One Thing Niacinamide 10% 150ml clear bottle
Promising for Large Pores
What Makes This Different

Most 10% niacinamide products are positioned as treatment serums in 30ml bottles at $15-25, which works out to 50-80 cents per ml. One Thing delivers the same clinically relevant concentration in a 150ml bottle for roughly 10 cents per ml, formatted as a generous essence rather than a rationed treatment. The format change alone makes this one of the most usable niacinamide products in the category.

One Thing

One Thing Niacinamide 10% Review

Budget Niacinamide MVP
serum liquid k beauty Paraben Free Fungal Acne Safe Cruelty Free Vegan

One Thing's Niacinamide 10% is the best value in the niacinamide category — a clinically relevant concentration in a 150ml essence bottle for roughly one-third the per-ml cost of most competitors. Clean, fragrance-free, and gentle enough to use twice daily from day one. If you want niacinamide as an everyday habit rather than a rationed treatment, this is the one.

$16.00
150ml
4.4 ★★★★★
5,200 reviews
Made in South Korea Launched 2020 All-year use PAO: 12 months
Buy at Amazon ♥
Run it through our tools Clashes with my routine? Pregnancy-safe? Find a cheaper dupe Patch-test it first
Verdicts

How well it fits each concern

Verdict by concern tap a concern for the case

Promisingfor Large PoresNiacinamide has trial-level evidence for large pores but no guideline or regulatory standing yet — promising, short of a recommendation; the other actives here are not yet assessed for it.Moderate evidenceGentleNo reviews collected yet

The case for it

  1. Niacinamide 10% has trial-level evidence for this concern but no guideline or regulatory standing yet.
  2. It is present at an effective concentration, declared or high in the ingredient list.
  3. The formula carries none of the triggers this concern is sensitive to.

What would change this: Guideline or regulatory standing for the active on this concern would move this from a promising bet to a recommendation.

Same rule for everyone. “Promising” is the verdict on 7,858 of 45,024 concern verdicts across the catalog; rule R9p decided 7,858 of them. Unchanged since September 5, 2026, engine 5.1.1.

Brand or formulator? Disclose a concentration or correct a fact →

Show the work
Rule
R9p — 0.5.0: 'Unproven' beside three filled dots read as one question answered twice with opposite words (7,018 rows). The chip measures standing, the dots measure trial volume; where the row carries at least one RCT or a tier-2 source (moderate dots) and the active is present at a working level, the honest word is Promising. Unproven is reserved for plausible-standing rows with limited or weak evidence, or an under-dosed form. Same rank as Unproven — a bet either way; the dots order them. · the full register
Carrying active
Niacinamide 10%
Standing
plausible — trials support it
Form
adequate (declared 10%) — studied range 4%, from the trials on the row; needs leave-on contact; judge it after ~8 weeks
Tolerability
gentle
Row checked
against its sources on July 17, 2026 (evidence table ev-2026.09-r228)

The studies behind the evidence row

All large pores products →
Good choicefor HyperpigmentationNiacinamide is a trial-supported active for hyperpigmentation; this liquid carries it at 10%.Moderate evidenceGentleNo reviews collected yet

The case for it

  1. Niacinamide 10% has trial-supported standing for this concern.
  2. It is present at an effective concentration, declared or high in the ingredient list.
  3. The formula carries none of the triggers this concern is sensitive to.

Same rule for everyone. “Good choice” is the verdict on 9,564 of 45,024 concern verdicts across the catalog; rule R5 decided 9,072 of them. Unchanged since September 5, 2026, engine 5.1.1.

Brand or formulator? Disclose a concentration or correct a fact →

Show the work
Rule
R5 — Trial-supported or guideline-supported active, adequately or plausibly dosed. · the full register
Carrying active
Niacinamide 10%
Standing
supported — trials support it
Form
adequate (declared 10%) — studied range 2–5%, from the trials on the row; needs leave-on contact; judge it after ~8 weeks
Tolerability
gentle
Row checked
against its sources on July 17, 2026 (evidence table ev-2026.09-r228)

The studies behind the evidence row

All hyperpigmentation products →
Promisingfor Excess OilinessNiacinamide has trial-level evidence for excess oiliness but no guideline or regulatory standing yet — promising, short of a recommendation; the other actives here are not yet assessed for it.Moderate evidenceGentleNo reviews collected yet

The case for it

  1. Niacinamide 10% has trial-level evidence for this concern but no guideline or regulatory standing yet.
  2. It is present at an effective concentration, declared or high in the ingredient list.
  3. The formula carries none of the triggers this concern is sensitive to.

What would change this: Guideline or regulatory standing for the active on this concern would move this from a promising bet to a recommendation.

Same rule for everyone. “Promising” is the verdict on 7,858 of 45,024 concern verdicts across the catalog; rule R9p decided 7,858 of them. Unchanged since September 5, 2026, engine 5.1.1.

Brand or formulator? Disclose a concentration or correct a fact →

Show the work
Rule
R9p — 0.5.0: 'Unproven' beside three filled dots read as one question answered twice with opposite words (7,018 rows). The chip measures standing, the dots measure trial volume; where the row carries at least one RCT or a tier-2 source (moderate dots) and the active is present at a working level, the honest word is Promising. Unproven is reserved for plausible-standing rows with limited or weak evidence, or an under-dosed form. Same rank as Unproven — a bet either way; the dots order them. · the full register
Carrying active
Niacinamide 10%
Standing
plausible — trials support it
Form
adequate (declared 10%) — studied range 2%, from the trials on the row; needs leave-on contact; judge it after ~8 weeks
Tolerability
gentle
Row checked
against its sources on July 17, 2026 (evidence table ev-2026.09-r228)

The studies behind the evidence row

All excess oiliness products →
Promisingfor AcneNiacinamide has trial-level evidence for acne but no guideline or regulatory standing yet — promising, short of a recommendation; the other actives here are not yet assessed for it.Moderate evidenceGentleNo reviews collected yet

The case for it

  1. Niacinamide 10% has trial-level evidence for this concern but no guideline or regulatory standing yet.
  2. It is present at an effective concentration, declared or high in the ingredient list.
  3. The formula carries none of the triggers this concern is sensitive to.

What would change this: Guideline or regulatory standing for the active on this concern would move this from a promising bet to a recommendation.

Same rule for everyone. “Promising” is the verdict on 7,858 of 45,024 concern verdicts across the catalog; rule R9p decided 7,858 of them. Unchanged since September 5, 2026, engine 5.1.1.

Brand or formulator? Disclose a concentration or correct a fact →

Show the work
Rule
R9p — 0.5.0: 'Unproven' beside three filled dots read as one question answered twice with opposite words (7,018 rows). The chip measures standing, the dots measure trial volume; where the row carries at least one RCT or a tier-2 source (moderate dots) and the active is present at a working level, the honest word is Promising. Unproven is reserved for plausible-standing rows with limited or weak evidence, or an under-dosed form. Same rank as Unproven — a bet either way; the dots order them. · the full register
Carrying active
Niacinamide 10%
Standing
plausible — trials support it
Form
adequate (declared 10%) — studied range 4–5%, from the OTC monograph or label; needs leave-on contact; judge it after ~8 weeks
Tolerability
gentle
Row checked
against its sources on July 17, 2026 (evidence table ev-2026.09-r228)

The studies behind the evidence row

All acne products →

Also listed for Dullness — the actives here (Niacinamide, Allantoin, Panthenol (Vitamin B5) are in our research queue for that concern; there is no verdict until their evidence rows are written. That is a gap in our table, not a mark against the product.

Where our review and the verdict differ. The review below was written on the formulation and the published trials; the verdicts above apply the stricter standing test in our methodology — an active earns a recommendation only with guideline or regulatory standing for the concern. Where the two disagree, the verdict is DermApproved’s position.

A verdict is DermApproved’s assessment of how well a product’s ingredients fit a concern — never a claim about what the product treats. Evidence dots and collected reviews sit beside it and are never blended in. Rules 0.5.1 · evidence table ev-2026.09-r228 · how we decide

Assessment

Pros & Cons

Pros

  • ✓ Clinically relevant 10% niacinamide concentration
  • ✓ Exceptional value at roughly 10 cents per milliliter
  • ✓ Fragrance-free, alcohol-free, and vegan formulation
  • ✓ Layers cleanly under any active or makeup without pilling
  • ✓ Generous 150ml size supports consistent twice-daily use
  • ✓ Includes allantoin and panthenol as irritation buffers

Cons

  • ✗ Can cause temporary flushing on sensitive or rosacea-prone skin
  • ✗ No added zinc for acne-specific formulation preferences
  • ✗ Plastic bottle packaging isn't premium-feeling
  • ✗ Requires 8-12 weeks of consistent use for PIH results
Review

Full Review

Here's a design question the skincare industry mostly got wrong: if niacinamide at 10% is the concentration dermatologists keep pointing to for sebum control and pigment management, and it's cheap to manufacture, why is it almost always sold in tiny 30ml dropper bottles marketed as precious treatment serums? A famously minimalist budget brand set that pricing template back in 2016, and nearly everyone who followed copied the format. One Thing arrived in 2020 with a different answer: put the same 10% niacinamide in a 150ml bottle, call it an essence, and let people actually use it every day without counting drops.

That format change matters more than it sounds. When a niacinamide product costs 80 cents per ml, users tend to rationalize it — small amounts, every other day, only on problem areas. When it costs 10 cents per ml, the calculation flips. You pour a generous puddle, pat it onto your whole face, use it morning and night, and treat it as an infrastructure layer rather than a special intervention. That's how niacinamide is supposed to work. The research on sebum reduction, barrier improvement, and post-inflammatory hyperpigmentation fading is based on twice-daily application over 8 to 12 weeks, not occasional spot treatment. The bottle wasn't the brand's first act, either — One Thing built its name on viral single-ingredient centella and hyaluronic essences, and this was the same philosophy pointed at a harder-working active.

The formula itself is almost impressively unambitious, which is the point. Niacinamide at 10%, butylene glycol and glycerin as humectants, allantoin and panthenol as barrier soothers, sodium hyaluronate for a hydration assist, a drop of adenosine (a Korean-regulated anti-wrinkle active that contributes a minor smoothing effect), 1,2-hexanediol for preservation, and water. That's the whole list — eleven entries, buffered to a skin-comfortable pH of 6, fragrance-free, vegan, and fungal-acne safe. No essential oils, no plant extracts chasing a trend, no unnecessary peptides or exotics. The ingredient deck is so short that any given drop of the essence is about 90% doing one job: delivering niacinamide.

On skin it's indistinguishable from water with a faint slip. It absorbs in seconds, leaves no tack, and pills under nothing — including sunscreens, silicone primers, and makeup. The lack of added zinc (a common companion ingredient in niacinamide formulas) means the texture stays thinner and cleaner than versions that include zinc PCA. It also means you don't get the slight grittiness that zinc sometimes contributes, which matters more than you'd think for daily wearability. A dime-sized pour patted in with the palms — after toner, before moisturizer — covers face and neck, and the old worry about layering niacinamide with vitamin C can be retired: that caution came from decades-old data on a different molecule under lab conditions, and in real-world routines the two coexist fine.

Results follow the usual niacinamide timeline. Oil control and pore appearance improvements show up around weeks 2 to 3 — not because pores actually shrink (they don't, physically) but because reduced sebum congestion and improved keratin turnover make pore openings look smaller. Post-inflammatory hyperpigmentation fading is slower, as always: expect 8 to 12 weeks of consistent twice-daily use before the flatter dark marks start to visibly fade. Users with compromised barriers often notice the barrier-calming effects first, within a week or two. Users expecting a dramatic transformation out of a 10 cents-per-ml essence will be disappointed, but users expecting incremental, cumulative improvement will be rewarded. The several thousand reviews accumulated across K-beauty retailers land on the same arc — users consistently report calmer oil output, smoother-looking pores, and appreciation for how far the bottle stretches, with the main complaints being the patience required for pigment work and first-week flushing on reactive skin.

The flushing caveat is worth mentioning. A small percentage of users — especially those with rosacea or very reactive skin — experience temporary vasodilation in the first week of using 10% niacinamide. This shows up as transient redness lasting 15 to 30 minutes after application, and it typically fades as the skin adapts. If you're in that camp, the solution is to introduce the essence every other day for the first two weeks rather than diving straight into twice-daily use. It's a real-world tolerance issue, not a formulation flaw, and it applies to any 10% niacinamide product. Going higher than 10% wouldn't help anyway — above that line, irritation risk climbs without clear added benefit, which is why this concentration is the sensible ceiling rather than a compromise. For everyone else the formula is about as low-risk as actives get, and it's safe during pregnancy and breastfeeding.

Value is where this product becomes almost a no-brainer. At roughly $16 for 150ml, you're paying around 10 cents per ml for a clinically relevant niacinamide concentration. A typical twice-daily face application lasts about three to four months, which works out to $4 to $5 per month. For comparison, prestige niacinamide boosters run north of forty dollars for 20ml — more than ten times the per-ml cost — and even the famously cheap budget dropper bottles work out to about five times more per ml. One Thing isn't a legacy derm brand with decades of clinical research behind its name, but it doesn't need to be. The active is off-patent and well-studied, the formula is minimal enough to leave almost nothing to get wrong, and the value is unbeatable. For niacinamide specifically, this is the one to beat.

Formula

Key Ingredients

The hero actives that drive this product's performance.

IngredientFunctionEvidence
Niacinamide 10% (10%) The entire point of this essence. At 10%, niacinamide sits at the top of the clinically useful range for reducing sebum output, improving barrier function, and fading post-inflammatory hyperpigmentation. With only gentle humectants and allantoin for company, there's nothing competing for skin-contact time or diluting the core active. Emerging for Hyperpigmentation
Adenosine A Korean-regulated anti-wrinkle active included at a low functional concentration. It provides a mild complement to the niacinamide, adding some smoothing and barrier-calming effects without introducing any irritation risk of its own. Not yet assessed
Panthenol Works alongside the niacinamide to reinforce barrier repair — particularly relevant here because 10% niacinamide on some skin types can cause a brief flushing response, and panthenol helps buffer that while the skin adapts. Not yet assessed
Allantoin A gentle soother added as an irritation buffer for a formula that contains a fairly high percentage of niacinamide. Its inclusion shows the brand understood that minimalism still requires a couple of calming agents when you're using an active at its upper functional limit. Not yet assessed
Full INCI List · pH 6

Water, Niacinamide, Butylene Glycol, 1,2-Hexanediol, Glycerin, Allantoin, Panthenol, Sodium Hyaluronate, Adenosine, Ethylhexylglycerin, Disodium EDTA

Safety & Formulation Facts
✓ Pregnancy Safe ✓ Fragrance Free✓ Alcohol Free✓ Oil Free✓ Silicone Free✓ Paraben Free✓ Sulfate Free✓ Cruelty Free✓ Vegan✓ Fungal Acne Safe
Compatibility

Skin Match

Best For
Works For
Routine Step

serum

Time of Day

AM & PM

Layering Tips

Apply after cleansing and hydrating toner, before heavier serums or moisturizer. Avoid layering directly with pure vitamin C (ascorbic acid) if you're sensitive — though research shows they coexist fine for most users.

Results Timeline

Oil control and pore appearance improvements often show within 2-3 weeks. Hyperpigmentation fading takes 8-12 weeks of consistent use. Barrier improvements are cumulative over 4-6 weeks.

Pairs Well With
hyaluronic-acidretinoidspeptidesazelaic-acid
Planning a combo? Check it against what you already use
Sample AM Routine
  1. Gentle cleanser
  2. Hydrating toner
  3. One Thing Niacinamide 10%
  4. Moisturizer
  5. SPF
Sample PM Routine
  1. Cleanser
  2. One Thing Niacinamide 10%
  3. Retinoid
  4. Moisturizer
Evidence

Science & Expert Perspective

The Science

Niacinamide is one of the most thoroughly studied cosmetic actives of the past three decades. A 2005 study in the British Journal of Dermatology (Hakozaki et al., originally published 2002 and replicated through 2005) demonstrated that topical niacinamide at 2-5% significantly reduced facial hyperpigmentation by interfering with melanosome transfer from melanocytes to keratinocytes — notably, without inhibiting tyrosinase activity, which is how it differs mechanistically from hydroquinone. A 2006 paper in the Journal of Cosmetic and Laser Therapy (Draelos et al.) found that 2% niacinamide reduced sebum excretion rates in Japanese and Caucasian subjects, with measurable results at 2-4 weeks. Higher concentrations, up to 10%, have shown additional barrier function improvements via upregulation of ceramide and free fatty acid synthesis. What's interesting about One Thing's 10% formulation specifically is that it uses the active at the upper edge of the clinically useful range while keeping the excipient list minimal enough to avoid dilution or interference. Most of the supporting cast — panthenol, allantoin, adenosine, sodium hyaluronate — is there to buffer the mild vasodilation response that a small minority of users experience at 10% niacinamide. The formula is calibrated for tolerance rather than maximum active delivery, and in real-world use that's the right trade-off.

Dermatologist Perspective

Dermatologists routinely recommend niacinamide at 2-10% as one of the most versatile actives in modern skincare. Skin-care clinicians recognize that niacinamide's mechanism — reducing melanosome transfer rather than inhibiting tyrosinase — makes it a useful complement to hydroquinone, azelaic acid, or tranexamic acid in hyperpigmentation protocols. It's also commonly used alongside topical retinoids to help offset retinoid-induced barrier disruption. Clinical guidance emphasizes that niacinamide is safe during pregnancy and compatible with virtually every other topical active, which is why it appears in so many 'universal add-on' recommendations. The 10% concentration in this essence is the upper edge of what most practitioners consider clinically useful before the risk of flushing or irritation outweighs the incremental benefit.

Guidance

Usage & Recommendations

How to Use

Apply to clean skin after your hydrating toner but before your moisturizer. A dime-sized amount is enough for the full face and neck — pat in with palms rather than using a cotton pad. Start every other day for the first two weeks if you have sensitive or reactive skin, then increase to twice daily once tolerance is established. Layers fine with vitamin C, retinoids, exfoliants, and peptides. Always follow with sunscreen in the morning. Safe during pregnancy and breastfeeding.

Value Assessment

At approximately $16 for 150ml, this is the best per-milliliter price on a clinically relevant 10% niacinamide formulation currently on the market. A typical twice-daily face application lasts roughly three to four months, working out to $4-5 per month. Compared to prestige niacinamide serums in the $40-60 range for 20-30ml, the value difference is roughly 10x in One Thing's favor. The brand is an emerging one without the legacy of a derm-developed line, but niacinamide at 10% is such a well-studied, off-patent active that there's very little formulation risk. For daily niacinamide habits, the value here is hard to argue with.

Who Should Buy

Anyone looking for an affordable daily niacinamide habit — especially users dealing with large pores, oiliness, post-inflammatory hyperpigmentation, or dullness. Also an excellent complement to retinoid routines, where niacinamide helps offset barrier disruption.

Who Should Skip

Skip if you have severe rosacea and have had prior flushing reactions to niacinamide at concentrations above 5%. This one is also wrong for you if you prefer a multi-active serum with added peptides or antioxidants — this deliberately contains nothing but niacinamide and its supporting cast.

Ready to try One Thing Niacinamide 10%?

Buy at Amazon ♥

Or visit the One Thing store on Amazon →

Details

Product Details

Texture

Thin, watery liquid with a barely perceptible slip

Scent

Unscented

Packaging

Clear plastic bottle with a screw top — same design language as the rest of the One Thing line

Finish
lightweightfast-absorbingnon-greasy
What to Expect on First Use

First few applications may cause mild flushing on sensitive skin as the niacinamide causes temporary vasodilation — this is normal and fades within 15-30 minutes. Most users tolerate it with no reaction at all. Visible oil-control and glow improvements typically begin around week 2-3.

How Long It Lasts

Around 3-4 months when applied morning and night to the face

Period After Opening

12 months

Opened yours? Track the toss-by date
Best Season

All Year

Certifications
cruelty-freevegan
Background

The Story Behind This Product

One Thing launched the Niacinamide 10% essence in 2020 as a follow-up to its viral Centella Asiatica and Hyaluronic Acid essences. The brand's pitch was simple: if 10% niacinamide is the clinically meaningful concentration for sebum control and pigmentation, why sell it as a precious 30ml dropper bottle instead of a generous everyday essence? It's now one of the brand's bestsellers globally.

About One Thing Emerging Brand (2–5 years)

One Thing launched in 2018 in South Korea with a minimalist single-ingredient philosophy. While the brand is still relatively new, its niacinamide essence uses a well-studied active at a clinically relevant concentration, making the formulation itself conservative even if the brand's track record is short.

Brand founded: 2018 · Product launched: 2020
Myth vs. Reality

Common Myths

Myth

You can't layer niacinamide with vitamin C.

Reality

This concern came from a 1960s study on pure niacin (not niacinamide) at very high temperatures. Modern formulations of niacinamide and L-ascorbic acid layer fine in real-world use, and this essence is stable enough to apply directly before or after any vitamin C serum.

Myth

Higher niacinamide concentrations always work better.

Reality

Above 10%, the risk of irritation and flushing increases without clear additional benefit. One Thing's 10% sits at the upper edge of the clinically useful range without crossing into the territory where most users develop reactions.

FAQ

Frequently Asked Questions

How does this compare to The Ordinary Niacinamide 10% + Zinc 1%?

Both deliver 10% niacinamide at a budget price, but One Thing's formula omits zinc PCA and uses a significantly larger 150ml format instead of 30ml. The One Thing version is less prone to pilling under makeup and more generous to use as an everyday essence rather than a rationed treatment.

Does Niacinamide 10% pair well with retinol?

Yes. Niacinamide and retinoids are actually a classic pairing — the niacinamide's barrier-supportive effect helps offset some of retinol's drying side effects. This essence layers cleanly underneath any retinoid product without causing pilling.

Can sensitive skin tolerate Niacinamide 10%?

Mostly yes, though a small percentage of users experience temporary flushing during the first week as their skin adjusts to 10% niacinamide. If that happens, try using it every other day for two weeks before moving to daily use.

Can I use it while pregnant or breastfeeding?

Yes. Niacinamide is considered safe during pregnancy and nursing, and the rest of the ingredient list contains only mild humectants and soothers — nothing restricted.

Will it help with acne?

Indirectly yes — niacinamide reduces sebum production and has mild anti-inflammatory properties, both of which support acne management. It won't replace benzoyl peroxide or salicylic acid for active breakouts, but it helps reduce post-acne discoloration and oiliness.

How long before I see results?

Oil-control and pore-appearance improvements typically show within 2-3 weeks. Post-inflammatory hyperpigmentation fading takes longer — expect 8-12 weeks of consistent twice-daily use for visible results.

Reviews

What Reviewers Tend to Say

Recurring themes our editors read across retailer reviews of this product — summaries in our words, not quotations, and not a substitute for your own patch test.

Common Praise

Noticeable improvement in oiliness

Large size for the price

Non-sticky feel

Visible pore appearance improvement

Common Complaints

Flushing reaction on very sensitive skin

Doesn't smell like anything (some expect a 'scent cue')

Needs patience for PIH fading

Notable Endorsements
Hyram Yarbro
Appears In
Best Serums for AcneSerums That Suit Large PoresBest Niacinamide SerumsNiacinamide for Large Pores: What the Verdicts SayNiacinamide for Oily Skin: What the Verdicts Say
Related Conditions
large poreshyperpigmentationexcess oilinessacne
Related Ingredients
niacinamidepanthenoladenosine