Wired But Tired? What Magnesium Can (and Can't) Do for Your Sleep and Stress

You know the feeling. Your body is done, but your brain is still answering emails at 23:40. "Wired but tired" has become the catch-all for modern burnout, and magnesium, glycinate in particular, has become its catch-all cure. It's in "sleepy girl mocktails" on TikTok and in gym WhatsApp groups as a cramp remedy. The mineral really does matter. The marketing has simply sprinted ahead of the science.

The mineral is genuinely important. The marketing is running well ahead of the science, though.

Why your body needs magnesium

Magnesium is involved in hundreds of enzyme reactions: energy production, muscle contraction and relaxation, nerve signalling, and the making of protein and bone. It's not a fringe nutrient. The NHS puts adult needs at 300 mg a day for men and 270 mg a day for women (ages 19 to 64), and says you should be able to get it all from a varied diet.

Good food sources are mostly the stuff South Africans already have in the kitchen:

• Nuts and seeds, such as almonds, cashews and pumpkin seeds (or peanuts, the budget hero)
• Leafy greens like spinach and morogo
• Wholegrains: brown bread, oats, and whole-maize or unrefined mealie meal
• Beans, lentils and chickpeas
• A square or two of dark chocolate (you're welcome)

The HN24 take if your diet is built on white bread, refined pap and takeaways, a supplement is a plaster. Fix the plate first.

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The stress and sleep story

The wellness pitch says magnesium calms the nervous system and helps you "switch off". There's a biological rationale, since magnesium plays a role in nerve signalling and the body's stress response. But the human trial evidence is thinner than the hype suggests. One often-quoted double-blind trial (Abbasi and colleagues, 2012) gave magnesium to older adults with insomnia and found improvements in sleep measures. It was small, though, and it ran in elderly people, many of whom may have had low intakes to begin with.

That's the pattern across the research. Magnesium seems most likely to help people who are short of it. If your levels are fine, extra magnesium probably won't knock you out.

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Cramps and recovery

On the performance side, magnesium is sold for cramps and recovery. Here the evidence is weaker still. Exercise-associated muscle cramps have many causes, including fatigue, heat, sodium loss and pacing, and trials of magnesium for ordinary cramps have generally been disappointing. If you cramp late in a hot Comrades training run, your pacing, fuelling and sodium are more likely culprits.

Glycinate, citrate, oxide: does the form matter?

Somewhat. Different forms are absorbed differently and have different side effects.

• Oxide is cheap and often packed into multivitamins. It's less well absorbed, and in larger doses it works as a laxative.
• Citrate is better absorbed. It's also known to loosen stools.
• Glycinate (bisglycinate) is magnesium bound to the amino acid glycine. It's usually gentler on the gut, which is a big part of its appeal. Claims that it's uniquely "calming" rest more on glycine and anecdote than on head-to-head human trials.

Check the label for elemental magnesium per capsule. A "500 mg magnesium glycinate" capsule may contain far less actual magnesium.

How much is too much?

The NHS says taking 400 mg or less a day of magnesium supplements is unlikely to cause harm. Higher doses commonly cause diarrhoea. People with kidney disease should not supplement without medical advice, because damaged kidneys can't clear excess magnesium. Magnesium can also interact with some antibiotics, osteoporosis drugs (bisphosphonates) and diuretics, so check with your pharmacist if you take regular medication.

The things that actually fix "wired but tired"

If you want better sleep, these beat any capsule:

1. A fixed wake-up time, weekends included. It anchors your body clock more than an early bedtime does.
2. Morning daylight. Ten to fifteen minutes outside, which is easy in a South African summer.
3. A caffeine cut-off about 8 hours before bed. That second flat white at 15:00 counts.
4. Less alcohol. It helps you fall asleep and then wrecks the second half of the night.
5. A wind-down buffer: 30 to 60 minutes without your inbox. The NHS sleep pages and its insomnia guidance both put routine and environment first.
6. Training earlier if late, intense sessions leave you buzzing.

If poor sleep has lasted months, or you snore loudly and wake unrefreshed, see a GP. Insomnia and sleep apnoea are both treatable, and no supplement fixes them.

Are you actually low? How to tell

Low magnesium is hard to spot from symptoms alone. Fatigue, muscle twitches and poor sleep have dozens of causes, and a standard blood test is a blunt tool, because most of your body's magnesium sits in bone and cells rather than in blood. You're more likely to run low if you:

• Eat few wholegrains, legumes, nuts or greens
• Drink heavily
• Have type 2 diabetes or a gut condition that affects absorption, such as coeliac disease or Crohn's
• Take certain medicines long-term, including some diuretics and proton-pump inhibitors (acid-reflux tablets)
• Are older, since absorption tends to fall with age

If several of those apply, ask your GP or pharmacist whether it's worth checking. Don't self-diagnose from an Instagram list of "signs".

One handful of pumpkin seeds or almonds, a bowl of oats and a serving of beans can take you a long way towards your daily magnesium. No capsule required.

A smarter wind-down routine

If you'd like to try magnesium, build it into a routine rather than treating it as a sedative:

1. About 90 minutes before bed: finish your last meal and stop alcohol.
2. About 60 minutes before bed: dim the lights and switch screens to night mode, or better, put them away.
3. About 30 minutes before bed: take a warm shower, stretch or read something on paper. If you use a supplement, take it here with water.
4. Lights out at a consistent time, in a cool, dark room. A fan and blackout curtains are worth their weight in gold in a South African summer.

The routine is doing most of the work. The magnesium is, at best, a supporting act.