I am a 45-year-old woman. How can I prevent my hair from turning grey or white? Do hair, skin and nail supplements work?

Grey hair occurs as a natural process of chronological ageing.

The onset of grey hair varies with a person’s ethnicity.

Generally, Caucasians begin to have grey hair in their mid-30s, Asians in their late 30s and Africans in their mid-40s.

If the greying occurs before the age of 20 in Caucasians, 25 in Asians and 30 in Africans, it is considered premature greying.

At 45, a person can expect to have a certain amount of grey hair. Both men and women are equally affected.

The colour of human hair is due to a process called melanogenesis. This is the production of melanin, a pigment that gives colour to our hair and skin.

Human hair follicles contain two types of melanin. The black-brown pigment, called eumelanin, is mainly present in black and brown hair. The yellow or red pigment, called pheomelanin, is present in blonde and auburn hair.

Grey hair occurs due to the loss of these pigment molecules, but the cause is not completely understood.

Genetic influence is considered to play a role.

Treatment options for grey hair are limited. The consumption of nutritional supplements containing various combinations of vitamins and minerals lacks rigorous scientific levels of evidence.

Similarly, the effectiveness of various over-the-counter lotions and shampoos that are marketed as being able to prevent hair from turning grey has not been validated in scientific literature.

The camouflage technique of using hair dyes remains the mainstay of therapy.

Hair dyes include temporary dyes (textile dyes), natural colouring (henna), and semi-permanent and permanent dyes. These natural or synthetic dyes are effective in concealing grey hair.

However, a significant number of people in Singapore develop an allergy to hair dyes – in particular, black colour dyes – due to the chemical, paraphenylenediamine (PPD).

The allergy may cause an itch, swelling or rash along the hairline, neck and face. If this happens, it is important to consult a dermatologist, who can conduct investigations and prescribe treatment.

An allergy to PPD may make a person sensitive to other related compounds. Once the allergy is confirmed, the person should avoid these substances.

By: Dr Oh Choon Chiat, Associate Consultant, Dept of Dermatology, Singapore General Hospital