Last updated: October 2026
Yes, stress can speed up greying, but it is rarely the main cause. Genes and age decide most of it. A 2020 mouse study showed how acute stress can wipe out the cells that colour hair, and a small 2021 human study found some stress-linked grey hairs regained colour once stress eased. Most greying is permanent.
Below: what the research actually shows, why hair goes grey, what counts as premature greying, other causes worth ruling out, whether grey hair can be reversed, and when to see a GP.
The short version: stress is a real but small part of the story. Going grey in your 20s? Look at your parents first. Early greying with tiredness, pins and needles or white skin patches is worth a GP blood test.
Does stress really cause grey hair? What the research shows
People have blamed shocks and hard times for grey hair for centuries, but the science only arrived recently.
The 2020 Harvard mouse study
Harvard researchers found that acute stress turned mice grey by rapidly using up their melanocyte stem cells, the reserve that supplies new pigment cells to each hair follicle. The stress hormone cortisol was not the driver: mice still went grey with their adrenal glands removed. Instead, the sympathetic (“fight or flight”) nerves released a burst of noradrenaline into the follicle, which made the stem cells activate all at once and then disappear for good. The greying was permanent, but this was mice under severe stress, so it doesn’t tell us how much everyday stress greys human hair.
The 2021 study on human hair
A Columbia University team studied 397 hairs from 14 healthy people aged 9 to 65. Hair grows about 1cm a month, so they could read each hair like a timeline and match colour changes to the donors’ own ratings of their stress over the same months.
Some grey hairs had naturally regained their colour. In one person, a group of hairs went grey during a stressful period and regained colour after a two-week holiday, when stress was at its lowest for the year. The researchers’ model suggests a threshold: hairs already close to going grey may tip over early under stress, and may come back once it passes. It is a small study, but the best human evidence we have.
So stress looks able to bring greying forward, mainly in hairs that were heading that way anyway. It also affects hair in other ways, such as extra shedding: see stress and hair loss.
Why hair goes grey
Hair gets its colour from melanin, made by pigment cells at the base of each follicle. With age these cells run down, the stem cell reserve that replaces them shrinks, and hairs grow through with less pigment or none. A head of “grey” hair is usually a mix of white and coloured hairs.
Pigment is only added while a hair is growing inside the follicle, so the hair you can see can’t change colour overnight. Timing varies a lot: a review in the International Journal of Trichology gives the average age greying starts as about 34 in white people and about 44 in Black people, and only 6% to 23% of people are half grey by 50.
Going grey in your 20s: what counts as early
Doctors call greying “premature” when it starts well before the usual age for your ethnic background.
| Background | Greying counts as premature if it starts before |
|---|---|
| White | 20 |
| Black | 30 |
| South Asian | about 25 (suggested by some authors; there is no agreed cut-off for Asian people) |
Why am I going grey at 25? Usually your genes: early greying runs in families, and in 2016 a UCL-led study of over 6,000 people reported the first genetic markers linked with greying. Smoking, some medical conditions and possibly stress can bring it forward. A few grey hairs in your 20s are common and rarely a worry on their own (see when to see a GP).
Other causes of early grey hair
Reviews of premature greying list several things linked with it. Some are fixable, which matters if you’re hoping to keep your colour.
| Cause | What we know | Can colour come back? |
|---|---|---|
| Genes and family history | The main cause of early greying | No |
| Smoking | Studies consistently link smoking with earlier greying, probably through oxidative damage to pigment cells | Unlikely, but stopping is worth it anyway |
| Vitamin B12 deficiency | In one older study, 55% of people with pernicious anaemia had gone grey before 50, against 30% of people without it. See B12 deficiency symptoms | Sometimes, once the deficiency is treated |
| Thyroid problems | Low thyroid hormone is linked with early greying, hair loss and hair changes. See underactive thyroid symptoms | Sometimes, with treatment |
| Vitiligo | The NHS says the lack of melanin can turn hair in affected areas white or grey, usually in patches | Ask a GP or dermatologist |
| Low iron, vitamin D or copper | Small studies have found lower ferritin, vitamin D or copper in people who greyed early, but results are mixed. See iron deficiency and vitamin D deficiency | Not proven |
| Stress and oxidative stress | Mouse research shows a clear route; human evidence is limited | Sometimes, for hairs near the threshold |
Stress shows up in many other ways first, from poor sleep to tension headaches. See stress symptoms for the full list.
Grey hair in men and grey beards
Men and women grey for the same reasons, mostly inherited, and there is no good evidence that stress greys men faster. Grey hairs tend to be coarser than coloured ones, and the same review notes that grey beard hairs can grow up to four times faster than pigmented ones, which is why a few can stand out so much. If you’re a man under pressure, sleep, blood pressure and burnout are bigger worries than hair colour: see stress in men and burnout symptoms.
Can grey hair be reversed?
Usually not, with two honest exceptions:
- A deficiency or thyroid problem. The review notes that treating low B12 or an underactive thyroid can reverse the greying. This only applies if a blood test shows you are actually deficient.
- Stress-linked hairs near the threshold can regain colour when stress drops, as the 2021 study showed. Hairs that have been white for years are very unlikely to.
Age-related and genetic greying is permanent. TikTok and Reddit are full of supplements, oils and serums said to reverse grey hair, but the review found that vitamins and minerals often given for it, such as biotin, zinc, copper and selenium, have not shown promising results. Where a supplement seemed to work, it was most likely correcting a real deficiency.
Grey hair myths
- “Pluck one grey hair and two grow back.” False. Each follicle makes one hair, and the hair that regrows will still be grey. Repeated plucking can damage the follicle, so snip it instead.
- “Stress can turn your hair white overnight.” Not literally. A rare condition called canities subita describes hair that seems to whiten suddenly. It has been linked with alopecia areata and other sudden hair shedding, which can leave grey hairs that were already there far more visible. See why is my hair falling out?
- “Everyone is half grey by 50.” No, only a minority are.
What you can do
- Check your family history. If your parents went grey early, there’s not much to fix, and that’s fine.
- Don’t smoke. It is one of the clearest lifestyle links with early greying.
- Rule out deficiencies if greying is early and you have other symptoms. A GP can check B12, folate, iron and thyroid. Don’t take high doses “just in case”: see vitamin B12 supplements for who needs them.
- Look after your stress levels for your sleep, skin and mood, even if it only saves a few hairs. Start with how to relieve stress, how to lower cortisol naturally and sleep deprivation.
- Colour it, or embrace it. If you dye, do the patch or strand test on the box every time.
A calm evening routine helps when life is busy. Our Magnesium Glycinate Sleep Complex is a caffeine-free evening drink with L-theanine, and magnesium contributes to normal psychological function and to a reduction of tiredness and fatigue. Some people take our Flow CBD Oil, with ashwagandha and maca, as part of their day. Neither product is for hair, and no supplement has been shown to stop or reverse greying. The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
When to see a GP
Grey hair on its own isn’t a reason to see a doctor. Book a GP appointment if:
- you are going grey before 20 (or 30 if you’re Black) and no one in your family did
- greying comes with tiredness, pins and needles, a sore or red tongue or memory problems, which can be signs of low B12
- you also have unexplained weight changes, feel unusually cold or hot, or have a fast or irregular heartbeat, which can point to a thyroid problem (see overactive thyroid symptoms)
- you notice white patches on your skin, or white hair in one patch
- your hair is suddenly falling out in clumps or patches
- a child has grey or white hair
If stress is affecting your sleep, work or mood, that is worth talking to a GP about too, whatever your hair is doing.
FAQs
Does stress cause grey hair?
It can speed it up. Mouse research shows acute stress can destroy the stem cells that colour hair, and a small human study linked some grey hairs to stressful periods. But genes and age cause most greying.
Can grey hair from stress be reversed?
Sometimes. A 2021 study found some hairs that went grey during stress regained colour when stress eased. This seems to apply only to hairs close to going grey anyway, not hairs that have been white for years.
Is it normal to have grey hair at 25?
Yes, a few grey hairs at 25 are common and usually down to genes. In white people greying only counts as premature before 20, and in Black people before 30. See a GP if it comes with other symptoms.
Does plucking a grey hair make more grow?
No. Each follicle grows one hair, so plucking can’t make more appear. The new hair will still be grey, and repeated plucking can damage the follicle, so snip it instead.
Can vitamin B12 deficiency cause grey hair?
Yes, B12 deficiency is linked with early greying, and colour can sometimes return once it is treated. Extra B12 won’t help if your levels are already normal, so ask your GP for a blood test.
Can stress turn your hair grey overnight?
No. The hair above your scalp can’t change colour. Rare cases of sudden whitening have been linked with conditions that cause sudden shedding, such as alopecia areata, which can leave existing grey hairs more visible.
Sources
- Zhang B, et al. Hyperactivation of sympathetic nerves drives depletion of melanocyte stem cells. Nature, 2020.
- Rosenberg AM, et al. Quantitative mapping of human hair greying and reversal in relation to life stress. eLife, 2021.
- Kumar AB, et al. Premature graying of hair: review with updates. International Journal of Trichology, 2018.
- Adhikari K, et al. A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features. Nature Communications, 2016.
- NHS. Vitiligo.
- UAMS Health. Does pulling one gray hair cause more to grow in its place?
This guide is general information, not medical advice. Evopure makes the Magnesium Glycinate Sleep Complex and Flow CBD Oil. Neither is intended to affect hair colour.
