New California Law Restricts Sales of Some Muscle-Building Supplements to Minors

California Gov. Gavin Newsom has signed legislation banning the sale of some "muscle-building supplements" to Californians under 18 years of age. The legislation (AB 2030), signed on Sept. 28, covers over-the-counter diet pills and dietary supplements for weight loss or muscle building. It will go into effect on Jan. 1, 2027.

"Nonprescribed, medically unapproved products may cause dangerous side effects," the governor's office said in its announcement. "Products can be mislabeled or contaminated with substances such as steroids."

California's law restricts minors' access to supplements marketed for muscle building — specifically, those that are "labeled, marketed or otherwise represented for the purpose of achieving weight loss or building muscle." Courts may consider whether a product contains "creatine, green tea extract, raspberry ketone, garcinia cambogia or green coffee bean extract," the legislation states.

The law does not impose an outright ban on all creatine products. Restrictions depend on how the supplements are labeled, advertised and marketed to consumers. The announcement does not specify whether whey protein or creatine products are included in the ban.

The law does not apply to people under 18 who have a prescription for an over-the-counter diet pill or dietary supplement for weight loss or muscle building.

The announcement cites research indicating that nearly one in 10 adolescents have used such products. It also references studies linking over-the-counter diet pill use to a sixfold greater likelihood of an eating disorder diagnosis within three years.

Sellers who do not adhere to the new law will face civil fines of up to $500 per violation.

The American Herbal Products Association, based in Maryland, released a statement opposing the law. "Lacking any scientific justification, AB 2030 casts a shadow over safe, beneficial products," said Robert Marriott, the association's vice president of regulatory and government affairs, in the statement. The organization argues that the law's scope is unclear and notes that it does not explicitly exempt protein products.

The Center for Science in the Public Interest, based in Washington, D.C., shared public support of the new legislation. The organization co-sponsored the legislation. "Manufacturers of these products often prey on kids and teens with deceptive claims that lack any scientific evidence," said Jensen Jose, a regulatory counsel at CSPI.

Dr. Sigrid Wolf, a pediatric sports medicine physician at Lurie Children's Hospital of Chicago, recently addressed the use of creatine products among teenagers. She is a member of the American Academy of Pediatrics' sports medicine committee. In an article published on HealthyChildren.org, the American Academy of Pediatrics' parenting website, she wrote that evidence of benefits is limited. "In some cases, they might even be dangerous," she wrote. "Creatine can come with negative side effects such as weight gain, dizziness, nausea, vomiting and diarrhea."

"Studies show that many supplements contain harmful substances that go undetected," she added, instead recommending prioritizing nutrition, training, sleep and hydration.

Fox News Digital reached out to Newsom's office for comment.