Hi
Histidine
HistidineHydrator
An amino acid that helps the skin hold water.
What it does
Histidine is an amino acid. The skin breaks down its own proteins into amino acids like it as part of its natural moisturizing factor, and in a formula it helps hold water. Drop has read no study of it on skin; it is listed for the job it does in the formula.
Browse all 706 ingredients — grouped by what they do, each with whatever evidence we can cite.
This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
Want more like this?
Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.