Female sex hormone secreted by the body but capable of being manufactured in a lab setting. Use of skin-care products with progesterone is controversial because natural progesterone is a misnomer. All topical products with progesterone or progestin are synthetic derivatives of this hormone. Moreover, the stated amount of progesterone in skin-care products has been found to vary widely, and there are no regulations for the use of this ingredient in over-the-counter products. A study published in the American Journal of Obstetrics and Gynecology
(June 1999, pages 1504–1511) states that “In order to obtain the proper (effective) serum levels with use of a progesterone cream, the cream needs to have an adequate amount of progesterone in it [at least 30 milligrams per gram]. Many over the counter creams have little [for example, 5 milligrams per ounce] or none at all. The creams that are made from Mexican yams are not metabolized to progesterone by women. The cream used in the above study (Pro-Gest) contains pure United States Pharmacopoeia [USP] progesterone.” Dr. John Lee, author and longtime proponent of topically applied progesterone, explains that “The USP progesterone used for hormone replacement comes from plant fats and oils, usually a substance called diosgenin, which is extracted from a very specific type of wild yam that grows in Mexico, or from soybeans. In the laboratory, diosgenin is chemically synthesized into real human progesterone. Some companies are trying to sell … ‘wild yam extract’ [or other plant extracts] … claiming that the body will then convert it into hormones as needed. While we know this can be done in the laboratory, there is no evidence that this conversion takes place in the human body.” Dr. Lee is quick to explain that he doesn’t sell any of these products and receives no profit from their sale. He also does not recommend the use of natural progesterone creams with any other active hormones or herbs.
When properly formulated, topical progesterone can slow certain age-related changes to female skin that would normally occur before and after menopause. Most notably, it seems to positively impact skin’s elasticity. However, other research has shown oral hormone supplementation “did not significantly alter mild to moderate age-related facial skin changes, and the study making that conclusion was much larger in scale and duration. Topical application of progesterone can cause a type of acne known as acne medicamentosa. This type of acne typically ceases once use of the offending medication is discontinued. Long-term studies of postmenopausal women applying topical progesterone cream showed that doing so did not affect bone density or reduce progression of asymptomatic atherosclerosis Additional sources for the information above: www.naturaldatabase.com; The Medical Clinics of North America, November 2009, pages 1,161–1,181; Menopause International, September 2009, pages 100–106; Journal of the American Academy of Dermatology, September 2008, pages 397–404; British Journal of Dermatology, September 2005, pages 626–634; Climacteric, June 2001, pages 144–150.)