One sector of the health care market that is booming these days? Dietary supplements. More than half of all Americans take them for everything from weight loss and muscle building to more energy and better sexual function. It’s a multibillion-dollar industry with customers of all ages, including infants.

It is also an industry with little oversight. Now a new study has linked dietary supplements to serious medical events, especially in children and young adults.

Harvard University researchers examined more than 40,000 incidents related to food and dietary supplements that were reported from 2004 to 2015. They found nearly 1,000 involved consumers from infants to age 25. About 17% of these events led to hospitalization, with 2% ending in death.

Negative outcomes were most common among those ages 18 to 25 who were taking weight-loss supplements. These complications included chronic diarrhea, constipation, dehydration and cardiac arrhythmia. Muscle-building supplements have been linked to testicular cancer, whereas those taken for sexual issues have been associated with higher blood pressure, insomnia and anxiety. Energy drinks have been tied to cardiac and neurological conditions.

There is little regulation of these products. Federal rules have created an honor system: Manufacturers are expected to ensure their products are safe before putting them on the market. The FDA has issued numerous warnings about supplements, some of which feature misleading labels and dangerous ingredients.

But until stricter regulations emerge, parents and young adults should do their homework. What is being sold as a boost to your system might actually be doing you harm.