Full Breakdown
Neanderthal Growth Hormone Receptor Variant Linked to Extra Muscle Mass in Modern Humans
8/7/2026, 8:00:55 PM
Discovery of a Functional Neanderthal Gene Variant
An international research team led by Hugo Zeberg of the Karolinska Institutet and Philipp Kanis of the Max Planck Institute for Evolutionary Anthropology identified two amino-acid changes that are unique to the Neanderthal version of the growth-hormone receptor (GHR). Laboratory experiments showed that cells expressing the Neanderthal GHR grew about 40 percent more when exposed to growth hormone than cells with the common modern-human receptor. Population-scale analysis of body-measurement data from more than one million adults revealed that carriers of the Neanderthal GHR have, on average, approximately 270 grams (0.6 lb) more muscle mass. The effect was not detectable in children up to age 11, suggesting that the influence emerges around puberty when growth-hormone levels rise sharply.
Genetic Origin and Geographic Distribution
The Neanderthal GHR entered the modern human gene pool through interbreeding that occurred roughly 47,000 years ago. Today the variant is most prevalent in South and East Asian populations, with up to 24 percent of individuals in some South-Asian groups carrying at least one copy, compared with around 0.5 percent of Europeans. The researchers note that the variant is primarily found in people of non-African ancestry.
Physiological Effects Beyond Muscle Mass
In addition to increased muscle, carriers exhibit subtle skeletal differences that echo Neanderthal anatomy: a slightly shorter rear section of the lower jaw and shorter tooth roots. These traits are modest and do not alone determine overall body shape.
Implications for Human Evolution and Health
The findings illustrate how a single genetic legacy from Neanderthals can still influence modern human physiology. Hugo Zeberg emphasizes that the Neanderthal GHR is only one of many genetic factors shaping growth and body composition and does not by itself explain the robust Neanderthal body type. Co-author Miriam Berreiter, a CrossFit practitioner, stresses that the variant is no substitute for training, underscoring that lifestyle remains the dominant determinant of muscular development.
Official Statements & Responses
- He added that individuals inheriting the variant from both parents could have roughly half a kilogram more muscle.
Verbatim Quotes
- “What struck me most was that two very different types of evidence told the same story,” — Philipp Kanis, study's first author
- “It is fascinating that one genetic change inherited from Neandertals can still have an effect on the human body today,” — Hugo Zeberg, senior study author
