Ingredient dictionary
Sodium Polynaphthalenesulfonate
A large, water-soluble salt made from linked naphthalene units. Its main job is to keep fine solid particles evenly spread in a liquid. Checked against our library November 6, 2026.
What Sodium Polynaphthalenesulfonate does
- Keeps pigment particles evenly spread through water
- Stops solid particles from clumping together
- Helps formulas stay smooth and uniform
Manufacturers start with naphthalene, a compound taken from coal tar or petroleum. It is treated to add sulfonate groups, linked into longer chains, and then neutralized with sodium.
Its many charged sulfonate groups make it dissolve easily in water. That lets it cling to tiny solid particles and push them apart, so they do not settle or clump. In cosmetics it is mostly a behind-the-scenes helper, so it usually goes unnoticed in the final texture.
Good for
Water-based makeup and skincare with color or solid particles that need to stay evenly mixed.
Frequently asked questions
Is Sodium Polynaphthalenesulfonate safe in skincare?
It is used in small amounts to keep particles evenly spread, and no specific safety flag applies to it here. Skin reactions are personal, though, so patch testing a new product on a small area first is a sensible habit.
Is it the same as naphthalene?
No. Naphthalene is the starting building block. The finished ingredient is a much larger salt made from many linked units, with different behavior. The two are not interchangeable.