Reprinted with the kind permission from Andrew Dott, MD, MPH and the Institute of Endocrinology and Reproductive Medicine
Progesterone is a natural hormone which is produced by the ovary during the second half of the menstrual cycle
There are two general forms of progesterone
There were two reasons why it was necessary to develop these synthetic progestins: First, progesterone has unpredictable absorption and side effects such as sedation and second, it was more expensive to produce than synthetic progestins. Today, however, the progesterone molecule can be manufactured from many plant sources such as Mexican wild yam and soy.
The progesterone most commonly used in the United States for menopause management is Medroxyprogesterone acetate (Provera®, Amen®, Cycrin®) which comes in 2.5 mg, 5.0 mg, and 10.0 mg tablets. Unfortunately, many women have side effects to this preparation— particularly the 10mg dose which is now felt to be unnecessary for most women and probably an overdose. There are other progestins including Norethindrone acetate (Aygestin®) 5 mg which is a bit too potent for most women and Norethindrone (NorQD®, Micronor®) 0.35 mg and dl-Norgestrel (Ovrette®) 0.075 mg which are birth control pills
Other forms of progesterone include micronized progesterone capsules and vaginal suppositories (manufactured by pharmacists (25 mg, 50 mg, 100 mg, 200 mg), progesterone in oil injection 50 mg/ml, depo-medroxyprogesterone acetate, and progesterone creams (manufactured by pharmacists) in varying concentrations. A 10% concentration is fairly typical. Crinolin® vaginal gel is manufactured in an 8% concentration.
Recent studies have shown that 100mg of micronized progesterone (Prometrium®) twice a day for 14 days or daily for 28 days is adequate for menopause management. There is some data to suggest that this form might have fewer side effects such as depression, bloating, and weight gain than synthetic progestins. Many progestins reverse some of the beneficial effect of estrogen on serum lipid profiles (which effect the risk for heart disease). There is some evidence to suggest that so called "natural progesterone" has less of these effects than some synthetic progesterones. There are no long term epidemiological studies whether this makes a practical difference or not.
The use of natural progesterone for the management of PMS remains very controversial. Studies in the 1980s could not demonstrate any effectiveness but other people claim they feel better. Newer theories suggest that PMS may be due to estrogen deficiency, not progesterone deficiency.
One can purchase progesterone creams and gels in health food stores. They range in potency from 5mg / tsp. to 1000mg / tsp.!! Absorption through the skin is very variable depending upon the type of vehicle (ointment, gel, cream) the medicine is placed in and where on the skin it is applied. So be careful with these!!! Depending on which preparation you use, you may experience no effects or an overdose with all of the problems mentioned above. If you are using topical hormones, it is important to let your health provider know. There are no long term epidemiological studies on the effectiveness of these preparations in menopause management.
Please also see Natural Estrogen, Selective Estrogens, and Fantasy Estrogens.
Dr. Andrew Dott teaches advances hysteroscopic and laparoscopic surgical techniques, is on the speaker's panels for several American pharmaceutical companies and is a professional lecturer. Among his lecture topics are female and male menopause, menopause, herbs and medications, endometriosis, and contraception. He is available to travel and give seminars on the topics covered in this website both nationally and internationally.