Baking soda affects your skin in several ways, both helpful and potentially harmful. With a pH around 8.3, it’s significantly more alkaline than your skin’s natural pH of 4.0 to 6.0, which means it can soothe itching and fight odor but also disrupt your skin’s protective barrier if overused. The effects depend entirely on how you use it, how much, and how often.
How Baking Soda Changes Your Skin’s pH
Your skin maintains a slightly acidic surface layer called the acid mantle, which sits between pH 4.0 and 6.0. This acidity is functional: it helps form the skin’s barrier, keeps moisture in, and keeps harmful microbes out. Baking soda has a pH of about 8.3, making it mildly alkaline.
When alkaline substances above pH 8.0 contact skin, the proteins in the outermost layer begin to swell. This swelling loosens the tightly packed structure that keeps your skin waterproof and protected. Alkaline agents also alter the lipid (fat) composition of the skin, which further weakens the barrier. For a brief, occasional application, your skin can recover. But repeated or prolonged exposure to baking soda can leave your skin dry, irritated, and more vulnerable to infection. People with eczema, rosacea, or naturally dry skin are especially susceptible to this kind of disruption.
Exfoliation: Gentle but Not Risk-Free
Baking soda’s fine, crystalline particles make it a mild physical exfoliant. When mixed into a paste with water, it can slough off dead skin cells, surface oil, and dirt. Compared to coarser scrubs, baking soda is less likely to cause micro-tears in the skin because its particles are relatively small and dissolve in water.
That said, “gentler than harsh scrubs” doesn’t mean gentle in absolute terms. The alkaline pH is doing its own damage while you scrub. If you use a baking soda paste on your face more than once or twice a week, you risk stripping the acid mantle faster than it can rebuild. Chemical exfoliants (like those containing salicylic acid or lactic acid) work at a skin-friendly pH and are generally a better choice for regular use.
Odor Neutralization on Skin
Body odor comes from bacteria on your skin breaking down sweat into acidic compounds. Because baking soda is alkaline, it directly neutralizes those smelly acids on contact. It can also slow the growth of odor-producing bacteria, which is why it appears in many natural deodorant formulas.
The tradeoff is that the same alkalinity that kills odor can irritate your armpits, which are among the most sensitive areas on your body. Many people develop redness, burning, or a rough rash after using baking soda deodorants daily. If you notice irritation, that’s the acid mantle telling you it’s been disrupted too frequently.
Antifungal Activity
Baking soda shows real antifungal effects, not just in folk tradition but in lab testing. A study published in Mycopathologia tested sodium bicarbonate against 70 fungal strains isolated from skin and nail infections, including dermatophytes (the fungi behind athlete’s foot and ringworm), yeasts like Candida, and molds. At a concentration of 10 grams per liter, baking soda inhibited the growth of 80% of all strains tested. Yeasts were the most sensitive, while molds required the highest concentrations to suppress.
In a follow-up test using actual infected skin scrapings and nail clippings from patients, fungal growth was completely stopped in 79% of specimens and reduced in another 17% after seven days of exposure. This doesn’t mean a baking soda paste will cure a stubborn fungal infection on its own, but it does explain why soaking in a baking soda bath can help manage mild fungal skin issues.
Soothing Itchy and Irritated Skin
The FDA classifies baking soda as a skin protectant that relieves minor irritation and itching. It’s listed alongside colloidal oatmeal as a soothing agent for rashes from poison ivy, poison oak, and poison sumac. Baking soda doesn’t neutralize urushiol, the oily compound that triggers the allergic reaction from these plants. Instead, it works as a drying agent and itch reliever once the rash has already developed.
For this kind of use, a paste applied to the affected area or a cool baking soda bath is the typical approach. The relief is temporary, and for severe reactions, topical corticosteroids are more effective. But for mild, widespread itching, baking soda is a low-cost option that many people find helpful.
Baking Soda Baths for Skin Conditions
Soaking in a baking soda bath is one of the safer ways to use it on skin, because the concentration is much lower than a direct paste. Great Ormond Street Hospital, one of the leading pediatric hospitals in the UK, provides specific guidelines: add 2 to 3 heaped tablespoons (30 to 45 grams) to a shallow bath, or up to 4 tablespoons (60 grams) for a full adult bath. Stir until dissolved, soak for 10 to 15 minutes, then pat dry gently and apply moisturizer while the skin is still slightly damp.
These baths are used to ease itching and irritation from conditions like eczema, psoriasis, and fungal skin infections. The diluted alkalinity softens the outer skin layer without the concentrated disruption of a paste. You can use them daily or several times a week. The key step most people skip is the moisturizer afterward. Because baking soda does shift your skin’s pH upward and can be slightly drying, sealing in moisture immediately after the bath makes a significant difference in how your skin responds.
Who Should Avoid It
Baking soda is not a good fit for everyone’s skin. If you have rosacea, active eczema flares, or very dry skin, the alkaline pH can worsen inflammation and barrier damage. Open wounds, cracked skin, and sunburned skin will sting and may heal more slowly with baking soda exposure. Children’s skin is thinner and more permeable than adults’, so baking soda pastes should be used cautiously, if at all, on young kids. Diluted baths are a safer alternative.
Even for people with resilient skin, frequency matters more than anything. A baking soda scrub once a week is very different from a daily application. Your skin needs time to restore its acid mantle between exposures. If you notice tightness, flaking, redness, or a stinging sensation that wasn’t there before, your skin barrier is telling you it’s compromised.