Neanderthal growth hormone receptor increases muscle mass

A study published in Current Biology on August 5, 2026, led by Hugo Zeberg of Karolinska Institute and Philipp Kanis of Max Planck Institute for Evolutionary Anthropology, found that a variant of the growth hormone receptor inherited from Neanderthals around 47,000 years ago increases signaling in cells. Laboratory experiments showed cells with the Neanderthal receptor grew 40% more than those with the common modern human version. Analysis of data from over 1.1 million adults in biobanks from the United Kingdom, Finland, Japan, South Korea, and Taiwan revealed that carriers have on average 285 grams more body weight, mostly muscle mass, and are slightly taller. The variant is most common in South and East Asia, with up to 24% of some populations carrying it. No effect was seen in children under 11, suggesting the effect emerges later, possibly during puberty. The study also linked the variant to subtle differences in jaw shape and tooth roots, resembling Neanderthal features.