5 Korean Niacinamide Serums Compared: 5%, 10%, 15%, 20% and 20.35%
This is a shopping comparison, not another guide to what niacinamide is. The five live formulas move from 5% to 20.35%, but the number is only one variable. Supporting actives, bottle size, texture, routine complexity and your tolerance determine whether a serum earns a place on the shelf.
Concentration creates a useful map, not a performance ranking. A lower-percentage composed formula may fit a routine better than a 20% standalone serum.
The short answer
AMPLE:N Blemi Shot Ampoule 50ml supplies the lowest declared niacinamide level in this group—50,000 ppm, equivalent to 5%—inside a multi-active tone-care formula with a vitamin C derivative and PHA/LHA positioning. Anua Niacinamide 10% + TXA 4% Serum 30ml is the watery 10% route paired with 4% tranexamic acid. K-SECRET Seoul 1988 Glow Serum 30ml raises niacinamide to 15% and pairs it with yuja. TIAM Pore Minimizing 21 Serum 40ml contains 20% niacinamide and 1% zinc PCA. Parnell Niacinamide 20.35 Rice Brightening Serum 30ml has the highest declared percentage, alongside rice extract and probiotic positioning.
For a first dedicated niacinamide serum, 5% or 10% is the more conservative shopping route. Fifteen to 20.35% is not automatically more effective and can be harder to fit around exfoliants, retinoids and other tone-care products. High concentration should solve a clear routine need, not satisfy a numerical competition.
Five niacinamide serums compared
| Product | Declared niacinamide | Supporting route | Format | Best fit |
|---|---|---|---|---|
| AMPLE:N Blemi Shot Ampoule | 50,000 ppm, equivalent to 5% | Vitamin C derivative, hexylresorcinol, PHA/LHA positioning | 50ml lightweight ampoule | Lower-percentage, multi-active tone care |
| Anua Niacinamide 10% + TXA 4% | 10% | 4% tranexamic acid and arbutin-tagged tone care | 30ml watery serum | Dedicated uneven-tone routine with light texture |
| K-SECRET Seoul 1988 Glow Serum | 15% | Yuja extract and hydrating glow positioning | 30ml serum | High-niacinamide citrus-botanical formula |
| TIAM Pore Minimizing 21 Serum | 20% | 1% zinc PCA | 40ml light serum | Experienced users focused on shine and texture appearance |
| Parnell Niacinamide 20.35 Rice Serum | 20.35% | Rice extract and probiotic positioning | 30ml clear serum | Highest-percentage rice-based route |
The table shows why “best niacinamide serum” is too broad a question. AMPLE:N carries the largest bottle and lowest percentage, yet the supporting exfoliant story makes it less neutral than the number suggests. Anua's 10% serum is a deliberate tone combination. K-SECRET, TIAM and Parnell move into concentrations that deserve a slow introduction rather than immediate daily use.
What the concentration number does—and does not—tell you
A declared percentage tells you how much niacinamide the brand says is present in the formula. It does not tell you how well you will tolerate the vehicle, whether the serum will pill, how stable the supporting ingredients are or how reliably you will use it. Formula performance cannot be reduced to one line on the label.
AMPLE:N lists 50,000 ppm. One percent equals 10,000 parts per million, so 50,000 ppm converts to 5% when the units refer to the same whole. That arithmetic helps place it on this comparison. It does not prove that its 5% plus multiple supporting actives is gentler than a simpler 10% serum.
Niacinamide is used cosmetically to support a more even-looking tone, reduce the appearance of excess shine and support the skin's barrier-related functions. Those are appearance and support claims. A serum does not permanently shrink pores, erase pigment, treat melasma or cure acne.
Why the highest percentage can be the wrong buy
High-concentration formulas may increase the chance of stinging, flushing, dryness or a compromised-feeling routine for some users. If the product causes persistent discomfort, the theoretical concentration advantage has no practical value. Comfort and adherence matter more than winning a label contest.
Product-by-product analysis
AMPLE:N Blemi Shot Ampoule 50ml: 5% inside a busy formula
The live listing combines 50,000 ppm niacinamide with vitamin C derivative care, hexylresorcinol and PHA/LHA support. Its 50ml bottle is the largest in this group, and the described finish is lightweight. The 5% level makes it the numerical starting point, but the supporting exfoliant route means it should not be treated as a neutral hydrator.
Choose AMPLE:N when you want a multi-active tone-care ampoule and can simplify other exfoliation. Do not stack it automatically with an acid toner, exfoliating pads and a retinoid. The phrase “blemish traces” should be read as visible post-blemish tone, not active-acne treatment. Use sunscreen because new discoloration is easier to prevent than to chase with more actives.
Anua Niacinamide 10% + TXA 4%: the targeted tone pair
Anua pairs 10% niacinamide with 4% tranexamic acid in a watery pink-toned serum. The live description emphasizes quick spread, a non-greasy finish and clean layering under moisturizer and sunscreen. This is the clearest middle-concentration choice for someone specifically shopping for niacinamide and topical tranexamic acid in one bottle.
Topical cosmetic tranexamic acid should not be confused with oral or injectable medication. The serum cannot diagnose or treat melasma, and dramatic claims about “correcting dark spots” need translation into gradual improvement in the appearance of uneven tone. Introduce it alone so you can judge comfort, particularly if other brightening formulas are already present.
K-SECRET Seoul 1988 Glow Serum: 15% with yuja
K-SECRET declares 15% niacinamide and yuja extract in a 30ml lightweight serum. It is positioned for dullness, uneven-looking tone, rough texture and glow. The citrus-botanical angle separates it from Anua's tranexamic-acid route and TIAM's zinc-PCA route.
Fifteen percent moves beyond the concentration used in many general daily serums. The formula may suit an experienced user who already knows niacinamide agrees with their skin and specifically wants the yuja story. Citrus-derived ingredients are not automatically photosensitizing in every finished cosmetic, but sensitive users should still verify the current ingredient list and patch test rather than relying on a fruit association.
TIAM Pore Minimizing 21 Serum: 20% niacinamide plus 1% zinc PCA
TIAM's “21” is explained by 20% niacinamide plus 1% zinc PCA. The 40ml bottle sits between AMPLE:N and the 30ml formulas. Its live listing is refreshingly direct: the high concentration may be too much for some routines, so introduce gradually and stop if irritation persists.
Choose TIAM when excess shine and visible texture are the commercial priority and you have already tolerated niacinamide. Zinc PCA can support an oil-control formula story, but the serum cannot permanently close pores. Pore visibility changes with oil, hydration, surface texture, lighting and genetics. A high percentage does not override those factors.
Parnell Niacinamide 20.35 Rice Serum: the highest number, rice route
Parnell states 20.35% niacinamide in a 30ml clear serum with rice extract and probiotic positioning. It is the numerical peak of this set by only 0.35 percentage point over TIAM. That tiny gap should not drive the decision. The meaningful difference is the supporting rice/probiotic story versus zinc PCA.
The live listing calls the formula gentle despite its high concentration. “Gentle” is not a guarantee. Select Parnell if you want this exact formula route and already tolerate concentrated niacinamide. Do not select it merely because 20.35 is larger than 20. The product image metadata in the catalog references another product, so this guide supplies its own accurate alt text rather than repeating that error.
The supporting formula changes the job
Exfoliant support: AMPLE:N includes PHA/LHA positioning. This may help a rough-looking surface but increases routine complexity. Use it on a different schedule from other leave-on exfoliants until tolerance is clear.
Tranexamic-acid support: Anua builds a concentrated tone-care pair. It is the most obvious choice for someone who has already decided on topical TXA, but that pair also makes the serum less redundant if you already own a separate tranexamic-acid product.
Botanical glow support: K-SECRET uses yuja. Parnell uses rice and probiotic language. These are different positioning routes, not proof that one brightens faster. The complete ingredient list and tolerability matter more than the familiarity of a food-derived name.
Oil and texture support: TIAM adds 1% zinc PCA. That formula architecture is more aligned with shine management than Parnell's rice route. Neither can alter pore anatomy or eliminate oil production.
How to introduce a dedicated niacinamide serum
Start with a stable cleanser, moisturizer and sunscreen routine. Apply the serum after cleansing and optional toner, before moisturizer. Use the brand's amount rather than filling the whole dropper. More product increases film and interaction with other layers; it does not accelerate results.
For 5% or 10%, begin every other day if your skin is reactive or the formula contains other actives. For 15% to 20.35%, a slower start is sensible even when you have used lower niacinamide levels before. Concentration and supporting ingredients changed together.
If using a retinoid, benzoyl peroxide, exfoliating acid or prescription product, avoid redesigning the entire routine in one night. There is no universal rule that niacinamide must be separated from every active, but practical tolerance is easier to assess when changes are isolated.
Morning or night?
Any of these may fit morning or night if the package allows and the formula layers well. Morning use must end with broad-spectrum sunscreen. Night use may be simpler for AMPLE:N or high-percentage formulas because there is less pressure to layer under makeup. Sunscreen remains necessary the next day.
Which concentration fits which shopper?
New to niacinamide: AMPLE:N has the lowest concentration, but its PHA/LHA story may not be the simplest. If exfoliants already bother you, a different low-complexity serum outside this five-product set may be a better first step. “Lowest here” does not mean universally beginner-friendly.
Comfortable with moderate niacinamide: Anua's 10% is the clearest commercial middle. Choose it when 4% topical tranexamic acid is desired too. If you do not want TXA, buying a paired formula adds an unnecessary variable.
Experienced and seeking a botanical glow formula: K-SECRET at 15% is the bridge into high concentration. Yuja is the differentiator; the percentage alone is not. Patch test and avoid combining it impulsively with several other tone serums.
Experienced and focused on shine: TIAM's 20% niacinamide and 1% zinc PCA is the most coherent fit. Use the smallest effective amount and track comfort. Tightness is not proof of better oil control.
Experienced and specifically interested in rice-based tone care: Parnell offers the highest declared percentage and rice route. Treat 20.35% as formula identity, not as a recommendation to leapfrog every lower concentration.
A thin, even serum film usually layers better than an oversized dropperful. Application amount is part of formulation performance.
Twelve mistakes that make niacinamide shopping harder
- Assuming 20% is twice as effective as 10%. Response is not a simple linear curve.
- Buying duplicate actives. Check toner, moisturizer and sunscreen for niacinamide first.
- Ignoring supporting ingredients. Acids, TXA, zinc and botanicals change the routine.
- Using a whole dropper. Excess film can pill and irritate.
- Starting daily at the highest concentration. Ease in and observe.
- Calling flushing “purging.” Niacinamide is not an exfoliation purge requirement.
- Expecting permanent pore shrinkage. Pore appearance is dynamic.
- Treating post-blemish marks as active acne. Tone care and acne treatment are different jobs.
- Skipping sunscreen. UV exposure works against visible tone goals.
- Stacking multiple brightening serums. Redundancy increases complexity, not certainty.
- Trusting an old ingredient list. Verify the current box.
- Continuing through persistent burning. Stop and reassess.
Price and bottle size: calculate useful value
AMPLE:N contains 50ml, TIAM 40ml and Anua, K-SECRET and Parnell 30ml. Use the live price divided by volume for a rough cost per milliliter. Then consider the amount you can use comfortably. A concentrated serum applied only twice before being abandoned is not good value.
High percentage may reduce the amount needed per application, but manufacturers do not establish equivalent doses across these formulas. Follow each product's instructions rather than trying to normalize drops by concentration. Dropper size, viscosity and spreading area differ.
Do not buy two 20% formulas to compare simultaneously. Finish a controlled trial with one. Store the bottle according to its label, keep the neck clean and avoid touching a dropper to skin. Appearance changes, odor changes or separation outside normal product behavior are reasons to consult the brand rather than improvising.
Beauty-claims review
Supported as catalog facts: the declared niacinamide concentrations, bottle sizes, named supporting ingredients and texture descriptions quoted conservatively from the current product listings.
Acceptable cosmetic framing: helps skin look brighter or more even, supports a smoother-looking texture, reduces the appearance of excess shine, and supports a healthy-looking barrier when the finished formula performs that way.
Claims requiring translation or rejection: “shrinks pores” becomes reduces the appearance of visible pores; “corrects dark spots” becomes supports gradual improvement in uneven-looking tone; “anti-aging” becomes supports smoother or more radiant appearance. Treating acne, melasma or inflammatory disease is outside this comparison.
Neither niacinamide nor topical tranexamic acid replaces medical assessment for changing pigmentation. New, asymmetric or rapidly changing dark areas, persistent irritation and scarring acne deserve qualified care. Cosmetics cannot diagnose the cause.
A controlled four-week comparison protocol
Photograph the same area in the same diffuse light before starting. Keep cleanser, moisturizer, sunscreen and makeup stable. Apply one serum at the same routine position and approximate amount. Record sting, redness, tack, pilling, dryness and visible shine at consistent times.
During week one, focus on compatibility, not brightness. During weeks two through four, track whether the routine is comfortable and whether tone or texture looks more even under the same lighting. Post-blemish marks often change slowly, and uncontrolled phone photos can exaggerate difference through exposure and white balance.
If irritation appears, stop the new serum and return to the stable routine. Do not immediately switch to another concentration. If symptoms are significant or persist, seek professional advice. A successful trial may simply show that the product layers well and does not destabilize the routine.
How to read results without fooling yourself
Immediate glow is usually a finish effect: hydration, light reflection and a smoother serum film. It is not evidence that a dark mark changed in minutes. Evaluate instant finish separately from gradual tone appearance. Both can be valuable, but they answer different questions.
Visible shine also needs context. A serum may leave a dewy film that looks shiny during the first hour while still supporting better-balanced routine comfort over time. Record whether shine comes from the product finish, oil emerging later, or a sunscreen layered above it. TIAM's zinc-PCA route should not be credited or blamed for every reflection in a photograph.
Post-blemish marks are not all alike. Red-looking marks, brown-looking marks and indented scars involve different visible changes. A niacinamide serum may fit a general tone-care routine, but it cannot rebuild an atrophic scar or identify whether pigment needs medical evaluation. Do not increase from 10% to 20% simply because the concern was misclassified.
Use a fixed decision threshold. Continue only if the formula is comfortable, layers reliably and provides a visible or experiential benefit that matters to you. A product does not deserve a permanent routine slot merely because it caused no reaction. Likewise, a modest improvement from a 5% formula can be more useful than an unstable cycle of high-concentration irritation and recovery.
When to step down instead of up
Move to a lower concentration or less complex formula if you notice recurring flush, tightness, scaling, stinging when moisturizer is applied, or repeated pilling that makes sunscreen uneven. These outcomes do not prove a niacinamide allergy, but they show that the current combination, amount or frequency is not working. Simplify first; do not add another “barrier serum” on top of the problem.
AMPLE:N Blemi Shot Ampoule
50ml multi-active ampoule with 50,000 ppm, equivalent to 5% niacinamide.
View product
Anua Niacinamide 10% + TXA 4%
Watery 30ml tone-care serum pairing 10% niacinamide and 4% tranexamic acid.
View product
K-SECRET Niacinamide 15% + Yuja
30ml high-concentration glow serum with 15% niacinamide and yuja.
View product
Parnell Niacinamide 20.35 Rice Serum
30ml highest-percentage option with rice extract and probiotic positioning.
View productFinal decision map
Choose AMPLE:N for the lowest niacinamide percentage and largest bottle when its multi-active exfoliant route fits. Choose Anua for the most balanced dedicated concentration and a specific 4% topical TXA pairing. Choose K-SECRET for 15% and a yuja-led glow formula. Choose TIAM for the most coherent high-concentration shine-and-texture route. Choose Parnell only when the 20.35% rice formula itself—not the record-high number—is what you want.
The rational answer may be none of them. If niacinamide already appears in multiple routine steps, another dedicated serum can add redundancy and irritation without filling a gap. Audit the ingredient lists you own before adding a concentration.
Frequently asked questions
Is 50,000 ppm niacinamide equal to 5%?
Yes, when both figures describe the same whole: 10,000 ppm equals 1%, so 50,000 ppm equals 5%.
Is 20% niacinamide better than 10%?
Not automatically. Higher concentration can be harder to tolerate, and the supporting formula may matter more than the numerical difference.
Can niacinamide permanently shrink pores?
No cosmetic serum permanently changes pore anatomy. It may reduce the appearance of shine and uneven texture, which can make pores look less obvious.
Can I use niacinamide with vitamin C?
Many modern formulas and routines combine them. Practical compatibility depends on the finished products and your skin, not an outdated universal prohibition.
Can I use niacinamide with retinol?
They can coexist, but introduce changes separately and follow prescription guidance. A calming reputation does not guarantee that niacinamide will prevent retinoid irritation.
Which serum is best for a beginner?
Within this set, the lower 5% concentration is the conservative number, but AMPLE:N also includes exfoliant positioning. A simpler lower-percentage formula outside this group may be a better true beginner choice.
Related ProtoClinical guides
For the ingredient-level question this article intentionally does not duplicate, read Does Niacinamide Minimize Pores?. Build a compatible base with the Korean foam cleanser comparison, the Korean face mist guide and the centella serum comparison.
Product status, inventory, concentration statements and listing claims were checked in the ProtoClinical Shopify catalog on August 10, 2026. Verify the current package because formulas and availability can change.
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