Neanderthal gene variant may increase muscle mass in people living today today
A gene variant inherited by modern humans from Neanderthals causes the body’s cells to respond more strongly to growth hormone. In a study published in Current Biology, researchers at Karolinska Institutet and several international universities report that adults who carry the variant have, on average, slightly greater muscle mass.
Neanderthals were generally more robustly built than people are today. The researchers examined a variant of the growth hormone receptor that modern humans inherited from Neanderthals around 47,000 years ago. Today, the variant is found mainly in South and East Asia, and in some populations in these regions it is carried by up to 24 per cent of people.
In laboratory experiments, the researchers studied two changes unique to the Neanderthal receptor. When stimulated with growth hormone, cells carrying the Neanderthal variant grew 40 per cent more than cells with the most common modern human version of the receptor.
“It is fascinating that a gene variant inherited from Neanderthals still affects people today. But this gene is only one of many factors that influence the body’s growth and shape,” says Hugo Zeberg, who led the study and is a senior lecturer at the Department of Physiology and Pharmacology, Karolinska Institutet.
The researchers analysed data from just over 1.1 million adults. The variant was associated with an average increase in body weight of 285 grams, almost all of which was due to greater muscle mass. By contrast, no effect was seen in more than 6,000 children aged 11 or younger, suggesting that the difference may emerge later, possibly during puberty.
“As someone who does CrossFit, I found it fun to link Neanderthal genetics to muscle mass. But not even a Neanderthal growth hormone receptor can replace training,” says co-author Miriam Berreiter of the same department.
Carriers of the variant also had slightly shorter tooth roots and subtle differences in jaw shape, features that resemble those seen in Neanderthals.
See the study for information on funding and potential conflicts of interest.
Publication
”Increased signaling of the Neanderthal growth hormone receptor”, Philipp Kanis, Miriam Berreiter, Daniel Sieme, Olivia Wootton, Xiang-Chun Ju, Nicholas E. Holzwart, David Ziliang Hu, Shu Tadaka, Makiko Taira, Kengo Kinoshita, Richard Agren, Johan G. Olsen, Tomislav Maricic, Hilary C. Martin, Birthe B. Kragelund, Svante Päbo, Andrew J. Brooks, Hugo Zeberg, Current Biology, online August 5, 2026, doi: 10.1016/j.cub.2026.07.025