Ingredient dictionary

Fructooligosaccharides

Also listed as: FOS, Oligofructose

Fructooligosaccharides are short chains of fructose sugar units that mainly act as humectants, helping a formula hold onto water. It is on the label of 20 products in our library. Checked against our library November 6, 2026.

What Fructooligosaccharides does

Holds water in the formula
Softens skin and hair
Supports a light, non-greasy texture

Fructooligosaccharides, often shortened to FOS, are small chains of fructose, a natural sugar. Makers either build them from sucrose using enzymes, or cut longer inulin chains from chicory root into shorter pieces.

Formulators use FOS because it dissolves easily in water and stays clear. It acts as a humectant, drawing water into a product and holding it on the skin or hair. In cleansers and shampoos, it adds a smooth, soft feel without a greasy film, which is why it appears in so many gentle washes.

Good for

Suits people who want a gentle, moisture-friendly wash for face, body, or hair. Often seen in sensitive-skin and baby products.

Frequently asked questions

Is fructooligosaccharides the same as inulin?

They are related but not identical. Inulin is a longer chain of fructose units. Fructooligosaccharides are shorter chains, and many are made by breaking inulin down. Both are sugar-based and act mainly as humectants in beauty products.

Is FOS gentle for sensitive skin?

FOS is generally considered well tolerated and is common in gentle washes. Still, any ingredient can irritate some people. If your skin reacts easily, test a small patch of a new product first and stop using it if redness or stinging appears.