Benefits
Cholesterol support: one uncontrolled pilot of a sister olive extract
In a 4-week single-arm pilot in 30 adults with raised LDL cholesterol on a low-fat Mediterranean diet, 100 mg daily of SelectSIEVE OptiChol, a hydroxytyrosol-rich olive extract from the same line, was followed by about 6.5 percent lower LDL and 9 percent higher HDL than at baseline. There was no placebo group, and SelectSIEVE Olive itself was not tested.
Antioxidant protection of LDL (olive polyphenol class evidence)
In a randomized crossover trial in 200 healthy men, olive oils richer in polyphenols raised HDL and lowered oxidative stress markers in step with polyphenol content; only the high-polyphenol oil lowered oxidized LDL. In a 16-week placebo-controlled trial in 49 adults with overweight and prediabetes, 15 mg of hydroxytyrosol daily lowered oxidized LDL and oxidation markers, with no change in blood lipids. Neither tested SelectSIEVE Olive.
Blood pressure, glucose and uric acid: small uncontrolled changes
In the same 4-week single-arm pilot of the sister extract SelectSIEVE OptiChol, systolic blood pressure went from about 133 to 130 mmHg, fasting glucose from 90 to 85 mg/dL and uric acid from 8.6 to 7.7 mg/dL compared with baseline. Diastolic pressure, triglycerides and waist size did not change. Without a control group these changes are unconfirmed.
Mechanism of action
Free radical scavenging by hydroxytyrosol
Hydroxytyrosol, the main polyphenol in hydroxytyrosol-standardized olive extracts such as OptiChol, acts as a free radical scavenger and metal chelator in laboratory work. In people, polyphenol-rich olive oil and a hydroxytyrosol supplement lowered oxidized LDL in the trials cited here. The hydroxytyrosol content of SelectSIEVE Olive has not been published, and this effect has not been measured for it.
Cholesterol pathways (maker's laboratory data)
Roelmi HPC states that its OptiChol olive extract inhibited HMG-CoA reductase, an enzyme in cholesterol production, in laboratory tests, and that olive polyphenols can act on LDL receptor pathways. The maker says these data are available on request; we found no published report, and they do not show the same effect in people or for SelectSIEVE Olive.
Clinical trials
Single-arm, non-randomized pilot study with no control group: after a 2-week low-fat, low-sodium Mediterranean diet run-in, participants took one 100 mg capsule daily of SelectSIEVE OptiChol (4 to 9 percent hydroxytyrosol, from olive oil production by-products of Coratina olives, made by Roelmi HPC) for 4 weeks while staying on the diet. OptiChol is a sister product in the SelectSIEVE line and is not stated to be the same extract as SelectSIEVE Olive. The paper reports no external funding and no conflicts of interest. (Cicero et al. 2022, Applied Sciences)
30 Italian adults aged 20 to 70 (mean 53) with polygenic hypercholesterolemia, LDL cholesterol between 115 and 190 mg/dL, low cardiovascular risk and no lipid-lowering treatment.
Compared with baseline (no control group), total cholesterol went from 238 to 225 mg/dL, LDL from 155 to 145 mg/dL and non-HDL from 198 to 177 mg/dL, while HDL rose from 44 to 48 mg/dL; systolic blood pressure, pulse pressure, fasting glucose and uric acid also fell slightly (all p < 0.05). Triglycerides, diastolic pressure, body mass index, waist size and liver enzymes did not change, and no adverse events were reported. During the diet-only run-in, total cholesterol had already fallen from 248 to 238 mg/dL and LDL from 161 to 155 mg/dL.
Randomized, controlled crossover trial (EUROLIVE) at 6 research centres in 5 European countries. Participants took 25 mL a day of three olive oils with low (2.7 mg/kg), medium (164 mg/kg) or high (366 mg/kg) polyphenol content for 3 weeks each, separated by 2-week washouts. It tested olive oil, not SelectSIEVE Olive. (Covas et al. 2006, Annals of Internal Medicine)
200 healthy men.
HDL cholesterol rose linearly with polyphenol content (by 0.025, 0.032 and 0.045 mmol/L), the total to HDL cholesterol ratio fell, and oxidative stress markers fell as polyphenol content rose; oxidized LDL fell significantly (by 3.21 U/L) only on the high-polyphenol oil. Triglycerides fell by about 0.05 mmol/L on all three oils.
Randomized, double-blind, placebo-controlled parallel trial of 15 mg hydroxytyrosol daily for 16 weeks; 52 people were randomized and 49 completed. The primary outcome was oxidized LDL. It tested a hydroxytyrosol supplement, not SelectSIEVE Olive, and the authors, from Spanish public research centres and a public university, declared no conflicts of interest. (Moratilla-Rivera et al. 2025, Clinical Nutrition)
Adults aged 40 to 70 with overweight and prediabetes.
Compared with placebo, hydroxytyrosol lowered oxidized LDL (p = 0.045), protein carbonyls (p = 0.031) and the DNA oxidation marker 8-OHdG (p < 0.01), prevented a fall in total antioxidant status and glutathione peroxidase activity, and lowered IL-6 (p = 0.05). Blood lipids, body measures and lifestyle measures did not change, and no adverse events were seen.