Doctors are issuing an urgent warning about a dangerous “heightmaxxing” trend in which teenagers are taking a cancer drug in the hope of becoming taller.
The medication, erdafitinib—often referred to online as “ERDA” or “Erta”—is primarily being used by teenage boys seeking extra height. It is approved for treating certain types of bladder cancer.
Reports indicate that some teenagers have obtained erdafitinib after seeing social media claims suggesting the drug can trigger additional growth.
Medical professionals strongly advise against using it without a prescription and close supervision, warning that the medication may cause permanent health problems while offering no proven height benefit.
Dr Stephanie Widmer, an emergency medicine physician in New York City, told Fox News Digital: “It’s extremely concerning that teenagers are experimenting with powerful cancer medications in an attempt to grow taller.
“These drugs were developed to treat serious medical conditions, not to enhance physical appearance, and taking them without a legitimate medical indication or physician supervision can have devastating consequences.”
Experts say possible complications include damage to developing growth plates, bone fractures, severe pain and injury to internal organs.
Erdafitinib, marketed under the brand name Balversa, has been approved by the Food and Drug Administration (FDA) for certain patients with advanced bladder cancer.
Doctors warn that teenage boys are taking a bladder cancer drug in the hope of gaining extra height
The drug works by blocking a protein involved in the growth of bladder cancer tumors, as well as other cells in the body, thereby slowing tumor development.
Some earlier research has raised the possibility that erdafitinib could accelerate bone growth in children and adolescents. However, scientists have challenged those findings, and there is no established evidence that the drug safely increases height.
Available only by prescription, erdafitinib has been associated with a range of side effects, including vision problems, nosebleeds, changes to the skin and nails, and intense muscle and bone pain.
Despite those risks, reports suggest some teenagers have bought the medication from overseas online sellers.
Johnson & Johnson manufactures the drug, which was approved in 2019 for bladder cancer patients whose disease has progressed after at least one previous treatment.
It is used specifically for urothelial carcinoma, the form of bladder cancer responsible for roughly 90 percent of the 84,000 cases diagnosed in the United States each year.
According to Rolling Stone, a 17-year-old identified only as Zak spent $300 on a one-month supply after deciding the drug might help him grow taller.
Zak said he gained several inches between the ages of 15 and 17 while taking erdafitinib, but also experienced severe joint pain and repeated nosebleeds. The symptoms became so serious that he worried he might require hospital treatment.
It remains uncertain whether erdafitinib can increase height, while side effects including nosebleeds and severe pain are well documented
“I was literally saving money every single day. I was putting money aside from my work and everything just for a medical bill from erda,” he told Rolling Stone.
Another 17-year-old, identified as James, told the publication that his fingernails turned yellow and began producing pus after he started taking the drug. He claimed to have grown approximately three inches within two months of beginning erdafitinib in late August.
“I was five foot five, so it was pretty bad. So then I just knew that there had to be something that could make me taller,” he said.
Johnson & Johnson told the publication that erdafitinib “has not been approved to increase height, and its safety and effectiveness have not been established for that purpose or for use in any children or adolescents.”
Doctors likewise stress that it is still unknown whether the drug can meaningfully increase a teenager’s adult height.
The online claims appear to be linked to a 2024 study published in the journal Hormone Research in Paediatrics. Researchers observed unexpected growth spurts in children taking erdafitinib for tumors affecting the central nervous system.
During puberty, bones lengthen at growth plates—areas of cartilage near the ends of bones. Growth is regulated in part by FGFR3, a naturally occurring substance. The researchers proposed that erdafitinib’s ability to block this pathway might have contributed to the observed growth spurts.
Dr Adalbert Raimann, a pediatric endocrinologist at the Medical University of Vienna in Austria and a co-author of the study, has nevertheless warned that using the drug carries significant dangers.
“And those receptors we’re targeting with ERDA, they’re present in basically every cell,” he told Rolling Stone. “So we have no idea, not in adults and especially not in kids in this developing system, what we are doing in five to 10 years.”
Once puberty is complete, the growth plates close permanently. As a result, erdafitinib is unlikely to alter bone growth after that stage.
Widmer said: “One of the biggest concerns is that these medications can cause serious side effects, including potentially permanent vision damage, elevated phosphate levels and other metabolic abnormalities.
“We’re talking about adolescents whose bodies are still developing, and exposing them to these risks for a cosmetic goal is particularly troubling.”
Widmer added: “We should be encouraging teenagers to prioritize their health, not teaching them to gamble with it.
“No amount of additional height is worth risking permanent damage to your vision or other serious and potentially unknown medical complications.”