INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid vs Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum
INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid scores 9.7/9.8 vs Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum at 5.2/9.8. INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid wins for active ingredients.
Head to head
Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid
Ultra Pure Hyaluronic Acid 1.5% Serum
Score comparison
INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid takes this one, winning 3 of 5 attributes.
Scores last verified: July 2026
Attribute battle
Hydration Efficacy
INNBEAUTY PROJECT WINSIrritation Risk
TIEActive Ingredient Strength
INNBEAUTY PROJECT WINSIngredient Transparency
INNBEAUTY PROJECT WINSFormulation Safety
TIEIngredient face-off
5% overlapOnly in INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid
40 unique
Only in Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum
5 unique
Why INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid comes out ahead
Where INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid really shines is active ingredient strength, scoring 9.8 compared to Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum's 2.0. Its formula features Tetrahexyldecyl Ascorbate, Niacinamide, and Ascorbic Acid in high positions, signalling meaningful concentrations.
Ingredient Transparency is another area of separation. INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid scores 8.5 here versus 6.0 for Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum. That difference comes down to how each formula is built — the ingredient list tells the story.
INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid brings Tetrahexyldecyl Ascorbate, Niacinamide, and Ascorbic Acid as actives, giving it an edge in targeted skincare benefits.
Best for your skin type
INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid is better if you have
- Sensitive skin — the low-irritation formula keeps things gentle
- Targeting specific concerns like aging or uneven tone — Tetrahexyldecyl Ascorbate does the heavy lifting
- Anyone who prefers clean, well-vetted formulations
Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum is better if you have
- Sensitive skin — the low-irritation formula keeps things gentle
- Anyone who prefers clean, well-vetted formulations
Value comparison
Both sit in the premium bracket, so value comes down to formulation quality. INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid gets the nod here with its 9.7 overall score — you're getting more for a similar outlay.
Our verdict
INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid wins this comparison with a meaningfully stronger ingredient profile and overall score.
Frequently asked questions
Which is better: INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid or Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum?
Based on ingredient analysis, INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid scores higher overall. See the full score breakdown above for details on each attribute.
Do INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid and Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% 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 INNBEAUTY PROJECT Pro C Serum Brightening Solution with 15% Vitamin C + Ferulic Acid and Kiehl's Since 1851 Ultra Pure Hyaluronic Acid 1.5% Serum?
The key differences are in their active ingredients and formulation approach. Check the attribute battle above for a detailed breakdown.