Theanine is an increasingly common ingredient (at least from what I’ve tested) in sleep supplements. It has a calming yet non-sedative effect, which is why it’s in sleep supplement blends and added to some existing blends like ZMA. In fact, my favorite version of ZMA includes l-theanine in addition to the normal zinc, magnesium, and vitamin B6 you find in this blend. (Find out why l-theanine is the most common form found in supplements in this article I wrote.)
Tyrosine, on the other hand, is not something you’ll commonly see in sleep supplements. Read below to find out why.
Though it’s an amino acid as well, tyrosine (commonly seen as l-tyrosine in most supplements) can actually be stimulatory. There’s some evidence that when taken before a stressful event, tyrosine may help fight the effects of stress. For that general reason, it’s commonly seen in many nootropic and “brain boosting” formulas like Alpha BRAIN (which I’ve actually tested before with some interesting results). So maybe not the best thing to take before bed for better rest, but a supplement you might come across in some mood and brain formulas (sometimes paired with l-theanine).
When taken as a supplement, tyrosine is converted into L-DOPA and from there neurotransmitters including dopamine.
Some sleep supplements today include serotonin precursor 5-HTP — New Mood and Max Sleep are two of my favorites that contain this ingredient. There’s some research and evidence suggesting 5-HTP and Tyrosine may be antagonistic. They may therefore reduce each other’s effects, something to potential keep in mind if stacking supplements containing these two compounds.