serenoa repens logo

Saw Palmetto in the treatment of androgenetic alopecia.


Alopecia is a general term for hair loss and requires further description. Androgenetic alopecia (AGA) is the most common cause of hair loss, presenting as loss of hair over the top (vertex) and the anterior mid-scalp area (receding hairline) in affected men. The term androgenetic alopecia denotes that both a genetic predisposition and the presence of androgens are necessary to cause expression. AGA is also referred to as male pattern hair loss and typically begins gradually in men in there 20s with incidence increasing 10% per decade.

Presence of Androgens must be present for baldness to occur

For centuries, it has been observed that the presence of androgens was necessary for Androgenetic Alopecia to express itself. In 400 BC Hippocrates observed that eunuchs (castrated males) did not become bald. Aristotle noticed this also.(1) Through out history it was also observed that the Italian Castrati (boys that castrated in order to train them as adult soprano singers, a practice which was ended by Pope Leo XIII in 1878) never became bald. Researchers knew that AGA had to be associated with the male hormone testosterone. It comes as no surprise that current research shows that the balding scalp contains miniaturized hair follicles and increased amounts of DHT compared to a hairy scalp. This suggests that it is the excess presence of dihydrotestosterone in the scalp tissue that causes AGA in those patients genetically predisposed.

Pathophysiology of Androgenetic Alopecia

In the body testosterone is broken down by an enzyme call 5 alpha reductase to dihydrotestosterone. (DHT). DHT, a potent metabolite of testosterone causes a gradual, progressive shrinkage in the length and caliber of genetically programmed hair follicles. This process is called miniaturization. Miniaturization results from shortening of the anagen phase and a decrease in the sit of the dermal papilla and volume of matrix cells. Consequently, each succeeding hair cycle results in production of smaller, finer hairs which contribute less to the overall appearance and density of the hair. These biochemical events occur at the cellular level of the hair follicle. Because the dermal papilla is highly vascular, it is continuously bathed in circulating androgens. It has been demonstrated that the dermal papilla is rich in androgen receptors and is the primary target of androgen action. (Choudhry et al., 1996) Cells in genetically programmed hair follicles contain the enzyme 5 alpha reductase. 5 alpha reductase converts testosterone into the more potent DHT (Chen, Zouboulis & Orfanos, 1996). 5 alpha reductase is found in higher quantities in the scalp follicles of affected men. (Sawaya & Price 1997) Androgen receptors in the cells of the dermal papilla bind with circulating DHT, forming androgen receptor complexes. This results in the androgen effects of miniaturization on the hair follicle. (Randall et al., 1992)

In conclusion, by inhibiting the breakdown of testosterone to DHT, hair loss can be prevented or at least kept to a minimum.

Treatments for Androgenetic Alopecia

5 Alpha Reductase inhibitors

Drugs in this class work by inhibiting the enzyme 5 alpha reductase, which limits the conversion of testosterone to DHT (Chen et al., 1996) Finasteride (propecia) is the first drug in this class to undergo extensive clinical trials in men. Finasteride has selective activity against 5 alpha reductase. As a result, serum and follicular DHT levels are significantly reduced (Dallob et al., 1994).

Saw Palmetto extract

Studies have shown that saw palmetto is an effective anti-androgen. It acts in a similar way that propecia does. Firstly it lowers levels of DHT in the body by blocking 5 alpa-reductase. Secondly Saw Palmetto blocks receptors sites on cell membranes required for cells to absorb DHT. Although no studies have been carried out on saw palmetto and its relation to hair growth, studies have been performed on the use of Saw Palmetto in the treatment of benign prostatic disease, which is similar to androgenetic alopecia in that it also depends on the production of dihydrotestosterone. All of the studies that have been performed to date show that Saw Palmetto is an effective anti-androgen and has shown conclusively to be effective in the treatment of benign prostatic disease.

One may assume from this that since Saw Palmetto is an effective anti-androgen and is used in the treatment of prostatic disease then it may also be effective in the treatment of androgenetic alopecia.


Some vitamins have been show to inhibit the activity of 5 alpha reductase and subsequent production of DHT. These vitamins therefore may be of great benefit in the treatment of androgenetic alopecia or preventing baldness. There has been studies in which zinc is shown to inhibit 5 alpha reductase activity and it has therefore been concluded that zinc is beneficial in disease and disorders related to an excess in DHT. There has also been studies which have show that vitamin B6, Zinc and azelaic combined together even in low concentrations resulted in a 90% inhibition of 5 alpha reductase activity.


Propecia has been tested and found to be effective in the treatment of AGA. However, its list of possible side effects include sexual adverse experiences. It also affects PSA levels, which is the screening indicator for prostrate cancer.

Saw Palmetto has been proven safe to use. It has no known drug interactions and is well tolerated by most people. The only noted side effect in a very small percent of people is upset stomach. Saw Palmetto can be taken with zinc, vitamin b6, and azelaic acid for a synergistic effect.


Normal healthy hair grows about ½ inch per month. It may take several months before any effects are noticed. Where the area is completely bald, hair may not grow, if the follicles are dead. It takes years for the hair to thin, so one must assume that it will take time to also reverse the process. Keeping the hair from further thinning is success in itself.


Chen, W., Zouboulis, Ch.C., & Orfanos, E.E. 1996) the 5-reductase system and its inhibitors. Dermatology, 193, 177-184

Choudry, R., Hodgins, M.B., Van der Kwast, T.H., Brinkmann, A.O., & Boersma, W.J.A. (1992) localization of androgen receptors in human skin by immunohistochemistry: implications for the hormonal regulation of hair growth, sebaceous glands and sweat glens. Journal of Endocrinology, 133 467-475

Dallob, A.L., Sadick, N.S., Unger, W., Lipert, S., Geissler, L.A., Gregoire, S.L., Nguyen, H.H., Moore, E.C., & Tanaka, W.K. (1994) The effect of finasteride, a 5-reductase inhibitor, on scalp skin testosterone and dihydrotestosterone concentrations in patients with male pattern baldness. Journal of Clinical Endocrinology and Metabolism, 79(3), 703-706.

Sawaya, M.E., & Price, V.H. (1997). Different levels of 5 alpha reductase type I & II, aromatase, and androgen receptors in hair follicles of women and men with androgenetic alopecia. The Journal of Investigative Dermatology, 10(3), 296-300.

(1) Eunuchs were plentiful during Hippocrates days, in that in the middle east they were used as guards and servants in harems or other women's quarters, and as chamberlains to kings. Eunuchs were considered the most suitable guards for the many wives or concubines a ruler might have in his palace.