Melatonin and sleep supplements: what works — and what is marketing

None

They are in every pharmacy and supermarket: melatonin, valerian, magnesium, chamomile, "sleep formulas" with cloud-shaped names. People sleep badly and the market responded. But what does the evidence actually say about each? Less than the labels promise — and it is worth knowing exactly what.

Melatonin: useful, but for the right problem

Melatonin is not a sleeping pill — it is a timing signal: it tells the body clock "night is coming". That is why it works reasonably well for problems of timing: jet lag, some support in shift work, and the late sleep onset of people whose clock runs behind. For typical chronic insomnia — the mind that will not switch off, waking in the early hours — the average effect in studies is modest: it shortens sleep onset by a few minutes. Practical notes: a low dose (0.5-2 mg) taken 1-2 hours before bed tends to work better than high doses at bedtime, and supplement quality varies enormously.

The others on the label

• Valerian — inconsistent results in studies; where it helps, the effect is small. Safe for most people in short-term use.
• Magnesium — weak evidence, except in people with a genuine deficiency. Not the miracle the social media videos claim.
• Chamomile, passionflower, hops — a mild calming effect is possible; as a relaxing ritual, worthwhile; as treatment, no.
• "Sleep formulas" — blends of the above, usually at low doses. Mostly you are paying for the packaging.

Two warnings

First: supplement does not mean harmless — melatonin and valerian interact with some medications (anticoagulants, antidepressants, anxiolytics); anyone on regular medication should speak to their doctor or pharmacist. Second: if you have used supplements every night for months "because without them I cannot sleep", the problem is no longer biochemical — it is conditioned insomnia with a ritual on top, and that is treated differently.

What actually treats insomnia

CBT-I remains the first-line treatment for chronic insomnia — more effective than any supplement, and than medication itself over the long term. In HICOA's Sleep Better Programme we combine it with hypnotherapy and, where needed, psychiatric support. Online or in Matosinhos.