Calming Complex with GABA Don't let occasional stress get you down. Theanine Serene contains the amino acids L-Theanine, to support relaxing brain activity, and taurine to ease tension, as well as the calming neurotransmitter GABA. It also features magnesium to support muscle and nerve relaxation, and calming holy basil leaf extract to gently soothe away the tension in your body.