Magnesium Hydroxide
Gentler, pH-Based Odor Control
Magnesium hydroxide is a naturally occurring magnesium salt. You may recognize it as the active ingredient in milk of magnesia, a simple mixture of magnesium hydroxide and water that has been used for generations to help neutralize excess stomach acid.
In personal care, magnesium hydroxide is valued for its alkaline nature, which helps neutralize acidic odor compounds and support odor control in natural deodorants.
Why Magnesium Hydroxide Is Used in Natural Deodorant
Body odor doesn’t come from sweat itself. Odor develops when skin bacteria break down components of sweat into acidic, odorous compounds.
Magnesium hydroxide helps manage odor by raising the pH of the underarm skin, effectively neutralizing the acid in sweat and creating an environment that is less favorable for odor formation. When the environment is less supportive of odor-producing bacteria, odor is reduced—without fragrance or masking agents.
Magnesium Hydroxide vs. Baking Soda
Both magnesium hydroxide and baking soda control odor by raising skin pH.
So, if magnesium hydroxide gets its antibacterial properties from its high pH (it is actually more alkaline than baking soda), why does magnesium hydroxide usually cause less irritation than baking soda?
Because they differ in how they react with water (in this case, sweat).
Baking Soda (Sodium Bicarbonate)
- Alkalinity: Alkaline
- Water Solubility: Highly water-soluble
- How It Works: Dissolves quickly in sweat, causing a rapid rise in pH
- Odor Control: Very effective at neutralizing odor
- Moisture Absorption: Excellent
- Skin Sensitivity: Can be irritating for some people due to the fast pH change
In short, baking soda dissolves more readily in sweat, which leads to a faster and more dramatic pH shift—one reason it can be more effective at odor control, but also more irritating for sensitive skin.
Magnesium Hydroxide
- Alkalinity: Even more alkaline than baking soda
- Water Solubility: Low water solubility
- How It Works: Dissolves slowly in sweat, raising pH gradually
- Odor Control: Effective, but typically milder
- Moisture Absorption: Less absorbent than baking soda
- Skin Sensitivity: Often better tolerated by sensitive skin
In short, magnesium hydroxide has slower, gentler odor control with a lower risk of irritation.
Why This Difference Matters
The key difference isn’t how alkaline these ingredients are — it’s how quickly they change the skin’s pH.
Magnesium hydroxide is less water-soluble, it takes longer to fully dissolve in the sweat. creating a more gradual change in pH. Think of it as a “slow-release” antibacterial, which allows the armpit a bit more time to adjust to the increase in pH. For some people, that slower adjustment is easier on the skin.
Choosing Between Magnesium Hydroxide & Baking Soda
- Baking soda often provides stronger odor control and better moisture absorption.
- Magnesium hydroxide is generally gentler and preferred by those who find baking soda irritating.
Neither is universally “better.” Skin chemistry is personal, which is why we offer deodorant options formulated with both ingredients.
