Hydroxytyrosol

3,4-Dihydroxyphenylethanol · Olive polyphenols

Snapshot

Indications	Contraindications
Oxidative stress markers^1–3 Inflammatory markers² Oxidized low-density lipoprotein² Cardiometabolic risk factors⁴ Endothelial function⁵ Cognitive health^6–8	Pregnancy or nursing⁹ Within two weeks of surgery⁹

Hydroxytyrosol is a phenolic alcohol from olive fruit, leaves, and oil whose antioxidant activity protects blood lipids from oxidative damage^{10, 11}. Supplementation is used for oxidative stress and inflammatory status, cardiometabolic risk markers, and endothelial function^{2, 5}. It is also used for cognitive aging and mitochondrial disease, where human data are sparse. Adults with overweight and prediabetes are the best-studied group.

The evidence is mixed. In a 2022 roundworm model, an olive extract rich in hydroxytyrosol delayed amyloid-induced paralysis and oxidative stress; human confirmation is lacking¹². Nearly two thousand products list hydroxytyrosol, mostly capsules of olive leaf or fruit extracts, and absorption varies with formulation and food matrix; see Form comparison.

On supplement labels in the United States, pregnancy and nursing are listed as reasons not to use⁹. The same labels route use alongside prescription medication to a physician first⁹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

67 sources, 53 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources