Natural deodorant gave you a rash? It is almost certainly the baking s

If you tried a natural deodorant and got a red, itchy rash a week or two in, you have not reacted badly to natural deodorant. You have reacted to one ingredient in it, and there are 13 products on this shelf made without that ingredient.

Baking soda is what makes most natural deodorant effective. It is also alkaline, and on a minority of people it eventually irritates the skin badly enough that they give up and go back to aluminium. That is an unnecessary trade.

This page is about that specific problem. If you are choosing your first one and have never had a reaction, the full guide to choosing a natural deodorant is the better starting point.

First, make sure that is what it is

How to tell it was the baking soda

Baking soda irritation has a recognisable shape. It appears one to three weeks in rather than on the first day, it turns up on both sides, it is red and itchy and sometimes leaves the skin looking darker, and it clears up within a week or two of stopping.

What it is not: an allergy. Baking soda is alkaline and your skin sits around pH 5. Enough days of that mismatch on thin, occluded, freshly-shaved skin and it gives up. It is a pH problem, not an immune one, which is why switching one ingredient fixes it.

If instead the reaction was immediate, or on one side only, skip to the last section — that points at fragrance rather than baking soda.

HiBar natural deodorant - pink iris and neroli

HiBAR Plastic-Free Deodorant - Sensitive Skin (Pink Iris & Neroli)

$17.00

A cardboard tube of HiBAR Natural Deodorant in Aloe & Sea Moss stands on a solid light blue background.

HiBAR Plastic-Free Deodorant - Sensitive Skin (Aloe & Sea Moss)

$17.00

Routine Natural Beauty Maggie’s Farm deodorant stick standing upright, showing full product packaging and branding.

routine Natural Deodorant Stick - Maggie's Farm

$28.00

What goes in instead

Magnesium and zinc do the same job, more gently

Odour is not sweat. It is bacteria feeding on sweat, and baking soda works by making your skin too alkaline for them. Magnesium hydroxide and zinc ricinoleate get to the same place differently — magnesium raises pH far more mildly, zinc binds the odour compounds instead of attacking what makes them.

The honest trade: on your hottest, longest day a baking soda formula is still a little stronger. That is a small price for being able to wear anything at all.

routine Natural Deodorant Cream - The Curator | Baking Soda Free

$28.00

routine Blackberry Betty natural baking soda free deodorant jar with cardboard packaging - cream-coloured deodorant in glass container next to brown box showing berry scent description - baking soda free formula for sensitive skin

routine Natural Deodorant Cream - Blackberry Betty | Sensitive Skin

$28.00

routine The Curator deodorant stick displayed on a creamy background showing cardboard packaging.

routine Natural Deodorant Stick - The Curator | Baking Soda Free

$28.00

routine Natural Deodorant Stick - Johnny's Cash

$28.00

While skin is still sore

A cream is kinder than a stick right now

Give it a week off first if you can. Going straight onto a new product over skin that is still inflamed makes it very hard to tell what is helping and what is not.

When you do start again, a cream applied with your fingers puts nothing rigid against sore skin — no dragging, and you control exactly how much goes on. The $5 travel size is enough to find out whether the formula suits you before spending $28.

Routine The Curator baking soda-free deodorant mini - cream cardboard box beside open glass jar showing light cream deodorant

routine Natural Deodorant Mini - The Curator | Sensitive Skin

$5.00

Routine Johnny's Cash baking soda free natural deodorant - glass jar with cream deodorant beside black packaging highlighting sensitive skin formula with cedar and pine scent

routine Natural Deodorant Cream - Johnny's Cash | Baking Soda Free

$28.00

Routine Johnny's Cash vegan natural deodorant - glass jar with cream deodorant beside black packaging highlighting beeswax-free formula with cedar and pine scent for plant-based lifestyles

routine Natural Deodorant Cream - Johnny's Cash | Vegan

$28.00

If it was not the baking soda

When fragrance is the real culprit

A reaction that arrived immediately, or on one side, or that persisted after moving to a baking soda free formula, usually points at the essential oils rather than the active.

These are unscented or made for reactive skin. Worth knowing that "unscented" and "fragrance-free" are not the same thing — some unscented products use a masking scent to cover the raw ingredients. If you have reacted before, the plainest formula on the shelf is the safer test.

The white and light blue plastic-free cardboard tube of HiBAR's Fragrance-Free Natural Deodorant for sensitive skin, shown closed against a solid blue background.

HiBAR Plastic-Free Deodorant - Sensitive Skin (Unscented)

$17.00

attitude deodorant - unscented leaves bar

$11.00

plastic free natural deodorant - red vine leaves (super leaves)

$12.00

How to be sure, and when to stop guessing

Two weeks of a red underarm is enough to put most people off the whole category, which is a shame, because the fix is a single ingredient.

If you are still not sure whether it was the baking soda: stop using anything for a week. If the rash clears and comes back within days of restarting the same product, you have your answer. If it clears and does not come back on a baking soda free formula, you definitely do.

And if a reaction persists across several different formulas, stop guessing and see a pharmacist or GP. Persistent contact dermatitis in that area is worth having looked at properly rather than solved by shopping.

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