Frequently asked questions

Hair turns grey when your genes tell the pigment-producing cells in your hair follicles to stop making melanin. Each individual strand gets its own signal. So let's say you've had a head full brown hair all your life. One day, as part of its natural growth cycle, one of those brown hairs falls out. When it re-enters its growth phase, it gets the signal from your DNA to skip the melanin and come back as a grey hair. Over time, more and more hairs get their "grow grey" signal, and eventually, you've got yourself a head of grey hair. On average, that process starts around age 30 for most Caucasians, mid-thirties for Asians, and around 40 for people of African descent.

Are you sitting down? All grey hair is actually white. Before you go entirely white, your hair is a combination of unpigmented and pigmented hairs. "A white hair is often laying against another hair that's darker," says P&G principal scientist Jeni Thomas, "and what your eye sees is the combination of those hairs, which appears 'grey.'"

Just like a white T-shirt is a magnet for stains, so is white hair. "Environmental elements, like smoking, pollution, hard water, plus product buildup, can leave a residue on your hair that makes your hair look dull and yellow," explains Estridge. "You've always had that residue," explains Thomas, "but if your hair is brown or red, the pigment had disguised the residue. Because grey hair is unpigmented, you see the residue as yellowness." (In blondes, the residue reads as "brassiness.")

The other issue is that grey hair is more vulnerable to free radical damage caused by the sun. Just as darker-pigmented skin does a better job of absorbing UV rays, so too does darker-pigmented hair. "When you don't have pigment in your hair, your hair is just more exposed," says Thomas. "A damaged hair fiber won't reflect light as brilliantly, so hair can take on a dull, yellow cast."

While the solution to brighter whites in your laundry is bleach, that's not the way to brighter hair. "Purple pigments cancel out yellow tones," explains James Corbett, aka The Gloss Boss and founder of the James Corbett Studio in NYC, "so reach for a purple shampoo and purple conditioner." Try Hair Biology Silver & Glowing Shampoo, a shampoo for grey hair, which resolves the grey from every angle: It gently but effectively cleanses to remove the dulling and yellowing residue; it's purple-hued to counteract any yellow tones; and it's infused with biotin, to help strengthen hair and make it more light-reflective. Follow up with Hair Biology Silver & Glowing Conditioner, which also has the balancing purple pigments and biotin. The duo works for every hair type and can be used once a week or as needed to make your white strands crisp and sparkling. (Psst: If you're a blonde, they also cut the brassy tones, so use this combo if you want to maintain a cool, ashy blonde.)

Well, that's a grey area. "You talk to people, and they'll say, 'Oh, those wiry greys.' And they'll pick one out, and they'll say. 'It's always the greys that are the wiry ones,'" says Thomas. "And I would say there's still the question: Is it really the greys that are the wiry ones, or are they just the most noticeable ones because you see them in contrast to the pigmented hairs?" As we get older, our scalp produces less sebum, or oil, that keeps our strands soft and pliable; all the hairs on our heads will become more dry and wiry. That grey hair has a reputation for being coarser may just be poor timing and bad PR.

But whether it's all-over texture changes or indeed the greys are more problematic, the solution is the same: "A deep conditioning treatment can keep your hair properly hydrated," says Corbett. To control the wiry ones when you style, try Hair Biology Argan Oil Taming Serum, a weightless hair smoothing serum that controls frizz while adding shine.