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Cosmia Bio Serum ecl… vs Kiehl's Retinol Skin… — Which Is Better? | Gracie

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Cosmia Bio Serum eclat a la vitamine c vs Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum scores 9.0/9.8 vs Cosmia Bio Serum eclat a la vitamine c at 7.2/9.8. Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum wins for active ingredients.

Head to head

Cosmia Bio

Serum eclat a la vitamine c

serum

7.2

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Niacinamide
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Kiehl's

Retinol Skin-Renewing Daily Micro-Dose Serum

serumpremium

9.0

Score comparison

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum takes this one, winning 2 of 5 attributes.

Cosmia Bio wins 0

Tied 3

Kiehl's wins 2

7.2Cosmia Bio

+1.8vs

9.0Kiehl's

Scores last verified: April 2026

Attribute battle

Hydration Efficacy

Kiehl's WINS

6.0

9.6

Cosmia Bio

Kiehl's

Irritation Risk

TIE

9.5

Cosmia Bio

Kiehl's

Active Ingredient Strength

Kiehl's WINS

3.2

7.8

Cosmia Bio

Kiehl's

Ingredient Transparency

TIE

8.5

Cosmia Bio

Kiehl's

Formulation Safety

TIE

9.0

Cosmia Bio

Kiehl's

Ingredient face-off

7% overlap

32Cosmia Bio

3Shared

42Kiehl's

Only in Cosmia Bio Serum eclat a la vitamine c

29 unique

Aqua (Water)Caprylic/Capric Triglyceride Propanediol Potassium Citrate Ascorbyl Glucoside Hydrogenated Ethylhexyl Olivate Gluconolactone Polyglycerin-3 Citrus Aurantium Dulcis (Orange) Fruit Extract Aloe Barbadensis Leaf Juice Powder+19 more

Shared ingredients

3 in common

Glycerin Tocopherol Cetearyl Alcohol

Only in Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum

39 unique

Aqua/Water Butylene Glycol Pentylene Glycol Niacinamide Cetyl Alcohol Isohexadecane Isononyl Isononanoate Diisopropyl Sebacate 2-Oleamido-1 3-Octadecanediol+29 more

Why Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum comes out ahead

Where Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum really shines is active ingredient strength, scoring 7.8 compared to Cosmia Bio Serum eclat a la vitamine c's 3.2. Its formula features Niacinamide, Acetyl Dipeptide-1 Cetyl Ester, and Adenosine in high positions, signalling meaningful concentrations.

Hydration Efficacy is another area of separation. Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum scores 9.6 here versus 6.0 for Cosmia Bio Serum eclat a la vitamine c. That difference comes down to how each formula is built — the ingredient list tells the story.

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum brings Niacinamide, Acetyl Dipeptide-1 Cetyl Ester, and Adenosine as actives, while cosmia Bio Serum eclat a la vitamine c relies on Ascorbyl Glucoside, Gluconolactone, and Citrus Aurantium Dulcis (Orange) Fruit Extract. Both approaches have merit, but the positioning and supporting ingredients make the difference.

Best for your skin type

Cosmia Bio Serum eclat a la vitamine c is better if you have

Sensitive skin — the low-irritation formula keeps things gentle
Anyone who prefers clean, well-vetted formulations

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum 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

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum comes in at premium pricing with a 9.0 score, which is solid value at that tier.

Our verdict

✶ Our verdict

+1.8 lead

Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum wins this comparison with a meaningfully stronger ingredient profile and overall score.

7.2Cosmia Bio

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9.0Kiehl's

Frequently asked questions

Which is better: Cosmia Bio Serum eclat a la vitamine c or Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum?

Based on ingredient analysis, Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum scores higher overall. See the full score breakdown above for details on each attribute.

Do Cosmia Bio Serum eclat a la vitamine c and Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum share ingredients?

Yes, they share common ingredients. Check the ingredient face-off section above for a detailed comparison.

What's the main difference between Cosmia Bio Serum eclat a la vitamine c and Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum?

The key differences are in their active ingredients and formulation approach. Check the attribute battle above for a detailed breakdown.

Full analysis: Cosmia Bio Serum eclat a la vitamine c→Full analysis: Kiehl's Retinol Skin-Renewing Daily Micro-Dose Serum→

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