Ronald Kaufman makes his special potion of yogurt and nutritional supplements.
"It's 20 different things that I put into the drink," Kaufman said.
But are supplements safe? It's hard to say. They're regulated as food, not drugs.
"Medications are tested and verified for potency and purity. With dietary supplements, there is no testing standard," registered dietician Erin Palinski said.
Protein, creatine and CLA are said to build muscle. But studies on creatine and CLA are mixed. All three are generally considered safe if taken at recommended levels.
"Even generally safe supplement ingredients, if you're taking them in too high a dose, can be potentially dangerous," Palinski said.
They can lead to dehydration, kidney stones and stomach problems. Athletes often use caffeine supplements to boost energy.
"In up to about 300mg per day, it may help increase athletic performance, but above that amount we can run at the risk, since it's a stimulant, of increasing blood pressure. In very high amounts, it can actually lead to seizures," Palinski said.
Some fat-burning supplements, which contain a mix of herbal ingredients, can also act as a stimulant.
"Long-term use of certain fat burners can have some very adverse events in the liver," said Dr. Taylor Wallace with the Council for Responsible Nutrition.
Experts say beware of Ephedra, which has been banned by the FDA. Avoid bitter orange, also called Synephrine. It's chemically similar to Ephedra and the government says there's little evidence it's any safer.
"This has been linked with many serious side effects, including stroke, heart attack," Palinski said.
If you do use supplements, experts say stick with reputable brands and retailers.
As you shop for supplements, look for a USP seal. That means the product meets stringent, voluntary standards for safety and purity.