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The Ordinary
Multi-Peptide Serum for Hair Density
hair treatments
The Ordinary
Multi-Peptide Serum for Hair Density
hair treatments
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36
Ingredients
5
Benefits
3
Actives
A concentrated serum that helps hair look thicker, denser, fuller, and healthier.
Key Insights
Haircare
6
Contains humectants
Contains oils
Lightweight
Moisturizing
Silicone-free
Sulfate-free
Active Ingredients
3
AHA
PHA
Signal peptides
Full Ingredients
36 total
AQUA
PROPANEDIOL
Humectant
BUTYLENE GLYCOL
Humectant
GLYCERIN
Humectant
CAFFEINE
Scalp Active
BIOTINOYL TRIPEPTIDE-1
ACETYL TETRAPEPTIDE-3
LARIX EUROPAEA WOOD EXTRACT
PISUM SATIVUM EXTRACT
SCUTELLARIA BAICALENSIS ROOT EXTRACT
TRITICUM VULGARE GERM EXTRACT
GLYCINE SOJA GERM EXTRACT
TRIFOLIUM PRATENSE FLOWER EXTRACT
CAMELLIA SINENSIS LEAF EXTRACT
APIGENIN
OLEANOLIC ACID
ARGININE
Amino Acid
GLYCINE
CALCIUM GLUCONATE
ZINC CHLORIDE
LACTIC ACID
Exfoliant
GLUCONOLACTONE
DEXTRAN
MALTODEXTRIN
HYDROXYETHYLCELLULOSE
XANTHAN GUM
PENTYLENE GLYCOL
Humectant
DIMETHYL ISOSORBIDE
POLYSORBATE 20
PPG-26-BUTETH-26
PEG-40 HYDROGENATED CASTOR OIL
Oil
TRISODIUM ETHYLENEDIAMINE DISUCCINATE
SODIUM METABISULFITE
SODIUM BENZOATE
PHENOXYETHANOL
CHLORPHENESIN
What this product is
Written from the ingredient list. Where it describes how a formula behaves, that is inferred from what the ingredients are and where they sit in the list, not measured.
Overview
Multi-Peptide Serum for Hair Density is a treatments from The Ordinary, aimed at fine hair, straight hair and wavy hair. On the evidence of its ingredient list, the formula works on moisture, frizz control and scalp soothing. The ingredients doing most of that work are Propanediol, Butylene Glycol and Glycerin. The list runs to 36 ingredients, 8 of which carry a role we recognise for hair.
How it feels on hair
The formula reads as lightweight: humectants lead and there is little in the way of heavy oil or silicone, so it should not weigh fine hair down. There are no silicones in the list. The formula leans to moisture rather than protein.
Protein
There is a small amount of protein in the list: Arginine.
On the scalp
For the scalp itself the formula carries Caffeine and Lactic Acid.
Build-up and porosity
Nothing in the list is the kind of ingredient that accumulates on hair.
Where it goes
It is a treatment step: after shampooing, left on, then rinsed out. -Apply a few drops or as needed to clean, dry scalp. -Massage into scalp thoroughly. -Apply once daily, ideally at bedtime. -This formula is a leave-on/-in treatment. -Do not wash hair or scalp after application.
What it is not for
Nothing in this formula is aimed at protein & strength, volume / lightweight, curl definition and color protection — not a fault, just the shape of what is in the bottle, and the reason one product rarely covers a whole routine. No ingredient here is one we recognise as supporting hair growth. Reducing breakage and growing hair are different things, and this formula's evidence is for the first.
In short
Working for it
- No sulfate detergents
- No silicones
- Fits the Curly-Girl method
- Nothing that builds up between washes
- Light enough for fine hair
- Suitable for colour-treated hair
- Fragrance-free
What it is
Treatments
Repairing
Who it suits
Read from the formula's weight, its build-up and its protein — not from a claim on the packaging.
Suits
Fine hair
Straight hair
Wavy hair
Take care with
Coarse hair
What it works on
Moisture
Frizz control
Scalp soothing
Oil control
Not what this one is for
Protein & strength
Volume / lightweight
Curl definition
Color protection
Damage repair
Build-up avoidance
Shine
Nothing in this formula is one we recognise as supporting hair growth. Reducing breakage and growing hair are different claims.
Cleansing agents
Sulfate-free.
Silicones
Silicone-free.
Protein
A small amount of protein.
ARGININE
Build-up and weight
Estimated from which ingredients are present and how high they sit in the list, not measured.
Reads as a lightweight formula.
Nothing here accumulates on hair.
Porosity
Inferred from the formula's weight, humectants and protein.
Low porosity
Suits
Cuticles are tight; moisture penetrates poorly.
Medium porosity
Suits
Cuticles are moderately open; moisture is absorbed well.
High porosity
Suits
Cuticles are open; moisture absorbs fast but is also lost rapidly.
Curly-Girl method
Fits the method: no sulfates, no persistent silicones, no drying alcohol.
On the scalp
Dry scalp
Sensitive scalp
Oily scalp
Where it goes on wash day
- Shampoo
- Conditioner
- Treatment
- Leave-in
- Oil
Composition claims
"Free from" is only claimed when every ingredient on the label resolved to one we know.
Fragrance-free
No drying alcohol
Paraben-free
Silicone-free
Microplastic-free
Sulfate-free
Dye-free
Safety
What the formula is made of
One ingredient usually does several jobs, so these counts add up to more than the list length.
8 of 36 ingredients carry a role we recognise for hair.
Humectant · 4
Amino Acid · 1
Exfoliant · 1
Oil · 1
Scalp Active · 1
Questions
What ingredients are in Multi-Peptide Serum for Hair Density?
AQUA, PROPANEDIOL, BUTYLENE GLYCOL, GLYCERIN, CAFFEINE, BIOTINOYL TRIPEPTIDE-1, ACETYL TETRAPEPTIDE-3, LARIX EUROPAEA WOOD EXTRACT, PISUM SATIVUM EXTRACT, SCUTELLARIA BAICALENSIS ROOT EXTRACT, TRITICUM VULGARE GERM EXTRACT, GLYCINE SOJA GERM EXTRACT, TRIFOLIUM PRATENSE FLOWER EXTRACT, CAMELLIA SINENSIS LEAF EXTRACT, APIGENIN, OLEANOLIC ACID, ARGININE, GLYCINE, CALCIUM GLUCONATE, ZINC CHLORIDE, LACTIC ACID, GLUCONOLACTONE, DEXTRAN, MALTODEXTRIN, HYDROXYETHYLCELLULOSE, XANTHAN GUM, PENTYLENE GLYCOL, DIMETHYL ISOSORBIDE, POLYSORBATE 20, PPG-26-BUTETH-26, PEG-40 HYDROGENATED CASTOR OIL, TRISODIUM ETHYLENEDIAMINE DISUCCINATE, SODIUM METABISULFITE, SODIUM BENZOATE, PHENOXYETHANOL, CHLORPHENESIN.
Is Multi-Peptide Serum for Hair Density sulfate free?
Yes. There is no sulfate detergent anywhere in the ingredient list.
Is Multi-Peptide Serum for Hair Density silicone free?
Yes. There are no silicones in the ingredient list.
Is Multi-Peptide Serum for Hair Density Curly-Girl friendly?
Yes. The list carries no sulfate detergent, no non-water-soluble silicone and no drying alcohol, which are the three the method excludes.
What hair type is Multi-Peptide Serum for Hair Density for?
By the weight and build-up of the formula it reads as suited to fine hair, straight hair, wavy hair. It may be less comfortable on coarse hair.
Does Multi-Peptide Serum for Hair Density contain protein?
Yes — Arginine. That is a small amount for this kind of product.
Does Multi-Peptide Serum for Hair Density cause build-up?
Nothing in the list is the kind of ingredient that accumulates on hair.
Is Multi-Peptide Serum for Hair Density good for a sensitive scalp?
It carries scalp-soothing ingredients and no harsh detergent.
Is Multi-Peptide Serum for Hair Density safe for colour-treated hair?
Nothing in the formula is the kind of ingredient that strips colour, and it carries conditioning ingredients that help it hold.
Where does Multi-Peptide Serum for Hair Density go in a haircare routine?
After shampooing: leave it on, then rinse it out.
Is Multi-Peptide Serum for Hair Density fragrance free?
Yes. No fragrance or declared fragrance allergen appears in the list.
Who makes Multi-Peptide Serum for Hair Density?
The Ordinary, a brand based in Canada.