Will a vitamin C serum fade dark spots on its own?

Across the reviewers we read, vitamin C is best understood as a brightening and antioxidant ingredient that evens overall tone and prevents new pigmentation, not a spot eraser. For stubborn hyperpigmentation, most reviewers pair it with sunscreen plus a dedicated treatment (azelaic acid, tranexamic acid, or a retinoid). Expect gradual improvement over 8–12 weeks, not overnight results.