Can Vitamin C Cure Canker Sores?

Vitamin C supplementation is not an evidence-based treatment for recurrent aphthous stomatitis—commonly known as canker sores. While vitamin C plays a critical role in collagen synthesis, wound healing, and immune function, clinical studies have not demonstrated that oral vitamin C deficiency causes or exacerbates aphthous ulcers in otherwise healthy individuals. Most patients with recurrent oral ulcers have normal serum ascorbic acid levels.

Although severe vitamin C deficiency (scurvy) can cause mucosal bleeding and gingival inflammation, it rarely presents with isolated, painful, round or oval ulcerations typical of aphthae. Moreover, randomized controlled trials evaluating vitamin C supplementation—either alone or in combination with other micronutrients—have failed to show consistent improvement in ulcer frequency, duration, or severity.

Current guidelines from the American Academy of Oral Medicine and the European Association of Oral Medicine emphasize symptomatic management and identification of potential triggers—including stress, local trauma, hormonal fluctuations, food sensitivities (e.g., chocolate, nuts, acidic foods), and comorbid conditions such as celiac disease, inflammatory bowel disease, or nutritional deficiencies in iron, folate, or vitamin B12. In select cases, topical corticosteroids, analgesic mouth rinses, or systemic immunomodulators may be indicated for severe or refractory disease.

Patients considering dietary supplements should consult a healthcare provider to rule out underlying deficiencies or systemic disorders—not assume vitamin C deficiency is the cause. Unnecessary high-dose supplementation carries risks, including gastrointestinal distress and increased urinary oxalate excretion, which may predispose to nephrolithiasis.