Numbuzin No.5 serum review: Vitamin Concentrated for most, Goodbye Blemish for a gel
Updated October 22, 2026
For most shoppers, the No.5+ Glutathione Vitamin Concentrated Serum, 30 ml is the No.5 to buy: it has the fuller tone-care formula (niacinamide, tranexamic acid, alpha-arbutin, glutathione and three forms of vitamin C), no fragrance or citrus oils in its ingredient list, and it costs $17.99 for 30 ml at Sleepy Hello, checked October 2026. Choose the No.5 Goodbye Blemish Serum, 50 ml instead if you want a lighter gel in a bigger 50 ml bottle and don't mind citrus oils in the formula.
The No.5 pads and sheet masks are add-ons rather than replacements. Pick one serum first, and add the pad only if you like a wipe-on toner step with gentle exfoliation built in.
This is a researched comparison of current US brand and retailer information, checked October 2026. We haven't worn or tested these products; texture descriptions come from Numbuzin and from our product pages, and the buying advice comes from comparing formulas, directions, sizes and prices.
What is Numbuzin No.5 for?
Numbuzin No.5 is the brand's line for dark spots, post-acne marks and dull, uneven-looking tone. Numbuzin sorts its whole range by number, and each number stands for a skin concern rather than a strength: No.1 is the soothing number, No.3 the pore-and-texture number, No.9 the firming one. The 5 isn't a percentage or a step count.
Numbuzin's US site groups these products under a "No.5 Line" filter. Sleepy Hello stocks four of them: the Vitamin Concentrated Serum, the Goodbye Blemish Serum, a toner pad and a sheet mask. All four are built around vitamin C and niacinamide; the Vitamin Concentrated Serum, the pad and the mask add glutathione, and the Vitamin Concentrated Serum and the pad add tranexamic acid. Goodbye Blemish has neither. Prices for all four are in the shortlist near the end.
Numbuzin's US site also sells a No.5 dark spot cream and a TXA ampoule, which we don't carry.
A quick glossary before the formulas. Niacinamide is vitamin B3, a common ingredient for uneven-looking tone and oiliness. Tranexamic acid (TXA) is used in leave-on formulas for the look of dark spots. Glutathione is an antioxidant that Korean brands often put at the center of tone-care lines. None of these works quickly, and daily sunscreen matters as much as any of them, because sun exposure keeps existing marks looking darker for longer.
What is the difference between Numbuzin No.5 Vitamin Concentrated Serum and Goodbye Blemish Serum?
The Vitamin Concentrated Serum is the more targeted formula, with no fragrance in its ingredient list; Goodbye Blemish is a lighter gel built around sea buckthorn extract, with citrus oils in the list. They share niacinamide and the same three vitamin C forms, and differ in most other ways.
No.5+ Glutathione Vitamin Concentrated Serum. Numbuzin's US product page lists water, butylene glycol, niacinamide, panthenol, tranexamic acid, 1,2-hexanediol, neopentyl glycol dicaprate, caprylic/capric triglyceride and sorbitol first. In plain terms: water and a humectant, then niacinamide, panthenol (pro-vitamin B5, which helps skin hold moisture) and TXA, all ahead of the preservative, then two light emollients. Further down are lingonberry fruit extract, shea butter, alpha-arbutin, glutathione, ceramide NP and three forms of vitamin C: 3-O-ethyl ascorbic acid, ascorbic acid and ascorbyl glucoside.
Sleepy Hello's product page states 5% niacinamide, 4% tranexamic acid and 5% panthenol; the Numbuzin US page we checked doesn't print percentages. Glutathione sits in the back half of the list, after xanthan gum, so the ingredient in the product name is a minor part of the formula. The list doesn't include fragrance or essential oils, though it does contain turmeric root extract and bisabolol. Our product page recommends it for dry, oily, combination, sensitive and acne-prone skin, and describes the texture as silky and slightly viscous, spreading easily with no sticky finish.
No.5 Goodbye Blemish Serum. The list opens with sea buckthorn (hippophae rhamnoides) extract, the "Vitamin Tree Extract" named in the product description, then butylene glycol, methyl gluceth-20, dipropylene glycol, glycerin, 1,2-hexanediol and niacinamide. That is a humectant-heavy base, which fits our product page's description of a refreshing gel that absorbs quickly without a greasy finish. The same three vitamin C forms appear further down, alongside licorice root, turmeric, centella, green tea, panthenol and sodium hyaluronate.
Two things it doesn't have are tranexamic acid and alpha-arbutin. Two things it adds are lemon peel, orange peel and lime oils, plus citral and limonene, which are fragrance components. If fragrance or citrus oils bother your skin, that settles the choice. No percentages are printed for any ingredient, and it is described as suitable for all skin types and daily use.
Size and price. The Vitamin Concentrated Serum is $17.99 for 30 ml, about $0.60 per ml. Goodbye Blemish is $27.99 for 50 ml, about $0.56 per ml. The cost per ml is almost the same, so the cheaper bottle up front is also the one with more named tone-care ingredients.
How do you use Numbuzin No.5 serum?
Apply it daily, after cleansing and toner and before moisturizer. The two serums have slightly different directions:
Vitamin Concentrated Serum: morning and evening, after cleansing and toning, dispense a few drops onto your face, spread gently and pat until absorbed. Add a second layer where you want more moisture, then moisturizer, and sunscreen in the morning.
Goodbye Blemish Serum: after cleansing and toning, apply 2 to 3 pumps over the face and tap lightly, then follow with face cream. For more, apply a thin first layer and then a second. The directions also suggest soaking a thin cotton pad with the serum and resting it on one area for three minutes before your cream. The directions say it can be used daily.
The morning sunscreen step belongs in any dark-spot routine. Round Lab 1025 Dokdo Sun Cream, listed at SPF 50+ PA++++, is $18.99 for 50 ml and is one of the sunscreens our serum page pairs it with. Beauty of Joseon Relief Sun: Rice + Probiotics, listed at SPF50+ PA++++, is the lower-cost pick at $12.99 for 50 ml.
Start the serum on its own. If you begin the serum, the pads and a new acid in the same week, you won't know which one your skin disagrees with. Give it several weeks before judging; Numbuzin's own results are measured at four weeks.
Can you use Numbuzin No.5 with vitamin C or retinol?
Yes, but you probably don't need a separate vitamin C serum, and retinol is simplest at a different time of day. Numbuzin doesn't publish layering guidance for either on the pages we checked, so this is our take from the ingredient lists.
Vitamin C. Both No.5 serums already contain three forms of vitamin C, including ascorbic acid (pure vitamin C) and two derivatives. A strong vitamin C serum on top doubles up on the same job. If you already own one you like, use it in the morning and keep No.5 for the evening, or alternate days, rather than stacking both at once. Our Korean vitamin C serum guide covers stand-alone options.
Retinol. The Vitamin Concentrated Serum is the easier No.5 to keep in a retinol routine: its supporting ingredients are panthenol and ceramide, and it has no citrus oils. The simplest split is No.5 in the morning under sunscreen and retinol at night. Once your skin is comfortable with retinol, you can apply No.5 first on retinol nights, let it absorb, then retinol and moisturizer. If your retinoid is prescribed, follow your clinician's directions instead.
Exfoliating acids. Keep the No.5 pad off your retinol nights. It contains gluconolactone (a PHA) and capryloyl salicylic acid (an LHA), both exfoliating acids, plus a textured exfoliating side. Retinol and exfoliating acids on the same night is a common route to stinging and flaking.
Numbuzin No.5 serum vs No.5 pads: which should you buy?
Buy the serum if you want one dark-spot step; buy the pads if you like a wipe-on toner step and want light exfoliation too. They overlap heavily, so most routines need only one to start.
The No.5 Vitamin-Niacinamide Concentrated Pad, 70 pads prints some actives in parts per million (ppm): niacinamide at 50,000 ppm, which is 5%, panthenol at 750.1 ppm and glutathione at 0.3 ppm, a trace amount. Its tone-care work rests on niacinamide, ascorbic acid, ascorbyl glucoside and tranexamic acid, with gluconolactone and capryloyl salicylic acid for exfoliation. Each pad has a smooth jelly side for hydration and a textured cotton-gauze side for exfoliation, and the list includes alcohol, low down.
Wipe a pad from the center of your face outward, avoiding the eye area, then pat in the leftover liquid. Alternatively, rest the jelly side on your face for 3 to 5 minutes as a short mask. At $18.99 for 70 pads in 180 ml of liquid, each pad costs about 27 cents.
Pick the pads if:
you already like a toner-pad step and want it to do tone work too
your skin looks rough or dull and you'd like gentle exfoliation in the same step
you'd rather not add another layer to your routine
Pick the serum if:
your skin is easily irritated, since the serum has no exfoliating acids
you already use retinol or another exfoliant
you want a leave-on layer with panthenol and ceramide alongside the tone-care ingredients
Using both is reasonable once you know each suits you: the pad is the toner step, and the serum follows it.
Where the mask fits. The No.5+ Glutathione Vitamin Concentrated Mask, 10 sheets is a 10-sheet box at $24.99, about $2.50 per sheet. The product description names glutathione, vitamin C, niacinamide, arbutin, hyaluronic acid, allantoin, polyglutamic acid and ceramide NP. Leave it on for 10 to 20 minutes, remove the sheet and pat in the remaining essence without rinsing. It is an occasional extra, and our product page doesn't print its full ingredient list yet, so check the box if you avoid specific ingredients.
Where to buy, and who should skip No.5
Here is the No.5 shortlist at Sleepy Hello, checked October 2026:
Skip Goodbye Blemish if fragrance or citrus oils bother your skin. Skip a second niacinamide-and-TXA serum if you already use one, such as the formula in our Anua Niacinamide 10 TXA 4 review; layering two similar serums adds cost more than benefit. If your main concern is rough texture and pores rather than marks, No.3 is the number for that: the No.3 Skin Softening Serum, 50 ml is $13.99.
Try any new serum on a small area for a few days first. Stop using it if you get burning, itching or a rash, and see a dermatologist for marks that are spreading, raised or changing.
Quick answers
Does Numbuzin No.5 work on dark spots?
Numbuzin publishes its own four-week figures. For the Vitamin Concentrated Serum it reports an 18.9% improvement in tone evenness and a 9.65% reduction in the look of dark spots; for the pad, 15.1% and 8%. The pages we checked don't describe the study size or method, so read these as brand claims, and expect results to depend on daily sunscreen.
Is Numbuzin No.5 good for acne-prone skin?
The Vitamin Concentrated Serum and the pad are both recommended for acne-prone skin, but No.5 is aimed at the marks breakouts leave behind, not at breakouts. If you prefer a lighter, gel feel, Goodbye Blemish is the alternative; it is described as suitable for all skin types, as long as the citrus oils and fragrance components in its list don't bother you.
Can you use Numbuzin No.5 serum every day?
Yes. The Vitamin Concentrated Serum's directions say morning and evening, and Goodbye Blemish's directions say it can be used daily. Use sunscreen every morning alongside either.
Is No.5+ different from No.5?
Neither Numbuzin nor our product page explains the plus sign. Sleepy Hello's product page says the serum's bottle and box were refreshed while the formula stayed the same, so you may receive either packaging during the transition.
Does Numbuzin No.5 serum contain fragrance?
The Vitamin Concentrated Serum's ingredient list includes no fragrance or essential oils. The Goodbye Blemish Serum's list includes lemon peel, orange peel and lime oils plus citral and limonene.
No.3 Skin Softening Serum is Numbuzin's pick for rough texture and pores; No.5 Vitamin Concentrated Serum is for dark spots. Formulas and prices compared.
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