Why does hair turn grey, and what can you do to slow down the process?

Cells at the base of the hair called melanocytes are responsible for producing the pigment that gives hair its colour. To do this, they need vitamin B12 and, in some cases, a deficiency in this vitamin can result in premature greying. However, once you pass the age of 30, the capacity of melanocytes to make pigment naturally begins to decrease, and they eventually burn out. The rate at which this happens is largely dictated by genetics, but smoking can also hasten the process. “Smoking depletes many vitamins in the body, and produces free radicals which can destroy cells,” says Lisa Gilbey, director of the Institute of Trichologists.

What about stress?

Marie Antoinette’s hair allegedly turned white in anticipation of her execution, and an immune condition called alopecia areata could have been to blame. It causes pigmented hairs to fall out, but spares grey hairs – giving the impression of rapid greying – and it can be triggered by stress in susceptible people. “You could go from looking pretty dark to blanched white over a few days,” says Des Tobin, director of the Centre for Skin Sciences at the University of Bradford.

Even if greying is inevitable, you can use some tricks to conceal it. “A good tip is to wear the hair down and forward rather than up, as white hairs are most often found around the hairline,” says Cos Sakkas, international art director at Toni & Guy in London. Temporary mousses or semi-permanent colours can be used to tone down and blend away greys, and strategic foil highlights or low lights can help to break up grey areas.

What causes split ends, and can they be repaired?

Split ends are the result of a hair shaft fracturing, usually due to excessive heat or chemical exposure. This leaves the hair dehydrated and less elastic – and more susceptible to breakage. Because long hair has been on your head for longer, it has often experienced more abuse than shorter hair, and therefore has more split ends.

Unfortunately, once you’ve got them, the only way to get rid of split ends is to cut them off. “Where the hair has split, the cuticle layer which normally protects the outside of the hair will not be present, so no product will fix this back together,” says Gilbey.

Does frequent washing make hair greasier?

No, but if you’re prone to greasy hair then vigorously massaging the scalp can stimulate oil production. In fact, frequent washing is more likely to dry hair out: “Your body wasn’t designed to undergo daily washing of the scalp with detergent, which is what shampoos are,” says Tobin. “Often we use conditioners to put back something that has been lost.”

However, conditioners can themselves make hair appear greasier because they smooth the cuticle – the scaly, outermost layer of hair – meaning grease travels down the hair faster. For this reason, conditioner is best used on the mid-lengths and ends only.

Does unwashed hair eventually clean itself?

In theory, hair should act as a wick; drawing oil and dirt away from the scalp and finally rubbing off on your pillows, clothes, and any other surfaces your hair touches. But this is less likely to work if you have long hair, and not washing hair for long periods can be unhygienic. “We all have micro-organisms living on our scalp which can cause itchiness and scaly scalp complaints if they are left to breed,” Gilbey explains.

Does plucking make hairs grow back thicker or in greater quantities?

“Pluck one grey hair, grow back two,” goes the adage. But hair follicles only produce one hair, and there’s no evidence in humans that plucking stimulates more hairs to grow. If anything, it’s likely to do the opposite: “Persistent plucking causes the hair follicle to die and eventually leads to permanent hair loss” says Bessam Farjo, co-founder of the Farjo Hair Institute in Manchester and medical director of the Institute of Trichologists. “This is commonly seen with eyebrows, which can become thin after years of being plucked. There is no difference when it comes to grey hairs, as the hair follicle structure is the same.”

However, in certain situations, injury to the skin and underlying tissue can stimulate hair to grow: for instance, people who have broken a bone sometimes report hair growing back thicker in the area surrounding the break. And recent studies in mice have suggested that certain patterns of plucking may trigger hair growth, although the process isn’t yet fully understood.

What causes baldness?

It depends. Hair grows in cycles, and being stressed or unwell can sometimes provide a shock that temporarily triggers more of it to enter the shedding phase. Then there’s pattern baldness, which accounts for more than 95% of hair loss in men and is also the most common cause of hair loss in women. The hair follicles on the scalp are sensitive to the hormone testosterone (which is also produced by women). “Testosterone causes miniaturisation of the follicles, which in turn produces finer and shorter hairs,” explains David Fenton of the British Association of Dermatologists.

Just how sensitive your follicles are is determined by your genetics; if lots of your ageing relatives have lost their hair then you are more likely to go bald yourself. Although there’s no cure for pattern baldness, you can slow down its progression. Propecia is a drug that is available on prescription, while Regaine is a lotion that can be bought over the counter. Both slow down this miniaturisation process.

Can anything make your hair grow faster?

A hundred strokes a day might have been the formula your granny espoused, but heavy brushing can do more harm than good. While some brushing is necessary to remove tangles, and can help draw protective oil along hair strands, “if anything, brushing will stress the hair”, says Tobin. Like greying, the rate at which your hair grows is determined by your genes. Careful massaging can increase blood flow to the scalp and boost the supply of oxygen and nutrients, but “it will not increase the speed of hair growth,” says Gilbey. However, consuming protein-rich foods such as flax seeds, walnuts, fish and avocados should help your hair, Farjo adds.