The most widely substances used are sitagliptin, linagliptin, vildagliptin, saxagliptin, and allogliptin
This remains an actively moving area, however: on February 27, 2026, the HHS Secretary publicly announced an intent to move roughly 14 of the 19 Category 2-listed peptides, reportedly including ipamorelin and CJC-1295, back toward Category 1 status, and multiple industry and legal-news outlets reported further FDA action in the following months easing Category 2-related restrictions on this group of peptides
The exact amount depends on individual needs and therapeutic goals
"Tryptophan Metabolic Pathways and Brain Serotonergic Activity: A Comparative Review"
We have found a study confirming this but it was the essential oil of the leaves and not the much more commonly used flowers and the two differ in their main chemical compounds very much