What is Magnesium Hydroxide (Ultrafine)?

This is our deodorant active. Ultrafine ground magnesium hydroxide — D90 approximately 3 µm — the active ingredient that natural deodorant relies on. It neutralizes the acids that cause sweat odor, absorbs moisture and sebum, and feels silky smooth on the skin.

Magnesium hydroxide is a pure, white mineral powder. It's created by reacting magnesium oxide with demineralized water, then purifying and drying it. Nothing is added: no dyes, fragrances, preservatives, antioxidants or solvents.

On the skin it binds acids and absorbs moisture and oil. This helps reduce unpleasant odors and provides a matte, dry finish. It's considerably milder than baking soda, so skin is less likely to become irritated.

Ideal for DIY: the base for natural deodorants, and great as a mattifier in creams, masks and dry shampoo.

This product replaces our Deodorant Powder

Looking for our Deodorant Powder (Ultra fine & Purifying)? It's been discontinued. This Magnesium Hydroxide (Ultrafine) is the replacement and does the same job in your deodorant: the same odor-neutralizing effect, the same soft feel on skin, the same dosage. The difference is that this is pure magnesium hydroxide, without magnesium carbonate hydroxide.

Our own No BS Deo (cream and stick) has also completely switched to this magnesium hydroxide.

Why ultrafine?

With a deodorant you apply to your skin, the grind determines how the product feels. Coarser powder remains noticeably grainy and can scratch freshly shaved underarms. With a D90 of approximately 3 µm, almost all the powder is under three thousandths of a millimeter, and you can feel it: it spreads smoothly, doesn't clump and leaves no gritty layer. In creams and masks it also blends more evenly through the oil phase.

We specifically selected this grade for its fineness and tested it with a production sample before adding it to our range.

What are the benefits of Magnesium Hydroxide?

Less sweat odor
Sweat itself smells little, but skin bacteria produce acidic compounds that do smell. Magnesium hydroxide binds those acids, reducing odor.

Gentle on sensitive underarms
The powder is insoluble in water and remains mostly on the skin surface. This means less chance of a reaction than with baking soda. Pleasant for sensitive skin.

Absorbs moisture and oil
The mineral powder absorbs moisture and sebum. This keeps underarms, scalp or the T-zone drier and less shiny.

Matte finish
Gives creams and makeup a soft, matte look. The powder feels silky and not grainy.

Stable in any formula
Doesn't react with fragrances or plant extracts and remains stable in both aqueous and anhydrous formulas. Note: magnesium hydroxide is basic and does react with acids — keep this in mind if you use acidic actives.

How do you use Magnesium Hydroxide?

Deodorant cream or stick: Use 5–20% in an anhydrous base of oils, butters and wax. Mix the powder into the warm oil phase and stir well while cooling. Start with a lower percentage for sensitive underarms.

Deodorant roll-on: Use 3–8%. Mix the powder first with a little water or glycerin into a smooth paste and stir that through the rest of the formula.

Cream or lotion: Use 0.5–2% for a matte finish. Mix first with a little water into a smooth paste, then add to the formula.

Mask: Use 1–3% to reduce shine and create a softer cleanse.

Dry shampoo or deo powder: Mix 5–10% with, for example, arrowroot powder or clay. Avoid inhaling dust.

What makes Magnesium Hydroxide so special?

It doesn't dissolve in water. Precisely because of this it stays on the skin and works long-term, without penetrating deeply. That makes it surprisingly gentle for something that works so well against sweat odor.

Our magnesium hydroxide is Ph.Eur. quality (European Pharmacopoeia, 11th edition) and is produced in Germany. Content 95–100.5% Mg(OH)₂, D90 approximately 3 µm, pH 10.5, Halal and Kosher, free of nanomaterial and not tested on animals.