Why Bodybuilders Are Pounding Down Breast Milk Breast milk may not necessarily do a body good.

 -- Bodybuilders will try just about anything to build bulging biceps, including apparently, drinking breast milk.

“It isn’t common, but I’ve known people who have done this. It’s certainly talked about quite a bit on the bodybuilding forums on the Internet,” said Brett Schoenfeld, a former competitive body builder and now an assistant professor of exercise science at CUNY Lehman College in New York City.

But experts say human breast milk will not pump you up.

“There is nothing specific in breast milk that will cause adults to gain muscle mass,” said Dr. Jacques Mortiz, the director of the division of gynecology at Mount Sinai Roosevelt in New York.

While studies do indicate that breast milk has numerous advantages for newborns and infants, Mortiz said there are virtually no studies looking at what it can do for any adult, let alone bodybuilders. That’s because there is no scientific reason it should help.

For example, if the idea is to take in more protein, one cup of breast milk contains 2.5 grams of protein per cup compared to 7.9 grams of protein in cow's milk, according to the USDA National Nutrition Database. It is also significantly higher in sugars and fat.

It’s far more expensive than cow’s milk, too. A gallon of milk costs $3.44 cents on average, according to last week’s USDA’s National Retail Report. One ounce of breast milk from an internet site costs up to $10 an ounce.

Because of poor collection, storage and shipping practices, milk from unregulated breast milk internet sites is also more likely to be contaminated than milk donated to regulated milk banks.

One recent study found that 89 percent of breast milk purchased over the Internet arrived above the recommended freezer temperature which potentially upped the risk of contamination. Another study confirmed this worry when it found Internet milk samples were harbored high colony counts of the staphylococcus bacteria, known to cause serious infections.

But Schoenfeld doesn’t believe the facts will stop a bodybuilder in search of an extra inch around the quads.

“Bodybuilders are a strange breed of individuals,” he said. “Even if this type of thing is completely unsupported by research, they’re prone to gym lore and willing to give it a shot if there is any potential effect.”

ABC News' Dr. Katharine Maglione contributed to this report.