The Los Angeles-based AIDS Healthcare Foundation says that the drug Serostim, commonly used by HIV patients to combat wasting and gain weight, is not essential for treatment, the New York Daily News reports. HIV-positive patients tend to use the costly medication to improve their appearance, not their health, according to the foundation. Serostim, manufactured by Serono Laboratories, costs more than $6,000 for a one-month treatment. Because the medication is so expensive, some HIV patients sell the drug on the black market to bodybuilders who use it to boost muscle mass. Most state Medicaid programs cover the medication. "At a time when Medicaid is cutting back, [Serostim] shouldn't be in the formula at all," said foundation president Michael Weinstein. Serono is being investigated by officials in Maryland, Florida, California, and New York for sales and marketing improprieties. The company is being investigated for possible improper billing of the drug to state Medicaid programs and for offering improper incentives to doctors and pharmacists to prescribe the drug. Counterfeit versions of the medication also have been reported on the market at least four times during the past three years.