Many women wonder about the relationship between progesterone and weight gain, especially if they are approaching or completing menopause. First of all, which progesterone are you talking about? The one your body makes? The one you get from your doctor that has progestins in it? Or the bioidentical one? These distinctions are important because each type of hormone has different effects in your body.
Does the progesterone in your body cause weight gain?
The progesterone your body makes is designed to support a pregnancy. It is much more abundant in the second half of your cycle if you are still menstruating. Progesterone increases body fat storage in order to protect the fetus from malnutrition when you are pregnant.
Estradiol (an estrogen your body makes) reduces body fat, so when the two are in balance there is no affect on your weight. It is when your hormones are out of balance that they contribute to weight gain or loss. High progesterone (relative to estradiol) also causes muscle tissue breakdown. Progesterone also decreases growth hormone and increases insulin and cortisol, two hormones that can contribute to weight gain.
What about bioidentical progesterone? Does it cause weight gain?
Bioidentical progesterone is a man-made substance that has an identical molecular structure to the progesterone your body makes. This progesterone is often referred to as natural progesterone. (For more info, see bioidentical progesterone.
This progesterone will act the same as the one your body makes: if it is well-balanced with estradiol and testosterone, it will not cause weight gain. Please note that I am referring specifically to estradiol, and not any other type of estrogen. Estradiol is the hormone that helps reduce body fat.
What about progestins and weight gain?
A progestin is also a man-made substance. The difference between progestin and bioidentical progesterone is the molecular structure. Progestins do not have an identical structure to the progesterone your body makes. Because of this, women often have side effects that don't exist with the other forms of progesterone.
Progestins can cause increased appetite, weight gain, and fluid retention. If you are taking these, you will have less of the above side effects if you are also taking some form of estrogen along with it. Side effects of oral progestin or progesterone are more probable than if you are using creams, patches or suppositories.
In summary, progesterone and weight gain may go together. All types of progesterone and progestins may contribute to weight gain and inhibit weight loss, if your progesterone level is out of balance relative to estradiol or nonhuman estrogens. The best way to manage this is with a doctor knowledgeable about the safest forms of replacement hormones and blood tests to determine your hormone levels.
There are many other issues related to weight gain and menopause, including low thyroid, stress, digestive issues, and your diet. You will find information about each of these issues on this site. See some related pages below.