The comparison · Sensitive skin edition
Magnesium vs. baking soda vs. aluminum: which deodorant chemistry can your skin live with?
If you're searching for a natural deodorant without baking soda that actually works — or wondering whether magnesium deodorant is any good for sensitive skin — this is the whole decision, laid out honestly. Including where our own product isn't the right answer.
The three chemistries, in one table
Every deodorant or antiperspirant on the shelf works one of three ways: it plugs the sweat duct (aluminum antiperspirants), it kills odor bacteria with high alkalinity (baking-soda naturals), or it suppresses odor bacteria gently at lower alkalinity (magnesium-hydroxide naturals, like Morrowen). Which one suits you is mostly a question of what your skin tolerates.
| — | Magnesium hydroxide (Morrowen's approach) | Baking soda (most naturals) | Aluminum salts (antiperspirant) |
|---|---|---|---|
| Stops odor | Yes — slows odor bacteria | Yes — strongly | Yes — by stopping sweat |
| Stops sweat | No (arrowroot absorbs) | No | Yes — plugs ducts |
| Effective pH vs. skin's 4.5–5.5 | Mildly above — gentle | ~9 — far above | Acidic — can sting post-shave |
| Sensitive-skin rash risk | Low | The classic cause | Moderate (fragrance/alcohol) |
| Yellow shirt stains | No — aluminum-free | No | Yes — aluminum + sweat |
| Adjustment period | 1–2 weeks off antiperspirant | 1–2 weeks, plus rash risk | None |
Is magnesium deodorant good for sensitive skin?
It's the gentlest of the three chemistries, which is why we built Morrowen around it. Magnesium hydroxide is poorly soluble and only mildly alkaline at the skin surface — enough to keep odor bacteria from thriving, not enough to disrupt the acid mantle the way baking soda's pH ~9 does. Pair it with colloidal oatmeal (the eczema-care staple) and you get odor control that reactive skin can wear daily. The honest trade-off: like every true deodorant, it doesn't stop sweat. If you need clinical-strength dryness, an antiperspirant is the correct product for you — no natural deodorant should pretend otherwise.
Why "natural deodorant without baking soda" is such a common search
Because the rash is that common. Baking soda anchors most of the natural aisle for cost reasons, and a meaningful share of people — especially anyone who shaves their underarms — eventually reacts to daily contact with a pH-9 powder on thin, occluded skin. The industry's usual fix is "sensitive" variants with less baking soda. Our position: less irritant is still irritant. Skip the ingredient entirely and use magnesium instead.
Quick chooser: Rash from your current natural deodorant → look for baking-soda-free, magnesium-based (this is Morrowen's lane). Need absolute dryness for medical or professional reasons → antiperspirant. Skin of steel and a tight budget → baking-soda naturals work fine for you. Reactive even to essential oils → choose a truly unscented option (ours contains none).
What about crystal / potassium alum deodorants?
Worth an honest mention: mineral-salt "crystal" sticks use potassium alum, which is technically an aluminum compound — fine if your concern is rash, confusing if your goal was avoiding aluminum altogether. They're gentle for many people but do little for odor by day's end for others. If you tried crystal and it wasn't enough, magnesium is usually the next stop.
Where Morrowen sits in this landscape
Morrowen is a single-product label: one magnesium-based, baking-soda-free, aluminum-free stick, buffered with colloidal oat, in Fog & Clover or truly-unscented. It exists specifically for the person who has already been burned — sometimes literally — by the baking-soda aisle. It is not the cheapest option, it will not stop you sweating, and if neither of those is a dealbreaker, it's the deodorant we think sensitive skin should be offered first. The full formulation reasoning is in our formulation notes, and the ingredient-by-ingredient breakdown is on the main page.
Morrowen is a deodorant, not an antiperspirant, and this comparison is education, not medical advice. If you have a skin condition, patch-test any new product inside the elbow for a few days first.
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