Baking Soda Baths for Itchy Skin: What the Evidence Actually Shows

Baking soda (sodium bicarbonate) baths are a widely recommended home remedy for itchy, irritated skin -- suggested for everything from eczema to poison ivy rashes to insect bites. The FDA does recognize sodium bicarbonate, alongside colloidal oatmeal, as a skin-protectant ingredient. But the evidence supporting baking soda baths specifically is considerably thinner and more anecdotal than the research behind colloidal oatmeal, and it isn't the right choice for everyone.

A plausible mechanism, not a proven one

Baking soda is mildly alkaline, with a pH around 8 to 9, compared to skin's naturally acidic pH of roughly 4.5 to 5.5. The leading theory is that shifting bathwater pH toward alkaline temporarily changes conditions at the skin surface in a way that reduces itch signaling and softens scale or crust. This is a reasonable, biologically plausible explanation, but the research behind it remains limited and mostly observational rather than the kind of well-controlled trial evidence that exists for colloidal oatmeal.

It isn't universally good for skin

Because baking soda shifts skin surface pH away from its normal acidic range, it can worsen irritation rather than help it for some people -- particularly those with rosacea, actively flaring eczema, or already very dry or compromised skin. The alkalinity can be drying with repeated or prolonged use, which is part of why moisturizing immediately afterward matters if a baking soda bath is used at all.

Safety notes worth taking seriously

Baking soda baths are generally not recommended on broken or open skin, and people with diabetes, heart disease, or who are pregnant or nursing are generally advised to check with a clinician first, since sodium bicarbonate can be absorbed through skin in meaningful amounts, particularly with prolonged soaking or extensive skin involvement. Feeling lightheaded, weak, or unusually drained during or after a baking soda bath is a signal to get out, sit down, and treat it as a genuine warning sign rather than something to push through.

If trying it

A common approach is roughly a quarter cup of baking soda dissolved in a warm (not hot) bath, or a small paste of baking soda and water applied briefly to a localized area rather than the whole body. Patch-testing a small area first, and moisturizing well afterward, are reasonable precautions. If itching or irritation is severe, persistent, or not improving, that's a better reason to see a clinician than to keep experimenting with home remedies.