Olive Leaf Extract

OLE’s major active compound oleuropein (and related phenolics such as hydroxytyrosol) shows antioxidant, anti-inflammatory, antiviral and some immunomodulatory effects in lab studies and in animal/human trials. Those mechanisms are plausibly relevant to supporting immune function (reducing oxidative stress, modulating inflammatory cytokines, and direct antimicrobial/antiviral activity). Frontiers MDPI

Key points:

• Antioxidant & anti-inflammatory: oleuropein and hydroxytyrosol scavenge free radicals and reduce pro-inflammatory markers in vitro and in vivo — this can protect immune cells from oxidative damage and temper excessive inflammation. FrontiersEMRO Dashboards
• Antiviral & antimicrobial activity (laboratory evidence): OLE/oleuropein has shown activity against several pathogens in cell studies, including respiratory viruses (e.g., RSV) and some evidence of hindering viral entry/replication in vitro. That is mechanistic support but does not equal proven clinical cure. MDPI Frontiers
• Immunomodulation (early human/animal data): some small human studies and preclinical work show effects on inflammatory markers, hematological parameters and outcomes relevant to infections/respiratory illness — promising but not definitive. ASH Publications SpringerLink

Important: there is no single universally-accepted clinical dosing guideline for every condition. Below are commonly used regimens reported in trials, reviews, and clinical references — but check with your clinician before starting.

Forms & standardization:

• OLE is sold as capsules, tablets, tinctures or powders. Look for products standardized for oleuropein (commonly 15–50% oleuropein depending on product). Standardization helps know how much active compound you’re taking. Frontiers Olive Wellness Institute

Typical adult dosing ranges reported in literature and product guidance:

• Common capsule/tablet range: ~500–1000 mg OLE daily, often divided into 1–2 doses. Many references describe products standardized to 15–20% oleuropein or higher; equivalent oleuropein content matters more than raw mg of “leaf extract.” Drugs.com wholehealth.com
• Clinical trials / study dosing: human trials vary — for example, trials looking at cardiovascular markers and some infection studies used extracts standardized and dosed in the above general range or per product specification. Always follow the specific product’s label or a prescriber’s guidance. SpringerLink ICHGCP

How to take it:

• Take with food if you experience GI upset. Divide daily dose (morning and evening) for steadier blood levels. WholisticResearch Olive Leaf
• For acute infections some protocols used continued dosing for several days to a few weeks; for general immune support a course of weeks to months is what many supplement protocols describe — but evidence for optimal duration is limited. Olive Leaf wholehealth.com

Monitoring and when to stop:

• If you are on blood pressure or blood sugar medications, anticoagulants, or pregnant/breastfeeding, stop and consult your clinician before use (see warnings below). Monitor blood pressure and blood glucose if you start OLE while on meds that affect those parameters. Drugs.com WebMD

Selected clinical trials & trials registry entries:

• Randomized trial – upper respiratory illness in athletes (Nutrients 2019): a randomized controlled trial that tested OLE supplementation and measured upper respiratory illness outcomes in high-school athletes. Useful clinical evidence about OLE and respiratory illness incidence/duration. MDPI
• Clinical trial registrations for infectious disease / COVID-19: trials have been registered to evaluate standardized olive leaf capsules in mild-to-moderate COVID-19 and other conditions (e.g., NCT04873349 — a placebo-controlled trial). Check outcomes once full results publish. ICHGCP ScienceDirect
• Ongoing / recent trials: other registered studies include trials on oleuropein for muscle fatigue and hematological parameters — these show ongoing clinical interest and experimentation but are not direct proof of immune restoration. ICHGCP ASH Publications

Systematic reviews and narrative reviews summarizing the evidence:

• Frontiers (2022) review on olive leaves as phytotherapy — thorough review of OLE pharmacology, antiviral/anti-inflammatory evidence and potential clinical applications (summarizes mechanisms and preclinical/clinical data). Frontiers
• MDPI review (2024) — comprehensive review of therapeutic potential, pharmacology and safety considerations. Good for mechanistic and evidence summaries. MDPI
• WHO-region / Pakistan Journal review (2020) — earlier review of olive leaf biological activities (antioxidant, antimicrobial, etc.). EMRO Dashboards

What the trials show overall:

• There is biological plausibility and promising early clinical signals (some RCTs/small trials) for supporting respiratory health and reducing certain risk markers, but evidence is not yet strong enough to call OLE a proven therapy for immune deficiency or for treating infections in place of standard care. Larger, well-designed clinical trials are still needed. MDPI Frontiers