What it is
Phosphoric Acid is a common inorganic acid used at low levels to lower or stabilize the pH of a product so that it sits in the intended range. Correct pH supports the stability and performance of other ingredients and the comfort of the finished product on skin. In sunscreens it is a functional aid rather than an active.
Safety & warnings
As supplied it is acidic, but in finished cosmetics it is used in small, neutralized amounts to set the product's pH and is well tolerated at use levels. It is not a fragrance allergen.
Origin & sourcing
Synthetic mineral acid; manufactured industrially and supplied as an aqueous solution.
Questions everyone asks
Why is phosphoric acid in my sunscreen?
It is used in small amounts to adjust and stabilize the product's pH so the formula stays in its intended range.
Is phosphoric acid an exfoliant?
No. In these products it functions as a pH adjuster, not as an exfoliating acid.