Cowage seed, also known as Mucuna pruriens, is used to support the serotonin system primarily due to its high content of L-DOPA, a direct precursor to dopamine. While L-DOPA itself is not a direct precursor to serotonin, there is some scientific rationale for its indirect effects on the broader monoamine neurotransmitter system, which includes serotonin, dopamine, and norepinephrine. Multiple clinical studies and animal research have shown that Mucuna pruriens supplementation increases dopamine levels, which may influence serotonin pathways due to the interconnectedness of these neurotransmitter systems in the brain. Some studies in humans, particularly those involving Parkinson's disease patients, demonstrate that Mucuna pruriens can improve mood and reduce symptoms like depression, which are often linked to serotonin deficits. However, direct clinical evidence showing that cowage seed specifically increases serotonin levels is limited, and most of the evidence is extrapolated from its effects on dopamine and the observed improvements in mood and well-being. Traditional Ayurvedic medicine also uses Mucuna pruriens for neurological and mood-related disorders, lending some historical precedent to its use for supporting neurotransmitter balance. In summary, while there is robust scientific evidence for Mucuna pruriens supporting dopamine, the evidence for its direct effect on the serotonin system is moderate but plausible, primarily due to the interplay between dopamine and serotonin in the brain.