09/08/2026
A randomised, double blind, placebo-controlled, parallel-group trial evaluated whether a combination of standardised olive leaf extract (OLE) and potassium could improve blood pressure and cardiometabolic risk factors in adults with untreated mild-to-moderate hypertension over 12 weeks. Seventy participants were randomised to placebo or OLE, with 68 included in the final intention-to-treat analysis. Participants had a mean age of 58.8 years, untreated systolic blood pressure was between 130 and 159 mmHg, and BMI was 18.5 to 35 kg/m².
The active intervention consisted of two film-coated tablets daily, each containing 500 mg hydroethanolic olive leaf extract and 150 mg potassium (as potassium citrate). Independent HPLC analysis confirmed an actual oleuropein content of 22.08%, equivalent to approximately 221 mg oleuropein per day. The daily dose corresponded to approximately 9 to 16 g of dried olive leaves.
Although office measured blood pressure declined significantly in both groups, there was no significant difference between active treatment and placebo. In contrast, seven-day home blood pressure monitoring demonstrated a clinically meaningful advantage for the intervention, with morning systolic blood pressure falling by 5.4 mmHg compared with 2.1 mmHg in the placebo group, and similar improvements observed in evening systolic pressure. Smaller reductions in diastolic blood pressure were also seen. The treatment additionally resulted in small reductions in total cholesterol, LDL cholesterol and triglycerides, while HDL cholesterol remained unchanged. Fasting glucose and HbA1c were unaffected, although fasting insulin and insulin resistance both fell by approximately 15%, with such changes representing favourable trends rather than clearly significant between-group differences. More significantly oxidised LDL was reduced by approximately 23%.
The intervention was well tolerated, with no product-related serious adverse events. Mild gastrointestinal symptoms were the most common adverse effects, and liver function, renal function and serum potassium remained within normal limits.
Overall, this was a well-conducted clinical trial providing moderate evidence that a standardised olive leaf extract with 300 mg potassium can modestly reduce home systolic blood pressure and improve selected cardiometabolic markers, particularly oxidised LDL, in adults with mild hypertension.
For more information see: https://pubmed.ncbi.nlm.nih.gov/41935461/
