Hydroxyphenylethanols

PhytochemicalPhenolic compoundBest with a meal

What is it

Hydroxyphenylethanols are a group of phenolic compounds found in olive oil and other plants. The best-known member is hydroxytyrosol, a notable antioxidant in extra-virgin olive oil.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Protection of LDL from oxidation

Good Evidence

The European Food Safety Authority authorized a health claim for hydroxytyrosol-rich olive polyphenols at 5 mg/day for protection of LDL cholesterol from oxidative damage.

How it works

Hydroxyphenylethanols donate electrons to neutralize free radicals, contributing to the antioxidant capacity of olive oil. Hydroxytyrosol in particular is the basis of an authorized EU health claim for protection of LDL cholesterol from oxidative damage. After ingestion, hydroxytyrosol and related compounds are absorbed in the small intestine and metabolized in the liver to sulfate and glucuronide conjugates. Plasma levels peak within an hour and decline over several hours.

Dosage

The European Food Safety Authority concluded that 5 mg of hydroxytyrosol per day from olive oil contributes to protection of LDL from oxidation, requiring 20 g of olive oil at typical hydroxytyrosol levels. Supplement doses range from 5 to 50 mg per day.

When and how to take it

Hydroxyphenylethanols are best consumed as part of a meal, typically with extra-virgin olive oil over food. Supplements have no critical timing requirement.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Olive leaf or fruit extract

Most supplements use olive leaf or olive fruit extract standardized for total polyphenol content.

Standardized to hydroxytyrosol or oleuropein content.

Pure hydroxytyrosol

Available as isolated ingredient in some specialty products.

Rapidly absorbed and conjugated.

Safety

Generally well tolerated at dietary and supplemental doses. Olive oil constituents have a long human-consumption history. Very high doses in animal studies showed no consistent toxicity.

Who should be cautious

No specific cautions at dietary doses. Pregnant or breastfeeding people should keep doses within food-range intake from olive oil.

Interactions

No significant interactions reported at dietary doses. Theoretical caution applies with high-dose antioxidant supplements alongside certain chemotherapy agents.

Food sources

Extra-virgin olive oil

Amount
20 g (about 1.5 tbsp)
%DV
—

Olives (cured)

Amount
10 olives
%DV
—

Frequently asked questions

What is the most important hydroxyphenylethanol?⌄

Hydroxytyrosol from olive oil is the best-studied member and is the subject of an authorized EU health claim.

Are olive polyphenol supplements as good as olive oil?⌄

Supplements can deliver standardized doses, but extra-virgin olive oil provides a broader matrix of polyphenols and monounsaturated fats.

References

Hydroxyphenylethanols on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Hydroxyphenylethanols (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.