Rhodiola crenulata (often grouped with its relative Rhodiola rosea) has a long history of use in traditional medicine, particularly in Tibet and China, where it is valued as an adaptogen—an herb believed to help the body resist physical, chemical, and biological stressors. Traditional texts describe its use for promoting stamina, energy, and mental well-being, though they do not specifically reference serotonin or detailed neurotransmitter pathways. In modern times, Rhodiola species have been studied for their potential influence on mood and stress responses, in part because of their adaptogenic reputation.

Some preliminary scientific studies (mostly on Rhodiola rosea, with less direct evidence for R. crenulata) suggest possible effects on neurotransmitter systems, including serotonin, by modulating the activity of monoamine oxidases and affecting the reuptake of serotonin in the brain. However, the evidence is limited, generally of low to moderate quality, and not specific to R. crenulata. There is a lack of robust clinical trials directly linking R. crenulata to serotonin modulation or to clinical outcomes related to serotonin-based mood disorders.

In summary, the use of Rhodiola crenulata for supporting the "serotonin body system" is primarily justified by traditional medicine practices, with only weak and indirect scientific evidence. Most claims are extrapolated from related species and from general adaptogenic effects rather than direct serotonin support.