The Study
Non-Identity of Gray Hair Produced by Mineral Deficiency and Vitamin Deficiency
This study looked at some rats and noticed their gray hair turned black after giving them extra minerals. But we don’t know if it was really the minerals, or if the rats were treated the same, or if this would even happen in people. So we can’t say the minerals caused the change.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Scientists gave special minerals to gray rats and their fur turned black again. Other rats that didn't get the minerals stayed gray.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 58 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This suggests minerals might affect hair color in animals, but it's not clear if it works the same way in humans.
- 2Gray rats became black after mineral supplements; control rats stayed gray.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Proceedings of the Society for Experimental Biology and Medicine
Year
1940
Authors
A. H. Free
Related Content
Claims (3)
People whose hair turns gray too early often have lower levels of iron, zinc, and copper in their bodies compared to people whose hair grays normally.
Scientists found that when rats were given extra minerals, their gray hairs turned back to black—but rats that didn’t get the minerals stayed gray.
In rats, if they drink less of the kind of milk that doesn’t have many vitamins, their fur might turn gray — it’s like their body isn’t getting enough good stuff, and that could show up as gray hair.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.