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;94:127-131. View abstract.
“I didn’t think it would be that bad honestly, but since I weight lift multiple times a weak, this supplement is doing me more harm than good. On a typical weight lifting day my workout is split into 5 sections. After taking 5-htp the night before I barely have enough energy to get through 1 section, and that is a serious problem, because of this I am quitting 5-htp all together.”
But like most peptides on the market, TB-500 has limited long term studies involving human use. Although I haven’t personally used TB-500 (I can’t, since I compete in WADA sanctioned sports like triathlon and obstacle course racing), from what I’ve seen and heard from bodybuilders and athletes using the peptide, the primary side effect is a temporary sense of lethargy. Also, some people report getting a head rush when injecting TB-500, but report this head rush goes away a few minutes after injecting.

Dr Sohère Roked is a GP in the UK with a specialist interest in integrative medicine. She prescribes 5-HTP to patients with anxiety and depression, alongside vitamins and other natural supplements, and sees no problem with it being used for mild conditions. "With the patients I see, generally I've seen good results with it. Antidepressants do work for some people, so I'm not against them completely, but others don't want to go down that path straight away. This gives them another option."
To identify newborn neurons, double immunofluorescent staining for BrdU/NeuN (mature neuronal marker) was performed (Fig.1). TBI alone significantly increased the number of newborn neurons (NeuN/BrdU-colabeled cells) in the DG of injured hemisphere. Tβ4 treatment significantly further increased the number of newborn neurons compared to saline controls. These data suggest that Tβ4 administration initiated 24 hours after TBI promotes neurogenesis in rats.

To untangle the ways different hormones together influence behavior in more naturalistic contexts, we worked with the Tsimane people in Bolivia. Traditional societies like the Tsimane are not living relics of the past, but their lifeways – small, tight-knit communities that produce their own food – can reveal the kinds of situations our hormone systems are well adapted to.

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.
Adam Guastella, a clinical psychologist at University of Sydney’s Brain and Mind Research Institute, and a pioneer in studies of how oxytocin can help people with autism, thinks the hormone can also help people in couple therapy by facilitating empathic communication. His research has shown that people who get oxytocin are more focused on positive emotion: they remember happy faces better than angry and neutral ones. Research by others has shown that oxytocin increases trust, generosity and our ability to identify emotion in facial expressions. It is perhaps by these mechanisms that the hormone improves communication.
5-HTP is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase with the help of vitamin B6.[40] This reaction occurs both in nervous tissue and in the liver.[41] 5-HTP crosses the blood–brain barrier,[42] while 5-HT does not. Excess 5-HTP, especially when administered with vitamin B6, is thought to be metabolized and excreted.[43][44]