The stress axis, from Russian work

The melanocortin family grew out of ACTH, the stress hormone, and Russian neuropeptide science has long worked that seam. A group at the Kurchatov Institute and Moscow State University, including Nikolai Myasoedov whose laboratory produced Semax, gave Melanotan II and Semax to rats under long-running unpredictable stress and found both reversed the loss of pleasure-seeking behaviour, prevented the adrenal gland enlarging, and restored BDNF in the hippocampus. BDNF is the growth factor that maintains and rebuilds nerve connections. That places this molecule in the stress-and-mood layer as well as the skin layer.