Gisou's Honey Gloss Collagen Drops, a $25 hair oil, deliver surface conditioning rather than any structural repair, according to trichologist and Aware Hair co-founder Tina Mui. Speaking to Who What Wear, Mui explained that hair is made primarily of keratin, not collagen, so the ingredient functions in haircare "much more as a protein treatment than a 'collagen treatment.'" The formula uses hydrolyzed collagen, meaning the protein is broken into smaller peptides that can deposit onto damaged or porous areas of the hair strand.
Those peptides can improve smoothness, softness, shine and manageability, and provide surface hydration that Mui said is useful for scalp dryness. But she was clear that topical collagen "isn't repairing hair from the inside out or directly stimulating hair growth," and called it best suited to people whose hair has grown dry or hard to manage from heat styling, rather than heavily color-treated or chemically processed hair. The drops also contain the brand's Mirasalehi honey, sourced from founder Negin Mirsalehi's family-owned bee garden in the Netherlands.