Melatonin is known as the hormone that is vital for sleep, but it may also cut your risk of cancer, help prevent Alzheimer's and Parkinson's, and reduce the sagging skin and thinning hair that accompany ageing.
Melatonin works by helping to break down the body's active and energetic hormones, slowing brain activity and allowing us to rest.
But researchers now believe the hormone - found in walnuts, grapes and porridge - could protect against the potentially harmful magnetic fields created by power cables, reduce cholesterol, boost the immune system and help children suffering from autism.
You don't hear much about melatonin's bid for super hormone status in Britain because, unlike in the U.S., where it can be bought over the counter in supplement form, here, the drugs watchdog, the MHRA, has ruled it should be prescription only.
However, from this month, you will be able to buy a weaker melatonin herbal supplement.
But you may not need supplements: keeping artificial light to a minimum in the bedroom could do the trick. The hormone, made by the pineal gland in the brain, can be produced only in darkness.
Female night shift workers have low levels of melatonin and a significantly raised risk of breast cancer. So do airline stewardesses, whose rhythms of sleeping and waking are disturbed.
On the other hand, blind women, who can't see light, are 50 per cent less likely to have breast cancer.
Melatonin's anti-cancer effect may be down to the fact it is a powerful antioxidant - five times more potent than vitamin C - that mops up free radicals linked to cancer.
Experts have found there is something in the blood of women who have had a good night's sleep that can slow tumour growth dramatically.
And there's mounting evidence to suggest disruption of the melatonin rhythm may also lead to chronic fatigue and depression.