitivity, and promoting ovulation. Professor Jerilynn Prior’s lab has just completed a clinical trial of cyclic progesterone therapy for PCOS.
💡 Tip: The progestins of hormonal birth control are not progesterone. And many progestins are actually androgenic or testosterone-like (see below).
Perimenopause and menopause
With the menopause transition, first progesterone and then estrogen drop away while androgens slightly increase before resuming their gradual decline with age. So, menopause is a situation of relatively high testosterone compared to estrogen and progesterone, and those high androgens can cause the redistribution of fat from subcutaneous bum fat or gynoid to visceral or android fat—leading to a thicker waist and heavier upper body.
Treatment with menopausal hormone therapy (estrogen and progesterone) can help by improving insulin sensitivity and increasing SHBG, the protein that binds and inactivates testosterone. Progesterone can also improve metabolic health and promote weight loss by stimulating metabolic rate, supporting thyroid function, and, of course, lowering testosterone.
Taking too much testosterone or androgenic progestins can worsen insulin resistance and cause weight gain.
Birth control
Androgenic (testosterone-like) progestins can cause insulin resistance and weight gain. The most androgenic progestins are levonorgestrel, norethindrone, and etonogestrel, which are found in many pills, Nuvaring, Mirena IUD, and the Nexplanon implant. Read Does birth control cause weight gain?
Anti-androgenic progestins, on the other hand, can improve insulin sensitivity and promote weight loss. Anti-androgenic progestins include drospirenone, norgestimate, dienogest, and cyproterone. Unfortunately, stopping an anti-androgenic progestin can cause rebound weight gain.
The link between high testosterone and insulin resistance
There’s a bi-directional relationship between high testosterone and insulin resistance.
In one direction, insulin resistance or high insulin can stimulate ovarian cells to make more testosterone. That happens with PCOS and menopause. In the other direction, testosterone can cause or worsen insulin resistance. That happens with PCOS, menopause, and androgenic progestins. Together, high testosterone and insulin resistance can promote weight gain, acne, facial hair, irregular periods, and an increased long-term risk of type 2 diabetes.
The solution has two parts: 1) reverse insulin resistance and 2) lower androgens, which, in turn, can improve insulin resistance.
- To reverse insulin resistance, follow the recommendations in my book Metabolism Repair for Women.
- To lower androgens, identify and correct your type of PCOS so you can start to ovulate and make estradiol and progesterone. You can also consider cyclic progesterone therapy or other natural anti-androgen supplements. Menopausal hormone therapy can also be helpful; just make sure it’s body-identical estrogen and progesterone.
