What Does Niacinamide Do? The Science-Backed Guide
If you've spent any time in skincare communities — Reddit's r/SkincareAddiction, TikTok, or just reading ingredient panels — you've come across niacinamide. It's everywhere. And unlike most trending ingredients, the science genuinely backs it up.
So: what does niacinamide do, exactly? This guide breaks it down — from the biology behind it to how to use it in a routine that gets real results.
What Is Niacinamide?
Niacinamide is a form of vitamin B3, also called nicotinamide. It's water-soluble and used at concentrations between 2% and 10% in skincare. At 5% — the concentration in Firmly's Niacinamide Gel Moisturiser — it hits the sweet spot: effective enough to produce visible results, gentle enough for daily use on virtually any skin type.
The Key Skin Benefits of Niacinamide
It Strengthens the Skin Barrier
Niacinamide increases the production of ceramides and other lipids in the skin's outer layer. A stronger barrier means better moisture retention, less sensitivity, and fewer reactions to environmental stressors. Studies published in the Journal of Dermatological Science show visible barrier improvement in as little as four weeks of daily use.
It Reduces the Appearance of Pores
Pores don't physically shrink — pore size is largely genetic. But niacinamide reduces excess sebum production and keeps pores clear, making them appear significantly smaller over time. Research confirms it reduces sebum excretion rates in oily and acne-prone skin, which directly affects pore visibility.
It Improves Skin Texture
Uneven texture is caused by dead skin cell buildup, clogged pores, and slow cell turnover. Niacinamide improves the overall skin environment — reducing congestion and supporting the skin's ability to renew itself. The result with consistent use: smoother, more even texture.
It Fades Hyperpigmentation
Niacinamide inhibits the transfer of melanin to skin cells, gradually fading dark spots, post-acne marks, and uneven tone. It's not as fast as vitamin C, but significantly better tolerated by sensitive skin.
It Calms Redness and Inflammation
Multiple studies confirm niacinamide's anti-inflammatory properties. It reduces redness from acne, rosacea, and general irritation — making it one of the few actives that works across almost every skin concern.
Niacinamide for Pores: The Honest Answer
Niacinamide doesn't permanently alter pore size. What it does is address the main reasons pores appear large: excess sebum, congestion inside the pore, and loss of skin elasticity around it. After 8–12 weeks of consistent daily use, most people see a visible difference. Not overnight — but real, sustainable improvement.
How to Use Niacinamide in Your Routine
Niacinamide is one of the easiest actives to add to any routine. It's stable, plays well with most other ingredients, and can be used morning and evening.
- Step 1: Cleanse
- Step 2: Apply water-based serums (niacinamide works here)
- Step 3: Moisturise — or choose a moisturiser that already contains niacinamide
Firmly's Moisturising Day Cream with Niacinamide 5% contains 5% Niacinamide alongside hyaluronic acid, glycerin, and vitamin E — delivering the benefits without adding an extra step.
Who Should Use Niacinamide?
Almost everyone. It's suitable for oily, dry, combination, and sensitive skin. Safe for daily use AM and PM. Compatible with retinol, AHAs, vitamin C, and hyaluronic acid. Fully vegan. The only exception: very sensitive skin should patch test first — as with any new ingredient.
Frequently Asked Questions
How long does niacinamide take to work?
Most studies show visible results in 4–8 weeks with consistent daily use.
Can I use niacinamide every day?
Yes. It's gentle enough for twice-daily use in most formulations.
Does niacinamide cause purging?
No. Niacinamide is not an exfoliant and does not cause purging. Any new breakouts in the first weeks are likely a reaction to other ingredients in the formula.
Can niacinamide replace retinol?
They do different things. Niacinamide is ideal for pores, texture, and sensitivity. Retinol is better for anti-aging and cell turnover. Used together, they complement each other well.
Ready to add niacinamide to your routine? Firmly's Shop Niacinamide Gel Moisturiser delivers 5% niacinamide in a lightweight, vegan formula designed for daily use.