There’s a double helix in my local Sephora. It’s roughly the size and shape of a soda can, and it is accompanied by a placard referencing patents and peptides, as if in a science fair. It’s trying to sell me a hair mask. Online, the company responsible for this display describes itself as a “biology-first haircare brand, powered by biotech.” It practices “biomimetic hairscience,” and, thanks to “a decade of complex research into the bioscience of hair,” has patented a peptide that repairs hair “