Vitamin C, niacinamide or tranexamic acid: which one for which spot

Pigmentation is the most searched skin concern in India, and the three ingredients people search alongside it are vitamin C, niacinamide and tranexamic acid. They are often sold as interchangeable. They are not. Each works on a different step of how pigment is made and moved, and each suits a different kind of mark. Start by naming the mark, then pick.

Three kinds of dark spot

Most dark spots fall into one of three groups, and the routine depends on which.

• Post-inflammatory marks. The flat red-brown spot left where a pimple, a bite or a scratch was. Caused by inflammation, not sun, and usually fades on its own in weeks to months if nothing irritates it.
• Sun spots and tanning. Scattered brown spots on the cheeks, forehead and hands, and the general darkening that Indian skin does quickly in sun. Caused by ultraviolet light switching pigment production up.
• Melasma-type patches. Larger, symmetrical, blurred-edge patches on the cheeks, upper lip or forehead that deepen with sun, heat and hormonal changes such as pregnancy or contraception. Stubborn, and prone to returning.

The first two respond well to over-the-counter ingredients and sunscreen. The third can improve with them too, but it is the one where a dermatologist earns their fee, because it comes back and because prescription options exist that we do not sell.

Vitamin C: for tone and prevention

Vitamin C does two jobs. It is an antioxidant, mopping up the reactive molecules that sun and pollution generate, and it interferes with tyrosinase, the enzyme at the start of pigment production. That makes it a prevention ingredient as much as a correction one: it evens overall tone and slows new spots more than it erases old ones.

The pure form, L-ascorbic acid, is the most studied and the least stable; it oxidises in air and light and can sting at higher strengths. Encapsulated and derivative forms trade some potency for stability and comfort. Use it in the morning, under sunscreen, where it adds to the protection.

Niacinamide: for marks and redness

Niacinamide, a form of vitamin B3, works later in the pigment story. It slows the transfer of pigment from the cells that make it to the skin cells that display it. It also calms redness and supports the barrier, which is why it is the first choice for post-acne marks: it fades the brown while helping the skin stop producing new marks. It is well tolerated at usual strengths and layers with almost anything, including vitamin C.

Tranexamic acid: for the stubborn patches

Tranexamic acid started life as an oral medicine that reduces bleeding. Dermatologists noticed it lightened melasma in some patients, and topical versions followed. It works on a signalling pathway between skin cells and pigment cells that sun and inflammation switch on, which is why it suits the patches that other ingredients barely touch. Low-strength topical versions are sold without a prescription. If your patches are symmetrical and hormonal, use it with a dermatologist in the loop rather than alone, because they can add options and track the result properly.

Which one for which spot

The three can be used together. The old warning that vitamin C and niacinamide cancel each other came from lab tests of unstable forms at high temperatures; modern formulas layer without trouble. Our Lit Happens keeps them in two chambers, vitamin C in one and niacinamide with tranexamic acid in the other, so they stay stable until they are pumped together.

The part nobody wants to hear

None of the three works without sunscreen, and the melasma-type patches will return without it. A broad-spectrum sunscreen every morning, reapplied if you are outdoors, does more for dark spots than any serum, and it is the reason a good serum keeps its results.

Pigment comes back faster than it fades. Sunscreen is the whole strategy, not the footnote.

See a dermatologist if a spot changes shape, colour or size, if patches are spreading, or if three months of sunscreen and one active have not moved anything. Those are not signs to buy another serum.