Magnesium or melatonin: which one really helps you sleep?

Magnesium and melatonin always come up in the same conversation, as if they were alternatives for the same thing. They are not. One regulates your body's clock; the other helps muscles relax. Here I explain what each does, when it makes sense, and why neither should be the first thing you change.

What melatonin does

Melatonin is a hormone your body already produces. It rises when it gets dark and tells your brain it's night. This is what regulates the sleep-wake cycle.

As a supplement, melatonin is not a sedative. It doesn't "turn you off." What it does is anticipate the signal of night. Therefore, it mainly helps when your internal clock is out of sync: jet lag, shift work, or the tendency to fall asleep and wake up too late.

Natural production also decreases with age, which explains why some older people notice a difference. Low doses, around 0.5 to 1 mg, are usually sufficient. More is not better. Timing matters more than quantity: taken close to bedtime, at regular hours.

What magnesium does

Magnesium is a mineral, not a hormone. It participates in hundreds of bodily processes, including muscle and nerve function. It helps muscles relax.

In practice, magnesium makes more of a difference to those with low levels. If you have cramps, restless legs, or muscle tension at night, it might be worth it. The forms most associated with sleep are glycinate and bisglycinate, typically between 200 and 400 mg.

The evidence is more modest than much advertising suggests. Magnesium does not put anyone to sleep. It creates conditions for a more relaxed body, and the rest follows from there.

Which to choose, after all

It depends on your problem, not the trend.

If your problem is rhythm — you fall asleep late, you've changed time zones, you do shift work — melatonin is what makes sense to try. If your problem is tension — cramps, tense muscles, agitation — magnesium is the more logical candidate.

And if you don't know what your problem is? That's precisely the sign that neither of them is the first step.

Neither is the first line of defense

I see many people buying supplements before changing the basics. It's the other way around. A supplement, at best, refines. It doesn't fix a room with too much light, a phone in bed, or a mattress that no longer supports you.

Before thinking about magnesium or melatonin, address your environment and routine. You have the complete list in our sleep hygiene guide with 12 habits, and a simple technique to calm down before sleeping in the 4-7-8 method. If you want to delve deeper into the topic of supplements in general, I wrote about what works and what is placebo.

And the basis of everything is physical: the mattress where you spend a third of your life. If you suspect yours is no longer helping, the guide to choosing the ideal mattress will help you understand.

Before taking either

Melatonin is regulated, and not all doses are freely sold. Excess magnesium has effects, especially intestinal ones. Neither is indicated for everyone.

If you are pregnant, breastfeeding, taking medication, or have a health condition, speak to your doctor or pharmacist before starting. This does not replace medical advice.

If the doubt is about the physical side of sleep — mattress, pillow, position — that part is my expertise. Call me and in ten minutes I'll help you understand what makes sense: +351 21 150 95 04.

See also

Ana Cristina, Dreamura Sleep Advisor

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