5-HTP is a naturally occurring amino acid and precursor in the biosynthesis of the chemical messenger serotonin. Low serotonin levels are associated with depression, anxiety, sleep disorders, weight gain and other health problems. Recent research has found the use of 5-HTP in mood disorders is beneficial.

• Angst J, Woggon B, Schoepf J. The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study. Arch Psychiatr Nervenkr (1970).1977;224(2):175-186.
• Birdsall TC. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med Rev. 1998;3(4):271-280.

Theanine is an analogue of amino acid glutamate and is particularly found in green tea. As a structural analog of glutamate, the theanine is absorbed in the small intestine after oral ingestion. It can also cross the blood–brain barrier intact and elevates levels of GABA, serotonin and dopamine which regulate emotions and mood in our brain. and has been studied for its potential ability to reduce symptoms of anxiety and depression.

• Dietz C, Dekker M. Effect of Green Tea Phytochemicals on Mood and Cognition. Curr Pharm Des. 2017;23(19):2876-2905.doi:10.2174/1381612823666170105151800
• Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. 2008;11(4):193-198.doi:10.1179/147683008X301513

Gamma aminobutyric acid (GABA) is a naturally occurring amino acid that works as a chemical messenger in the brain. GABA blocks certain brain signals and decreases activity in the nervous system. By inhibiting neural activity, GABA facilitates sleep, reduces mental and physical stress, lowers anxiety, and creates a calmness of mood.

• Petty F. GABA and mood disorders: a brief review and hypothesis. J Affect Disord. 1995;34(4):275-281. doi:10.1016/0165-0327(95)00025-i
• Boonstra E, de Kleijn R, Colzato LS, Alkemade A, Forstmann BU, Nieuwenhuis S. Neurotransmitters as food supplements: the effects of GABA on brain and behavior. Front Psychol. 2015;6:1520. Published 2015 Oct 6.doi:10.3389/fpsyg.2015.01520