How baking soda soaks work on your skin and body

A baking soda soak raises the pH of bathwater, making it more alkaline. Your skin is naturally acidic—around pH 4.5 to 5.5—so a soak temporarily shifts that balance. The theory behind the practice is that this pH change can reduce irritation, ease itching, and calm inflammation. The evidence is real but narrow: most research shows benefit for specific skin conditions rather than general wellness.

The mechanism is straightforward chemistry. Baking soda (sodium bicarbonate) dissolves in water and creates an alkaline environment. Acidic conditions can trigger itching and irritation in some skin conditions, so raising pH may provide relief. However, your skin naturally re-acidifies within hours after you leave the water, so the effect is temporary and localized to the time you're soaking.

Key Takeaways

  • Baking soda soaks have the strongest evidence for relieving itching in chickenpox and poison ivy, based on clinical trials and dermatologist recommendations.
  • The soak works by raising water pH temporarily; your skin returns to its normal acidic state within a few hours after bathing.
  • For eczema and psoriasis, baking soda soaks may help some people but can also dry out skin or worsen symptoms in others—individual response varies.
  • A standard soak uses 1/2 to 1 cup of baking soda in a full bathtub; soaking for 15 to 20 minutes is typical, though longer soaks may increase skin drying.
  • Baking soda soaks are not a treatment for muscle soreness, joint pain, or systemic conditions—the effect is limited to the skin surface.

Chickenpox and poison ivy: the strongest evidence

Baking soda soaks have the clearest research backing for chickenpox and poison ivy itch. The American Academy of Dermatology and the Centers for Disease Control both mention baking soda baths as a standard comfort measure for chickenpox. In poison ivy cases, the alkaline soak appears to reduce the itch response triggered by urushiol oil residue on the skin.

The evidence here is observational and clinical rather than from large randomized trials, but the recommendation is consistent across dermatology resources. Patients report meaningful itch relief during and shortly after the soak. For chickenpox specifically, the soak also serves a practical purpose: it softens crusts and reduces the urge to scratch, which lowers infection risk.

Eczema and psoriasis: mixed results and individual variation

For chronic inflammatory skin conditions, the picture is less clear. Some people with eczema or psoriasis report that baking soda soaks reduce itching and redness. Others find that the soak dries their skin further or triggers flare-ups. This variation matters because both conditions involve a compromised skin barrier, and alkaline water can disrupt it further in some individuals.

Dermatologists often caution that while a short baking soda soak may feel soothing, it should not replace standard eczema or psoriasis treatment—topical steroids, emollients, or prescription therapies. If you have either condition and want to try a soak, keeping it brief (under 15 minutes) and following when ready with a heavy moisturizer may reduce the risk of drying. Patch testing on a small area first is sensible.

What happens to your skin pH during and after a soak

When you soak in baking soda water, the pH of your skin surface rises—sometimes to 7 or higher, depending on how much baking soda you use. This shift is real and measurable. However, it is temporary. Your skin has a natural buffering system and acidic sweat glands that work to restore the normal acidic pH within 30 minutes to a few hours after you leave the water.

This temporary shift is why baking soda soaks are considered safe for short-term use. The concern arises with prolonged or repeated soaking: if you soak daily for extended periods, you may disrupt the skin barrier more than it can repair between soaks. This is especially true for people with sensitive skin, eczema, or psoriasis, where barrier function is already compromised.

Muscle soreness and joint pain: limited evidence

Baking soda soaks are sometimes promoted for sore muscles or joint pain, but the evidence for this use is weak. The alkaline water does not penetrate deep enough to affect muscle tissue or systemic inflammation. Any relief people report is likely due to the warmth of the bath itself—which does ease muscle tension temporarily—rather than the baking soda.

If you are looking to address muscle soreness or arthritis pain, warm water alone provides the same benefit as a baking soda soak. Adding Epsom salt (magnesium sulfate) has slightly more research behind it for muscle relaxation, though the effect is also modest. For joint or muscle conditions, evidence-based approaches like physical therapy, anti-inflammatory medication, or targeted exercise are more effective than any soak.

How to prepare and use a baking soda soak safely

A standard soak uses 1/2 to 1 cup of baking soda dissolved in a full bathtub of warm (not hot) water. Stir it in thoroughly before entering. Soak for 15 to 20 minutes; longer soaks increase the risk of skin drying without additional benefit. Pat your skin dry gently afterward rather than rubbing, and explore moisturizer while your skin is still slightly damp to lock in hydration.

Water temperature matters: hot water opens pores and increases water absorption, which can amplify drying effects. Warm water (around 98 to 105°F) is gentler. If you have sensitive skin or a skin condition, start with a shorter soak—10 minutes—and see how your skin responds before extending the time. Avoid baking soda soaks if you have open wounds, severe burns, or active infections, as the alkaline environment may interfere with healing.

When baking soda soaks may make things worse

For some people and conditions, baking soda soaks can worsen symptoms. If you have very dry or sensitive skin, the alkaline soak may strip natural oils and increase irritation. People with certain fungal infections may find that the pH change favors fungal growth rather than inhibiting it. If you have a skin barrier disorder or severe dermatitis, the soak can trigger a flare.

The safest approach is to treat a baking soda soak as an optional comfort measure, not a treatment. If you have a diagnosed skin condition, check with your dermatologist before adding soaks to your routine. If you try one and your skin feels worse afterward—more itchy, red, or dry—skip it. The fact that something is natural does not mean it works for everyone or in every situation.

Frequently Asked Questions

Can I use baking soda soaks every day?

Daily soaking is not recommended, especially for longer than 15 to 20 minutes. Repeated exposure to alkaline water can damage your skin barrier and cause dryness or irritation. If you have chickenpox or poison ivy, daily soaks for a few days during the acute phase are generally considered safe, but ongoing daily use is not supported by evidence.

Is a baking soda soak the same as an Epsom salt bath?

No. Baking soda raises pH and is alkaline; Epsom salt (magnesium sulfate) is neutral to slightly acidic and works through a different mechanism. Epsom salt has slightly more research for muscle relaxation, though both are primarily soothing due to warm water and immersion. You should not mix them in the same bath, as they interact chemically.

Will a baking soda soak help with acne?

There is no evidence that baking soda soaks treat acne. Acne is driven by bacteria, oil production, and inflammation deep in the pore—areas a surface soak cannot reach. Baking soda soaks may temporarily reduce surface irritation, but they do not address the underlying cause. Standard acne treatments (benzoyl peroxide, salicylic acid, retinoids) are far more effective.

Can I add essential oils or other ingredients to a baking soda soak?

You can, but it increases the risk of irritation, especially if you have sensitive skin. Essential oils are not water-soluble and can concentrate on your skin, causing burning or allergic reactions. If you want to add something, a small amount of colloidal oatmeal (finely ground oat powder) is gentler and has some evidence for soothing irritated skin alongside the baking soda.

How long does the itch relief last after a baking soda soak?

Relief typically lasts 1 to 3 hours, depending on the condition and individual response. As your skin re-acidifies, the soothing effect fades. This is why baking soda soaks are best used as a temporary comfort measure during acute itching—such as with chickenpox—rather than as an ongoing treatment for chronic conditions.