Intravaginal Vitamin C for the Treatment and Prevention of Bacterial Vaginosis: A Systematic Review and Meta-analysis
Intravaginal vitamin C may modestly increase short-term cure and may lower six-month recurrence, but evidence is low certainty.
*Systematic review and meta-analysis of randomized trials; Level 1a (OCEBM).
*Systematic review and meta-analysis of randomized trials; Level 1a (OCEBM).
Citation
Khaikin Y, Elangainesan P, Winkler E, Liu K, Selk A, Yudin MH. Intravaginal Vitamin C for the Treatment and Prevention of Bacterial Vaginosis: A Systematic Review and Meta-analysis. Obstetrics & Gynecology. 2026;147:491–500. doi:10.1097/AOG.0000000000006092.
Background
Bacterial vaginosis is a common cause of bothersome vaginal discharge and often comes back after antibiotics. Vitamin C placed in the vagina may help by making the vaginal environment more acidic.
Patients
Nonpregnant patients with bacterial vaginosis in randomized trials (9 trials; 1,107 total). Excluded: trials enrolling only pregnant patients; pregnancy-specific outcomes.
Intervention
Intravaginal vitamin C, usually 250 mg daily for 6–8 days (one prevention trial used a 6-day course monthly).
Control
Placebo or no treatment, or metronidazole.
Outcome
Cure (clinical or laboratory) and recurrence; side effects.
Follow-up Period
Treatment trials: up to 30 days (typically 1–3 weeks). Recurrence trial: 6 months.
Results
| Comparison | Outcome | Vitamin C vs comparator | Risk ratio (95% confidence interval) | NNT |
|---|---|---|---|---|
| Vitamin C vs placebo/no treatment | Cure at 1–3 weeks (primary) | 66% vs 42% | 1.57 (1.03–2.39) | 5 |
| Vitamin C vs metronidazole | Cure at 1–2 weeks (primary) | 62% vs 52% | 1.20 (1.03–1.41) | 10 |
| Vitamin C vs placebo | Recurrence by 6 months (primary) | 16% vs 32% | 0.50 (0.27–0.93) | 7 |
Side effects (such as irritation or burning) were uncommon and similar between groups.
Limitations
Most trials had moderate-to-high risk of bias and poor reporting. Follow-up for cure was short (no primary-treatment trial beyond 30 days). Only one trial evaluated recurrence. Results may not generalize broadly, and vitamin C products may not be regulator-approved in some countries.
Funding
Canadian academic awards and scholarship; sponsors not involved; no conflicts reported.
Clinical Application
Consider intravaginal vitamin C as an option when antibiotics are undesired or as an add-on, but discuss low-certainty evidence and limited long-term data.
Discussion
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In this systematic review/meta-analysis of randomized trials, intravaginal vitamin C increased short-term bacterial vaginosis cure versus control (66% vs 42%; RR 1.57, 95% CI 1.03–2.39). Given low-certainty evidence, bias concerns, and ≤30-day follow-up, would you change practice or offer it selectively? The review reported short-term cure in 66% of patients receiving intravaginal vitamin C versus 42% in controls, with RR 1.57. Which interpretation best distinguishes the absolute and relative effects?