The vitamins, manufactured by Mira Health Products Ltd, based in New York, contain methasterone, a controlled substance, and dimethazine, CNN reported.
"Products marketed as a vitamin but which contain undisclosed steroids pose a real danger to consumers and are illegal," said Howard Sklamberg, director of the Food and Drug Administration's compliance office.
The FDA started an investigation into the vitamins after receiving 29 complaints about the product, including that it caused fatigue, muscle pain and cramps, and liver and thyroid problems, the FDA said.
Some patients were hospitalized, the FDA said. None of those affected by the vitamin have died.
The FDA advised anyone who is experiencing the symptoms after using Healthy Life Chemistry By Purity First's vitamin B-50 supplement to seek medical care and report the matter to the FDA.