What does magnesium hydroxide do in deodorant?

Short answer: magnesium hydroxide is a mild alkaline mineral used in deodorant to control underarm odor. It makes the surface of the skin less friendly to the bacteria that turn sweat into smell — without the sharper alkalinity of baking soda. It is not an antiperspirant and does not reduce sweating.

The cosmetic job it does

Fresh sweat is largely odorless. Skin bacteria break its components down, and the byproducts are what you smell. Magnesium hydroxide shifts surface conditions enough to slow that process down. That's the whole mechanism — a cosmetic effect on odor at the skin surface.

Why we picked it

• Gentle by design. Its low solubility means it acts steadily rather than aggressively.
• No fragrance needed. Because it addresses odor rather than masking it, we don't need synthetic fragrance to cover anything.
• Neutral feel. No tingle, no cooling, no residue.
• Short list friendly. One mineral handles odor, so the rest of the jar can be fat and starch.

What magnesium hydroxide is not

It's worth being blunt, because the internet isn't. Magnesium hydroxide in a deodorant does not detox anything, does not deliver magnesium to your body in a meaningful way, does not treat any skin condition, and does not stop you from sweating. Anyone telling you otherwise is selling harder than we are.

How it sits in our formula

Four ingredients: grass-fed and finished tallow and organic cold-pressed coconut oil as the conditioning base, organic arrowroot powder for surface moisture, magnesium hydroxide for odor. Each one has exactly one reason to be there.

Keep reading

See its counterpart in what arrowroot powder does in deodorant, compare it to soda in magnesium hydroxide vs. baking soda, or check the research and sources we work from.