There is no pill that does for women what Viagra does for men yet. Some doctors have experimented with the male hormone testosterone to enhance a woman's libido, but without the benefit of rigorous trials. Now a new study, conducted by Dr. Glenn Braunstein at Cedars-Sinai Medical Center in L.A., has taken some of the uncertainty out of testosterone therapy. Nearly 450 women who had lost their ovaries were given either a testosterone patch or a placebo. After six months of treatment, the women on 300 mcg of testosterone a day reported an 81% increase in satisfying sexual activity and a 66% increase in sexual desire. Some women in both the testosterone and the placebo groups experienced side effects, such as headaches, acne and increased facial hair.