Research
Vitamin C for Bladder Health: Evidence, Interactions and Cautions
Vitamin C is an ingredient used in bladder supplements marketed to women. Below is what it has actually been studied for, how strong that evidence is, the drug interactions and cautions on record, and the primary source our grade rests on — all drawn from the HerWellReport ingredient dataset.
Also sold as: Ascorbic acid; L-ascorbic acid
What the evidence says about Vitamin C
A 2018 BMC Pregnancy and Childbirth systematic review of non-antibiotic UTI prevention in pregnancy found a single relevant trial, Ochoa-Brust 2007, in which 110 pregnant women took 100 mg ascorbic acid daily and 12.7% developed infection versus 29.1% of controls. The reviewers flagged unclear intention-to-treat analysis and selection bias, because non-adherent women and those with serious side effects were excluded from the analysis. The acidification premise that most bladder supplements sell also does not hold up: 500 mg six-hourly failed to produce a significant fall in urine pH in spinal cord injury patients, and 4 g daily alongside methenamine had no significant effect on mean urine pH in catheterised patients. There is no trial in midlife or postmenopausal women.
The grade "very limited" means: very limited — Mostly animal, laboratory or anecdotal evidence, with at most a single weak human study. Grades are explained in full on our methodology page.
Read the primary source this grade rests on (opens in a new tab).
Vitamin C drug interactions
- Chemotherapy and radiotherapy (discuss with your oncologist before supplementing)
- niacin plus simvastatin (antioxidants may blunt the rise in HDL)
Who should be careful with Vitamin C
- Upper intake level is 2000 mg a day for adults
- higher doses cause diarrhoea, nausea and abdominal cramps
- high intakes raise urinary oxalate and uric acid excretion, so avoid them if you have had calcium oxalate stones, pre-existing hyperoxaluria or renal disease
- theoretical risk of excess iron absorption in haemochromatosis
Read more on HerWellReport
- Best Bladder Control Supplements for Women (2026): What’s Actually in Them
- Confitrol24 Review (2026): The Trial Is Real, But the Label Doesn’t Say How Much
- O Positiv MENO Review: The Capsule and the Gummy Aren’t the Same Dose
- Urox Bladder Control Review (2026): The Trial Behind It, and the Hidden Dose
- Utiva Cranberry PACs Review (2026): Does the Dose Match?
This entry is generated from row "Vitamin C (ascorbic acid)" of the HerWellReport ingredient dataset (v2.1, updated 2026-09-23). The dataset is free to reuse under CC BY 4.0 — how to cite it. Ingredient evidence is not evidence for any finished product, and nothing here is medical advice.