What each formula contributes
The Ordinary combines named cosmetic peptides, caffeine and botanical complexes. The INKEY List describes caffeine, Redensyl and betaine; its checked list does not name a cosmetic peptide. Redensyl alone does not turn a product into a peptide serum.
Both are options for readers avoiding added scent in the checked formulas. Neither is a dedicated copper-peptide product. If copper brought you to the comparison, return to the copper shortlist before choosing between these two.
Bottle value needs a second calculation
The selected INKEY bottle is 150 ml versus The Ordinary’s 60 ml. That is a volume comparison, not a verified duration comparison. Use the current purchase total and your known usage to estimate monthly cost.
Both brands have regional storefronts. Compare local stock, delivery and the exact ingredient list instead of converting a US sticker price into a European bargain.
Our decision rule
The Ordinary is the more relevant first reference if you want a conventional peptide blend. The INKEY List is worth comparing when your brief is a low-cost scalp-care routine and you are open to caffeine without peptides. We have not tested their textures or established that one gives better results.
Sources & further reading
Product pages establish brand claims and label facts. They do not independently validate efficacy. Sources checked 14 September 2026.
- The Ordinary: Multi-Peptide Serum for Hair Density — official product and ingredients
- The INKEY List: Caffeine Stimulating Scalp Treatment — official product and ingredients
- 2023 primary study: GHK-Cu delivery in ionic liquid microemulsions