A growth hormone receptor inherited from Neanderthals remains present in some modern populations – and appears to amplify growth-related signaling. Credit: Stock

A Neanderthal-derived growth hormone receptor still carried by some people today appears to amplify growth-related signals in cells.

Some people alive today still carry a version of the growth hormone receptor inherited from Neanderthals, and its effects can be measured in their bodies. Neanderthals were typically more powerfully built than most modern humans, with skeletal evidence of substantial muscle mass as well as features including pronounced brow ridges and relatively short tooth roots.

Growth hormone plays an important role in the development of muscles and bones. Produced by the pituitary gland at the base of the brain, it circulates through the bloodstream and acts by attaching to receptors on the surfaces of cells, which transmit the hormone’s signal into the cell.

Researchers led by Hugo Zeberg of Karolinska Institutet and Philipp Kanis of the Max Planck Institute for Evolutionary Anthropology examined the Neanderthal form of this receptor. They identified two changes that are absent from the receptor version found most commonly in modern humans.

Neanderthal receptor strengthens growth signals

When the researchers tested the Neanderthal receptor in laboratory-grown cells, those cells showed a stronger response to growth hormone. They grew 40 percent more than cells carrying the more common modern human receptor. Most of the increased response could be traced to one of the two Neanderthal-specific changes.

The receptor variant entered the modern human gene pool through interbreeding with Neanderthals about 47,000 years ago. Its frequency varies substantially today. In some South Asian populations, as many as 24 percent of people carry it, and it is also particularly common in East Asia. Among Europeans, the frequency is around 0.5 percent.

“What struck me most was that two very different types of evidence told the same story,” says Philipp Kanis, first author of the study and a postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology. “Cells grown in the laboratory responded more strongly, while data from more than a million people showed signs of the same effect in the body. It is rare to see laboratory and population evidence fit together so clearly.”

Effects appear after childhood

The influence of the Neanderthal receptor does not appear to become evident during early growth. After examining body measurements from more than 6,000 children, the researchers found no association with growth through age eleven. The findings suggest that its effects could emerge later, possibly near puberty, when growth hormone levels rise substantially. Among adults, carriers of the Neanderthal version had an average of about 270 grams more muscle mass.

“As someone who does CrossFit, I was delighted to find Neanderthal genetics and muscle mass coming together in the same study,” says co-author Miriam Berreiter. “But even a Neanderthal growth hormone receptor is no substitute for training.”

Skull and teeth retain subtle traces

The inherited receptor variant was also associated with small differences in the skull and teeth. People who carried it tended to have a slightly shorter rear portion of the lower jaw and shorter tooth roots, both of which more closely resemble features typical of Neanderthals.

“It is fascinating that one genetic change inherited from Neanderthals can still have an effect on the human body today,” says Hugo Zeberg, senior author of the study. “But this is only one of many genetic influences on growth and body shape. It cannot explain the Neanderthal body type on its own, and it certainly does not determine a person’s overall appearance.”

Reference: “Increased signaling of the Neanderthal growth hormone receptor” by Philipp Kanis, Miriam Berreiter, Daniel Sieme, Olivia Wootton, Xiang-Chun Ju, Nicholas E. Holzwart, David Ziliang Hu, Shu Tadaka, Makiko Taira, Kengo Kinoshita, Richard Ågren, Johan G. Olsen, Tomislav Maricic, Hilary C. Martin, Birthe B. Kragelund, Svante Pääbo, Andrew J. Brooks and Hugo Zeberg, 5 August 2026, Current Biology.
DOI: 10.1016/j.cub.2026.07.025

Funding: Max Planck Foundation, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish Brain Foundation, Okinawa Institute of Science and Technology, NOMIS Stiftung, Novo Nordisk Foundation

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