Inhibitory neurotransmitter support. High-quality 5-HTP plus co-factors. Suggested uses: low mood, anxiousness. Serene is an amino acid formula that supports serotonergic neurotransmission. As an inhibitory neurotransmitter, optimal serotonin levels are important for promoting healthy sleep and a positive mood. Serene contains vitamin and mineral cofactors essential for serotonin synthesis.