A strong hint of how they work comes from the npr-1 gene, which makes a protein that responds to neuropeptides.

Those globular proteins, most importantly a relatively small one called lipid transfer protein 1 and a larger one called Z23, are less ionizable and less plentiful than the surfactants in shampoo.

Rats treated with a small protein, named 15-1, show less scar formation (in center) compared to control animals because of reduced inflammation and collagen formation.