Modern research suggests the niacinamide-Vitamin C incompatibility—historically feared to generate nicotinic acid—is minimal at typical cosmetic concentrations and storage temperatures. Many current serums combine both successfully. The greater practical concern is pH conflict: Vitamin C wants pH below 3.5 while niacinamide is most stable and effective above pH 5.0. A skilled cosmetic chemist can help you find a workable pH compromise or recommend a derivative pairing that resolves the tension.
Read the full guide on Vitamin C formulation challenges →