Brands market 10% niacinamide as the upgrade from 5%. The clinical data tells a less flattering story: most of the benefit comes from the first 4-5%, and concentrations above 5% start adding irritation without adding much performance.
Where the dose-response curve flattens
Niacinamide regulates sebum, reduces inflammation, supports the barrier, and inhibits melanosome transfer (the step that delivers pigment to skin cells). A 2017 review pooled in vitro and in vivo data and found the curve flattens between 4 and 5%: the next 5 percentage points add roughly 10-15% more effect, but flushing and irritation reports rise sharply.
The Ordinary Niacinamide 10% + Zinc 1% sold huge volumes on the higher number. The reformulated version dropped to 5% in 2024 for irritation complaints. Paula's Choice 10% Niacinamide Booster works for some users; for those who flush, swap to The Inkey List Niacinamide (10%, lower-irritation vehicle) or Naturium Niacinamide Serum 12% (slow-release, gentler than the percentage suggests).
Who actually benefits from 10%
Persistent post-inflammatory pigmentation
Higher dose helps slightly more, especially layered with azelaic acid.
Heavy sebum + visible pores
The sebum-regulation effect scales modestly with dose. Worth trying 10% for two months; if no change, drop back.
Sensitive skin
Stay at 4-5%. CeraVe Resurfacing Retinol Serum (4% niacinamide + retinol) is the gentler option.
Combining niacinamide with the rest of the routine
Niacinamide layers safely with vitamin C, retinoids, and most acids. The old myth about niacinamide cancelling vitamin C is debunked (covered in our piece on that topic). Apply niacinamide after lower-pH actives, before moisturiser.
If you use both niacinamide and a retinoid: niacinamide buffers retinoid irritation when applied first. This is why so many retinoid-plus-niacinamide combinations exist as single products.
Signs you're at the wrong dose
Stinging on application: too high or too acidic a vehicle. Worsening redness over weeks: dose is wrong for your sensitivity. New whiteheads or congestion: you may be reacting to the silicone or filler in that specific product, not to niacinamide itself — try a different brand at the same percentage before giving up.
The percentage on the label isn't the headline. Vehicle, supporting actives, and your individual tolerance matter more. Start at 5%, hold for six weeks, then decide whether more would help.