Benefits
Blood sugar and insulin markers
Pooled analyses of randomized trials, most in adults with type 2 diabetes, found propolis taken by mouth, mostly as tablets or capsules, modestly lowered fasting glucose, HbA1c and insulin resistance versus placebo. The trials were small, used extracts from many regions, and certainty was rated low to moderate. In one 8-week Japanese trial insulin resistance did not change. It does not replace diabetes care.
Cholesterol and triglyceride levels
A pooled analysis of 22 trials found small drops in LDL cholesterol (about 9 mg/dL) and triglycerides (about 10 mg/dL) and a small rise in HDL, with no change in total cholesterol. In a 90-day trial of 94 adults with type 2 diabetes, HDL rose while LDL, triglycerides and total cholesterol did not change versus placebo. These are modest shifts in lab values, not proven effects on heart health.
Inflammation markers such as CRP
A pooled analysis of 27 trials reported lower CRP, IL-6 and TNF-alpha with propolis, but results varied widely between trials. A separate analysis limited to type 2 diabetes found lower CRP but no change in IL-6 or TNF-alpha, rating that evidence very low certainty. These are blood markers, not symptoms.
Antioxidant status in blood tests
The same pooled analysis found higher total antioxidant capacity, glutathione and glutathione peroxidase after propolis, but no change in malondialdehyde or superoxide dismutase. The diabetes-only analysis also found no change in those two markers. Lab markers of oxidative stress do not show a health outcome on their own.
Throat and upper respiratory comfort during colds
In a single trial of 122 adults with mild cold symptoms, a poplar-type propolis throat spray left 83% symptom-free by day 3, versus about 28% on placebo; everyone had recovered by day 5. One author worked for the extract supplier, and this was a spray rather than a swallowed capsule. We found no published trial showing that propolis on its own prevents colds.
Mouth lining comfort with oral capsules
In a small pilot of 19 people with recurring canker sores, 500 mg/day of propolis by capsule for about a year was linked to fewer outbreaks than placebo. A later review rated all propolis evidence for mouth ulcers very low certainty, and most of it came from rinses, pastes and sprays rather than swallowed tablets or capsules.
Mechanism of action
Composition depends on the plants bees visit
More than 800 compounds have been found in propolis. Poplar-type propolis from Europe and other temperate regions is dominated by flavonoids and caffeic acid esters, while Brazilian green propolis carries prenylated compounds such as artepillin C. This is why results from one extract may not apply to another.
Polyphenols are absorbed and cleared quickly
In a 10-person absorption study of a standardized poplar extract, dozens of phenolic metabolites peaked in the blood about an hour after intake, mainly as glucuronide and sulfate forms, and were mostly cleared in urine within 3 hours. The authors suggested more than one dose a day to keep levels up.
Antimicrobial and anti-inflammatory activity in the lab
Propolis compounds show antimicrobial, antioxidant, anti-inflammatory and immune-modulating activity in cell and animal studies. These lab findings help explain why it is studied for colds and inflammation, but they do not show the same effects in people.
Clinical trials
GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials of oral propolis on blood pressure, blood lipids and blood sugar (Bahari et al. 2025, Br J Nutr).
22 trials with 1,164 adults, many with type 2 diabetes or other metabolic conditions; extracts from different regions and doses.
Propolis lowered triglycerides (about 10 mg/dL), LDL (about 9 mg/dL), fasting glucose (about 7 mg/dL), HbA1c (0.32 points), insulin, HOMA-IR and systolic pressure (about 2 mmHg), and raised HDL (about 2 mg/dL). Total cholesterol and diastolic pressure did not change. Certainty was rated moderate for LDL, HDL, glucose and HbA1c.
Systematic review and meta-analysis of randomized controlled trials, with GRADE rating, of propolis on glucose, lipids, inflammation and oxidative stress in type 2 diabetes (Zhang et al. 2025, Front Nutr).
12 randomized trials with 731 adults with type 2 diabetes.
Propolis lowered fasting blood sugar, HbA1c, HOMA-IR, LDL, triglycerides and CRP and raised HDL. It had no effect on total cholesterol, TNF-alpha, IL-6, SOD or MDA. The authors rated the glucose and lipid evidence low certainty and the inflammation evidence very low, mainly because of risk of bias and imprecision.
Randomized, double-blind, placebo-controlled trial of Iranian (poplar-type) propolis capsules, 500 mg twice daily for 90 days (Zakerkish et al. 2019, Sci Rep).
94 adults with type 2 diabetes (50 propolis, 44 placebo).
Compared with placebo, propolis lowered HbA1c, 2-hour post-meal glucose, insulin, HOMA-IR, hs-CRP and TNF-alpha and raised HDL. Fasting glucose, triglycerides and LDL did not differ between groups. A single-center trial with no reported industry funding.
Randomized, double-blind, placebo-controlled trial of Brazilian green propolis for 8 weeks (Fukuda et al. 2015, Biomed Rep).
80 Japanese adults with type 2 diabetes (41 propolis, 39 placebo).
Insulin resistance (HOMA-IR) did not improve. Uric acid and kidney filtration (eGFR), also listed among the main measures, worsened from baseline on placebo but not on propolis; this is a within-group comparison, and a later meta-analysis listed no between-group differences in this trial's blood sugar, lipid or inflammation results. A lower dose of a different propolis type did not reproduce the insulin effects seen elsewhere.
Systematic review and meta-analysis of randomized controlled trials of oral propolis on inflammatory and oxidative stress biomarkers in adults (Bahari et al. 2025, Front Nutr).
27 trials (29 treatment arms) in adults, published 2003 to 2023, covering healthy people and people with diabetes and other conditions; most were run in Iran.
Propolis lowered CRP (by 1.23 mg/L), IL-6, TNF-alpha and MCP-1 and raised total antioxidant capacity, glutathione and glutathione peroxidase. IL-10, IL-2, IL-8, MDA and SOD did not change. Heterogeneity between trials was high (I2 about 87 to 93% for CRP, IL-6 and TNF-alpha).
Single-center, randomized, double-blind, placebo-controlled trial of a standardized poplar-type propolis oral spray, 2 to 4 sprays three times daily (12 to 24 mg polyphenols/day) for 5 days; one author is from extract supplier B Natural (Esposito et al. 2021, Phytomedicine).
122 otherwise healthy adults with self-reported mild, uncomplicated upper respiratory tract infection (58 propolis, 64 placebo).
By day 3, 83% of the propolis group had no symptoms, while 72% of the placebo group still had at least one. All participants had recovered by day 5, so the gain was about two days. No adverse reactions were linked to the spray. This tested a throat spray, not a swallowed supplement, and has not been repeated in an independent trial.
Randomized, double-blind, placebo-controlled trial of standardized Brazilian green propolis extract (EPP-AF) 900 mg/day for 10 days alongside hospital care; two authors are from Apis Flora, the extract's maker (Silveira et al. 2023, Sci Rep).
188 adults hospitalized with COVID-19 (98 propolis, 90 placebo).
Hospital stay, the primary outcome, was 6.5 vs 7.7 days, not a significant difference (p = 0.22). Oxygen need and kidney injury did not differ. Secondary infections were less frequent with propolis (6.1% vs 18.9%).
Randomized, double-blind, placebo-controlled pilot of 500 mg propolis capsules once daily, with outbreaks recorded every two weeks (Samet et al. 2007, Clin Oral Investig).
People with recurrent aphthous stomatitis (canker sores); 19 participants and about 13 months of follow-up according to a later systematic review.
More people on propolis than placebo had at least a 50% drop in outbreak frequency (one-sided p = 0.04), and self-rated quality of life improved. A 2024 review re-analysed it with a wide, non-significant risk ratio and rated the evidence very low certainty. A very small pilot.