Many articles have been written about the synergies between L-theanine and caffeine and in fact entire product lines are available in the market, such as supplements that contain substantial amounts of both L-theanine and caffeine
It is not intended for human administration, clinical use, diagnosis, treatment, prevention of disease, or resale for investigational purposes
Patients are running uncontrolled experiments on themselves
(2015), and Vindry et al
Also, for people who dont eat meat and dairy at all, the latter is definitely advised, as you simply cant eat the amount of meat and dairy alternatives to get enough B12 (unless youd like to eat 1,5 containers of fortified soy yoghurt each day)
It is generally used for conditions such as melasma, sun damage, and postinflammatory hyperpigmentation