Neanderthal Genes May Still Be Shaping Human Strength, New Study Finds

For decades, Neanderthals have often been portrayed as the muscular cousins of modern humans—built for survival in Ice Age Europe with broad chests, powerful limbs, and exceptional physical endurance. Now, scientists have discovered that a small piece of their genetic legacy may still be influencing the bodies of some people living today.

A new international study has revealed that a Neanderthal version of the growth hormone receptor (GHR) gene can increase muscle development in modern humans. The findings suggest that ancient DNA inherited through interbreeding thousands of years ago continues to shape human anatomy, providing fresh insights into evolution, genetics, and physical performance.

Ancient DNA That Never Truly Disappeared

Neanderthals disappeared as a distinct human species around 40,000 years ago, but they never vanished completely. When early Homo sapiens migrated out of Africa, they interbred with Neanderthals living across Europe and Asia. As a result, most people of non-African ancestry still carry around 1–2% Neanderthal DNA in their genomes.

Scientists have spent years identifying which inherited genes remain active and what they actually do. Some influence immunity, others affect skin pigmentation, sleep patterns, or metabolism. The latest research adds another important trait to that growing list: muscle growth.

The Growth Hormone Receptor Makes the Difference

Researchers focused on the Growth Hormone Receptor (GHR), a protein found on the surface of cells that responds to human growth hormone. This receptor plays a critical role in regulating growth, bone development, tissue repair, and muscle formation throughout life.

The team discovered that Neanderthals carried a unique version of this receptor containing subtle genetic differences from the version found in most modern humans. Although the changes involve only a few amino acids, laboratory experiments showed they significantly increase the receptor’s response to growth hormone.

When scientists inserted the Neanderthal receptor into cultured cells, those cells grew roughly 40% faster after exposure to growth hormone compared with cells carrying the modern human receptor. This provided direct biological evidence that the ancient variant remains highly functional today.

More Than One Million People Were Studied

To understand whether this effect also appears in real populations, researchers analyzed genetic and health information from more than 1.13 million individuals across multiple international biobanks, making this one of the largest studies ever conducted on inherited Neanderthal traits.

The results consistently showed that people carrying the Neanderthal GHR variant tend to have:

1. Greater lean muscle mass throughout the body.
2. Slightly taller average height.
3. Wider hip measurements.
4. Subtle differences in jaw shape and tooth structure.

Importantly, these differences are relatively small and do not dramatically alter a person’s appearance. Most carriers would never know they possess the ancient genetic variant without DNA testing.

Stronger Muscles—But Not a Shortcut

Despite the headlines, researchers emphasize that inheriting the Neanderthal receptor does not automatically make someone stronger or more athletic.

Muscle development still depends primarily on exercise, nutrition, overall health, and lifestyle. The ancient gene simply appears to make the body’s growth hormone signaling slightly more efficient, giving carriers a modest biological advantage rather than replacing the need for training.

Scientists involved in the study stressed that even with Neanderthal genetics, regular physical activity remains essential for building strength.

A Window Into Human Evolution

Beyond fitness, the research provides valuable clues about why Neanderthals developed such robust physiques.

Living in Ice Age Europe required enormous physical endurance. Hunting large animals, surviving harsh winters, and adapting to extreme environments likely favored stronger bodies. The enhanced growth hormone receptor may have been one of several genetic adaptations that helped Neanderthals thrive under these demanding conditions.

Today, fragments of those same adaptations continue to influence certain populations long after Neanderthals disappeared as a separate species.

Where Is the Gene Found Today?

The Neanderthal GHR variant is not evenly distributed worldwide.

Researchers estimate it appears in only a small percentage of Europeans but is considerably more common among East Asian and South Asian populations, reflecting the complex history of ancient human migrations and interbreeding after modern humans left Africa.

What Comes Next?

Scientists believe this discovery is only the beginning. Many Neanderthal genes remain poorly understood, and future studies may uncover additional links between ancient DNA and modern health, metabolism, immunity, aging, or disease resistance.

As genomic databases continue expanding, researchers expect to identify more inherited traits that connect present-day humans with our extinct relatives, offering an increasingly detailed picture of how ancient evolution still shapes modern biology.

Rather than viewing Neanderthals as a completely separate chapter in human history, studies like this reveal that parts of their biology continue to live on inside millions of people around the world.