Vipivotide tetraxetan is a high potent inhibitor of prostate-specific membrane antigen (PSMA)(Ki of 0.37 nM).

Kentsin, a contraceptive tetrapeptide, is originally extracted from hamster embryos. Kentsin prevents the maturation of Graafian follicles and consequently inhibits ovulation. Kentsin has opiate properties on gastrointestinal motility.

Phenothrin, also called sumithrin, is a synthetic pyrethroid that kills adult fleas and ticks. It has also been used to kill head lice in humans.