Those workout supplements you’ve been taking may be creating big problems for your body, new research has found.

A study including 195 men between the ages of 18 and 65 who go to the gym at least twice a week have found that an alarming amount of people are abusing legal supplements that they may think are perfectly safe — but aren’t, according to an NPR report.

The study was published at the American Psychological Association’s annual convention, and found that those who regularly consume legal supplements like whey protein, creatine, and L-carnitine may think that they’re completely safe, since they are legal and don’t have the stigma that the illegal bodybuilding substances like steroids of yesteryear. But even though people don’t want to bulk up to Arnold Schwarzenegger type levels, that doesn’t mean the substances they’re using are safe, even though they’re going to a muscular, lean look and not a bulky, ripped one.

The study had people answer questions about their use of supplements as well as their lifestyle — their diet, self-esteem, and other things.

The study found that about 40 percent of participants have been increase their use of supplements over time, and about 22 percent were using them to replace meals. Physicians had advised patients to cut back on supplements about 8 percent of the time due to side effects. About 3 percent have been hospitalized because of damage done to their kidney or liver, which can be caused by protein powders, creatine, and other supplements. Users of supplements were also more likely to have eating disorders and associated problems.