Post-menopausal women increasingly are taking testosterone to boost their enthusiasm for sex and enhance their feeling of well-being.

Doctors around the world are prescribing testosterone for women who have a medical condition known as hypoactive sexual desire disorder, which is lack of interest in sexual activity that takes a toll on relationships.

In clinical trials, women who used a testosterone patch reported having sex one additional time a month. While the Food and Drug Administration did not approve the use of testosterone for women with libido problems in the United States, the therapy is accepted for women in Europe.

I think women in the U.S. are turning to testosterone skin gels and pellets off-label because data from the Women's Health Initiative has made them reluctant to take estrogen at menopause. It linked estrogen with an increase in heart disease in women older than 60.

Unfortunately, there is little data in for women about the effects of testosterone on heart disease. Testosterone is changed into estrogen in the body, suggesting it may have the same effects as estrogen replacement in women.

So should women take testosterone? The answer for the majority is no, as there is little evidence on its long-term safety.

Women with severe sexual problems may consider using testosterone, but only in relatively low doses. The medicine should not increase the blood testosterone level above 100 nanograms per deciliter, an already high level in women. Unfortunately, some physicians are prescribing higher doses and risking a very high likelihood of side-effects.

The bottom line: A woman should be very cautious before taking testosterone and realize that it could accelerate heart disease.

SLUCare physician John Morley is director of geriatrics at St. Louis University and a geriatrician at St. Louis VA Medical Center. E-mail him at morley@slu.edu. The Aging Successfully column for seniors rotates each week with XX Files, a women's health column.