What it is
Triheptanoin is an ester of glycerin with the C7 fatty acid heptanoic acid, producing a low-viscosity oil that spreads readily and absorbs with a dry, silky after-feel. It is valued as a lightweight emollient and as a carrier that can dissolve oil-soluble ingredients and disperse pigments or UV filters. In sunscreens it helps thin heavier bases and improve sensory feel.
Safety & warnings
Triheptanoin is generally well tolerated with a low likelihood of irritation. Being a light, low-molecular-weight ester, it is considered a relatively low-comedogenicity emollient compared with heavier plant oils.
Origin & sourcing
Synthesized by esterifying glycerin with heptanoic acid; the heptanoic acid can be derived from natural oils such as castor oil or produced synthetically.
Questions everyone asks
Why is triheptanoin used instead of a heavier oil?
Its short C7 chains make it light and fast-absorbing, giving a dry, silky finish that many sunscreens and serums prefer over richer oils.
Does triheptanoin help with sun filters?
It can act as a solvent and carrier, helping dissolve oil-soluble UV filters and disperse pigments evenly in the formula.