What is in it and what does it cost?
The 60 mL standard bottle on The Ordinary’s US site was $24 ($0.40/mL) on November 12, 2026. The published formula lists Biotinoyl Tripeptide-1, Acetyl Tetrapeptide-3, glycerin, caffeine and several plant extracts. Check the package if buying from a different region.
Manufacturer · US offer, ingredients and directionsThe Ordinary Multi-Peptide Serum for Hair Density
How much evidence is there for the finished serum?
The brand describes a change in the appearance of fullness. Its public listing did not provide a finished-product trial protocol and comparator we could evaluate. The peptide names alone cannot tell you what the serum will do. This review uses published information and is based on the label and offer.
Alternative with a lower bottle price
Verb Density Peptide Hair Serum was $22 for 1 US fl oz. It also lists Biotinoyl Tripeptide-1 and adds niacinamide and fragrance. It costs less at checkout for the size shown and more per mL.
Manufacturer · US offer and ingredientsVerb Density Peptide Hair Serum, 1 fl oz
Alternative with a different peptide
Briogeo MegaStrength+ Peptide Density Serum lists Copper Tripeptide-34 and caffeine. The checked $57 offer is higher upfront. Consider whether the different formula and directions justify the price for you.
Manufacturer · US offer and ingredientsBriogeo MegaStrength+ Peptide Density Serum