Neanderthal gene variant linked to increased muscle mass in modern humans

Researchers led by Hugo Zeberg of the Karolinska Institutet in Sweden and Philipp Kanis of the Max Planck Institute for Evolutionary Anthropology in Germany identified a Neanderthal‑derived version of the growth‑hormone receptor that makes cells respond about 40 % more strongly to growth hormone. Laboratory experiments showed the variant‑bearing cells grew significantly larger, and analysis of data from more than one million adults revealed carriers have, on average, roughly 270 grams more muscle mass. The variant entered the human gene pool around 47 000 years ago through interbreeding with Neanderthals and is most common in South and East Asian populations (up to 24 % in some groups) and rare in Europeans (≈0.5 %). The effect becomes apparent after childhood, likely around puberty when growth‑hormone levels rise. While the gene contributes to greater muscle development, it does not replace the benefits of training.

The study was published in Current Biology on 5 August 2026 and reported by multiple international outlets, confirming the consistency of laboratory and population evidence.