3 MIN READ 

The Real Reason Baking Soda Causes Underarm Rashes 

Let’s talk about an ingredient that shows up far too often in “natural” deodorants, baking soda, also known as sodium bicarbonate. This ingredient  helps in naturally removing underarm odor permanently, but might just cause more issues If you’ve ever dealt with irritation, itchiness, or red, angry rashes after switching to a natural deodorant, baking soda might be to blame. 

Why Baking Soda Is Problematic 

Baking soda has a very high pH, which makes it alkaline. The skin on your underarm, on the other hand, is slightly acidic, which helps keep your skin barrier healthy and bacteria in check. 

When you apply an alkaline ingredient like baking soda to this already sensitive area, it throws off your pH balance, disrupting the skin barrier and making it more prone to: 

If you've ever watched a vinegar and baking soda volcano explode in science class, that's the kind of reaction happening on a micro level in your underarms. Not great for your skin. 

What to Look For on Labels 

Baking soda often hides under its INCI name: sodium bicarbonate. It may sound harmless, but for people with sensitive skin, it's one of the most common irritants in natural deodorants. 

Flip the packaging over. If sodium bicarbonate is anywhere near the top or middle of the list, the product likely contains a significant amount—and it might not be worth the risk if you’re already prone to irritation. 

Other Options 

Look for deodorants with natural but safe and non-irritating ingredients like activated charcoal and natural starches to absorb odor and moisture without disrupting your skin’s pH. These won’t irritate your skin, but works with other ingredients to remove underarm odor.