Melanotan II is a synthetic analogue of the α-melanocyte stimulating hormone (α-MSH). α-MSH is a melanocortin I receptor agonist which has a role in human pigmentation by stimulating production of eumelanin. Melanotan II was originally developed as a treatment for sexual dysfunction. However, the proposal was abandoned when development of the metabolite bremelanotide was established.
Three groups of mice were individually placed in cages with aggressive mice and experienced social defeat, a stressful experience for them. One group was missing its oxytocin receptors, essentially the plug by which the hormone accesses brain cells. The lack of receptors means oxytocin couldn't enter the mice's brain cells. The second group had an increased number of receptors so their brain cells were flooded with the hormone. The third control group had a normal number of receptors.
Serotonin syndrome (Serotonin toxicity) is caused by an excess of serotonin in the brain. It is most often caused by taking more than one Serotonin-enhancing substance at the same time, such as 5-HTP and an antidepressant medication. Symptoms range in severity according to the level of intoxication and may include increased heart rate, tremor, sweating, mental agitation, seizures, shock, organ failure and death (9).
Horvath, G. A., Stockler-Ipsiroglu, S. G., Salvarinova-Zivkovic, R., Lillquist, Y. P., Connolly, M., Hyland, K., Blau, N., Rupar, T., and Waters, P. J. Autosomal recessive GTP cyclohydrolase I deficiency without hyperphenylalaninemia: evidence of a phenotypic continuum between dominant and recessive forms. Mol.Genet.Metab 2008;94(1):127-131. View abstract.
Potential side effects of 5-HTP include heartburn, stomach pain, nausea, vomiting, diarrhea, drowsiness, sexual problems, vivid dreams or nightmares, and muscle problems. Because 5-HTP has not been thoroughly studied in a clinical setting, possible side effects and interactions with other drugs are not well known. According to the US National Institute of Health TOXNET, 5-HTP has not been associated with serotonin syndrome or any serious adverse events in humans. Across multiple studies, 5-HTP also been reported to not cause any noticeable hematological or cardiovascular changes. 5-HTP also has not been associated with eosinophilia.