J Chromatogr B Biomed Sci Appl 746:297304 Pan Y, Berman Y, Haberny S, Meller E, Carr KD (2006) Synthesis, protein levels, activity, and phosphorylation state of tyrosine hydroxylase in mesoaccumbens and nigrostriatal dopamine pathways of chronically food-restricted rats
As a drug, it is artificially able to mimic the hormone and is generally used for people with type 2 diabetes or obesity , becoming an aid to slow digestion and promote satiety, thus contributing to weight loss Although it is a natural hormone, it can be used as a drug in the cases mentioned above
You are either buying fake product, contaminated product, or dramatically underdosed product
A landmark study published in Nature Medicine (Koeth et al., 2013) demonstrated that gut bacteria metabolise L-carnitine into trimethylamine N-oxide (TMAO), a compound associated with atherosclerosis in animal and observational human studies
Across repeated weekly doses the drug accumulates to a steady state, so trough levels hold high enough to maintain therapeutic effect, without a cliff-like drop before the next dose