Can You Mix Niacinamide and Vitamin C?

Why

The cancellation myth traces back to 1960s studies where pure ascorbic acid and niacinamide were heated together in unbuffered water solutions. Under that prolonged heat and moisture they reacted to form nicotinic acid (niacin), which can cause a temporary flush. Those beaker conditions do not exist on your face: modern serums are pH-balanced, often contain stabilisers, and are not simmered for hours. On skin, at room temperature, the two coexist without any meaningful conversion. Chemically they also do genuinely different jobs. Vitamin C, as L-ascorbic acid, is an antioxidant that donates electrons to neutralise free radicals and is a cofactor for collagen synthesis, working best at low pH around 3. Niacinamide supports the skin's NAD-dependent repair enzymes, curbs the transfer of pigment to surface cells, and strengthens the barrier, comfortable across pH 5 to 7. Both fade hyperpigmentation but by separate routes, so combining them broadens the effect rather than blunting it.

How to combine them

The simplest morning approach is vitamin C on clean, dry skin first, because it prefers a low pH and direct contact. Wait about a minute, then apply niacinamide, moisturizer and broad-spectrum sunscreen. If you would rather split them, vitamin C in the morning and niacinamide at night both works and lets each ingredient headline its own routine. Many modern brightening serums combine the two deliberately at compatible concentrations, and those are perfectly reasonable to use. If your skin is sensitive, start with the gentler derivative forms of vitamin C, which are less acidic and stack even more easily with niacinamide. There is no mandatory long wait time and no need to buffer with moisturizer between them unless your skin is reactive.