EGF and FGF at 10ppm each — the maximum concentrations allowed by Korean MFDS regulations. Most Western growth factor serums use lower concentrations or different growth factors entirely (like TNS Advanced+'s TNS technology). Combined with guaiazulene and adenosine, the formula is structurally distinct.
Klairs Blue Youth Activating Drop is the brand's flagship anti-aging ampoule combining EGF and FGF at 10ppm each (the highest concentrations allowed by Korean MFDS), guaiazulene for calming, adenosine for documented anti-aging action, and blueberry for antioxidant support. Fragrance-free, alcohol-free, vegan, and cruelty-free. At 39 dollars for 20ml, this is one of the best-formulated K-beauty growth factor serums.
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: A researched evidence row for the lead active would replace this with a verdict.
Same rule for everyone. “Supporting role” is the verdict on 8,197 of 45,024 concern verdicts across the catalog; rule R8 decided 4,250 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The case for it
What would change this: A researched evidence row for the lead active would replace this with a verdict.
Same rule for everyone. “Good choice” is the verdict on 1,938 of 45,024 concern verdicts across the catalog; rule F2 decided 1,938 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
Also listed for Post-Procedure — the actives here (Botanical Extracts, Guaiazulene, Adenosine, Growth Factors (EGF) 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.
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
Korean cosmetic regulations are unusually specific about growth factors: EGF and FGF are each capped at 10 parts per million in any over-the-counter formula, and the Blue Youth Activating Drop sits right at that ceiling. That single regulatory detail tells you most of what makes this Klairs ampoule interesting, because the entire K-beauty growth factor approach is built differently from the Western anti-aging serums you might be comparing it to in your head. Rather than relying on retinoids to force cell turnover or acids to slough the surface, this little 20ml bottle leans on signaling molecules that your skin already knows how to read. EGF, listed here as sh-Oligopeptide-1, is a synthetic recombinant version of Epidermal Growth Factor, and it nudges keratinocytes toward proliferation and renewal at the surface. FGF, the sh-Polypeptide-1 on the label, supports fibroblast activity and collagen synthesis in the deeper layers. Both of these growth factors decline naturally as we age, which is the gap the formula is trying to address. The evidence on topical growth factors is promising rather than ironclad, and Klairs deserves credit for not overpromising here. The work is cumulative and quiet, not the kind of thing that announces itself overnight.
What keeps the formula from being a one-trick novelty is the supporting cast. Adenosine carries the most settled science of the bunch: it is a nucleotide that the Korean MFDS recognizes as a functional anti-wrinkle ingredient, and it has documented activity in softening fine lines through cellular signaling. That gives the ampoule a genuinely well-established active alongside the more speculative growth factors. Then there is guaiazulene, which does double duty in a way I find genuinely elegant. The deep blue color of this serum is not a dye or a marketing flourish; it comes straight from this chamomile- or guaiac-derived compound, which also brings real anti-inflammatory, skin-calming chemistry to the table. Blueberry fruit extract rounds things out with anthocyanin antioxidants. The rest of the ingredient list stays admirably lean, with water, butylene glycol, lecithin, and glycerin handling the base and a minimal preservation system rather than a pile of filler.
The sensory experience matches the restraint of the formula. This is a watery ampoule, almost shockingly thin, that you dispense as two or three drops and press into clean skin. It vanishes in seconds and leaves no tackiness behind, which makes it easy to layer under everything else in a routine. The blue tint is striking in the bottle but does not transfer onto your face during normal use. The one thing to watch is fabric: spill it on a light towel or pillowcase and that guaiazulene blue can leave a mark, so handle the dropper with a little care. There is no fragrance and no alcohol, which is part of why the formula reads as so sensitive-skin-friendly. From the first application, skin tends to feel notably calm and conditioned, and that immediate soothing is the guaiazulene earning its keep.
Where this product asks for patience is the anti-aging payoff. Over four to eight weeks of daily use, the adenosine contribution to fine lines and the growth factor support for renewal and barrier resilience start to become observable, but the operative word is cumulative. If you are looking for a serum that visibly resurfaces or dramatically firms in a fortnight, this is not built for that, and some users find it almost too gentle for what they wanted. It is a maintenance and conditioning treatment more than a transformation. There is also a real caveat around pregnancy: growth factor safety during pregnancy simply has not been well established, so this is one to set aside if you are expecting or nursing until more data exists.
On value, thirty-nine dollars for twenty milliliters lands in mid-tier K-beauty territory. It is not the cheapest ampoule on the shelf, and a 20ml bottle will not last forever at daily use, but the formulation depth genuinely justifies the spend. You are paying for growth factors at the maximum regulated concentration, a recognized functional anti-wrinkle active in adenosine, and a calming agent that doubles as the product's signature, all in a fragrance-free, alcohol-free, vegan, and cruelty-free package. Klairs has been a reliable established brand since around 2010, best known for its toner and vitamin C drops, and this flagship treatment fits that track record of competent, transparent formulation. For the price, the active load is unusually honest.
Who should reach for this? Anyone with sensitive, reactive, or barrier-stressed skin who wants a growth factor and adenosine anti-aging treatment that will not sting or sensitize. It slots cleanly into almost any routine, plays well alongside most other actives, and is forgiving enough for beginners stepping into the anti-aging category for the first time. It is also a smart pick if you appreciate the K-beauty philosophy of gradual, signaling-based renewal over aggressive resurfacing. I would steer away from it if you are pregnant, if you specifically want dramatic and fast visible results, or if you would rather put your money toward a proven retinoid. But for everyone else, this is one of the better-formulated growth factor ampoules at an accessible price, and it earns its blue.
The hero actives that drive this product's performance.
| Ingredient | Function | Evidence |
|---|---|---|
| EGF (sh-Oligopeptide-1) + FGF (sh-Polypeptide-1) (10ppm each) | Synthetic recombinant Epidermal Growth Factor and Fibroblast Growth Factor at 10ppm each — the highest concentration allowed by Korean MFDS regulations. EGF supports keratinocyte proliferation and skin renewal; FGF supports fibroblast activity and collagen synthesis. Both naturally decline with age. | Limited for Aging |
| Guaiazulene | Derived from chamomile or guaiac, contributes the formula's distinctive blue color and provides documented anti-inflammatory action through skin-soothing chemistry. The blue color is genuinely from this ingredient. | Not yet assessed |
| Adenosine | A nucleotide with documented anti-aging activity — improves skin elasticity and reduces fine lines through cellular signaling pathways. Approved by Korean MFDS as a functional anti-wrinkle ingredient. | Limited for Aging |
| Vaccinium Angustifolium (Blueberry) Fruit Extract | Antioxidant fruit extract contributing additional support to the EGF/FGF anti-aging work. Blueberry anthocyanins have documented antioxidant activity. | Not yet assessed |
Water, Butylene Glycol, sh-Oligopeptide-1, sh-Polypeptide-1, Vaccinium Angustifolium (Blueberry) Fruit Extract, Lecithin, Sorbitan Sesquioleate, 1,2-Hexanediol, Caprylyl Glycol, PEG-60 Hydrogenated Castor Oil, Glycerin, Chlorphenesin, Guaiazulene, Ethylhexylglycerin, Adenosine
treatment
AM & PM
Apply after toner and before other serums. The watery ampoule absorbs quickly. Compatible with most other actives including vitamin C, niacinamide, and retinoids (apply at different times).
Skin feels notably calm and conditioned immediately. Within 4-8 weeks of daily use, the EGF/FGF and adenosine contributions to skin renewal and fine line improvement become observable.
Recombinant EGF (Epidermal Growth Factor, sh-Oligopeptide-1) supports keratinocyte proliferation and skin renewal at concentrations documented in K-beauty research. FGF (Fibroblast Growth Factor, sh-Polypeptide-1) supports fibroblast activity and collagen synthesis. Both are naturally present in skin and decline with age. Korean MFDS regulations cap cosmetic concentrations at 10ppm each. Adenosine is approved by Korean MFDS as a functional anti-wrinkle ingredient — has documented activity in fine line improvement. Guaiazulene is chamomile-derived with anti-inflammatory action. Together they form a structurally coherent anti-aging treatment.
Dermatologists generally view growth factor skincare as a meaningful supplementary anti-aging approach alongside retinoids and sunscreen. The Klairs Blue Youth Activating Drop fits cleanly into K-beauty routines targeting anti-aging with growth factor mechanism. Pregnancy use should be discussed with obstetrician.
Apply 2-3 drops after toner in the morning and evening routine. Allow to absorb before applying moisturizer. Compatible with most other actives.
At 39 dollars for 20ml, sits in mid-K-beauty pricing. Comparable Western growth factor serums (TNS Advanced+ at 295 dollars) deliver different growth factor technology at far higher cost. K-beauty alternatives at similar pricing focus on different actives. The value proposition is the maximum-regulated EGF and FGF concentrations at K-beauty pricing.
K-beauty routines targeting anti-aging with growth factor mechanism, sensitive skin needing calming anti-aging, and vegan/cruelty-free routine adherents seeking K-beauty alternatives to Western growth factor serums.
Pregnancy routines (growth factor safety not well-established), users wanting aggressive visible anti-aging (this is cumulative), and budget-conscious shoppers at the K-beauty tier (cheaper Klairs options exist).
Ready to try Klairs Blue Youth Activating Drop?
Buy at Amazon ♥Watery ampoule with distinctive blue color from guaiazulene — absorbs quickly into a non-tacky finish.
Fragrance-free.
20ml glass bottle with dropper applicator.
Apply 2-3 drops to clean face. The water-like texture absorbs almost instantly. Skin feels notably calm immediately. The blue color from guaiazulene is distinctive but does not stain skin during normal use.
About 2-3 months at daily use.
All Year
Klairs developed the Blue Youth Activating Drop as the brand's flagship anti-aging treatment, with the blue color from guaiazulene as a signature visual identity.
Klairs (Dear, Klairs) is a Korean skincare brand from Wishtrend established around 2010. Known for the Supple Preparation Toner and Freshly Juiced Vitamin Drop. The EGF Blue Youth Activating Drop (also marketed as Midnight Blue Youth Activating Drop) features EGF and FGF peptides at 10ppm each — the highest concentration allowed by Korean MFDS regulations.
EGF in skincare is unsafe.
Recombinant EGF at the concentrations approved by Korean MFDS has documented safety data from K-beauty research. The concern about growth factors and cancer is theoretical rather than evidence-based at topical cosmetic doses.
The blue color is just dye.
The blue color comes from guaiazulene, which has documented anti-inflammatory activity. The color is genuinely from this functional ingredient rather than added dye.
Both names refer to the same Klairs product — the 'EGF Blue Youth Activating Drop' is the current naming, 'Midnight Blue Youth Activating Drop' is the original marketing name. Same formulation.
At Korean MFDS-approved concentrations (10ppm each), yes — extensive K-beauty safety data backs the use. Theoretical concerns about growth factors and cancer have not been substantiated at topical cosmetic concentrations.
Yes — from guaiazulene (a chamomile-derived ingredient with anti-inflammatory action). Not added dye.
Caution — growth factor safety during pregnancy is not well-established. Most obstetricians recommend pausing growth factor products during pregnancy as a precautionary measure.
Yes — vegan and cruelty-free certified.
Adenosine is a nucleotide approved by Korean MFDS as a functional anti-wrinkle ingredient with documented activity through cellular signaling pathways.
TNS Advanced+ uses TNS (Tissue Nutrient Solution) technology with growth factors and cytokines from cultured human fibroblasts. Klairs uses synthetic recombinant EGF and FGF. Different technologies; both target similar concerns at different price points.
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.
Genuinely calming on sensitive skin
EGF and FGF at maximum regulated concentrations
Adenosine for documented anti-aging
Vegan and cruelty-free
Growth factor safety in pregnancy not well-established
Blue color from guaiazulene can stain
May be too gentle for users wanting aggressive anti-aging
39-dollar price is mid-tier K-beauty
Verified answers from our questions library — the nuance a product page cannot carry.
