Why Your Hair Grows in a Spiral — And What Your Birthplace Has to Do With It

FEATURE – What if the direction your hair grows in isn't down to chance, or even your hairdresser — but to where you were born? That's the surprising conclusion of a scientific study by French researchers, which earned them an Ig Nobel Prize in Anatomy.

Table of Contents

1. A study that makes you smile… then think
2. The Ig Nobel Prizes: when science goes off the beaten track
3. The subject: why hair grows in spirals
4. The researchers behind the discovery
5. How the study was conducted
6. What the results actually show
7. What this tells us about hair
8. What this study does not say
9. Key takeaways
10. Sources

1. A study that makes you smile… then think

Every year, certain scientific studies attract attention not because they promise a new drug or a medical breakthrough, but because they ask questions nobody had really thought to ask.

Why do almost all of our hairs form a spiral on the scalp? Why does that spiral turn one way rather than the other? And crucially: why might the direction vary depending on where you live?

These are precisely the questions a group of French researchers set out to answer — eventually earning themselves an Ig Nobel Prize.

2. The Ig Nobel Prizes: when science goes off the beaten track

The Ig Nobel Prizes are awarded each year to research that "first makes you laugh, then makes you think." Despite the name, they don't reward bad science — they celebrate serious work that tackles unexpected subjects.

Behind the humour, the message is clear: science also explores the small details of everyday life, sometimes the most mundane ones, in pursuit of a deeper understanding of the human body.

3. The subject: why hair grows in spirals

In the vast majority of humans, hair doesn't grow in perfectly straight lines. It forms one or more hair whorls, typically located at the back or crown of the scalp.

These whorls can turn:

• clockwise,
• or counterclockwise.

Long considered a simple anatomical curiosity, they are actually of real scientific interest — because they are linked to developmental biology, the study of how our bodies form during embryonic life.

4. The researchers behind the discovery

The study awarded the Ig Nobel Prize in Anatomy was led by, among others:

• Roman Khonsari, craniofacial surgeon at Hôpital Necker – Enfants Malades (Paris),
• Marjolaine Willems, medical geneticist at the CHU of Montpellier.

Their work is firmly rooted in serious research on the genetics and development of the skull and scalp.

5. How the study was conducted

To determine whether the direction of hair whorls is random or not, the researchers observed:

• the rotation direction of hair whorls in individuals from different regions of the world,
• comparing people born in the Northern Hemisphere with those from the Southern Hemisphere.

The goal: to identify any statistical tendency based on geographic location — which would suggest a genetic or developmental influence rather than pure chance.

6. What the results actually show

The findings, while surprising, are clear:

• the direction of hair whorl rotation is not distributed randomly,
• there are statistically significant differences between populations from the Northern and Southern hemispheres,
• these differences suggest that whorl formation is partly genetically determined.

In short: depending on where in the world a person develops, there is a different probability of hair growing clockwise or counterclockwise.

7. What this tells us about hair

This research has nothing to do with hair loss per se — but it serves as a useful reminder: hair is far more than an aesthetic accessory. Its implantation, orientation, and structure are the result of complex biological mechanisms, shaped by:

• genetics,
• embryonic development,
• and possibly environment.

Understanding these mechanisms helps researchers better grasp certain scalp anomalies, malformations, and more complex developmental conditions.

8. What this study does not say

To be clear:

• this study cannot predict hair loss or baldness,
• it offers no solution to stimulate regrowth,
• and it doesn't challenge the hormonal or genetic causes of alopecia.

Its value is primarily fundamental and scientific, not therapeutic.

9. Key takeaways

• The direction of hair growth is not entirely random.
• A French study awarded an Ig Nobel Prize shows differences linked to where a person develops.
• Hair whorls are influenced by genetics and developmental biology.
• This is serious research, despite its unusual subject matter.
• It illustrates just how scientifically complex hair really is.

10. Sources

• Journal of Stomatology, Oral and Maxillofacial Surgery – "Genetic determinism and hemispheric influence in hair whorl formation"
• Annals of Improbable Research – Ig Nobel Prize in Anatomy
• Official Ig Nobel 2024 communications
• Publications and communications from R. Khonsari and M. Willems