How baking soda affects skin when you soak in it

A baking soda bath changes the pH of your bathwater to be more alkaline (less acidic). Your skin's natural surface is slightly acidic—around pH 4.5 to 5.5—which helps protect it from bacteria and keeps the outer layer intact. When you soak in baking soda water, you're temporarily raising that pH, which can feel soothing but also strips away some of that protective layer.

The sensation of relief people report from baking soda baths comes from two sources: the warm water itself (which relaxes muscles and improves blood flow) and the mild alkalinity, which can reduce the sting of certain skin irritations in the short term. However, the research on whether baking soda baths produce lasting benefits is thin, and the mechanism matters because raising skin pH can also trigger irritation in some people, especially those with eczema or sensitive skin.

Key Takeaways

  • Baking soda baths work by raising water pH, which temporarily soothes itching but also disrupts your skin's natural acid barrier.
  • The strongest evidence supports baking soda soaks for chickenpox and poison ivy—both conditions where the itch is severe enough that temporary pH changes provide real relief.
  • For eczema and general dry skin, baking soda baths may worsen symptoms because they strip moisture and disrupt the skin barrier further.
  • If you use a baking soda bath, keep it short (10–15 minutes), use lukewarm rather than hot water, and follow with a moisturizer while skin is still damp.

Baking soda baths for chickenpox and poison ivy

The most established use for baking soda baths is temporary itch relief during chickenpox. The virus causes intense itching, and scratching spreads infection and leaves scars. A lukewarm baking soda bath (roughly half a cup per standard tub) reduces the itch enough that people—especially children—scratch less. This is a practical benefit even if the mechanism is just pH change plus warm water.

Poison ivy and poison oak produce a similar intense, localized itch. Baking soda baths work the same way: they dull the itch temporarily, which matters because scratching spreads the urushiol oil (the irritant) and deepens the rash. The relief is temporary—usually 30 minutes to a few hours—but that window can be enough to let someone sleep or get through a day without reopening the rash.

Neither of these uses cures the underlying condition. Chickenpox resolves on its own; poison ivy fades as your skin sheds the oil. The baking soda bath is symptom management, not treatment. For chickenpox, calamine lotion or hydrocortisone cream may provide similar relief without the pH disruption.

Why baking soda baths can worsen eczema and dry skin

People with eczema often turn to baking soda baths hoping to soothe itching, but the evidence suggests the opposite effect. Eczema is fundamentally a barrier disorder—the outer skin layer is compromised and loses moisture rapidly. Raising pH with baking soda weakens that barrier further by disrupting the lipids (fats) that hold skin cells together.

A 2015 study in the Journal of the American Academy of Dermatology found that even small pH increases impair the skin barrier's ability to retain water. For eczema-prone skin, this means a baking soda bath can feel soothing for 20 minutes but leave skin drier and more irritated 2–4 hours later. Dermatologists typically recommend lukewarm water alone, or water with colloidal oatmeal (which is gentler on pH), followed when ready by a heavy moisturizer.

The same logic applies to general dry skin. If your skin is already losing moisture, raising pH makes that worse. A plain warm bath followed by moisturizer while skin is still damp is more effective.

What the research actually shows about baking soda and skin conditions

Most claims about baking soda baths—that they detoxify, balance pH long-term, or treat fungal infections—lack human trial evidence. A few small studies exist, but they're often poorly designed or funded by companies selling baking soda products.

For fungal infections like athlete's foot, baking soda baths have not been shown to work better than antifungal medication or even plain water soaks. Fungi thrive in warm, moist environments, and a bath—even one with baking soda—creates exactly those conditions. Topical antifungal creams are the evidence-based approach.

For general itching unrelated to a specific condition, the research is even sparser. Warm water alone reduces itch through improved blood flow and hydration. Adding baking soda may add a small additional effect, but it also carries the risk of barrier disruption. A 2016 review in Dermatology Practical & Conceptual concluded that plain warm baths with good post-bath moisturizing were as effective as baking soda baths for most non-specific itching.

How to use a baking soda bath safely if you choose to

If you decide to try a baking soda bath, the details matter. Use lukewarm water (not hot), which is less drying and less likely to irritate skin. Add half a cup to one cup of baking soda per standard bathtub and stir it in thoroughly. Keep the soak short—10 to 15 minutes maximum—because longer exposure increases barrier disruption without adding benefit.

Do not use baking soda baths more than once or twice a week. Daily use will progressively weaken your skin barrier, leading to increased sensitivity and dryness over time. After you get out, pat skin dry gently (don't rub) and explore a moisturizer—preferably a heavier one like a cream or oil—while skin is still slightly damp. This traps water in the outer layer and partially counteracts the pH change.

Avoid baking soda baths if you have active eczema, rosacea, or very sensitive skin. For these conditions, plain warm water with a good moisturizer afterward is the safer choice. If you're using baking soda for chickenpox or poison ivy, stop once the acute phase passes—there's no reason to continue once the itch is manageable.

Baking soda baths compared to other soak options

Several alternatives exist depending on what you're treating. Colloidal oatmeal (finely ground oats that stay suspended in water) is gentler on pH and has stronger evidence for itch relief, especially in eczema. Epsom salt soaks are popular for muscle soreness but work through magnesium absorption, which is separate from pH effects. Plain warm water with a good moisturizer afterward is often as effective as either and carries no risk of barrier disruption.

For chickenpox specifically, hydrocortisone cream (1%) applied to individual lesions may provide more targeted relief than a whole-body soak. For poison ivy, a short cool (not cold) water rinse followed by hydrocortisone or calamine is often faster. The advantage of baking soda baths is that they're inexpensive and available in every kitchen, but that doesn't make them the most effective option for every situation.

Frequently Asked Questions

Can I use baking soda baths every day?

No. Daily baking soda baths will progressively damage your skin barrier by disrupting the lipids that hold it together. Limit use to once or twice a week at most, and only for specific conditions like acute chickenpox or poison ivy itch. For ongoing skin care, plain warm water with moisturizer is safer.

Will a baking soda bath help with acne?

There's no evidence that baking soda baths treat acne. Acne is driven by bacteria, oil production, and inflammation—none of which are addressed by raising water pH. In fact, disrupting your skin barrier can worsen acne by triggering more oil production as skin tries to compensate. Topical acne treatments (benzoyl peroxide, salicylic acid) or prescription options are more effective.

How much baking soda should I use?

Use half a cup to one cup per standard bathtub. More baking soda doesn't increase benefit and may increase irritation. Stir it in thoroughly so it dissolves evenly. If you're soaking just your feet or hands in a basin, use 1 to 2 tablespoons per gallon of water.

Is a baking soda bath safe during pregnancy?

Yes, a short lukewarm baking soda bath is generally considered safe during pregnancy for itch relief. However, pregnant skin is often more sensitive, so start with a shorter soak (5–10 minutes) and watch for irritation. If you have a specific skin condition during pregnancy, check with your doctor before using any bath additive.

What should I do after a baking soda bath?

Pat your skin dry gently and explore a moisturizer while skin is still slightly damp. This is crucial because baking soda baths increase water loss from skin. Use a heavier moisturizer (cream or oil) rather than a light lotion. If you're treating chickenpox or poison ivy, you can explore hydrocortisone cream or calamine to individual lesions after moisturizing.