Teens Take Cancer Drug to Grow Taller
Doctors warn that erdafitinib, approved for bladder cancer, is not proven to add height and can cause side effects.
Updated on Nov. 6, 2026 in Cancer
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Some teenagers are taking erdafitinib, a cancer drug sold as Balversa, in an attempt to increase their height, despite doctors warning the practice is dangerous. The drug was approved in 2019 for certain advanced bladder cancers in adults, and Johnson & Johnson states it is not approved to increase height.
Why it matters
Teenagers are obtaining the prescription medicine from overseas online sellers and sharing height gains and side effects on social media. The belief that it can add height traces to reports of unexpected growth in children receiving the drug during cancer treatment, which has not been established as a reliable effect.
The height claims rest on one teenager's own measurements and on a July 2024 report of unexpected growth in two children receiving the drug during cancer treatment. Neither is a controlled study in healthy teenagers, so the evidence cannot show that erdafitinib increases height.
The players
Johnson & Johnson
Johnson & Johnson markets Balversa, the brand name for erdafitinib, and states the drug is not approved to increase height.
Adalbert Raimann
Adalbert Raimann is a paediatric endocrinologist at the Medical University of Vienna who has commented on the risks of the practice.
Andrew Dauber
Andrew Dauber is a paediatric endocrinologist at Children's National Hospital who has commented on the risks of the practice.
The details
Erdafitinib is designed to block fibroblast growth factor receptors, proteins involved in cell growth, which is why it treats certain bladder tumors. Teenagers discuss the drug as "erda" on social media, sharing height updates, days taken and side effects. Reported side effects in one user included nosebleeds, extremely dry skin and severe joint pain.
Timeline
2019: Erdafitinib approved for certain advanced bladder cancers in adults.
July 2024: Study reported unexpected growth in two children receiving the drug.
Age 15 onward: Zak began taking erdafitinib on and off.
Health Landscape
Erdafitinib is an approved oncology drug whose growth-related effect in children was first noted during cancer treatment in a July 2024 report. Using a cancer medicine for height in healthy teenagers falls outside its approved use and the evidence supporting it.
Parents and teenagers should know that prescription cancer medicines bought online without a prescription carry unknown risks, and that side effects such as nosebleeds and joint pain have been reported. Anyone concerned about growth or height is better served by a conversation with a paediatric doctor.
The takeaway
Growth concerns in teenagers are best raised with a paediatric endocrinologist rather than addressed with prescription medicines sourced online. Doctors warn that using erdafitinib for height is dangerous.
Further reading
For context on the drugs at the centre of this trend, see our Cancer coverage.
Source note: This article includes information reported by NDTV.
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