What Is Potassium Borate?
Potassium borate, often listed on labels as dipotassium tetraborate, is an inorganic salt formed when boric acid reacts with potassium hydroxide. The result is a white, water-soluble powder that easily dissolves into cosmetic formulations. Borates have been used for more than a century in household and personal care items because they help keep products stable. As cosmetic science advanced formulators noticed that potassium borate was especially good at keeping a product’s acidity level where it should be, so it began appearing in creams and lotions during the mid-20th century. Today it is typically produced in large reactors where purified boric acid is mixed with a measured amount of potassium hydroxide, then dried and milled into a consistent powder ready for use.
You are most likely to find potassium borate in moisturizers, facial masks, anti-aging serums, sunscreens, cleansing milks and leave-on treatments. Its main role is behind the scenes helping other ingredients work as intended while extending the shelf life and overall performance of the formula.
Potassium Borate’s Cosmetic Benefits/Uses
Below is the key way this ingredient supports a formula
Buffering: Potassium borate helps keep the product’s pH in the ideal range so active ingredients remain effective and the formula feels comfortable on the skin. By preventing sudden pH shifts it also protects the product from breaking down too quickly which improves shelf life and consistency.
Who Can Use Potassium Borate
Potassium borate is considered suitable for most skin types, including dry, oily, combination and normal skin, because it is used at very low levels and does not clog pores or add oil. People with very sensitive or compromised skin can generally tolerate it as well, though anyone with a known boron allergy should avoid products containing it.
Because potassium borate is a mineral-based ingredient that does not rely on animal derivatives at any stage of production, it is appropriate for vegans and vegetarians.
The small amounts found in cosmetics are not known to pose risks to women who are pregnant or breastfeeding. That said this is not medical advice and anyone who is expecting or nursing should check with a healthcare professional before adding new skincare products to their routine.
Potassium borate does not cause photosensitivity, so it will not make skin more prone to sunburn. It also plays well with common actives like vitamin C and niacinamide, helping them stay in their optimal pH range.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical potassium borate can vary from person to person. The points below describe potential outcomes that are unlikely for the average user when the ingredient is properly formulated and used as directed.
- Mild skin irritation
- Redness or stinging on very sensitive or broken skin
- Allergic contact dermatitis in individuals with a boron sensitivity
- Eye irritation if the product accidentally gets into the eyes
If any of these reactions occur stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 0 – Potassium borate is a highly water-soluble inorganic salt that does not leave an oily or waxy residue on skin, so it will not obstruct pores or contribute to blackheads.
This makes the ingredient suitable for those who are prone to acne or frequent breakouts.
Because it is used at very low concentrations and quickly dissolves into a formula’s water phase, there is no realistic scenario in which it would build up on the skin’s surface.
Summary
Potassium borate is mainly valued as a buffering agent that locks a product’s pH into the sweet spot where other actives stay effective and textures stay pleasant. By neutralizing excess acidity or alkalinity it safeguards formula stability and shelf life.
Although it performs an essential backstage role it is not a headline ingredient, so it is less talked about than trendy actives like retinol or peptides. Still many mainstream moisturizers, masks and sunscreens rely on it quietly doing its job.
Safety data show it is well tolerated across skin types when used within normal cosmetic limits, with irritation or allergy being rare. As with any new product though a quick patch test is a smart habit to confirm individual compatibility.