Table 1. Characteristics of included studies.

Study reference	Country	Study design	Age/ Mean age	Male/ Female (%)	Number of participants included	Number of participants completed the intervention	Participants in intervention group	Participants in comparator group	Indication	Drugs	Comparator	Duration of trials	Outcome
Javadi et al., 2019	Iran	Randomized, double-blind placebo controlled clinical trial	30–60 years old Olive leaf extract: 53.8 ±  8.0 Placebo: 55.6 ±  8.8	45/55	60	60	30	30	Hypertensive patients	Olive leaf extract 250 mg, one tablet twice daily	Placebo, one tablet twice daily	12 weeks	1. Metabolic parameters-FBS and Insulin, HOMA-IR 2. Biomarkers of inflammation-TNF-alpha, IL-6 and 1L-8 3. Liver function- AST, ALT 4. Kidney function- Creatinine
Yaghoobzadeh et al., 2020	Iran	Randomized, double-blind placebo-controlled clinical trial	30-60 years old Olive leaf extract: 52.9 ± 10.3 Placebo: 57.9 ± 10.8	50/50	60	60	30	30	Essential hypertension	Olive leaf extract 250 mg, one tablet twice per day	Placebo, one tablet twice per day	12 weeks	1. BP 2. Blood lipids 3. Oxidative stress (total antioxidant capacity (TAC), glutathione (GSH), Malondialdehyde (MDA))
Wong et al., 2014	Australia	Randomized, double-blind, placebo-controlled cross-over	18–80 years old 58.5 ± 10.7	54/46	39	37	19	18	Blood pressure of 130–160 mmHg systolic and 85–100 mmHg diastolic	Combined formulation of Olive leaf extract 500 mg, green coffee bean extract 100 mg and 150 mg of beetroot powder per tablet, two tablets daily	Placebo, two tablets daily	(Data taken only at 6 weeks before cross- over of treatment arm)	1. BP 2. Blood lipids 3. Fasting blood glucose, insulin levels and HOMA-IR
Susalit et al., 2011	Indonesia	Randomized, double-blind active-controlled clinical trial	20-65 years old Olive leaf extract: 51.5 ± 5.8 Captopril: 49.7 ± 6.8	16.7/83.3	179	148	72	76	stage 1 hypertension with systolic blood pressure of 140-159 mmHg and diastolic blood pressure of either <90 mmHg or in between 90 and 99 mmHg	Olive leaf extract 500 mg, one tablet twice daily	Captopril 12.5 mg–25 mg, one tablet twice daily	8 weeks	1. BP 2. Lipid profile 3. Safety endpoints-liver function, renal function, Adverse effects
Perrinjaquet-Moccetti et al., 2008	Germany	Open, controlled, parallel-group, co-twin study	18 and 60 years old Olive leaf extract: 35.7 ± 14.8 Control (lifestyle modification): 38.1 ± 14.7	30/70	20 Monozygotic twins	20 Monozygotic twins completed	10	10	Untreated suboptimal blood pressure ≥120 mmHg systolic or 80 mmHg diastolic	Olive leaf extract 500 mg versus lifestyle modification (no medication) once daily		8 weeks	1. BP 2. Blood lipids 3. body weight