Last updated: November 2026
Magnesium stearate is a fine white powder, the magnesium salt of stearic acid, used in tiny amounts to stop tablet and capsule powders sticking to machines. It isn’t a magnesium supplement: it is only about 4% magnesium, so a capsule gives a negligible amount. EFSA found no safety concern at the levels used (checked November 2026).
Our own Magnesium Glycinate Sleep Complex is a powder you stir into water, with no magnesium stearate.
What is magnesium stearate?
It is magnesium bound to stearic acid, a saturated fatty acid found in cocoa butter, shea butter and meat. In food it is the additive E 470b, “magnesium salts of fatty acids”. Makers add a little to the powder before pressing tablets or filling capsules, so it flows smoothly, doses stay even and nothing sticks to the machine.
It is only about 4% magnesium by weight, against about 14% for glycinate. If a 500mg capsule fill were 1% magnesium stearate, that is about 0.2mg of magnesium (our sums), against the 300mg (men) or 270mg (women) a day the NHS says adults need. Our types of magnesium chart shows how the real supplement forms compare.
Is magnesium stearate safe?
At the amounts used, yes:
- EFSA (2018): the European Food Safety Authority re-evaluated E 470b and found no safety concern at the levels used, with no need for a numerical acceptable daily intake (ADI).
- UK: E 470b is on the list of approved food additives in Great Britain.
- Genetic safety: a 2017 study found no sign that it damages DNA in standard lab and animal tests.
iIf you have a known allergy or intolerance, check the full label and ask a pharmacist.
Magnesium stearate myths: what the evidence shows
| The claim | What the evidence shows |
|---|---|
| “It weakens your immune system” | This traces to a 1990 lab study that added stearic acid to isolated T cells in a dish. It didn’t test magnesium stearate, or people eating it. |
| “It stops you absorbing nutrients” | Over-mixing a lubricant can slow how fast a capsule dissolves in lab tests, so makers test their formulas. In one capsule study its amount was among the least important factors. We found no human evidence that normal amounts block absorption. |
| “It’s a hidden trans fat” | Stearic acid is a saturated fat, not a trans fat. EFSA did suggest limits on trans fats in the specification, because some batches are made from hydrogenated oils. |
“No magnesium stearate” on a label is a preference, not a safety warning.
How to spot it on a label
Look in the ingredients list for:
- “Anti-caking agent: magnesium stearate” or “magnesium salts of fatty acids”
- “Vegetable magnesium stearate” (made from plant fats)
- E 470b, more often seen on food than on supplements
- Others doing the same job: stearic acid, calcium stearate, silicon dioxide, rice flour
It is usually near the end. For how much magnesium you get, read the nutrition panel for elemental magnesium in mg. Our guide to how much magnesium per day explains the numbers, and magnesium powder vs tablets covers the format question.
Is magnesium stearate vegan?
It can be either: stearic acid comes from plant fats such as palm, coconut or shea, or from animal fat. A product marked vegan, or listing “vegetable magnesium stearate”, uses a plant source. Otherwise, ask the brand (worth doing if you avoid palm oil too).
Does Evopure’s magnesium contain magnesium stearate?
No. Our Magnesium Glycinate Sleep Complex is a powder you stir into water, with no magnesium stearate: with nothing to press or fill, it needs no flow agent. The per-serving table from the product page, checked November 2026:
| Key ingredients | Per 4.75g serving |
|---|---|
| Magnesium (elemental), 77% NRV | 290mg |
| Magnesium bisglycinate | 1,000mg |
| Magnesium citrate | 900mg |
| Glycine | 500mg |
| Oat straw 10:1 extract | 300mg |
| Hops 4:1 extract | 200mg |
| Chamomile 4:1 extract | 200mg |
| Passionflower 4:1 extract | 200mg |
| L-theanine | 100mg |
The full list adds berry flavouring, citric acid, DL-malic acid, beetroot powder, inulin and stevia. One serving gives close to the NHS daily figure for adults (300mg for men, 270mg for women) and stays inside the NHS guide of 400mg a day or less from supplements.
Our pick
Magnesium Glycinate Sleep Complex
Magnesium Glycinate Sleep Complex is a berry drink powder with 290mg of magnesium (77% NRV) per 4.75g scoop from bisglycinate and citrate, plus glycine and L-theanine, and no magnesium stearate. Magnesium contributes to a reduction of tiredness and fatigue and to normal psychological function.
Add Magnesium Glycinate Sleep Complex to bag See ingredients and reviews
Vegan and made in the UK, for adults (18+) only. Free UK delivery over £45, 14-day returns on unopened items.
Subscribe £22.49One-off £29.99
View productThe box below also shows our reishi hot chocolate (cacao contains a little natural caffeine) and Sleep CBD Oil. On the 500mg Sleep CBD Oil, 0.2ml gives 10mg of CBD; our serving is up to half a pipette (0.35ml, 17.5mg).
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.
iIf you take any regular medicines, check with your GP or pharmacist first. We don’t recommend our products during pregnancy or breastfeeding.
Comparing brands? See our UK magnesium supplement guide, and for the evening angle, magnesium for sleep.
Sources 8
- EFSA (2018). Re-evaluation of salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b). EFSA Journal.
- Food Standards Agency (gov.uk). Approved additives and E numbers.
- Hobbs CA and others (2017). Magnesium stearate exhibits a lack of in vitro and in vivo genotoxic potential. Toxicology Reports. PMID 29090120.
- Tebbey PW, Buttke TM (1990). Immunosuppressive action of stearic acid on T cells. Immunology. PMID 2379942.
- Barrocas P and others (2023). Over-blending effect of lubricants on capsules manufacturing. PMID 36987819.
- Piscitelli DA and others (1998). Formulation changes, dissolution and bioequivalence of piroxicam capsules. PMID 9834946.
- NHS. Vitamins and minerals: magnesium.
- PubChem. Magnesium stearate.
General information, not medical advice. Spotted something out of date? Email support@evopure.co.uk.
