In the February issue of The Journal of Clinical Endocrinology & Metabolism, Dr. Kathleen Mulligan of the University of California, San Francisco and colleagues note that although HAART has helped reduce HIV-associated wasting, weight and lean body mass are not fully or consistently restored after its initiation.

Megestrol acetate, they add, can help by stimulating appetite and promoting weight gain. However, much of the weight gained is fat.

To investigate whether testosterone might help increase lean body mass, the researchers studied 79 HIV-positive men who had a body mass index of less than 20 or who had lost 5% of their body mass. They were randomized to receive megestrol 800 mg daily along with testosterone enanthate 200 mg or placebo.

At 12 weeks, the combination group had gained a median of 5.3 kg and the placebo group had gained 7.3 kg. However, lean body mass accounted for 3.3 kg in both groups. There were no significant differences between groups in the magnitude or composition of weight gain.

There were also no differences between groups in sexual functioning at baseline. However, at the end of the study, sexual functioning was unchanged or improved in the combination group, but worsened significantly in the placebo group.

Dr. Mulligan told Reuters Health that "these results provide another demonstration of the potent appetite-stimulating effects of megestrol acetate. However, clinicians should be aware of the potent suppressive effects of megestrol acetate on adrenal and gonadal hormones and carefully monitor its use."

Commenting on the findings, author of an accompanying editorial Dr. William J. Evans, added that "megestrol acetate suppresses testosterone production, resulting in either loss of muscle -- or only fat as the tissue added with weight gain -- as well as reduced libido and impotence."

"Even replacing testosterone," concluded Dr. Evans of the University of Arkansas for Medical Sciences, Little Rock, "appears to be ineffective in adding muscle to the weight gain."

J Clin Endocrinol Metab 2007;92:420-421,563-570.

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