California Gov. Gavin Newsom has signed a law barring people under 18 from buying certain over-the-counter diet pills and supplements marketed for weight loss or muscle building. The measure, AB 2030, was signed Sept. 28 and takes effect Jan. 1, 2027.
The governor’s office said nonprescription products that have not been medically approved can carry risks, including dangerous side effects. Some may also be mislabeled or contaminated with substances such as steroids.
The law applies to products labeled, advertised or otherwise presented as a way to lose weight or build muscle. Courts may take ingredients such as creatine, green tea extract, raspberry ketone, garcinia cambogia and green coffee bean extract into account when deciding whether a product falls under the restrictions.
It does not prohibit every creatine product. Whether a supplement is covered will depend in part on how it is marketed. The law also makes an exception for minors with a prescription for a relevant over-the-counter product.
The announcement cited research suggesting nearly one in 10 adolescents have used these products. It also referenced studies that found young people who used over-the-counter diet pills were six times more likely to receive an eating disorder diagnosis within three years.
It remains unclear whether whey protein or some creatine products will be affected. Retailers who violate the law could face civil fines of up to $500 per violation.
The American Herbal Products Association, a Maryland-based trade group, opposes the measure. Robert Marriott, the group’s vice president of regulatory and government affairs, said the law lacks scientific justification and could cast doubt on products that are safe and beneficial.
The association has also raised concerns about the law’s scope, including the fact that it does not specifically exempt protein products.
The Center for Science in the Public Interest, which co-sponsored the legislation, supports it. Jensen Jose, the group’s regulatory counsel, said manufacturers often target children and teens with claims that are not backed by scientific evidence.
Dr. Sigrid Wolf, a pediatric sports medicine physician at Lurie Children’s Hospital of Chicago and a member of the American Academy of Pediatrics’ sports medicine committee, has said evidence for creatine’s benefits in teens is limited. In some cases, she wrote, the products could be dangerous.
Wolf has also noted possible side effects, including weight gain, dizziness, nausea, vomiting and diarrhea. Many supplements, she added, contain harmful substances that testing may not detect. She recommends that young athletes focus on nutrition, training, sleep and hydration.
