Olive leaf extract (Olea europaea, oleuropein)

Olive leaf extract (Olea europaea) with oleuropein is sold as a supplement for cancer prevention. There is no convincing evidence of benefit for this use – the data needed to show that such supplements lower cancer risk simply are not there. What does lower risk are approaches with proven benefit: quitting smoking, age- and risk-appropriate screening, and vaccination against HPV and hepatitis B. Do not use this extract in place of prevention or treatment with proven benefit, since that can mean missing the care you need.

Olive leaf extract (Olea europaea) and its compound oleuropein are marketed as an immune supplement and antiviral support, including for herpes simplex. No convincing benefit has been shown for herpes – there is no evidence base for this use. Herpes simplex flare-ups respond to antiviral drugs such as aciclovir, valaciclovir, and famciclovir, and the sooner treatment starts, the better it works. Olive leaf extract is harmless, but don't use it instead of treatment with proven benefit, since that can mean missing the care you actually need.

Olive leaf extract is sold as a «natural antihypertensive» promising blood pressure reduction in stage 1. The Susalit 2011 RCT in 232 prehypertensive and stage-1 hypertensive patients compared olive extract 1000 mg/day with captopril 12.5-25 mg twice daily over 8 weeks: both lowered systolic BP by about 11 mmHg; the difference was not significant. Limitations: single-centre design, no placebo group, small sample, short duration. No RCT on olive leaf extract with cardiovascular mortality, MI or stroke endpoints. EMA HMPC 2014 recognises «traditional use for mild blood pressure elevation». ESC 2024 and SEH-LELHA 2022 in HTN first-line list lifestyle modification (DASH, salt restriction, physical activity) and as needed ACE inhibitors or ARBs combined with diuretic or calcium channel blocker; olive leaf is not in international guidelines. If olive leaf extract was recommended as a substitute for ACE inhibitor or sartan in confirmed HTN, consider seeking a second opinion.

Olive leaf extract (Olea europaea), whose active component is oleuropein, is marketed as a supplement for immune support and for preventing colds and other respiratory infections. There is no convincing evidence for this use: good-quality clinical trials showing an effect on how often people catch a respiratory infection or how it runs have not been done. For a cold, rest, fluids, and symptom relief are what actually help, and the main protection against flu is vaccination. The substance itself is harmless in normal dietary amounts, but do not use it instead of treatment with proven benefit, since that can mean missing the care you need.