There are many reasons women lose their hair, including menopausal complications and alopecia areata, an inherited condition that results in thinning hair and patchy hair loss. Minoxidil, the active ingredient in Rogaine for men, was approved for women's use at the 2 percent concentration in 1991. The more potent 5 percent dose approved for men in 1997 has yet to gain FDA approval for use in women.
In a double-blind study conducted by Anne W. Lucky, MD, et. al. and published in the Journal of the American Academy of Dermatology in 2004, the 5 percent treatment group showed statistically significant improvement over the placebo and 2 percent solution groups. The study evaluated effects on three end points: nonvellous hair growth; scalp coverage; and patient perception of hair growth, an analysis of the psychosocial effect of female pattern baldness.
Low Blood Pressure
A side effect of any minoxidil for women is slightly lowered blood pressure, and using the 5 percent solution prescribed to men can intensify that affect. Low blood pressure can cause dizziness, fatigue or even fainting upon standing.
Unwanted Hair Growth
Many women using the five percent Rogain for men experience unwanted hair growth, usually on the face. Some of this is due to the product dripping down to the face after application, but even careful use cannot prevent the effect entirely as the minoxidil enters the blood stream through contact with the scalp.
Pregnancy and Nursing
Minoxidil falls into the U.S. Food and Drug Administration's category "C," meaning that in some animal studies, there have been adverse effects on the fetus, but there are no reliable human trials with pregnant women. Category "C" drugs should be avoided by pregnant women unless the benefits far outweigh the risks. Nursing mothers are also advised against using Rogaine in the company's literature as the drug is transmitted through breast milk. The patient should either discontinue Rogaine use or discontinue nursing depending upon treatment need.