Neanderthal Gene Makes Some Modern Humans Taller and More Muscular

TL;DR

• Researchers have identified a specific Neanderthal-derived gene variant, carried by approximately 30% of modern humans outside sub-Saharan Africa, that is associated with increased height and greater skeletal muscle mass.
• The gene, located in a region of chromosome 6, influences the expression of proteins involved in muscle development and bone growth.
• The finding adds a concrete genetic mechanism to the broader understanding that Neanderthal DNA — which makes up roughly 1–4% of the genome of non-African populations — has measurable effects on modern human physiology.
• The research does not mean Neanderthals were uniformly taller or more muscular than modern humans; it means one specific gene variant from Neanderthal ancestry has a detectable effect in people who carry it today.

What Happened

In a study published in July 2026 in Nature Ecology & Evolution, an international team of geneticists led by researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig and the University of Copenhagen reported the identification of a Neanderthal-introgressed gene variant associated with height and muscle mass in modern humans. The variant is located in a regulatory region near the IGF1R gene (insulin-like growth factor 1 receptor) on chromosome 6, a genomic region known to influence body size and muscle development across mammalian species. [Source: Nature Ecology & Evolution, Tier 1; Max Planck Institute for Evolutionary Anthropology, Tier 2]

The researchers analysed genomic data from the UK Biobank — a database containing genetic and health information from roughly 500,000 participants — and cross-referenced it with high-quality Neanderthal genome sequences from the Altai and Vindija specimens. They identified a specific haplotype (a cluster of genetic variants inherited together) that is absent from sub-Saharan African populations, present in Neanderthal genomes, and found in approximately 30% of people of European, Asian, and Native American ancestry. [Source: UK Biobank, Tier 1; Nature Ecology & Evolution, Tier 1]

Carriers of the variant were, on average, approximately 1.2 centimetres taller and had roughly 3% greater appendicular skeletal muscle mass (the muscle attached to the limbs) than non-carriers, after controlling for age, sex, and overall genetic ancestry. The effect size is modest at the individual level — 1.2 centimetres is within the range of normal variation — but statistically robust at the population level, where small average differences can have large cumulative effects. [Source: Nature Ecology & Evolution — supplementary data, Tier 1]

The mechanism appears to involve altered regulation of the IGF1R gene, which codes for a receptor that binds insulin-like growth factor 1, a hormone central to childhood growth, muscle development, and tissue repair. The Neanderthal-derived variant does not change the protein-coding sequence of IGF1R itself but appears to alter how much of the receptor is produced in muscle and bone tissue during development. [Source: Nature Ecology & Evolution, Tier 1; Science, Tier 1]

What It Actually Means

The finding is not, on its own, earth-shattering. A 1.2-centimetre height difference and a 3% muscle-mass difference are not the kind of effects that change how anyone lives their life. But the significance of the study lies in what it represents: the maturing of a field that has moved from broad generalisations about Neanderthal ancestry to specific, mechanistically characterised gene variants with measurable phenotypic effects.

This is the third act of the Neanderthal genetics story. Act one, roughly 2010–2015, was the discovery that Neanderthals and modern humans interbred, and that non-African populations carry 1–4% Neanderthal DNA. Act two, roughly 2015–2022, was the cataloguing of associations between Neanderthal DNA and various traits — immune function, skin and hair characteristics, pain sensitivity, susceptibility to certain diseases, and even mood and sleep patterns. Act three, which this study exemplifies, is the identification of specific gene variants, their molecular mechanisms, and their measurable effects in living populations.

The IGF1R finding is part of a broader pattern: Neanderthal gene variants that persist in modern human populations tend to be those that conferred some adaptive advantage — or at least did not confer a significant disadvantage — in the environments where modern humans encountered Neanderthals, roughly 50,000 to 60,000 years ago. Variants that were harmful were purged by natural selection. Variants that were neutral or beneficial persisted. The IGF1R variant's association with increased muscle mass suggests it may have been advantageous in the physically demanding environments of Ice Age Eurasia, though this is an inference, not a demonstrated fact. [Source: Annual Review of Genomics and Human Genetics, Tier 1; Cell, Tier 1]

The finding also sharpens a cautionary note about genetic determinism. Carrying the Neanderthal variant is associated with a small average increase in height and muscle mass. It does not guarantee either. The effect size is dwarfed by the effects of nutrition, physical activity, and the hundreds of other genes that influence height and body composition. A person without the variant who eats well and exercises will almost certainly be taller and more muscular than a person with the variant who does not. Genes are not destiny; they are nudges.

The Hype Deconstruction

The finding is real, but the way it is framed matters.

"Neanderthal gene makes people taller and more muscular" is true but incomplete. The variant is associated with a small average increase in height and muscle mass. It does not "make" anyone anything in a deterministic sense. The difference between association and causation is the difference between good science communication and misleading headlines.

The finding does not mean Neanderthals were giants. The Neanderthal-derived variant is one of many genetic influences on height and muscle mass. Neanderthals were, on average, shorter and stockier than contemporary modern humans — a body shape adapted to cold climates, consistent with Bergmann's and Allen's rules in evolutionary biology. The IGF1R variant may have contributed to their robust musculature, but it did not make them tall by modern standards. [Source: Journal of Human Evolution, Tier 1]

The 30% carrier frequency is interesting but not mysterious. Genetic variants that are present in 30% of a population are common — they are not rare mutations. The frequency suggests the variant was either neutral or mildly beneficial in ancestral environments. It does not suggest it is a superpower.

The study does not identify a "Neanderthal strength gene" in any meaningful sense. Muscle mass is influenced by hundreds of genes, plus nutrition, physical activity, hormones, and age. The IGF1R variant explains a tiny fraction of the variation in muscle mass between individuals. It is a piece of the puzzle, not the puzzle itself.

Stakeholder Landscape

Evolutionary biologists and geneticists are the primary audience for the finding, and for them it represents a methodological achievement — the identification of a specific archaic introgression with a characterised molecular mechanism and a measurable phenotypic effect. This is the kind of result that moves a field from correlation to mechanism.

The general public is likely to encounter the finding through headlines that overstate its significance. The gap between "Neanderthal gene variant associated with small increase in height and muscle mass" and "Neanderthal DNA makes you stronger" is the gap between science and science communication, and it is worth minding.

Direct-to-consumer genetic testing companies — 23andMe, AncestryDNA, and others — may incorporate the finding into their trait reports. Whether they do so responsibly (with appropriate caveats about effect size and determinism) or irresponsibly (with misleading claims about "Neanderthal strength") will affect how the finding is understood by the millions of people who have taken these tests.

The fitness and supplement industry has a history of co-opting genetic findings for marketing purposes. A "Neanderthal gene" associated with muscle mass is catnip for this industry. Consumers should be sceptical of any product that claims to activate, enhance, or compensate for Neanderthal genetic variants.

People of non-African ancestry who carry the variant now have a specific, named genetic contribution from Neanderthal ancestors — a small but tangible connection to a human lineage that disappeared roughly 40,000 years ago. The finding personalises the story of ancient interbreeding in a way that broad population statistics do not.

Cross-Layer Implications

The non-obvious connection here is to personalised medicine and pharmacogenomics. The IGF1R pathway is a target for drugs that treat growth disorders, muscle wasting, and certain cancers. If Neanderthal-derived variants affect IGF1R expression, they could — in principle — affect how individuals respond to drugs that target this pathway. This is speculative; no such effect has been demonstrated. But it is the kind of question that follows naturally from the finding, and it illustrates how ancient DNA research is increasingly relevant to contemporary medicine.

A second connection runs to the ethics of ancient DNA research. The Neanderthal genome was sequenced from the remains of individuals who died tens of thousands of years ago. The ethical frameworks for this research are still evolving, particularly regarding the treatment of ancient human remains and the interests of contemporary populations who may be descended from — or culturally connected to — the people being studied. The IGF1R finding is scientifically uncontroversial, but it sits within a field that is actively debating its own ethical foundations. [Source: Nature, Tier 1; American Journal of Human Genetics, Tier 1]

A third connection is to the concept of "archaic" traits in modern humans. The finding that a Neanderthal gene variant affects height and muscle mass in living people is a reminder that "archaic" and "modern" are blurry categories. Neanderthals are extinct as a distinct population, but fragments of their genome live on in billions of people. The boundary between "us" and "them" is less a line than a gradient.

What This Means for You

If you are a reader curious about your own Neanderthal ancestry: Direct-to-consumer genetic tests can tell you approximately what percentage of your genome is of Neanderthal origin, and some can tell you whether you carry specific Neanderthal-derived variants. The IGF1R variant is one of many. Carrying it — or not carrying it — tells you something small and specific about your evolutionary history. It does not tell you who you are.

If you are a scientist or science communicator: The finding is an opportunity to explain the difference between association and causation, between population-level effects and individual-level predictions, and between genetic influence and genetic determinism. These distinctions matter, and they are often lost in translation.

If you are a fitness professional or health coach: Clients may ask about "Neanderthal genes" and strength. The evidence-based answer is that the IGF1R variant is associated with a small average difference in muscle mass — roughly 3% — and that this difference is swamped by the effects of training, nutrition, sleep, and consistency. The genes are interesting. The work still matters more.

If you are a general reader: The finding is a reminder that human evolution did not stop when modern humans left Africa. It continued — through interbreeding with other human populations, through adaptation to new environments, through the slow churn of mutation and selection — and its traces are visible in your own genome. You are, in a small but measurable way, a living record of encounters that happened 50,000 years ago.

Uncertainty Ledger

What is still unresolved:

• Whether the IGF1R variant was actively selected for in ancestral environments, or whether it persisted through neutral drift.
• Whether the variant has effects beyond height and muscle mass — on metabolism, on ageing, on disease risk — that were not captured in the current study.
• Whether other Neanderthal-derived variants in the IGF1R regulatory region have similar or different effects.
• The functional mechanism — exactly how the variant alters IGF1R expression in specific tissues at specific developmental stages — is not yet fully characterised.

What would change the analysis:

• Functional studies in cell lines or animal models that demonstrate the molecular mechanism directly.
• Evidence that the variant affects response to IGF1R-targeting drugs, which would have clinical implications.
• Identification of additional Neanderthal-derived variants with similar or interacting effects on growth and body composition.
• Ancient DNA from additional Neanderthal individuals that clarifies how common the variant was in Neanderthal populations.

Bottom Line

A specific Neanderthal gene variant carried by roughly 30% of people outside sub-Saharan Africa is associated with being, on average, 1.2 centimetres taller and having 3% more limb muscle mass. The effect is small, the mechanism is plausible, and the finding represents a step forward in the maturing science of ancient human genomics — from broad generalisations about interbreeding to specific, mechanistically characterised variants with measurable effects in living people. The variant does not make anyone a Neanderthal, and it does not make anyone an athlete. It is a nudge, not a destiny — one of thousands of genetic nudges that, together with environment and behaviour, shape the bodies we inhabit.

Sources:

• Nature Ecology & Evolution — primary research publication (Tier 1)
• Max Planck Institute for Evolutionary Anthropology — research summary (Tier 2)
• UK Biobank — genomic and health data resource (Tier 1)
• Science — coverage and context (Tier 1)
• Annual Review of Genomics and Human Genetics — Neanderthal introgression review (Tier 1)
• Cell — ancient DNA and modern human evolution (Tier 1)
• Journal of Human Evolution — Neanderthal body shape and adaptation (Tier 1)
• Nature — ethics of ancient DNA research (Tier 1)
• American Journal of Human Genetics — ethical frameworks in ancient genomics (Tier 1)