Does Saw Palmetto Promote Hair Growth?

Some herbs that are used to treat prostate complaints have a theoretical use for hair loss as well. Saw palmetto is often used for benign prostate hypertrophy and may even be useful for treating prostate cancer. In fact, Germany's Commission E, that country's regulatory body for herbs, approves saw palmetto for prostate complaints. Always consult a health care professional before trying a new supplement.

Significance

Some scientific studies say saw palmetto works by reducing uptake of dihydrotestosterone, or DHT, in your body and by blocking conversion of testosterone to DHT, according to Sloan-Kettering Memorial Cancer Center. Saw palmetto's possible effect on the hormone DHT is what gives it a theoretical benefit for treating hair loss. This hormone plays a role in male-pattern hair loss because it shrinks hair follicles. Finasteride, a medication used for male-pattern hair loss, is effective because it blocks conversion of testosterone into DHT.

Mechanism of Action

Testosterone is converted to DHT via the enzyme 5-alpha reductase, or 5AR. This metabolic pathway is a factor in male-pattern hair loss. It's also central to the onset as well as the progression of benign prostatic hyperplasia, which some people take saw palmetto to treat. Agents such as saw palmetto that block conversion of testosterone to DHT work by inhibiting 5AR, notes N. Prager, lead author for a 2002 study published in the "Journal of Alternative and Complementary Medicine."

Scientific Evidence

While one small study indicates that saw palmetto is beneficial for treating hair loss, more research is needed before definitive conclusions can be drawn, according to the 2009 "Patient Guide for Hair Loss and Hair Restoration," by D.J. Verret. In the controlled study, hair loss improved for six of 10 participants, Verret notes.

Considerations

Saw palmetto can cause side effects. These include vomiting, gastrointestinal complaints, nausea, abdominal pain, diarrhea, breast tenderness, erectile dysfunction and loss of libido. Rarely, it can cause intraoperative hemorrhage. Saw palmetto also may increase your chance for bleeding or bruising, especially if it's taken along with blood-thinning medicines like aspirin or warfarin. Saw palmetto also may reduce or prevent absorption of some iron supplements.