By: Akanksha
Social media is full of trends that promote self-improvement, with one of the most popular trends being looksmaxxing. This involves young men exchanging tips and strategies to improve their appearance. A new trend has emerged on TikTok and online forums, known as heightmaxxing. Many young men feel that everything in life, especially dating, is better if they are tall. Therefore, some teens are turning to black market cancer drugs to grow a few inches.
Teenagers have begun taking a prescription cancer drug known as erdafitinib (or ‘erda’/’erta’) and documenting it on social media. On TikTok, teenage boys are sharing updates on how much they’ve grown. This includes measuring their height with a tape measure and showing how much they’ve grown by placing the tape against some markings on a wall. They are also comparing how many days they’ve been taking the drug and what side effects they’re experiencing.
The drug, sold under the brand name Balversa, was originally approved in 2019 to treat certain advanced bladder cancers in adults. Doctors have used it in clinical trials for children with rare central nervous system cancers. However, teenagers online believe it can help them grow taller due to medical reports showing children experiencing unexpected growth when taking the drug for cancer.
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A 17 year old New York TikToker, Zak, became obsessed after spending too much time looking at social media content about male height standards and getting teased at school for not being as tall as the girls in his class.
He purchased the drug when he was 15, and it cost him around $300 per month. He explained to Rolling Stone that he didn’t like other people towering over him and having to look up to people. He didn’t know how to put it, but it felt like he was not in control.
As he knew he was taking a cancer drug that wasn’t prescribed, he was prepared for the worst. However, he has still taken it on and off for two years. He further explained that he was literally saving money every single day and was putting money aside from his work and everything just for a medical bill from using erda.
This trend has come from real cases that teens found online. Doctors noticed that a few children with cancer were experiencing unexpected growth spurts while taking erdafitinib. A study published in July 2024 in the medical journal Hormone Research in Pediatrics documented two children receiving treatment for central nervous system tumors who experienced a sudden growth spurt.1 Another medical case report noted a teen experiencing over 5 inches of growth; however, it came with severe skeletal issues.2
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During puberty, our bones grow because there are areas of soft cartilage at the ends of our bones known as growth plates. Once puberty has ended in early adulthood, these growth plates fuse together, indicating that the individual has reached their maximum height.1
Erdafitinib stops certain proteins, fibroblast growth factor receptors, from working in the body.
FGFR3 is a protein that helps regulate bone growth. Researchers believe that blocking its activity may explain why some children taking erdafitinib experienced unexpected growth spurts. In the two reported cases, their growth plates became wider, and more minerals accumulated in the developing parts of their bones near the growth plates.1
However, this explanation is based on observations in just two children. It does not mean that erdafitinib can safely increase height in healthy teenagers. There is also no evidence that the drug can reopen growth plates once they have fused.
While this makes sense scientifically, the doctors involved in the research are horrified to see healthy teens using their paper as a guide. Dr. Adalbert Raimann explained to Rolling Stone that the children in his study were suffering from rare and life-threatening cancers and had tried other treatments.1 Doctors were willing to put up with the harsh side effects because they were trying to save the children.
Taking a drug that affects pathways throughout the body is a huge risk to growing teens. Dr. Raimann warned Rolling Stone that those receptors they were targeting with erda were basically present in every cell. Therefore, they had no idea, not in adults and especially not in children in a developing system, what they were doing in five to ten years.
A February 2026 study by researchers from the US Food and Drug Administration (FDA), published in Pediatric Blood & Cancer, identified five children who developed bone or growth-related complications while taking erdafitinib. These included two cases of slipped capital femoral epiphysis (SCFE), a condition in which the upper part of the thigh bone slips out of its normal position at the hip joint, and two cases of unusually rapid growth. One child with rapid growth also developed severe kyphoscoliosis, a condition in which the spine curves abnormally in more than one direction.
The children were between 10 and 15 years old, with a median age of 13. The complications appeared a median of 137 days after they started taking erdafitinib. Doctors stopped the drug permanently in all five cases, and three children needed surgery to correct the complications.
There are severe side effects to taking erdafitinib; the official guidelines state that patients can experience severe nausea, diarrhea, mouth ulcers, high phosphate levels in the blood (which can cause mineral build-up in soft tissues), and fingernail lifting.
Erdafitinib can also cause serious eye problems that may affect vision. These include central serous retinopathy (CSR), which occurs when fluid builds up under the retina, and retinal pigment epithelial detachment (RPED), in which a layer of cells beneath the retina separates from its normal position.
Zak explained that he had severe nosebleeds, dry skin, and joint pain. He told Rolling Stone that stretching his arm felt like his wrist was going to tear off. After waking up, it felt like his spine was bent and he had to spend at least an hour just stretching so that his spine felt better. Despite this pain, he claimed to have grown several inches between the ages of 15 and 17 after his height had plateaued. He has considered starting a cycle again.
Another 17 year old on the West Coast, who goes by the name James, showed Rolling Stone a plastic container of powder claiming to be erda during a Zoom call. He held his hand up to the camera, showing yellow fingernails oozing pus and lifting off his fingers. He said, “Bro, it’s bad,” to Rolling Stone.
The manufacturer of Balversa, Johnson & Johnson, has also commented on this trend. A spokesperson said that it has not been approved to increase height and its safety and effectiveness have not been established for this purpose or for any use in children or adolescents, advising patients to only take medications prescribed by a qualified doctor.
Doctors advise parents to look for any sudden complaints about hip or knee pain, changes to their skin, or any suspicious changes. Dr. Widmer told Fox News Digital that parents need to understand that this goes beyond teenagers being insecure about their height. They are talking about young people potentially obtaining prescription cancer medications and experimenting with them outside of medical supervision. If a child has concerns about their growth, that conversation belongs in a pediatrician’s office, not on an internet forum.
To conclude, Dr. Widmer said, “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.”
References:
Hartmann, G., A. Raimann, N. Stepien, A. A. Azizi, G. Hartmann, and J. Gojo. “Accelerated Linear Growth during Erdafitinib Treatment: An FGFR-Related, but Growth Factor and Sex Steroid-Independent Mechanism?” Hormone Research in Paediatrics 98, no. 6 (2025): 753–57.
Brizini, M., T. Drimes, C. Bourne, J. Streilein, A. Drapeau, J. Wrogemann, L. A. Archer, M. Del Bigio, and M. I. Vanan. “Case Report: Slipped Capital Femoral Epiphysis: A Rare Adverse Event Associated with FGFR Tyrosine Kinase Inhibitor Therapy in a Child.” Frontiers in Oncology 14 (2024): 1399356.
Nguyen, M. N., G. M. Dores, A. Nayernama, and S. C. Jones. “Postmarketing Cases of Erdafitinib-Associated Skeletal Growth Toxicity Events in Pediatric Patients.” Pediatric Blood & Cancer 73, no. 2 (2026): e70046.
US Food and Drug Administration. Balversa (Erdafitinib) Prescribing Information. Revised October 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/212018s011lbl.pdf.
(Rh/APC/MSM)
