A change in diet or the treatment of an underlying health condition may restore the lustre to a woman's hair - but options for men are limited.
More than 90 per cent of hair loss in men is caused by what Dr Riad Roomi, a specialist in hair restoration surgery, calls the baldness gene.
The condition results when dihydrotestosterone (DHT) produced by the skin attacks the hair follicles.
"Before a person is born it is decided if they're going to get the baldness gene or not," Dr Roomi said. "The hair follicle is programmed at the minute of conception."
To determine whether hair loss is caused by genetics or outside factors, experts look for a pattern.
The follicles that carry the baldness gene are found only at the front and crown area of the head. This is why balding men do not usually lose the hair on the side of their heads. The follicles have receptors that attract DHT, which then attacks them, causing hair loss.
The condition, androgenetic alopecia, is found in both sexes at roughly the same rate. But it is less visible in women, Dr Roomi said, because the female hormones oestrogen and progesterone keep the DHT at bay.
The earlier the gene acts, the more quickly it progresses, said Dr Sajjad Haider Khan, a hair restoration surgeon at Medcare Hospital in Dubai.
"If a man starts losing his hair in his early 20s, he could lose it all within 10 years," he said. "If he starts losing it in his 50s, it can take 30 years."
A number of natural lotions claim to block DHT and can be used with laser treatment to stimulate hair growth. There are two FDA-approved drugs that prevent further hair loss, minoxidil and finasteride.
Minoxidil, available over the counter, works as a DHT blocker, preventing the hormone from working on the follicle. Finasteride, originally used to treat enlarged prostate glands, inhibits DHT production and only works for men.
Seventy per cent of individuals who use the drugs from an early stage are successful in preventing hair loss, Dr Khan said. But the drugs must be taken continuously and both have potential side effects. Minoxidil can cause redness and itching, while finasteride causes reduced libido.
"If I get a young, unmarried man, I tell him it is unlikely to cause any problems for the first five to seven years," Dr Roomi said. "Then stop, perhaps at that point hair is not an issue or a new treatment develops."