What Does Niacinamide Do? Percentages, Pairings and Realistic Results

Niacinamide is vitamin B3, one of the most researched and best tolerated ingredients in skincare — and at around $6 for 30 ml from The Ordinary, one of the cheapest.

What the Evidence Supports

• Barrier repair: increases ceramide production, reducing water loss and sensitivity.
• Oil regulation: lowers sebum output over 4-8 weeks, which visibly reduces shine and pore appearance.
• Redness: anti-inflammatory, helpful in rosacea-prone and acne-prone skin.
• Pigmentation: blocks the transfer of melanin to skin cells, fading post-acne marks and sun spots gradually.
• Fine lines: mild improvement in elasticity with long-term use.

Which Percentage

2-5% delivers nearly all the documented benefits. 10% formulas work for oily skin but cause flushing, tingling or breakouts in some people. Higher is not better; if a 10% product irritates you, drop to 5% rather than abandoning the ingredient.

Layering

Niacinamide is compatible with almost everything: retinol, hyaluronic acid, peptides, moisturisers and sunscreen. The old warning about mixing it with vitamin C came from a lab study at high heat and does not apply to normal use — but if you notice flushing, simply use vitamin C in the morning and niacinamide at night.

How to Use

Apply the serum to clean skin before moisturiser, morning and/or evening. It is also common inside moisturisers and sunscreens, so check your labels before stacking three separate sources.

Timeline

Oil control and redness in 3-4 weeks. Post-acne marks in 8-12 weeks. Pores never disappear — pore size is genetic — but they look smaller when they are less congested and less stretched by oil.