Numbuzin

Numbuzin No.5 Glutathione Vitamin Concentrated Serum.

Q: Is Numbuzin No.5 Glutathione Vitamin Concentrated Serum worth it?

Yes. All 3 gurus who reviewed it give it their stamp of approval, for a Guru Score of 82%.

Q: What is Numbuzin No.5 Glutathione Vitamin Concentrated Serum's Guru Score?

Numbuzin No.5 Glutathione Vitamin Concentrated Serum holds a Guru Score of 82%. That is our read on how warmly the experts talk about it, based on the verdicts of 3 expert reviewers we have collected. At least one expert has named it a Top Pick in its category.

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Serums

About this product

A two-vial dark spot treatment ampoule with glutathione and tranexamic acid, designed as a one-month intensive course to target hyperpigmentation and brighten skin.

Guru Score

82%

Yay

3 experts · Moderate agreement

What the gurus are saying

This ampoule tackles hyperpigmentation visibly within a month of consistent use, with gurus calling it the strongest such serum on the Korean market. The brightening power is real, though several note a strong vitamin-like smell that some find off-putting (it fades with time) and a notably sticky texture. Best used as a one-month intensive before switching back to maintenance, and patch-testing first may help if you're sensitive to scent.

Synthesized from 3 expert reviews · most recent take August 2026

What they liked

Brightening ingredients
Lasts longer than expected
Good value at the price

What they flagged

Strong vitamin-like smell
Very sticky texture
Two-week supply requires repurchasing for ongoing use

Type

SerumsDrops & dropper

Where to buy

Ulta → Amazon → Google → iHerb →

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What the gurus are saying.

Every take we've logged from this product's reviews across YouTube. Click any row to watch the moment they said it.

All takes Yay takes Nay takes Mixed takes Hide sponsored

Mad About Skin

731k subs

✓Yay

"I don't use it every day because I feel it works best if you use it for about a month and then move on to maintenance, and it'll tackle [...] your hyperpigmentation within a month if you're consistent with it. [...] It comes with two vials, each lasting two weeks, so a month's worth of product. I use it as a one month [...] flash fix to get on top of things, and I'd say it's the strongest hyperpigmentation serum that exists on the Korean skincare market."

Top Pick: hyperpigmentation serum

All 3 takes from Mad About Skin

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"This is just a little miracle. It's got all your actives that you need for hyperpigmentation. Glutathione is doing a lot of the heavy lifting here, but there's lots of other actives in here that really help. [...] I find doing it in two-week bursts works best for me. I would fully recommend this. If you're on a hyperpigmentation journey and you want a flash two-week treatment that's just going to take you results from here to here, get this. You won't look back. So good."

FADE DARK SPOTS FAST - Best Dark Spot Serums 2026

"One of these vials gives you a two week supply, and the brand claims that within two weeks, people saw a 10% reduction in hyperpigmentation and the appearance of dark spots and discoloration. [...] I tried it and it actually works. It genuinely works. [...] You've got vitamin C, tranexamic acid, and glutathione all in really high doses, and the freshness is what makes it unparalleled. I would just caution people to use it for those two weeks and then use something else to maintain."

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AliceintheRabbitHole

59k subs

✓Yay

"I'm not going to finish this in two weeks like I thought, so it's lasting longer than I expected. In a week of use I feel like I'm already seeing results from this, though I have been pairing it with the Edom so maybe it's a synergistic effect. I'm wondering if this is the hyperpigmentation treatment I've been looking for."

All 2 takes from AliceintheRabbitHole

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"I hate to put this third in the video because my goodness, the ingredients look great, I love the system here, but as much as I don't like admitting it, I am affected by stinky skin care. I still smell this on me and it makes me feel a bit self-conscious. It's a two week supply, so we will give it a fair go, but it's hard to be that excited when a product smells that bad."

No BS Beauty

89k subs

✓Yay

"For brightening ingredients this one's got a ton of them. [...] It's got sea buckthorn water which is a great antioxidant brightening ingredient. We have tranexamic acid. We have niacinamide. We have ascorbic acid. We've got alpha lipoic acid, ubiquinone and then glutathione. So it's got a ton of brightening ingredients. It's a very strong serum you'd want to use this probably in your morning routine in place of vitamin C serum. You don't want to use this with vitamin C."

All 7 takes from No BS Beauty

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"This one's really nice at 26 bucks."

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"This one has several great brightening and antioxidant ingredients. It's got tranexamic acid, bifida ferment, which is great for soothing. It's got alpha arbutin for brightening, turmeric, great brightening and antioxidant. Then we've got ethyl ascorbic acid and ubiquinone, which is super great. I think CoQ10 is the name people might recognize, but this stuff is wonderful. No scent to it, super affordable at 15 bucks. You can't go wrong with a lot of stuff from Numbuzin."

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"It helped brighten my skin up a touch, which I need, obviously, all the help I can get. It's more of a two- to three-week type treatment. You're supposed to use it as a concentrated vitamin C serum in the morning, and then after a couple weeks, once you're finished, return to your normal vitamin C serum, or you can repurchase it. It's got some nice brightening ingredients. It did have a strong vitamin-ish scent, which I was not a fan of, but it does dissipate pretty quickly."

Best Brightening Product?! Numbuzin No.5 Glutathione TXA Advanced Dark Spot Ampoule Concentrate

"It helped brighten my skin. My skin needs all the brightening it can get. Works nicely in place of my typical vitamin C serum for a few weeks. The texture is light, so it's pretty easy to fit into any routine. For skin that has hyperpigmentation or brightening issues, it's certainly worth trying out. After two weeks, I did see [...] a subtle brightening of my skin, which it needs a lot of brightening. [...] I do think this helped brighten up my melasma a bit."

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"I guess vitamins smell. That's the only way I can describe it. Otherwise, this product feels nice. I have pretty dry skin, so take that as you will. It's got some fatty alcohols, shea butter, niacinamide, macadamia oil, betaglucan, ectoin, adenosine, and ceramides. It's got some silicones in there. Feels nice and thick, but not like the bubble soft one that's so thick where it's like whoa, for daytime way too much thickness, but this one's a little bit more friendly. So it feels nice."

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"It's a very concentrated ampule for helping with hyperpigmentation and dark spots. It's got tranexamic acid, glutathione, ascorbic acid, alpha lipoic acid, and ubiquinone in there. It looks quite nice. Doesn't look like it has any fragrance in it or anything. This is also sitting in my cart. Once I hit the free shipping limit, I'll definitely put it in."