"Neurotransmitter levels" refers to the amount of chemicals in our brain that help transmit messages between nerve cells, influencing our mood, behavior, and other brain functions. Full definition
When starting SSRI and SNRI drugs, patients experience an immediate increase in neurotransmitter levels in the brain, however, it takes 2 - 4 weeks before there are noticeable changes to mood. (taliand.com)
Depressed people do not in general have low neurotransmitter levels in the first place. (religion-online.org)
Even if it's not measuring body levels of neurotransmitters directly, the results of the Braverman test do indicate general trends in personality and neurotransmitter levels which can affect how you should train. (marksdailyapple.com)