# Neanderthal gene variant boosts muscle mass

> Live situation record from CLSTR: https://clstr.news/situations/neanderthal-gene-variant-boosts-muscle-mass
> Updated: 2026-08-18T13:19:24.000Z. Sources: 25. Developments: 3.

Researchers from the Karolinska Institutet (Sweden) and the Max Planck Institute for Evolutionary Anthropology (Germany) have identified a Neanderthal-derived version of the growth-hormone receptor (GHR) that influences muscle development. Published in the journal ‘Current Biology’, the study indicates that cells carrying this variant respond approximately 40% more strongly to growth hormone, leading to significantly larger cell growth. 

Analysis of data from more than one million modern adults shows that carriers possess, on average, roughly 270 grams of additional muscle mass. This effect appears to manifest after childhood, likely around puberty when growth-hormone levels rise, as researchers found no significant difference in muscle mass among children under the age of 11. The variant entered the human gene pool approximately 47,000 years ago through interbreeding and is most prevalent in East and South Asian populations (up to 24%) while remaining rare in Europeans (≈0.5%). While the gene contributes to greater muscle development, researchers noted it does not replace the benefits of physical training.

In related findings, research led by the Regeneron Genetics Center identified mutations in the FNIP1 gene associated with higher muscle mass. This mutation is linked to reduced abdominal fat and lower blood glucose levels, potentially resulting in a 60% lower risk of developing cardiometabolic diseases. This FNIP1 mutation is estimated to occur in approximately one in 7,000 people.

## Claims

- A Neanderthal gene variant affects the growth hormone receptor in modern humans. (corroborated by 3 sources)
- In laboratory tests, cells with the Neanderthal receptor showed approximately 40 percent higher growth than those with the common variant. (corroborated by 3 sources)
- Analysis of data from over one million adults found that individuals with the Neanderthal variant have an average of 270 grams more muscle mass. (corroborated by 3 sources)
- The physical effects of the gene variant appear to manifest in adulthood rather than childhood. (corroborated by 3 sources)

## Timeline

### 2026-08-18: Neanderthal genes linked to increased muscle mass in humans

A study in ‘Current Biology’ suggests Neanderthal DNA affects muscle mass via the GHR gene, making cells more sensitive to growth hormones and resulting in higher muscle mass in adults.

2 sources. https://clstr.news/cluster/neanderthal-genes-linked-to-increased-muscle-mass-in-humans

### 2026-08-08: Genetic studies link Neanderthal DNA and FNIP1 mutations to increased muscle mass

Researchers have discovered that Neanderthal-inherited gene variants and specific FNIP1 mutations are linked to increased muscle mass and reduced risks of metabolic diseases like diabetes.

13 sources. https://clstr.news/cluster/neanderthal-derived-growth-hormone-receptor-variant-linked-to-greater-muscle-mass

### 2026-08-05: Neanderthal gene variant linked to increased muscle mass in modern humans

A Neanderthal‑derived growth‑hormone receptor variant, identified by researchers at Karolinska Institutet and the Max Planck Institute, boosts muscle mass by about 270 g in adults and is common in South/East As

10 sources. https://clstr.news/cluster/neanderthal-gene-variant-linked-to-increased-muscle-mass-in-modern-humans

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Cite as: Neanderthal gene variant boosts muscle mass. CLSTR, https://clstr.news/situations/neanderthal-gene-variant-boosts-muscle-mass