Head to head
Leave-In Molecular Repair Hair Mask vs Multi-Peptide Serum for Hair Density
K18 Leave-In Molecular Repair Hair Mask and The Ordinary Multi-Peptide Serum for Hair Density tie on our overall score — the choice comes down to what you value most.
Benefit fingerprints
What each one does.
K18 Leave-In Molecular Repair Hair Mask
The Ordinary Multi-Peptide Serum for Hair Density
Side by side
Every detail, compared.
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- Damage repair
- Split ends
- Smoothing
- Frizz control
- Hair growth support
- Scalp care
- Volume
- • Bleached, highlighted or chemically processed hair
- • Heat-damaged hair that breaks easily
- • Anyone who wants a fast, no-rinse repair step
- • Fine or thinning-looking hair wanting a low-risk cosmetic serum
- • Adding to an existing scalp routine on a budget
- Quick routine: four minutes on towel-dried hair, no rinsing
- Patented K18PEPTIDE targets bleach, color, chemical and heat damage, per the brand
- Many bleached and chemically treated hair reviewers report noticeably stronger, softer hair
- Inexpensive at $24 for 60 ml
- Lightweight, fragrance-free, silicone- and alcohol-free leave-on formula
- Combines several peptide complexes with caffeine in one serum
- $75 for 50 ml is expensive
- Must go on unconditioned hair, which changes most wash-day routines
- Cosmetic claims only; not a replacement for medical hair-loss treatments
- Needs nightly application for months before any change is visible
Affiliate links — we may earn a commission. How we make money
Affiliate links — we may earn a commission. How we make money
FAQ
Quick answers.
Which is better, Leave-In Molecular Repair Hair Mask or Multi-Peptide Serum for Hair Density?
K18 Leave-In Molecular Repair Hair Mask and The Ordinary Multi-Peptide Serum for Hair Density tie on our overall score — the choice comes down to what you value most.
Which is better value?
K18 Leave-In Molecular Repair Hair Mask works out to about $44.36 / oz and The Ordinary Multi-Peptide Serum for Hair Density to about $11.83 / oz, based on typical non-Amazon retail prices when we last checked.
How do you score them?
Both are scored on the same five-factor rubric (results, formula & ingredients, texture & experience, value, community love), using the formula or specs, verified creator reviews, community consensus and value. Brands can’t pay for placement.