In this video, I’m digging into The Ordinary Multi-Peptide Serum for Hair Density—and the big question is: how is a $24 serum getting such dramatic before-and-afters when The Ordinary makes zero hair growth claims? I reached out to the brand directly, and their response was basically a list of the trademarked complexes inside (Redensyl, Procapil, Capixyl, Baicapil, AnaGain) plus a very careful “these complexes may influence” kind of statement. That wording is what sent me down a multi-day rabbit hole. So I pulled supplier dossiers and technical files (hello, UL Prospector) to see what the trademark owners claim these ingredients do—mechanisms like influencing hair follicle stem cells, dermal papilla signaling, microinflammation, and growth phase regulation. And yes, the suppliers include in vitro, ex vivo, and small clinical studies with before-and-afters… but I also call out the limitations I kept seeing over and over: vague methodology, small sample sizes, short timelines, missing controls, and marketing-heavy language. My main takeaway: the science is interesting and the mechanisms are plausible, but the evidence quality varies a lot—so I’ll tell you how I’d think about using this serum (and what I would not do, like replacing proven treatments based on supplier marketing).