Benefits
Less LDL oxidation in a 16-week placebo-controlled trial
In a randomized double-blind trial in 49 adults aged 40 to 70 with overweight and prediabetes, Hytolive capsules supplying 15 mg of hydroxytyrosol a day for 16 weeks lowered oxidized LDL, the trial's main outcome, compared with placebo (p = 0.045). The blood lipid profile did not change. The maker funded the study.
Other oxidative stress markers in the same trial
In the same 16-week trial, protein carbonyls and 8-OHdG, a marker of oxidative damage to DNA, fell compared with placebo, and total antioxidant status and glutathione peroxidase activity held steady instead of declining. IL-6, an inflammation marker, was lower (p = 0.05). Body measurements, sleep, well-being and physical capacity did not change.
EU olive oil polyphenol claim: applies to olive oil, not capsules
The EU authorizes the claim that olive oil polyphenols contribute to the protection of blood lipids from oxidative stress only for olive oil containing at least 5 mg of hydroxytyrosol and its derivatives per 20 g, with the benefit tied to 20 g of that oil daily. It does not cover hydroxytyrosol capsules such as Hytolive.
Blood pressure: no Hytolive result; a different olive extract was null
No Hytolive trial has reported a blood pressure result. In an 8-week placebo-controlled trial in 56 adults with systolic pressure of 130 mmHg or more, a different olive leaf and fruit extract supplying 25 mg of hydroxytyrosol and 124 mg of oleuropein a day lowered systolic pressure by about 8 mmHg, but placebo lowered it by about 7 mmHg, with no significant difference.
Mechanism of action
Catechol antioxidant chemistry; enzyme induction not confirmed in people
Hydroxytyrosol has a catechol (two adjacent hydroxyl groups) structure that neutralizes free radicals in laboratory tests, and cell and animal studies suggest it switches on the Nrf2 pathway that controls the body's own antioxidant enzymes. In a one-week placebo-controlled human trial, 5 or 25 mg a day of hydroxytyrosol did not change the expression of these enzymes in blood cells.
Clinical trials
Randomized, double-blind, placebo-controlled parallel trial: one capsule supplying 15 mg of hydroxytyrosol, or placebo, daily for 16 weeks; the registration (NCT06295913) names the Hytolive capsule and lists Genosa I+D as collaborator, and trade press reports the maker funded it, although the paper declares no conflicts of interest (Moratilla-Rivera et al. 2025, Clinical Nutrition)
52 adults aged 40 to 70 with overweight and prediabetes were randomized and 49 completed (24 hydroxytyrosol, 25 placebo).
Oxidized LDL, the main outcome, fell compared with placebo (p = 0.045), as did protein carbonyls and 8-OHdG, a marker of DNA oxidation. Total antioxidant status and glutathione peroxidase activity were kept from declining and IL-6 was lower (p = 0.05). Blood lipids, body measurements, sleep, well-being and physical capacity did not change, and no adverse events were seen.
Open-label pilot with randomized withdrawal: hydroxytyrosol from Hytolive (liquid or powder) daily for 12 months, then children were randomly assigned to stop or continue for 6 more months; funded by the Hong Kong government Health and Medical Research Fund (Wong et al. 2025, Orphanet Journal of Rare Diseases)
9 children and teenagers aged 3 to 17 with inherited mitochondrial disorders, taking 10 mg a day (ages 3 to 10) or 30 mg a day (ages 11 to 18).
Most children showed no definite change in the main outcome, a mitochondrial disease rating score, and no clear difference appeared after stopping. Quality-of-life scores improved in some children while taking it. No adverse effects were reported. With no placebo group and 9 participants, it mainly shows that the doses were tolerated.