Vitabiotics Ultra Magnesium: What Form Is It, Is It Good for Sleep and Side Effects (UK)

What form of magnesium is in Vitabiotics Ultra Magnesium?

Magnesium hydroxide. Vitabiotics’ own FAQ says so, adding that hydroxide has “a high amount of elemental, or actual, magnesium per weight”. Here is what the label showed on 12 November 2026:

Full ingredients: magnesium hydroxide, then bulking agents (microcrystalline cellulose, dibasic calcium phosphate and potato starch), a tablet coating (hydroxypropylmethylcellulose, glycerin and calcium carbonate as a colour), anti-caking agents (silicon dioxide, stearic acid, purified talc and magnesium stearate) and polyvinylpyrrolidone.

What the label says it’s for: Vitabiotics uses authorised magnesium claims, such as the reduction of tiredness and fatigue, normal muscle and nervous system function, normal psychological function and normal bones and teeth. Its FAQ says it may suit people with hectic lives, those wanting extra bone support and the over 50s. New to the forms? See types of magnesium.

Is magnesium hydroxide well absorbed?

There is less research on hydroxide than on citrate, oxide or glycinate, and the studies that exist are small:

• A Norwegian study of 18 female students compared magnesium hydroxide tablets with citrate and lactate tablets and a chloride solution. Magnesium in the urine, a common way to estimate absorption, rose by a similar amount with each.
• A 2025 crossover study in 20 young adults compared seawater-derived magnesium hydroxide with seawater-derived magnesium citrate at the same magnesium dose. Both raised absorption compared with placebo, and they didn’t differ from each other.

People often mix hydroxide up with magnesium oxide, which is a different compound. The well-known studies showing low absorption, a US study finding about 4% absorbed and a UK trial where citrate was better absorbed than oxide over 60 days, tested oxide, not hydroxide. No study has tested Ultra Magnesium itself. See our magnesium oxide guide and magnesium citrate guide.

Your stomach. Magnesium hydroxide is also the active ingredient in milk of magnesia, a laxative, and in some antacids. It works by drawing water into the bowel. That doesn’t make a supplement a laxative, but it’s why loose stools are the side effect to watch for, as with most magnesium. More in magnesium for constipation.

Other Vitabiotics magnesium products

“Is Vitabiotics magnesium glycinate or citrate?” depends on which product you mean. On 12 November 2026 vitabiotics.com listed three:

So the 3-in-1 Complex is the Vitabiotics product with glycinate in it, as one of three forms. The gummies list sucrose and glucose syrup in their ingredients. Vitabiotics says the tablets aren’t suitable for children and the gummies aren’t suitable for under 12s. For blends of several forms, see magnesium complex and magnesium malate.

Is Vitabiotics magnesium good for sleep?

Vitabiotics doesn’t describe Ultra Magnesium as a sleep product: sleep isn’t mentioned on the product page. That’s in line with UK rules: there is no authorised health claim linking magnesium to sleep.

Here is where the research on magnesium and sleep stands:

• A 2021 review found just three trials in 151 older adults. People fell asleep about 17 minutes faster than with placebo, but the authors rated the evidence low to very low quality.
• A 2025 German trial gave 155 adults with poor sleep 250mg of magnesium as bisglycinate or a placebo. Insomnia scores improved a little more with magnesium at 4 weeks; the authors called the effect small.
• We found no sleep trials using magnesium hydroxide.

iMagnesium isn’t a sedative, so most people shouldn’t expect to feel sleepy after a tablet. See does magnesium make you sleepy? and our full guide to magnesium for sleep. If poor sleep goes on for weeks, speak to your GP, and see our sleep hygiene guide.

Vitabiotics Ultra Magnesium side effects and who should check first

The product page has no side effects section, so these come from magnesium in general:

• Loose stools or diarrhoea: the most common one. The NHS says more than 400mg of magnesium for a short time can cause diarrhoea. Vitabiotics’ directions are to take it with your main meal.
• Medicines: Vitabiotics says Ultra Magnesium can generally be used alongside medication, and to ask your doctor or pharmacist for specific advice. The NHS advises leaving 2 to 4 hours between antacids (some contain magnesium hydroxide) and other medicines.
• Kidney disease: high blood magnesium is most often seen in kidney failure, so check with your GP or kidney team first.
• Label warnings: Vitabiotics says to check with your doctor or pharmacist if you are under medical supervision, have epilepsy or have food allergies. It’s made on a site that may handle nuts and peanuts.

iPregnancy and children: Vitabiotics says the tablets aren’t suitable for children. Speak to your midwife, GP or pharmacist before taking any supplement in pregnancy, and see magnesium in pregnancy and magnesium for kids. More detail in our magnesium side effects guide.

How much magnesium a day, and adding it up

The NHS says adults need 300mg a day (men) or 270mg (women), and that 400mg or less a day from supplements is unlikely to cause harm. The “100% NRV” on the label means 375mg is the nutrient reference value used for labelling, which is set higher than the NHS figures. Magnesium from food doesn’t count towards the 400mg.

Taking it with vitamin D, zinc or calcium? Vitabiotics says it can generally be used with its other products. See magnesium and vitamin D, magnesium and zinc and magnesium and calcium, plus how much magnesium per day for the full picture.

When to take it: Vitabiotics says two tablets a day with your main meal, swallowed with water and not chewed, and that results build over several weeks of regular use. See the best time to take magnesium and how long magnesium takes to work.

Vitabiotics Ultra Magnesium vs magnesium glycinate

Many people search for this because glycinate is popular for evening routines. A neutral comparison:

As one glycinate example, our own Magnesium Glycinate Sleep Complex is a drink powder rather than a tablet: 290mg of magnesium (77% NRV) per 4.75g serving from bisglycinate and citrate, against 375mg (100% NRV) from hydroxide in two Ultra Magnesium tablets. In one small trial in 12 people who had part of their bowel removed, glycinate was absorbed as well as oxide overall, better in those who absorbed least, and better tolerated by all. The most important thing for any form is to take an amount within the NHS guide, regularly. See magnesium glycinate and magnesium powder vs tablets.

Where Evopure fits

Evopure isn’t connected with Vitabiotics. If you’d like a magnesium glycinate powder or something for an evening routine, here’s what we make. They’re different products, not like-for-like swaps.

• Magnesium Glycinate Sleep Complex: a berry powder with magnesium bisglycinate and citrate (290mg of magnesium per serving), glycine, L-theanine, chamomile, passionflower, hops and oat straw. Magnesium contributes to a reduction of tiredness and fatigue and to normal psychological function.
• Reishi Mushroom Adaptogenic Complex: a reishi hot chocolate with reishi mushroom, cocoa and maca, for a warm evening mug. It contains a little natural caffeine from the cacao. See reishi cacao.
• Sleep CBD Oil: broad spectrum CBD with 0% THC, plus passion flower and a terpene blend led by myrcene. 10mg of CBD is about 0.2ml of the 500mg oil. CBD isn’t a treatment for sleep problems. See CBD and sleep and how much CBD to take.

The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.

All three are vegan and made in the UK, and our Sleep CBD Oil is third-party lab tested. They’re for adults (18+) only, and we don’t recommend our products during pregnancy or breastfeeding.

Related guides

• Holland and Barrett’s own magnesium range.
• Wild Nutrition magnesium: form, dose and how to take it.
• Comparing brands? See what’s in Solgar magnesium.
• Together Health magnesium and its Night Time capsules.
• Bioglan magnesium: forms and doses.
• If you are comparing glycinate capsules, our page on New Leaf magnesium glycinate sets out its magnesium per serving.
• Boots also sells its own magnesium; see Boots magnesium and its label maths.
• Vitabiotics Ultra Magnesium also sits alongside Superdrug’s own-brand magnesium on its website.
• Vitabiotics Ultra Magnesium is also stocked by Tesco; see what magnesium Tesco sells.
• Vitabiotics also makes an ashwagandha tablet: see what’s in Vitabiotics Ultra Ashwagandha.
• For blends with many more forms, see 12 in 1 magnesium: what’s in it and is it worth it.
• For a brand-neutral checklist on forms, doses and labels, see how to choose a magnesium supplement.
• Taken too much? Our guide explains how to get magnesium out of your system and when to get help.
• Asda stocks Ultra Magnesium tablets and Ultra citrate gummies; see Asda magnesium for the full range we found.
• Vitabiotics Ultra Magnesium tablets and gummies are both sold at Morrisons; see Morrisons magnesium.
• Tablets need processing aids to press well; magnesium stearate is the most common one, and it doesn’t count towards your magnesium.