Most affordable brightening serums pick one or two actives. This one stacks niacinamide, tranexamic acid, alpha-arbutin, glutathione and three forms of vitamin C — on a base that's ~60% antioxidant lingonberry extract instead of water — and still comes in fragrance-free for around $24. That density of evidence-backed brighteners at this price is genuinely rare.
An almost absurdly loaded brightening serum that stacks niacinamide, tranexamic acid, alpha-arbutin, glutathione and three forms of vitamin C on a base that's mostly antioxidant lingonberry extract — all fragrance-free for around $24. The glutathione is more glow bonus than skin-whitener, but the well-dosed core brighteners deliver real results, making this outstanding value for fading dark spots and dullness.
The case for it
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 →
The studies behind the evidence row
The case for it
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 →
The studies behind the evidence row
The case for it
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 →
The studies behind the evidence row
The case for it
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 →
The studies behind the evidence row
The case for it
Same rule for everyone. “Not for this” is the verdict on 488 of 45,024 concern verdicts across the catalog; rule R10 decided 488 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
Also listed for Dullness — the actives here (Niacinamide, 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
Read the ingredient list on most serums and the first word is 'water.' Read this one and the first word is lingonberry — Vaccinium vitis-idaea fruit extract, present at a staggering ~60% — with water not appearing until sixth on the list, after niacinamide, panthenol and tranexamic acid. That single fact tells you almost everything about Numbuzin's approach. This is a brand built on cramming the maximum density of evidence-backed actives into transparent, affordable 'concentrated' serums, and the No.5+ might be the most loaded of the lot. The question worth answering is whether that density translates into results or just a flashy label — and the encouraging answer is mostly the former.
Start with the foundation, because it's unusual. Lingonberry extract isn't a filler; it's a berry naturally rich in vitamin C, arbutin and fruit acids, which means the entire serum is built on an antioxidant-and-brightening matrix rather than plain water. Every other active here sits on that vitamin-loaded base. It's a genuinely clever structural choice, and it's the reason the formula can claim antioxidant credibility before you even reach the marquee ingredients. Whether the brand's exact percentage is marketing flourish or literal, the practical effect is a serum that feels and behaves like a concentrate.
Then come the brighteners, and this is where the serum earns its keep. Niacinamide sits at a clinically meaningful 5% and tranexamic acid at 4% — both real, working doses, not label decoration. Niacinamide interrupts the transfer of pigment to skin cells, while tranexamic acid blocks the inflammatory signaling that triggers melanin production further upstream; together at these concentrations they're one of the better-evidenced brightening pairings in skincare. Alpha-arbutin adds a third mechanism, directly inhibiting the tyrosinase enzyme that makes melanin. That's three distinct, well-supported approaches to hyperpigmentation in one bottle, which is why this serum tackles dark spots and uneven tone more comprehensively than single-active products. The 'plus' upgrade over the original No.5 — glutathione plus three forms of vitamin C — layers antioxidant defense and radiance on top.
A word of honesty about that glutathione, since it's the headline of the 'plus' name and the reason the serum went viral. Topical glutathione has become a K-beauty obsession off the back of the 'inner glow' supplement and IV-drip craze, and the marketing implication is dramatic skin-whitening. At 100 ppm in a serum, that's not what's happening. Glutathione here is a legitimate antioxidant that supports radiance and even tone, but it is not a bleaching agent, and the real pigment-correcting work is being done by the niacinamide, tranexamic acid and arbutin. Buy this for those proven brighteners and treat the glutathione as a welcome glow bonus, not a miracle, and you'll be happy; expect dramatic whitening and you've misunderstood the product.
What genuinely impresses is that all this active density comes without the usual costs. The serum is fragrance-free — a real achievement for a product this stacked — and Numbuzin had the sense to buffer the brightening load with a generous 5% panthenol plus ceramide NP, beta-glucan, allantoin and soothing licorice. That barrier-and-soothe counterweight is what keeps a serum carrying this many actives comfortable on daily use rather than a recipe for irritation. In practice it feels hydrating, leaves a subtle radiance, and applies with a slight tack that vanishes the moment a moisturizer goes over it. There's no sting, though the sheer number of actives means genuinely sensitive skin should still patch test and introduce it slowly.
The limitations are minor and honest. The slightly tacky finish from the dense formula bothers some people, though it's a non-issue once sealed with cream. The 30 ml bottle is small and lasts six to eight weeks. It contains shea butter, which makes it non-vegan and rules it out for anyone strictly managing fungal acne. And as with any pigment treatment, results demand patience and, above all, religious daily sunscreen — without it, you're filling a leaky bucket. None of these dent the core proposition much.
That proposition is value, and here the serum is close to unbeatable. Around twenty-four dollars buys you a fragrance-free serum carrying clinical-level niacinamide and tranexamic acid, plus arbutin, glutathione and multi-form vitamin C, on an antioxidant berry base. Brightening serums with a fraction of this active density routinely cost two or three times as much. The people who'll love it are anyone battling dark spots, post-acne marks, melasma or general dullness who wants maximum proven brighteners per dollar. The ones who should think twice are the very sensitive, who may prefer to introduce these actives one at a time, and strict vegans or fungal-acne sufferers ruled out by the shea butter. For everyone else, this is one of the smartest brightening buys in K-beauty right now — a genuine powerhouse at a budget price, as long as you pair it with the sunscreen it depends on.
The hero actives that drive this product's performance.
| Ingredient | Function | Evidence |
|---|---|---|
| Lingonberry Extract (Vaccinium Vitis-Idaea, ~60%) (~60%) | The base this whole serum is built on: instead of mostly water, the largest ingredient is a huge dose of lingonberry fruit extract, naturally rich in antioxidant vitamin C, arbutin and AHAs. It's the antioxidant-and-brightening foundation that lets every added active here sit on a vitamin-loaded matrix rather than plain water — the structural choice that defines the formula. | Not yet assessed |
| Niacinamide (5%) + Tranexamic Acid (4%) (5% / 4%) | The brightening workhorses, both at clinically meaningful doses: niacinamide interrupts pigment transfer to skin cells while tranexamic acid blocks the melanin-triggering pathway upstream. Together at these percentages they form an evidence-backed one-two punch against dark spots and uneven tone that anchors the serum's fade-pigmentation claim. | Emerging for Hyperpigmentation |
| Glutathione + Multi-Form Vitamin C (3-O-Ethyl Ascorbic Acid, Ascorbic Acid, Ascorbyl Glucoside) | The 'plus' upgrade over the original No.5: glutathione (the headline antioxidant) joins three forms of vitamin C and the lingonberry's natural ascorbic content to layer antioxidant defense and a brightening, radiance-boosting effect on top of the niacinamide-TXA core, broadening the attack on dullness and oxidative stress. | Not yet assessed |
| Alpha-Arbutin | A targeted tyrosinase inhibitor that adds a third mechanism to the brightening stack, gently curbing melanin synthesis to complement the niacinamide and tranexamic acid — the reason this serum hits hyperpigmentation from several angles at once rather than relying on a single pathway. | Limited for Hyperpigmentation |
| Panthenol (5%) + Ceramide NP + Beta-Glucan (5%) | The barrier-and-soothe counterweight to a brightening-heavy formula: a generous 5% panthenol plus ceramide NP, beta-glucan and allantoin hydrate and calm, which is what keeps a serum stacked with this many actives comfortable rather than irritating on daily use. | Not yet assessed |
Ingredient standings describe the active at treatment-level doses and vehicles; this product's own condition grades weigh its actual formula.
Vaccinium Vitis-Idaea Fruit Extract (604,074ppm), Butylene Glycol, Niacinamide (50,000ppm), Panthenol (50,000ppm), Tranexamic Acid (40,000ppm), Water, 1,2-Hexanediol, Neopentyl Glycol Dicaprate, Caprylic/Capric Triglyceride, Sorbitol, Bifida Ferment Lysate, Chondrus Crispus Extract, Butyrospermum Parkii (Shea) Butter, Saccharum Officinarum (Sugarcane) Extract, Alpha-Arbutin, Sodium Hyaluronate, Melia Azadirachta Flower Extract, Ocimum Sanctum Leaf Extract, Melia Azadirachta Leaf Extract, Curcuma Longa (Turmeric) Root Extract, Corallina Officinalis Extract, Tremella Fuciformis (Mushroom) Extract, Pentylene Glycol, Glycerin, 3-O-Ethyl Ascorbic Acid (2,000ppm), Bisabolol, Tromethamine, Ethylhexylglycerin, Adenosine, Hydrogenated Lecithin, Allantoin, Glutathione (100ppm), Ceramide NP, Beta-Glucan, Dipotassium Glycyrrhizate, Tocopherol, Ascorbic Acid, Ascorbyl Glucoside, Tocopheryl Acetate, Hydroxypropyl Cyclodextrin, Ubiquinone, Thioctic Acid, Potassium Hydroxide, Behenyl Alcohol, Carbomer, Xanthan Gum, Disodium EDTA
serum
AM & PM
Smooth it on after toner and before moisturizer, morning and/or night. Its brightening actives pair naturally with a hydrating routine and, in the morning, with sunscreen — non-negotiable when treating pigmentation. It layers fine with most things; if you also use a strong leave-on exfoliant or retinoid, alternate them to evenings this serum sits out, to avoid overloading skin.
Immediate: skin looks hydrated and subtly more radiant. Short-term (2-4 weeks): a brighter, more even-looking surface and softened dullness. Full benefit (8-12 weeks): visible fading of dark spots and post-acne marks with daily use and diligent sun protection, since pigment correction is inherently slow.
This serum's brightening rests on a stack of well-evidenced mechanisms. Niacinamide at 5% has robust clinical data for reducing hyperpigmentation by inhibiting the transfer of melanosomes from melanocytes to keratinocytes, with studies showing visible improvement in spots and tone at this concentration. Tranexamic acid, at 4% topically, has growing clinical support for treating melasma and post-inflammatory hyperpigmentation by interrupting the plasmin-mediated signaling that stimulates melanin production — a different and complementary pathway to niacinamide. Alpha-arbutin is a tyrosinase inhibitor with evidence for gently reducing melanin synthesis, adding a third mechanism. The multiple vitamin C forms (3-O-ethyl ascorbic acid, ascorbic acid, ascorbyl glucoside) and the lingonberry's natural ascorbic content provide antioxidant and brightening support, though the stability and efficacy of vitamin C depend heavily on form and formulation. Glutathione is a well-studied systemic antioxidant, but evidence for topical glutathione as a depigmenting agent is limited and far weaker than for the core actives; at 100 ppm it is best understood as antioxidant and radiance support, not a depigmenter. The supporting cast is well-grounded: panthenol and ceramide NP have strong barrier-repair and hydration data, and beta-glucan and allantoin are evidenced soothers. The honest synthesis: the serum's pigment-correcting claims are well supported by the niacinamide, tranexamic acid and arbutin trio, while glutathione and the antioxidant extras are a plausible, promising bonus rather than the primary engine.
Brightening serums that combine niacinamide and tranexamic acid are increasingly favored in clinical discussion for hyperpigmentation, because the two actives target distinct steps in melanin production and have independent bodies of evidence — tranexamic acid in particular has become a notable topical option for melasma and post-inflammatory marks. Alpha-arbutin is a reasonable adjunct tyrosinase inhibitor. The standard clinical caveat with any pigmentation treatment is that consistent, daily broad-spectrum sun protection is non-negotiable, since UV exposure both drives and undoes pigment correction. Topical glutathione, despite its popularity, is viewed cautiously in clinical literature, where evidence for meaningful topical depigmentation is limited; it is reasonably regarded as an antioxidant rather than a primary lightening agent. The inclusion of panthenol, ceramides and soothing agents is a sensible way to improve tolerability of a multi-active formula, and the fragrance-free base is a plus for reactive skin, though those with sensitivity should still introduce a serum this dense gradually.
Smooth a few drops over the face after cleansing and toning, morning and/or night, before your moisturizer. Treat it as your brightening treatment step and seal it with a cream to offset the slightly tacky finish. In the morning it must be followed by broad-spectrum sunscreen — sun protection is what makes any pigmentation treatment work, and skipping it wastes the serum. It layers comfortably with hydrating products; if you also use a strong leave-on exfoliant or retinoid, alternate them onto nights this serum sits out so skin isn't overloaded. Introduce it gradually if your skin is sensitive or new to multi-active serums.
On value this serum is hard to beat. For around twenty-four dollars you get a fragrance-free formula carrying niacinamide and tranexamic acid at full clinical strength, plus alpha-arbutin, glutathione and three forms of vitamin C, on an antioxidant berry base — an active density that brightening serums costing two to three times as much rarely match. There's a single 30 ml size, which lasts six to eight weeks with regular use, so the per-month cost is modest. You're genuinely paying for the actives rather than packaging or branding, which is the heart of Numbuzin's value proposition. The only asterisk is that the glutathione headline is more marketing than mechanism — but since the proven brighteners alone justify the price, that doesn't undermine the deal. For results-per-dollar on hyperpigmentation, this is among the strongest options in its bracket.
This is an excellent choice for anyone tackling dark spots, post-acne marks, melasma or general dullness who wants the maximum density of proven brighteners for the money. It suits normal, combination and dry skin especially, and its fragrance-free, well-buffered formula makes it approachable even for those who usually find brightening serums harsh — provided they introduce it sensibly.
Very sensitive or reactive skin may do better introducing niacinamide, tranexamic acid and vitamin C one at a time rather than all at once, so this dense stack could be overwhelming. Strict vegans and anyone closely managing fungal acne should pass because of the shea butter, and those hoping topical glutathione will dramatically whiten their skin should reset expectations before buying.
Ready to try Numbuzin No.5+ Glutathione Vitamin Concentrated Serum?
Buy at Amazon ♥A lightweight but slightly viscous serum that goes on with a faint tack from the dense humectant-and-active load, then settles into a soft, hydrated finish once a moisturizer goes over it.
Fragrance-free, with only a faint natural berry-and-base note from the high lingonberry content and no added perfume.
A frosted bottle with a dropper, letting you dose the concentrated serum precisely; standard, functional brand packaging.
First use feels hydrating and leaves a subtle radiance, with a slightly tacky finish that disappears under moisturizer. There's no sting despite the active load, though very sensitive skin should patch test given the niacinamide and vitamin C. Brightening is gradual — expect comfort and glow early, with dark-spot fading over weeks.
Around 6-8 weeks of once-or-morning and night from the 30 ml bottle.
All Year
It's the 'plus' upgrade to Numbuzin's cult No.5 Vitamin Concentrated Serum, adding glutathione and berry extracts to the original vitamin formula. The move reflects the K-beauty glutathione craze — the antioxidant became a viral 'inner glow' obsession — and Numbuzin's whole numbered-serum identity of packing maximum actives into transparent, affordable concentrates.
Numbuzin launched in 2020 and quickly became a viral K-beauty brand known for its numbered, actives-forward 'concentrated' serums. This No.5+ is the upgraded glutathione version of its popular No.5 vitamin serum; the formulas lean on transparent, high-percentage labeling, though independent clinical validation of the specific products is limited.
Topical glutathione will dramatically whiten your skin like the supplements or IV drips claim.
Glutathione at 100 ppm in a serum is an antioxidant that supports radiance and even tone, not a skin-bleaching agent. The real brightening here comes from the well-dosed niacinamide, tranexamic acid and arbutin; glutathione adds antioxidant support, not dramatic depigmentation. Treat it as a glow booster, not a whitening miracle.
It targets dullness, dark spots and uneven tone using a stack of brighteners — 5% niacinamide, 4% tranexamic acid, alpha-arbutin, glutathione and three forms of vitamin C — on an antioxidant lingonberry base. Expect gradual brightening and fading of pigmentation with daily use and sun protection.
The No.5+ adds glutathione and antioxidant berry extracts to the original vitamin formula and adjusts the active levels. It's a more antioxidant-focused, radiance-boosting upgrade, while the original leans more straightforwardly on vitamins and brightening ingredients. They're distinct products, not the same serum renamed.
Not in the dramatic way supplements claim. At the 100 ppm here, glutathione works as an antioxidant supporting radiance and even tone, not as a bleaching agent. The serum's real brightening comes from the well-dosed niacinamide, tranexamic acid and arbutin; glutathione is a glow bonus.
Yes — and you should pair it with daily sunscreen, which is essential when treating pigmentation. It layers fine with hydrators and most routines; if you also use a strong leave-on exfoliant or retinoid, alternate nights so skin isn't overloaded with actives at once.
It's fragrance-free and buffered with 5% panthenol, ceramides and soothing extracts, which helps, but it's a very active-dense serum. Most skin tolerates it well; the genuinely sensitive should patch test and introduce it slowly given the niacinamide and vitamin C content.
No on both counts — it contains shea butter, which makes it non-vegan and means it isn't suitable for those strictly managing fungal acne (malassezia). It is cruelty-free.
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.
Visible brightening and dark-spot fading
Incredible active density for the price
Hydrating and non-stripping
Fragrance-free and gentle for an actives serum
Slightly tacky finish from the dense formula
Too many actives at once for very sensitive skin
Small 30 ml size
Contains shea butter, so not vegan or fungal-acne safe
Verified answers from our questions library — the nuance a product page cannot carry.
