CYoung has worked through more than 30 serums, and her approval rate sits at 49%. Roughly half earned her nod, half did not. She is honest about both sides, and the reasons she gives are specific enough to be useful.
What does CYoung recommend in serums?
When she approves a serum, it usually does at least one thing really well: a light, comfortable feel, or an active ingredient at a concentration that actually works. Her highest praise went to the Innisfree Black Tea Youth Enhancing Serum, which she called her holy grail and said has the highest repurchase rate of anything she owns. She recommends the COSRX 6 Peptide Skin Booster Serum for all skin types and says it pairs well with retinol. For very sensitive skin, she keeps coming back to the d'Alba White Truffle Double Serum & Cream, which she says really works when skin is reactive. Brightening serums get her approval too, as long as the formula is stable. She liked the COSRX 23% Ascorbic Acid Pure Vitamin C Serum despite the scent, and praised the Haruharu Wonder Centella 4% Tranexamic Acid Dark Spot Go Away Serum for its gel texture, saying anyone can handle it and it is not too heavy.
In her words
"This is my Holy Grail, the Innisfree black tea ample, so famous, a high moisturizing ample. [...] I used it about two years ago and loved it so much that I gave it to my mom, who is in her sixties with very dry skin, and she used it too. This is the product with the highest repurchase rate, and I'm not the only one, when I look at reviews there were a lot of people who bought it a few times. The texture is awesome, it's very moist and spreads well."
"I have recommended this cosrx peptide serum for about two years now, all skin types can go ahead and use it. It has multi-peptides in it and feels like a watery toner, but it's amazing if you pair it with a retinol, no problem at all."
"This one is from d'Alba. I use so many bottles of it. During Covid I had a lot of Korean clients whose skin was really sensitive from everybody wearing masks, so I was looking for a product that really works for really sensitive skin, and this was the one. If you're really sensitive, try this one."
"What I don't like about vitamin C in general is that some products are so yellow you look like SpongeBob, and it has a smell that's not easy to apply. This one has a bit of an oil layer so you have to mix it before applying, it does have a scent but I think it's bearable. Overall I love it so much and I think it's worth the hype."
"This dark spot serum has a gel formula, so if you live in a tropical country and never liked sticky products, or you have oily acne prone skin, you will love it. There is no problem adding it to your skincare routine because it is not too heavy, everybody can handle it. It has tranexamic acid and is very low irritant, and they also have a 4 percent version."
"It has a mild sting that doesn't last long, so if you have sensitive skin be careful, but it's great, the lightest texture of the three, it absorbs fast and it's very comfortable, more moisturizing than I expected."
How many serums has CYoung reviewed?
CYoung has reviewed 39 serums, for an approval rate of 49%. 19 approved, 10 mixed, and 10 skipped.
What has CYoung skipped in serums?
CYoung named the Glow Recipe Guava Vitamin C Dark Spot Brightening Treatment Serum her biggest disappointment. Both bottles she opened turned yellow within days. Vitamin C does oxidize, but she felt this one moved too fast. She also skipped the Anua Rice 7% Ceramide Hydrating Barrier Serum. The hydration felt like it vanished almost immediately, and she said anyone hoping to repair their skin barrier would be disappointed. Her bottle was also leaking. On the Tirtir SOS Serum, she said it was just a normal serum for dry skin and too sticky for combination or oily skin. Not a strong no, just not worth the price for her. As for SkinCeuticals C E Ferulic, she flagged that many people in the beauty industry find it too aggressive, and that a lot of users reported breakouts after using it.
"My biggest disappointment was Glow Recipe's freshly juiced vitamin C drop. I opened two brand new bottles and both turned yellow within days. I know vitamin C oxidizes but this one was way too fast, I felt like I was racing the bottle. I would skip it."
"This is another new Anua serum, and I don't like it, I don't even like the packaging, mine is leaking, that sucks, and it's not even that cheap, which makes me so annoyed. I expected more because it says ceramide, and a ceramide based product should mean a lot more hydration and be good for dry, mature skin. At first it feels slippery like a snail serum, but it's gone so quickly. Anybody expecting their skin barrier to get better from using this will be disappointed."
"This serum isn't that bad, but I won't spend that much money to buy it again, the price globally was okay, but here in Korea it isn't that affordable. I don't agree with calling it an SOS Serum, because an SOS Serum should do something good when your skin is angry and red, and I think the Purito serum would work better for that. This one is just a bit sticky, a normal serum for dry skin, if you have combination or oily skin it will feel even more sticky. It's okay, but I won't buy it again."
"SkinCeuticals is an expensive brand a lot of people worship, their vitamin C serums are like two hundred fifty dollars. People say it's very effective, but makeup artists and people who work in beauty say it's too aggressive, and so many people got breakouts after using it."
What should you take from CYoung's picks?
CYoung's record on serums shows she holds things to a practical standard. Light texture, real activity, stable formulas, and fair value for the price are the things she keeps coming back to. The one serum she named a winner outright is the Numbuzin No.3 Vitamin Concentrated Serum. Her approved list is a solid place to start if you want to know what she trusts enough to repurchase and recommend to clients with sensitive or dry skin.
Watch CYoung say it
Every verdict here comes from a video. These are the moments themselves, each one jumping straight to the bit about that product.
- Numbuzin No.3 Vitamin Concentrated SerumNamed a winnerWatch at 5:06
- Glow Recipe Guava Vitamin C Dark Spot Brightening Treatment SerumSkipped itWatch at 16:54
- Anua Rice 7% Ceramide Hydrating Barrier SerumSkipped itWatch at 6:31
- Tirtir SOS SerumSkipped itWatch at 5:16
- SkinCeuticals C E FerulicSkipped itWatch at 7:10
- Klairs Freshly Juiced Vitamin C SerumSkipped itWatch at 7:32
- Dr. Althea Vitamin C Boosting SerumSkipped itWatch at 9:49
- Anua Azelaic Acid 10% Hyaluron Redness Soothing SerumSkipped itWatch at 7:42
- AXIS-Y Dark Spot Correcting Glow SerumSkipped itWatch at 3:56
- Beauty of Joseon Glow Deep Serum: Propolis + NiacinamideSkipped itWatch at 3:31
- Purito Wonder Relief Centella Serum UnscentedSkipped itWatch at 15:53
- Innisfree Black Tea Youth Enhancing SerumRated itWatch at 9:18
- COSRX 6 Peptide Skin Booster SerumRated itWatch at 11:50
- d'Alba White Truffle Double Serum & CreamRated itWatch at 6:36
- COSRX 23% Ascorbic Acid Pure Vitamin C SerumRated itWatch at 6:05
- Haruharu Wonder Centella 4% Tranexamic Acid Dark Spot Go Away SerumRated itWatch at 10:44
- Skin1004 Niacinamide 10% AmpleRated itWatch at 6:57
- Medicube Triple Collagen SerumRated itWatch at 8:23
- I'm From Rice SerumRated itWatch at 3:59
- Haruharu Wonder Black Rice Facial OilRated itWatch at 10:09
- Medicube Vitamin C SerumRated itWatch at 33:45
- Numbuzin No.3 Skin Softening SerumRated itWatch at 3:53
- Medicube PDRN Pink Peptide SerumRated itWatch at 2:33
- Equalberry Bakuchiol Plumping SerumRated itWatch at 6:25
About this expert
See everything CYoung has reviewed
Related guides
This guide reflects what CYoung said across her videos about 39 products in serums, aggregated by The Guru Index. Sponsored takes are excluded. The approval rate is the share of these products she approved. It is general information, not medical advice.