Progesterone: The Forgotten Hormone

Progesterone: The Forgotten Hormone

Estrogen’s forgotten sister, progesterone, is often overlooked. For example, a woman who has a full hysterectomy (causing a surgical menopause) may be given solely estrogen and no progesterone. This is because many doctors focus on the hot flashes due to low estrogen that can occur after a full hysterectomy. But if progesterone is not important, why do women produce so much of it and why are there receptors for it all over the body? Even men produce a little bit of progesterone!


  • Maintains the endometrium
  • Protects against breast cysts
  • Helps use fat for energy
  • Natural diuretic
  • Calms anxiety and PMS
  • Prevents cyclical migraines
  • Promotes normal sleep patterns
  • Facilitates thyroid hormone function
  • Helps normalize blood sugar levels
  • Normalizes blood clotting
  • Helps restore normal libido
  • Stimulates new bone formation
  • Necessary for survival of embryo

All the actions of progesterone are vital but I do have a favorite: progesterone’s ability to decrease anxiety. Why? Not too long ago, I saw a new female patient over 40 who was suffering from panic attacks. Her doctor had prescribed an anti-anxiety medication but it didn’t eliminate the anxiety or panic. She claimed the anxiety came out of nowhere only a few months prior. Nothing in her life could explain why this was happening.

The question for me as if she had entered perimenopause (those years leading up to menopause when the hormones become erratic). I tested progesterone 7 days before an expected period, the best time to access overall progesterone values. Not surprisingly, her progesterone levels were very low. I prescribed a bio-identical progesterone and within a few months, her doctor took her off the anti-anxiety medication. She didn’t need it anymore! I can’t describe the joy it gave me to see this woman get her life back. She went from crippling anxiety to a happy life again.

*Please do not go off of any prescribed medications. This always needs to be done under doctor supervision and in the case of antidepressant and antianxiety medications, there is a strict tapering schedule that must be supervised by a trained medical professional.


  1. Menstrual irregularities – Long cycles, irregular cycles, short luteal phase (if the time from ovulation to your period is less than 10 days), a diagnosis of the polycystic ovarian syndrome, menstrual cramping, spotting mid-cycle or before your full period flow begins.
  2. Infertility – Progesterone is one of the primary hormones involved in achieving and maintaining a healthy pregnancy. If you are having difficulty conceiving or have suffered a miscarriage, your progesterone levels may be low.
  3. Anxiety, mood swings, memory issues and insomnia – Progesterone concentrations are 20 times higher in the brain than the blood. It has a soothing effect; promoting sleep and counteracting anxiety and panic. It contributes to the lessening of the memory problems seen with low hormone levels. In excess though, it can cause depression.
  4. Slow metabolism, weight gain around the midsection, sugar cravings – Progesterone promotes the use of fat for energy, thus opposing the estrogenic tendency to fat storage. It normalizes blood sugar levels but can cause insulin resistance at high levels by interfering with the action of insulin. It has a thermogenic effect—it makes you warmer by increasing blood flow to the skin.
  5. Premenstrual migraines- Progesterone exerts a neurovascular effect in decreasing migraines caused by estradiol and estrone, 2 estrogens.
  6. Thyroid disorders- Progesterone is beneficial to thyroid function. It helps keep zinc and potassium in cells, which allows thyroid hormone to enter and be converted into the active form (T3).
  7. Osteoporosis- Progesterone actually promotes bone rebuilding.
  8. Allergies- Progesterone seems to reduce the severity of allergic reactions. Women who develop allergies after age 35, should have their progesterone levels checked.
  9. Stress– It’s called the progesterone steal. When a woman is overworked and stressed out, her body will make cortisol (the adrenal hormone) from progesterone.


Progesterone comes in both topical and oral forms. Oral is best used for PMS anxiety, migraines, and insomnia. This is because the oral form can more readily enter the bloodstream and cross the blood-brain barrier. Topical is best for menstrual irregularities and infertility. It is commonly prepared as a cream or suppository.

Bioidentical progesterone is identical to what the human body produces so is considered much safer than non-identical progestins. Most bioidentical progesterone prescriptions are at 100 mg or less per day and not all of that is absorbed. To put this in comparison, a pregnant woman may produce as much as 350 mg of progesterone per day.

Research has suggested that non-bioidentical progesterone (progestins) are associated with an increased risk of breast cancer. Does it follow that bioidentical progesterone would as well? We cannot say for sure but we do know that women who’ve had multiple pregnancies have a lower incidence of breast cancer. It is theorized that this is due to high levels of estriol and/or progesterone. Also, studies have also shown that women with higher blood levels of progesterone survive breast cancer at higher rates. It may be that bioidentical progesterone is protective against cancer but we at this time, we cannot know with certainty.

When asked if bioidentical hormones are safe? My answer is that they are identical to what our body has always produced and that safety has to be put into perspective. Have you or anyone you know taken the oral birth control pill? The hormones contained in them are not bioidentical and at much higher doses. In my practice, I prescribe bioidentical hormones are the lowest, most effective dosages and test to ensure hormone levels do not rise too high.

Stay tuned for my next article on women’s libido and testosterone. Until then, be well!