For healthcare professionals. Compounded preparations are dispensed on a doctor’s prescription.
Short answer: A 2023 Cochrane systematic review found that cranberry products probably reduced symptomatic, culture-verified UTIs in women with recurrent UTIs (8 studies, 1,555 participants; RR 0.74, 95% CI 0.55 to 0.99) (The Cochrane database of systematic reviews, 2023; PMID 37068952). That finding is about cranberry products, not isolated proanthocyanidins.
What this review is, and what it is not
Cochrane systematic reviews pool randomised trials on one question. This one, Cranberries for preventing urinary tract infections (The Cochrane database of systematic reviews, 2023; PMID 37068952), is the fifth update of a review first published in 1998. Its question is whether cranberry products prevent UTIs in susceptible populations. It is a review of cranberry products as they were tested in trials. It is not a review of isolated proanthocyanidins.
The review’s background notes that cranberries contain proanthocyanidins, which inhibit the adherence of p-fimbriated Escherichia coli to the urothelial cells lining the bladder. That is mechanism described in the background. It is not a result in people, and it is not the basis of the clinical findings below.
What the review searched and included
The authors searched the Cochrane Kidney and Transplant Specialised Register up to 13 March 2023, drawing on CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register Search Portal and ClinicalTrials.gov. They included randomised or quasi-randomised trials of cranberry products compared with placebo, no specific treatment, or another intervention for UTI prevention. The update added 26 new studies, bringing the total to 50 included studies with 8,857 randomised participants (PMID 37068952).
Forty-five studies compared cranberry products with placebo or no specific treatment, across six participant groups. Twenty-six of those 45 could be pooled for the outcome of symptomatic, culture-verified UTIs, with 6,211 participants. For that pooled outcome the abstract reports moderate-certainty evidence that cranberry products reduced the risk of UTIs (RR 0.70, 95% CI 0.58 to 0.84; I² = 69%) (PMID 37068952).
The finding in women with recurrent UTIs
In women with recurrent UTIs, the review reports that cranberry products probably reduced the risk of symptomatic, culture-verified UTIs: 8 studies, 1,555 participants, RR 0.74, 95% CI 0.55 to 0.99, I² = 54% (The Cochrane database of systematic reviews, 2023; PMID 37068952). The upper limit of the interval, 0.99, sits very close to no effect, so the size of any benefit is uncertain even where the point estimate favours cranberry.
Other groups in the same review
The same review reports the outcome in children (5 studies, 504 participants; RR 0.46, 95% CI 0.32 to 0.68; I² = 21%) and in people with a susceptibility to UTIs due to an intervention (6 studies, 1,434 participants; RR 0.47, 95% CI 0.37 to 0.61; I² = 0%) (PMID 37068952). These are different populations from women with recurrent UTIs. Each figure should be quoted with its own population label, and none should be used to describe another group.
Summary of the pooled results
| Population group, as reported | Studies | Participants | RR (95% CI) | I² | PMID |
|---|---|---|---|---|---|
| All studies pooled for symptomatic, culture-verified UTIs | 26 | 6,211 | 0.70 (0.58 to 0.84) | 69% | 37068952 |
| Women with recurrent UTIs | 8 | 1,555 | 0.74 (0.55 to 0.99) | 54% | 37068952 |
| Children | 5 | 504 | 0.46 (0.32 to 0.68) | 21% | 37068952 |
| Susceptibility to UTIs due to an intervention | 6 | 1,434 | 0.47 (0.37 to 0.61) | 0% | 37068952 |
Who the review is for
The populations in this review are recurrent UTI in women, children, and people with a susceptibility to UTIs due to an intervention. A prescriber treating a different group should say so on the request and should not extend the figures to that group. Where a request concerns a patient outside these groups, the decision rests on the prescriber’s assessment of that patient, not on this review.
What the review cannot tell a prescriber
The review describes cranberry products. It does not describe an isolated proanthocyanidin preparation, and the abstract does not report the proanthocyanidin content of the products it pooled. Heterogeneity is substantial in the overall pooled result (I² = 69%), so that figure summarises studies that differed from one another.
A prescriber who needs the review’s full conclusions should read the review itself before any clinical decision.
A compounded proanthocyanidin request is a different product
A compounded cranberry proanthocyanidin request is a different product from the cranberry products in this review. A figure from the review may not be attached to a proanthocyanidin capsule or powder, and a prescriber should not describe a proanthocyanidin preparation as having the review’s result. Any preparation the prescriber requests is written and assessed on its own content.
Naming the active and its content
The request names the active as cranberry proanthocyanidins. A request that names only “cranberry” does not identify the active, because a cranberry product in a trial is not the same thing as a named proanthocyanidin content. The request states the content the prescriber requires, together with the strength per unit.
Capsule or powder: how the form is written
For cranberry proanthocyanidins, the form the request names is a non-sterile capsule or a powder in a container. The prescriber states the proanthocyanidin content the preparation must supply, because that content is what the request specifies, not the fruit it came from. For a capsule, the request gives the proanthocyanidin content in each capsule and the number to be made. For a powder, it gives the content per measured dose and the total amount in the container. Liposomal or ordinary delivery is the prescriber’s decision, recorded with its reason.
Excipients and the delivery system
Excipients the patient must avoid are named in full on the request, and any documented reaction the patient has had is written beside them. The prescriber also states whether an ordinary or a liposomal form is required and gives the clinical reason for that choice.
When a proanthocyanidin request goes beyond registered options
A proanthocyanidin request goes beyond what a registered option offers only where that option cannot supply the content, the form or the excipient profile this patient requires. The prescriber names which of the three is missing and why, so the pharmacy can see the reason before preparation begins.
Related reading
For a separate active with its own randomised trials and a 2025 meta-analysis on a related clinical question, see the D-mannose evidence article. The Good Compounding Practice (GCP) standard governs each proanthocyanidin preparation, and the GCP laboratory page details it.
How to prescribe
Name the active as cranberry proanthocyanidins, then state the strength per unit, the form, the quantity and the directions. Add the patient’s name and the prescriber’s name, signature and date. A registered doctor writes this request for a single named patient, never for general use.
A prescriber sends the signed request to Lynnity via the contact page. The items a prescriber checks before sending are listed in the prescriber’s checklist for referrals, prescriptions and GCP compliance.
Specification review: Vitthia Rama Murti, RPh (RPh 15632).
Frequently asked questions
What did the 2023 Cochrane review find for cranberry products and recurrent UTIs?
In women with recurrent UTIs, cranberry products probably reduced symptomatic, culture-verified UTIs: 8 studies, 1,555 participants, RR 0.74, 95% CI 0.55 to 0.99 (The Cochrane database of systematic reviews, 2023; PMID 37068952). The review concerns cranberry products, not isolated proanthocyanidins.
Do the Cochrane figures apply to a cranberry proanthocyanidin capsule or powder?
No. The review assessed cranberry products, and its abstract does not describe a proanthocyanidin-only preparation. Its figures must not be attributed to a proanthocyanidin capsule or powder.
What must a request for a cranberry proanthocyanidin preparation state?
The request names the active as cranberry proanthocyanidins, the content required, the strength per unit, the form, the quantity, the directions, the patient, and the reason a registered option does not fit. It is written by a registered doctor and made only for that patient under Good Compounding Practice (GCP).