In women, too much testosterone can cause insulin resistance and abdominal weight gain.
That’s why androgen excess is a factor in the weight gain associated with polycystic ovary syndrome (PCOS), menopause, and some types of birth control.
The link between testosterone and insulin resistance is most clear with the hormonal condition PCOS, in which high androgens made (mostly) by the ovaries cause insulin resistance and impair ovulation. Impaired ovulation, in turn, causes low progesterone and therefore robs the system of progesterone’s beneficial anti-androgen effect. Which in turn, causes more high androgens and more insulin resistance, creating a vicious cycle that I discuss in my new peer-reviewed paper.
Natural progesterone can help to lower androgens, improve insulin sensitivity, and break the cycle of PCOS. That’s why Professor Jerilynn Prior’s protocol of cyclic progesterone therapy for PCOS is currently undergoing a clinical trial.
👉 Tip: There’s no progesterone in hormonal birth control. Contraceptive drugs are progestins, many of which are androgenic or testosterone-like (see below).
With menopause, progesterone and estrogen drop away while androgens slightly increase before resuming their gradual decline with increasing age (as happens in both men and women). The resulting situation of high testosterone compared to estrogen and progesterone causes a change in fat distribution from an hourglass body shape to a squarer shape with a thickened waist and heavier upper body.
Taking hormone therapy (estrogen and progesterone) can therefore have a beneficial anti-androgen effect in menopause and improve insulin sensitivity. For example, estrogen therapy directly improves insulin sensitivity and lowers testosterone by increasing sex hormone-binding globulin (SHBG), the protein that binds and inactivates testosterone. Progesterone indirectly improves insulin sensitivity by stimulating metabolic rate and lowering testosterone.
Taking testosterone, on the other hand, can worsen insulin resistance and cause weight gain.
Progestins with a “high androgen index” are testosterone-like and so can cause insulin resistance and weight gain. They include levonorgestrel, norethindrone, and etonogestrel, found in many pills, Nuvaring, Mirena IUD, and the Nexplanon implant.
Progestins with a “low androgen index” can promote weight loss while they’re being taken but then cause rebound weight gain when they’re stopped. Anti-androgen progestins include drospirenone, norgestimate, dienogest, and cyproterone.
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.
There are two parts to the solution: 1) reverse insulin resistance and 2) lower androgens, which, in turn, can improve insulin resistance.
- To reverse insulin resistance, follow the recommendations in my updated blog post Reverse insulin resistance in 4 easy steps.
- To lower androgens, try to correct your type of PCOS to establish regular ovulation to make estrogen and progesterone. You can also consider using cyclic progesterone therapy or other natural anti-androgen supplements. If you are already in menopause (and can therefore no longer ovulate), consider taking bioidentical estrogen and progesterone.