COSRX The 6 Peptide Skin Booster Serum vs Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide
Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide scores 9.3/9.8 vs COSRX The 6 Peptide Skin Booster Serum at 8.5/9.8. Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide wins for active ingredients.
Head to head
The 6 Peptide Skin Booster Serum
Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide
Score comparison
Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide edges ahead, winning 1 of 5 attributes.
Scores last verified: July 2026
Attribute battle
Hydration Efficacy
TIEIrritation Risk
TIEActive Ingredient Strength
Kiehl's Since 1851 WINSIngredient Transparency
COSRX WINSFormulation Safety
TIEIngredient face-off
20% overlapOnly in COSRX The 6 Peptide Skin Booster Serum
32 unique
Shared ingredients
8 in common
Only in Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide
31 unique
Why Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide comes out ahead
Where Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide really shines is active ingredient strength, scoring 7.7 compared to COSRX The 6 Peptide Skin Booster Serum's 6.5. Its formula features Niacinamide, Acetyl Dipeptide-1 Cetyl Ester, and Adenosine in high positions, signalling meaningful concentrations.
Ingredient Transparency is another area of separation. COSRX The 6 Peptide Skin Booster Serum scores 8.8 here versus 8.5 for Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide. That difference comes down to how each formula is built — the ingredient list tells the story.
Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide brings Niacinamide, Acetyl Dipeptide-1 Cetyl Ester, and Adenosine as actives, while cOSRX The 6 Peptide Skin Booster Serum relies on Niacinamide, Acetyl Hexapeptide-8, and Dipeptide Diaminobutyroyl Benzylamide Diacetate. Both approaches have merit, but the positioning and supporting ingredients make the difference.
Best for your skin type
COSRX The 6 Peptide Skin Booster Serum is better if you have
- Sensitive skin — the low-irritation formula keeps things gentle
- Dry or dehydrated skin that craves moisture, thanks to Dipropylene Glycol
- Anyone who prefers clean, well-vetted formulations
Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide is better if you have
- Sensitive skin — the low-irritation formula keeps things gentle
- Dry or dehydrated skin that craves moisture, thanks to Glycerin
- Targeting specific concerns like aging or uneven tone — Niacinamide does the heavy lifting
Value comparison
At mid-range pricing with a score of 8.5, COSRX The 6 Peptide Skin Booster Serum is a decent pick. Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide sits at the premium level with a 9.3 score — the higher investment pays off in formulation quality.
Our verdict
Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide edges ahead with a slightly stronger formulation, but COSRX The 6 Peptide Skin Booster Serum is still a solid pick.
Frequently asked questions
Which is better: COSRX The 6 Peptide Skin Booster Serum or Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide?
Based on ingredient analysis, Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide scores higher overall. See the full score breakdown above for details on each attribute.
Do COSRX The 6 Peptide Skin Booster Serum and Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide share ingredients?
Yes, they share common ingredients. Check the ingredient face-off section above for a detailed comparison.
What's the main difference between COSRX The 6 Peptide Skin Booster Serum and Kiehl's Since 1851 Micro-Dose Anti-Aging Retinol Serum with Ceramides & Peptide?
The key differences are in their active ingredients and formulation approach. Check the attribute battle above for a detailed breakdown.