A cranberry plant (Vaccinium macrocarpon) with a red berry among the leaves
Kristine Paulus · CC BY 2.0
How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Cranberry
A small red fruit from North America (Vaccinium macrocarpon). In women prone to recurrent urinary tract infections, it reduces the risk by about a quarter; nothing in elderly people in nursing homes, and no solid evidence to treat an infection that is already there.
Benefits
- Reduces the risk of a new urinary tract infection by 26% in healthy women prone to recurrences (meta-analysis of 7 trials, 1,498 participants)
- Probably reduces urinary tract infections in women with recurrent infections, in children and after certain medical procedures (2023 Cochrane review: 50 studies, 8,857 participants)
- As juice: 27% fewer urinary tract infections than with liquid placebo, and 49% fewer antibiotics (meta-analysis of 20 trials, 3,091 participants)
- 500 mg of whole fruit powder per day: 52% fewer culture-confirmed urinary tract infections in 150 women with recurrent infections
- A slightly better total cholesterol / HDL ratio and slightly less insulin resistance (HOMA-IR), with no effect on LDL or fasting blood glucose (meta-analysis of 16 studies)
Precautions
Kidney stones: in 15 participants, cranberry tablets increased oxalate in the urine, and the authors advise against cranberries for people at risk of stones. Anticoagulants (warfarin): one published case of increased INR after cranberry sauce, and other case reports pointing in the same direction; controlled trials do not find any notable interaction (30 patients: a slight increase in INR at a single time point; 10 patients on high-dose juice: nothing). If you are taking an anticoagulant, tell your doctor. The Cochrane review sees no more digestive disorders than with placebo. Limitations: the 2023 Cochrane review does not support cranberries in the elderly, pregnant women or in cases of bladder emptying problems; two nursing home trials (185 women, 928 residents) find little or no effect, no more than the trial in 171 multiple sclerosis patients. The 2012 version of the same review (24 studies) saw no effect. No decrease in blood pressure in the meta-analysis of 12 trials, and no significant effect on the eradication of Helicobacter pylori.
Recommended dosage
Every day, depending on the product: 500 mg of whole fruit powder, 240 mg of extract or a cranberry beverage, for 24 weeks to one year.
How to take it
- For whom: positive trials focus mainly on women who have repeated urinary tract infections.
- Dose: 500 mg of whole fruit powder per day in two trials (150 and 182 women), 240 mg of extract per day for 12 months in a trial of 160 women, a cranberry beverage every day for 24 weeks in a trial of 373 women.
- Duration: continuously, from 24 weeks to one year in the trials.
- Proanthocyanidins: two trials measure their extract in proanthocyanidins (36 and 72 mg per day), in patients with multiple sclerosis and in elderly women in nursing homes; neither trial finds an effect.
- To treat an infection that is already there: the 2023 Cochrane review finds no trials meeting its criteria; one trial versus an antibiotic (fosfomycin) reports better well-being with cranberries, which is not enough to decide.
Did you know?
The same question, two answers: in 2012, the Cochrane review (24 studies) found no effect of cranberries against urinary tract infections; in 2023, with 50 studies and 8,857 participants, it concludes that it probably reduces their risk in women prone to recurrences.
What the studies say
This systematic review and meta-analysis, pooling 12 randomized clinical trials, evaluated the effect of cranberry consumption on blood pressure. Overall results showed no statistically significant reduction in systolic or diastolic blood pressure. Although subgroup analyses indicated significant reductions under certain conditions (e.g., juice, less than 8 weeks, young participants for SBP), cranberry was not found to be effective for overall blood pressure management.
Bahreyni LZ, Amini MR, Sheikhi L, Taheri E, Rahimi P, Samarin MM, Sheikhhossein F, Etesamnia S, Lohrasbi N, Hekmatdoost A. — Clinical cardiology (2026) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more