Niacinamide is the quiet achiever of Korean skincare. It does not have a TikTok moment the way snail mucin does. It does not come with a dermatologist's endorsement segment the way retinol does. It just works, on almost everyone, almost immediately, which is why it appears in roughly 60 percent of the Korean serums we sell.
This is what it actually does, why the 10 percent concentration that dominates Western marketing is the wrong benchmark, and how to fit it into a Canadian routine.
What niacinamide actually is
Niacinamide, also called nicotinamide, is a form of vitamin B3. It is water-soluble, pH-stable across the 5 to 7 range (which is the range of most Korean skincare), and one of the most well-tolerated ingredients ever studied. You can apply it on the same day as vitamin C, retinol, AHAs, BHAs, and ceramides without fighting any of them. This is rare.
The skin-relevant actions include:
- Increasing ceramide production in the skin.
- Regulating sebum secretion from sebaceous glands.
- Inhibiting the transfer of melanin from melanocytes to surrounding skin cells (the brightening effect).
- Reducing inflammatory mediators, useful for rosacea and acne.
- Improving skin elasticity over sustained use.
The list is long because vitamin B3 is involved in hundreds of cellular processes. Skincare marketing has mostly focused on two: pore appearance and brightening.
The 10 percent myth
The Ordinary launched a 10 percent Niacinamide + 1 percent Zinc serum in 2016 and it became the bestselling niacinamide product in the English-speaking world. The 10 percent number became a benchmark. It should not have.
Published research on niacinamide dose-response, including the 2015 Bissett et al. review and subsequent trials, shows that the effective concentration range is roughly 2 to 5 percent for most skin outcomes. Above 5 percent, improvements plateau. Above 10 percent, the irritation rate increases.
The most common complaint we hear from customers who started on a 10 percent serum is "my face turned red and burned a little." That is niacinamide at a dose higher than your skin needs.
A well-formulated 5 percent niacinamide serum, ideally paired with zinc and hyaluronic acid, will outperform a 10 percent serum on most skin over a 12-week comparison. Korean brands almost exclusively formulate at 2 to 5 percent because of this.
Niacinamide: a form of vitamin B3 that regulates sebum, strengthens the barrier, and supports pigmentation control. Most effective at 4 to 5 percent. See full entry.
What niacinamide does to pores
Niacinamide does not physically shrink your pores. No topical ingredient does, and any marketing claiming otherwise is wrong. Pore size is largely genetic.
What niacinamide does is reduce sebum output and the oxidation of sebum at the pore opening. A pore looks larger when it is filled with oxidized (darkened) sebum and stretched by trapped dead skin cells. Reduce the sebum and the oxidation, and the pore visually contracts. The actual anatomical diameter has not changed, but the appearance has.
Over 8 to 12 weeks of consistent use, this is measurable. Pair with a low-strength BHA (see AHA vs BHA vs PHA) for additional effect.
Niacinamide for oily skin in a Canadian summer
Toronto and Montreal summers reach 70-plus percent humidity, which is a skincare problem that does not exist in the same form in Seoul or Vancouver. Humid heat pushes sebum production into overdrive, which is why August is the month our Montreal customers restock niacinamide most often.
We go deeper into summer routines in Building a Summer K-Beauty Routine for Humid Canadian Cities, but the niacinamide-specific advice is: switch from a rich serum to a niacinamide-forward toner or gel in June. The lighter format matches what your skin is doing.
The Korean niacinamide products worth knowing
Some By Mi AHA-BHA-PHA 30 Days Miracle Serum
Contains 5 percent niacinamide plus three exfoliating acids. Aggressive but effective for acne-prone skin; introduce slowly, two to three nights per week.
Naturium Niacinamide Gel 5%
Not Korean but sold across Canadian markets as a K-beauty-adjacent option. Gel texture, 5 percent niacinamide, zinc. Good for combination skin.
COSRX The Niacinamide 15 Serum
COSRX's higher-strength option, sold primarily for targeted dark spot use, not all-over face application. Use as a spot treatment, not as a daily serum. The 15 percent concentration is too strong for barrier-compromised skin.
Beauty of Joseon Glow Deep Serum
2 percent niacinamide plus rice extract and alpha-arbutin. A gentle brightening combination that works as an everyday morning serum.
Mary & May Niacinamide Tranexamic Acid Ampoule
Pairs niacinamide with tranexamic acid, which is a stronger melasma-fighting ingredient. Good for Canadians of South Asian, East Asian, and Mediterranean heritage who see melasma flare in spring and summer.
Layering niacinamide with everything else
This is where niacinamide shines. It fights with almost nothing.
With vitamin C: the old "do not combine" rule was based on a 1960s study using high-heat conditions. In modern formulations at skin-friendly pH, niacinamide and vitamin C layer without issue. Some people prefer to alternate morning (vitamin C) and night (niacinamide); others stack them. Both work.
With retinol: excellent pairing. Niacinamide reduces the irritation profile of retinol, which is why many Korean products formulate them together.
With AHAs and BHAs: safe to layer, though very sensitive skin may want to alternate.
With ceramides and hyaluronic acid: perfect pairing. Niacinamide boosts native ceramide production, multiplying the effect of an applied ceramide cream.
A realistic starter routine
If you are just adding niacinamide for the first time:
- Start with a 4 to 5 percent serum, evening only, for the first week.
- Patch test on your inner jawline if you have very sensitive skin.
- Move to twice-daily use by week two if no irritation appears.
- Apply after toner, before moisturizer.
- Give it 8 to 12 weeks before judging results.
The results are not dramatic week-to-week. They are cumulative, and you tend to notice them when you compare photos across a season.
The summary
Niacinamide is the "start here" active ingredient for most Canadians. It is safer than retinol, gentler than vitamin C, and works for a broader skin type range than either. Pick a Korean 4 to 5 percent formulation, use it consistently, and do not be tempted by the 10 percent marketing. Your skin will respond better to the lower dose, and you will stick with it longer.
Stickiness is the active ingredient behind every good skincare routine. Niacinamide makes it easier to be consistent because it does not fight you.