Ingredient review
Sodium Borate
INCI: Sodium Borate
Sodium borate helps stabilize pH and preserve formulas, but it can be irritating for sensitive skin at higher concentrations.
In plain English
Sodium borate, also known as borax, is a naturally occurring mineral salt. In skincare, it's used in tiny amounts to keep the product's pH balanced and to help other preservatives work better. You'll find it in creams, lotions, and bath bombs. While it's generally safe, it can cause irritation if too much is used or if you have very sensitive skin.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- natural
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Sodium Borate can be useful, but watch for some irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Sodium Borate.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
Sodium borate is the sodium salt of boric acid, mined from evaporated ancient lake deposits. In cosmetics, it acts as a buffer to maintain a stable pH and can enhance the effectiveness of certain preservatives.
How it works
Sodium borate releases borate ions in water, which help neutralize acids or bases to keep the formula's pH steady. This stability prevents the product from becoming too acidic or alkaline, which could irritate skin or degrade other ingredients. It also helps some preservatives work more efficiently.
Pros
pH stabilizer
Sodium borate helps keep your product's pH consistent, which means it stays gentle and effective from first use to last.
Preservative booster
It helps other preservatives work better, so your cream or lotion is less likely to grow mold or bacteria over time.
Cons and cautions
Potential irritant
At higher concentrations, sodium borate can cause stinging, redness, or dryness, especially if you have sensitive or compromised skin.
Not for damaged skin
If your skin barrier is broken or you have a rash, sodium borate may worsen irritation, so it's best to avoid it until skin heals.
Best for
- People using stable, pH-balanced creams or lotions
- Those who enjoy bath bombs and fizzy bath products
Use caution if
- Individuals with very sensitive, irritated, or eczema-prone skin
- Anyone with open wounds or severe skin damage
Usage tips
Safety summary
Sodium borate is considered safe in cosmetics at regulated concentrations. However, it can cause skin irritation in sensitive individuals or when used above recommended levels. It should not be ingested or applied to broken skin.
Research notes
Studies confirm sodium borate's low acute toxicity in topical use at cosmetic levels. The Cosmetic Ingredient Review (CIR) panel has deemed it safe with restrictions. No strong evidence links cosmetic use to systemic toxicity.
Common label clues
- Typical concentration
- 0.1% to 2% in leave-on products; higher in rinse-off products
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database with concentration limits (up to 3% for leave-on, 5% for rinse-off). Not for use on damaged skin.
- Common uses
- Creams, Lotions, Bath bombs, Emulsions
- Environmental note
- Sodium borate is mined from natural deposits, and its extraction has a moderate environmental footprint. It is biodegradable and does not accumulate in the environment.
Good to know
- Sodium borate is sometimes listed as 'borax' on ingredient labels.
- It is not the same as boric acid, though they are chemically related.
- The EU and FDA consider sodium borate safe in cosmetics at concentrations up to 5% for rinse-off products and 3% for leave-on products.
Common questions
What is Sodium Borate in beauty products?
Sodium borate, also known as borax, is a naturally occurring mineral salt. In skincare, it's used in tiny amounts to keep the product's pH balanced and to help other preservatives work better. You'll find it in creams, lotions, and bath bombs. While it's generally safe, it can cause irritation if too much is used or if you have very sensitive skin.
What does Sodium Borate do in a beauty product?
Sodium borate releases borate ions in water, which help neutralize acids or bases to keep the formula's pH steady. This stability prevents the product from becoming too acidic or alkaline, which could irritate skin or degrade other ingredients. It also helps some preservatives work more efficiently.
Is Sodium Borate safe for most people?
Sodium borate is considered safe in cosmetics at regulated concentrations. However, it can cause skin irritation in sensitive individuals or when used above recommended levels. It should not be ingested or applied to broken skin.
Who should be careful with Sodium Borate?
Individuals with very sensitive, irritated, or eczema-prone skin Anyone with open wounds or severe skin damage
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.