Niacinamide

Niacinamide is a form of vitamin B3, and it is one of the small number of skincare actives where the evidence is decent and the marketing has not had to invent anything.

What it does is unusual for a topical ingredient: rather than acting on the surface, it prompts the skin to make more of its own materials. The literature describes it as increasing “protein synthesis and the production of ceramide and fatty acids within the skin”, with the result being “the stabilization of epidermal barrier function, reduction in transepidermal water loss, and an increase in the moisture content in skin”.

A better barrier is the mechanism behind most of the things it is sold for: less redness, less water loss, and over time a more even tone.

The number that matters is not on the label

Formulations are described in the literature as “ranging in concentration from 2% to 5%”. That is the range the work was done at.

A serum can list niacinamide and contain 0.5 percent. Another can contain 5 percent. Both print the same word, and below the 1 percent mark the ingredient order carries no information at all, which is the rule set out in the guide to reading a cosmetics label.

So this is a case where a number on the front of the pack is worth more than the entire back. Products that state a percentage can be compared with the research. Products that do not have told you the ingredient is present and nothing else.

The 10 percent question

Some products advertise much higher concentrations, and the assumption that more is better does not survive contact with the evidence.

The studied range tops out around 5 percent. Above it the reported benefit does not scale and irritation becomes more likely, particularly flushing, which is a known effect of the related compound niacin. A product at 10 percent is not a stronger version of the studied thing; it is outside what was studied.

If your skin stings with a high-strength niacinamide serum and not with a 5 percent one, the ingredient is behaving as expected rather than the product being faulty. The general approach is on the page for skin that reacts to everything.

Pregnancy

This is one of the few actives with nothing to set aside. It is not a retinoid, it is not an acid, and no clinical body attaches a pregnancy caution to it.

That makes it a reasonable answer to a question the pregnancy pages get asked constantly, which is what remains once the retinoids are put down. The clinically named options are on the page on what skincare you can use while pregnant, and niacinamide sits alongside them as an ingredient with no caution rather than one that has been positively cleared.

The B3 that is not this one

Niacin and niacinamide are both vitamin B3 and they behave differently on skin. Niacin causes flushing; niacinamide does not, at ordinary concentrations. Products occasionally list “niacin” in error, and the two are not interchangeable.

Taken by mouth, high-dose niacin is a different matter again, with its own clinical uses and its own cautions, and none of that transfers to a cream.