ABS-201

ABS-201 is a monoclonal antibody against the prolactin receptor which is under development for the treatment of androgenic alopecia and endometriosis. It is taken by long-lasting subcutaneous injection.
The drug is claimed to work by activating dormant hair follicles and causing them to move from the telogen phase to the anagen phase. ABS-201 has been found to produce robust hair regrowth in mice and balding macaques that was greater than that with minoxidil. It might also be able to reverse greying of hair.
ABS-201 is under development by AbSci. As of October 2025, it is in the preclinical research stage of development for alopecia. A phase 1/2a clinical trial for alopecia is being planned for late 2025 or early 2026. The development of ABS-201 is being overseen by prominent hair loss researcher Rodney Sinclair. The chemical structure of the drug does not yet appear to have been disclosed.