Niacinamide is everywhere in skincare, but what does it actually do at the cellular level? Here's the science, the concentrations that matter, and how to use it effectively.
Niacinamide has become one of the most talked-about skincare ingredients of the last decade. It shows up in serums, moisturisers, cleansers, sunscreens, and just about everything else. But behind the marketing buzz, there is genuine science that makes this ingredient worth paying attention to.
This guide will walk you through exactly what niacinamide is, how it works at the cellular level, which concentrations actually matter, and how to incorporate it into your routine for real results. No hype, just evidence.
What Is Niacinamide?
Niacinamide — also known as nicotinamide — is one of the two primary forms of vitamin B3. The other form is nicotinic acid (niacin). While they share a vitamin classification, they behave very differently on your skin. Niacinamide is the form used in skincare because it does not cause the uncomfortable flushing and redness that niacin can trigger.
Your body uses niacinamide to produce two coenzymes that are essential for cellular energy: NAD+ (nicotinamide adenine dinucleotide) and NADP+ (nicotinamide adenine dinucleotide phosphate). These coenzymes are involved in over 400 biochemical reactions in the body, including DNA repair, cellular communication, and antioxidant defence.
When applied topically, niacinamide is absorbed into the skin and converted into NAD+ and NADP+ locally. This is where the magic happens.
How Niacinamide Works at the Cellular Level
Understanding the mechanisms behind niacinamide helps explain why it addresses so many different skin concerns simultaneously.
1. Strengthening the Skin Barrier
Your skin barrier — the outermost layer called the stratum corneum — is made up of skin cells (corneocytes) held together by a lipid matrix of ceramides, cholesterol, and fatty acids. Think of it as a brick wall: the cells are bricks, and the lipids are mortar.
Niacinamide stimulates the production of ceramides and other intercellular lipids. A 2000 study published in the British Journal of Dermatology found that topical niacinamide significantly increased ceramide and free fatty acid levels in the stratum corneum, resulting in measurably improved barrier function and reduced transepidermal water loss (TEWL).
Why this matters: A stronger barrier means your skin retains moisture better, is less reactive to irritants, and heals faster from damage.
2. Regulating Sebum Production
Niacinamide has been shown to reduce the rate of sebum excretion — the oil your sebaceous glands produce. A clinical study published in the Journal of Cosmetic and Laser Therapy (2006) found that a 2% niacinamide moisturiser significantly reduced sebum production and pore size over four weeks compared to a placebo.
Why this matters: Less excess oil means fewer clogged pores, reduced shine, and a lower risk of acne breakouts.
3. Inhibiting Melanin Transfer
One of niacinamide's most well-documented effects is its ability to reduce hyperpigmentation. It does not stop your body from producing melanin. Instead, it inhibits the transfer of melanosomes (melanin-containing packets) from melanocytes to keratinocytes — the surrounding skin cells.
A landmark study in the British Journal of Dermatology (2002) demonstrated that 5% niacinamide significantly reduced hyperpigmentation and increased skin lightness after eight weeks of use, compared to a vehicle-only control.
Why this matters: Dark spots from acne, sun damage, or hormonal changes fade more effectively without disrupting your skin's natural melanin production process.
4. Anti-Inflammatory Action
Niacinamide inhibits the release of pro-inflammatory cytokines and histamine in the skin. Research published in Dermatologic Surgery (2005) showed that topical niacinamide reduced redness, blotchiness, and yellow skin tone — all markers of chronic low-grade inflammation.
Why this matters: Reduced inflammation means calmer skin, less redness from acne, and fewer reactive flare-ups.
5. Supporting Collagen Production
While not as powerful as retinoids for this purpose, niacinamide does stimulate fibroblast activity and boost collagen synthesis. A study in the International Journal of Cosmetic Science (2004) found that 5% niacinamide improved fine lines, wrinkles, and skin elasticity over 12 weeks.
Why this matters: Over time, niacinamide contributes to firmer, more resilient skin — a meaningful benefit for long-term skin health.
What Concentration of Niacinamide Do You Need?
This is where things get practical. Not all niacinamide products are created equal, and concentration matters more than most brands want to admit.
2% Niacinamide
Best for: Sensitive skin, barrier support, gentle oil control.
At 2%, niacinamide is well tolerated by virtually all skin types and still delivers meaningful barrier-strengthening and mild oil-control benefits. If you are new to active ingredients or have reactive skin, this is a solid starting point.
5% Niacinamide
Best for: Acne, oil control, brightening, general skin health.
This is the concentration used in the majority of peer-reviewed clinical studies. At 5%, you get the full spectrum of niacinamide's benefits — barrier repair, sebum reduction, melanin transfer inhibition, and anti-inflammatory action — with minimal risk of irritation. For most people, 5% is the sweet spot.
10% Niacinamide
Best for: Stubborn hyperpigmentation, significant oil control, pronounced skin tone unevenness.
Higher concentrations like 10% are designed for people who need more aggressive brightening or oil regulation. The trade-off is a slightly higher chance of irritation, particularly if your skin barrier is already compromised.
A 2016 study in the Journal of Clinical and Aesthetic Dermatology compared 2%, 4%, and 5% niacinamide formulations and found dose-dependent improvements in skin quality — with higher concentrations yielding more visible results but also slightly more tingling in some users.
The key takeaway: Start at 5% if you have normal or oily skin. Step up to 10% only if your skin tolerates it well and you need more visible brightening or oil control.
Which Skin Concerns Does Niacinamide Help?
Acne and Breakouts
Niacinamide reduces oil production, calms inflammation, and strengthens the barrier that protects against bacterial infection. While it is not a replacement for dedicated acne treatments like benzoyl peroxide or salicylic acid, it is an excellent supporting ingredient that makes breakouts less frequent and less severe.
Enlarged Pores
By reducing sebum production and improving skin elasticity, niacinamide makes pores appear smaller over time. It does not physically shrink pores (nothing can), but it reduces the congestion and oiliness that make pores look larger.
Dark Spots and Uneven Skin Tone
Through melanin transfer inhibition, niacinamide fades post-inflammatory hyperpigmentation (PIH) from acne, sun spots, and melasma. It works gradually — expect 6-8 weeks for visible improvement — but the results are meaningful and well-supported by evidence.
Barrier Damage and Sensitivity
If your skin is reactive, red, or easily irritated, niacinamide helps rebuild the lipid barrier that protects against environmental aggressors. It is one of the gentlest active ingredients available and rarely causes the irritation associated with acids or retinoids.
Fine Lines and Texture
By boosting collagen and improving hydration at the cellular level, niacinamide smooths skin texture and softens fine lines over extended use.
How to Use Niacinamide in Your Routine
When to Apply
Niacinamide is stable, water-soluble, and plays well in both AM and PM routines. Apply it after cleansing and before moisturiser. If using a serum format, apply it to slightly damp skin for better absorption.
Morning Routine
- Cleanser
- Niacinamide serum
- Moisturiser
- Sunscreen SPF 30+
Evening Routine
- Cleanser
- Niacinamide serum (or alternate with other treatments)
- Moisturiser
How Long Until Results?
- Oil control: 2-4 weeks
- Barrier improvement: 2-4 weeks
- Brightening / dark spots: 6-8 weeks
- Texture and fine lines: 8-12 weeks
Be patient. Niacinamide works gradually, but the results are cumulative and long-lasting.
What to Pair Niacinamide With
Niacinamide is remarkably versatile and pairs well with almost every other skincare ingredient.
Excellent pairings:
- Hyaluronic acid — Hydration plus barrier repair is a powerful combination
- Ceramides — Doubling down on barrier strengthening
- Salicylic acid (BHA) — Niacinamide calms the irritation that BHAs can cause
- Retinol — Niacinamide buffers retinol irritation while boosting barrier function
- Vitamin C — Despite the old myth, modern formulations of niacinamide and vitamin C work beautifully together (more on this below)
- SPF — Always. Especially when treating hyperpigmentation.
What About the Niacinamide + Vitamin C Myth?
You may have heard that niacinamide and vitamin C (ascorbic acid) should never be used together. This claim originated from a single study conducted in the 1960s under extreme laboratory conditions — high heat and prolonged exposure — that do not reflect how skincare products behave on human skin at room temperature.
Modern cosmetic chemistry has thoroughly debunked this myth. When used in contemporary formulations at normal pH ranges, niacinamide and vitamin C do not cancel each other out or form problematic by-products. You can safely use them together, or in the same routine (one in the morning, one at night), without any concern.
What NOT to Pair Niacinamide With
Honestly, there is very little that conflicts with niacinamide. The only scenario to be cautious about is layering niacinamide at high concentrations (10%+) with other potent actives like strong AHAs (glycolic acid 15%+) or high-concentration retinol on compromised skin. This is less about ingredient conflict and more about avoiding over-treatment on a weakened barrier.
Rule of thumb: If your skin is irritated, simplify your routine. Niacinamide and moisturiser are enough until your barrier recovers.
What the Research Says: Key Studies
For those who want to go deeper, here are the foundational studies that support niacinamide's benefits:
- Tanno et al. (2000) — British Journal of Dermatology: Topical niacinamide increases ceramide and fatty acid synthesis in the stratum corneum
- Draelos et al. (2006) — Journal of Cosmetic and Laser Therapy: 2% niacinamide reduces sebum excretion rate and pore size
- Hakozaki et al. (2002) — British Journal of Dermatology: 5% niacinamide reduces hyperpigmentation by inhibiting melanosome transfer
- Bissett et al. (2005) — Dermatologic Surgery: Topical niacinamide improves multiple signs of ageing including fine lines, wrinkles, and uneven tone
- Wohlrab & Kreft (2014) — Skin Pharmacology and Physiology: Comprehensive review of niacinamide's dermatological benefits including barrier function, anti-inflammatory activity, and sebum regulation
How Clarity Skin Uses Niacinamide
Our Brightening Serum features 10% niacinamide combined with 4% tranexamic acid — a targeted formula designed for stubborn hyperpigmentation and uneven skin tone. We chose 10% because for visible brightening results, particularly on post-acne marks and sun spots, the higher concentration delivers meaningfully faster results than the standard 5%.
Tranexamic acid works synergistically with niacinamide: while niacinamide inhibits melanin transfer between cells, tranexamic acid interrupts the inflammatory pathways that trigger excess melanin production in the first place. Together, they address hyperpigmentation from two different angles.
The Bottom Line
Niacinamide is one of the most well-researched, well-tolerated, and genuinely effective skincare ingredients available. It strengthens your barrier, controls oil, fades dark spots, calms inflammation, and supports long-term skin health — all without the irritation that comes with many other active ingredients.
If you add one ingredient to your routine this year, make it niacinamide. Start at 5%, be consistent for 6-8 weeks, and let the science do its work.
Ready to See Niacinamide in Action?
Clarity Skin's Brightening Serum delivers 10% niacinamide with 4% tranexamic acid — the concentrations that research supports for real, visible results on dark spots and uneven tone. Science-backed, medical-student formulated, and designed for people who want their skincare to actually work. Shop the Brightening Serum and our full collection and start seeing the difference.
