Key takeaways
- Greying is 60–90% genetic — set at conception.
- Chronic stress can accelerate it; recent research shows it's partly reversible.
- There's no proven supplement or serum that reverses grey hair.
- "Overnight greying" from shock is a myth; the timeline is longer.
What actually causes grey hair
Hair follicles contain pigment-producing cells called melanocytes. Over time, these cells accumulate damage, produce less pigment, and eventually stop. When they stop, the hair that grows out is white or silver — the natural colour of unpigmented keratin.
The main driver is genetics. If your parents went grey at 40, you probably will too. If they held their colour to 60, so will you, most likely.
The role of stress — real, but limited
A 2020 Harvard study found that acute stress can, in mice and possibly humans, temporarily deplete melanocyte stem cells. There's evidence in some individuals of partial reversibility once the stress passes.
But this doesn't mean stress "causes" grey hair in most cases. Genetics still dominates. Managing stress is a good idea for many reasons; expecting it to restore your childhood hair colour is not one of them.
A little grey at 40 is not a crisis. It's biology. Nothing has gone wrong.
— Nadia Farooq
What people try, and what actually works
The supplement industry sells hope in a bottle. Catalase. B vitamins. Peppercorn extracts. Copper. There is no supplement with credible evidence of reversing established grey hair in a healthy adult.
- What has some evidence: correcting a documented B12 or copper deficiency, addressing acute severe stress
- What has none: most anti-grey supplements, hair "detoxes," or scalp serums
- What always works: dye, or the confidence to leave it alone
The cultural piece
A generation ago, going grey was near-universally hidden. Now, silver hair is having a cultural moment. The choice between colouring and letting it come through is genuinely just a preference — no health consequence either way.
Both are fine. Neither is virtuous.
The takeaway
Grey hair is 90% genetics and biology, gently modulated by stress and nutrition. There is no miracle reversal. If you dislike it, dye it. If you're okay with it, don't. Save the supplement money for something that has evidence — like our Mediterranean plate guide.
