Last updated: October 2026
Magnesium and zinc do different jobs, and you need far more magnesium: about 270 to 300mg a day, against 7 to 9.5mg of zinc. Magnesium supports energy, muscles and the nervous system; zinc supports immunity, skin and fertility. Most people get enough zinc from food, while magnesium intakes are more often low. You can take both together.
This guide compares what each does, how much you need, signs you might be low, whether to take them together (including ZMA), and safe upper limits.
Magnesium vs zinc at a glance
| Magnesium | Zinc | |
|---|---|---|
| Daily need (NHS) | 300mg men, 270mg women | 9.5mg men, 7mg women |
| Supplement upper limit (NHS) | 400mg or less a day is unlikely to cause harm | No more than 25mg a day unless a doctor advises |
| Main roles | Energy, muscles, nervous system, bones, electrolyte balance | Immune system, skin, hair and nails, fertility, testosterone, vision |
| Best food sources | Leafy greens, nuts, seeds, wholegrains, beans | Meat, shellfish, dairy, bread and cereals |
| Who’s more likely to be low | Teenagers, people eating few wholegrains and greens, older adults, heavy drinkers | Vegans and vegetarians, older adults, people with gut conditions |
| Best time to take | Often the evening | With food, to avoid nausea |
What magnesium does
Magnesium contributes to:
- the reduction of tiredness and fatigue
- normal energy-yielding metabolism
- normal functioning of the nervous system and normal psychological function
- normal muscle function
- the maintenance of normal bones and teeth
- electrolyte balance
Many people take it in the evening as part of a wind-down routine. See magnesium for sleep and types of magnesium.
What zinc does
Zinc contributes to:
- the normal function of the immune system
- the maintenance of normal skin, hair and nails
- normal fertility and reproduction, and normal testosterone levels in the blood
- normal cognitive function
- the maintenance of normal vision
- the protection of cells from oxidative stress
On colds, a 2024 Cochrane review found zinc probably doesn’t prevent them, but may shorten them slightly if taken once symptoms start, at the cost of more side effects such as nausea and a bad taste.
Which do you need more of?
By amount, magnesium: roughly 30 times more. By risk of a shortfall, also usually magnesium. UK diet surveys show many teenagers, and some adults, get less magnesium than they need, mainly because diets are low in wholegrains, nuts, seeds and greens. Zinc shortfalls are less common in people who eat meat and dairy, but more likely in vegans, as plant zinc is less well absorbed.
| If you… | Focus on |
|---|---|
| Feel tired, get muscle cramps or want an evening routine | Magnesium |
| Are vegan or vegetarian | Zinc (and check B12, iron and iodine too) |
| Exercise hard and sweat a lot | Both, mainly from food |
| Are over 65 or eat little | Both; consider a multivitamin |
See signs of magnesium deficiency. If you think you’re low in either, your GP can check.
Can you take magnesium and zinc together?
Yes, at normal supplement doses. Very high zinc doses (over 140mg a day in one study) can reduce magnesium absorption, but that’s far above anything you should take. If you take them separately, zinc with breakfast and magnesium in the evening is an easy routine.
Our Magnesium Glycinate Sleep Complex contains no zinc, so it’s easy to pair with a zinc supplement or multivitamin without doubling up. It gives 148mg of magnesium per serving from bisglycinate and citrate, with glycine, L-theanine and botanicals.
ZMA: is it worth it?
ZMA is a sports supplement combining zinc, magnesium aspartate and vitamin B6, marketed for strength and testosterone. In a trial in resistance-trained men, eight weeks of ZMA made no difference to hormones, strength or body composition compared with placebo. It’s fine as a convenient way to get all three, but not a performance booster unless you were low to begin with.
Upper limits and side effects
- Magnesium: too much from supplements mainly causes diarrhoea. Keep to 400mg a day or less, and speak to your GP first if you have kidney problems.
- Zinc: no more than 25mg a day from supplements. Long-term high doses reduce copper absorption, which can lead to anaemia and weaker bones. Zinc on an empty stomach can cause nausea.
- Medicines: both can reduce absorption of some antibiotics and other medicines. Ask your pharmacist about timing.
- Add up your total if you take a multivitamin as well.
FAQs
Is magnesium or zinc better?
Neither; they do different jobs. Magnesium supports energy, muscles and the nervous system; zinc supports immunity, skin and fertility. Low magnesium intake is more common.
Can I take magnesium and zinc at the same time?
Yes, at normal doses. Only very high zinc doses interfere with magnesium. Many people take zinc in the morning and magnesium in the evening.
How much zinc should I take a day?
Adults need 7 to 9.5mg a day, mostly from food. The NHS advises no more than 25mg a day from supplements unless a doctor advises.
Is it OK to take magnesium and zinc every day?
Yes, within the NHS limits: up to 400mg of magnesium and 25mg of zinc a day from supplements.
Is magnesium or zinc better for sleep?
Magnesium is the one people use in an evening routine. There’s little evidence for zinc and sleep.
Does ZMA work?
In trained athletes, ZMA didn’t improve strength, hormones or body composition compared with placebo. It may help if you were low in zinc or magnesium.
Sources
- NHS. Vitamins and minerals: magnesium and zinc.
- Nault D et al. Zinc for prevention and treatment of the common cold. Cochrane Database Syst Rev, 2024.
- Spencer H et al. Inhibitory effects of zinc on magnesium balance and magnesium absorption in man. J Am Coll Nutr, 1994.
- Wilborn CD et al. Effects of zinc magnesium aspartate (ZMA) supplementation on training adaptations. J Int Soc Sports Nutr, 2004.
- GOV.UK. National Diet and Nutrition Survey.
