Acetylcholine

Acetylcholine is a neurotransmitter used in the autonomic nervous system, both as an internal transmitter for the sympathetic nervous system and as the final product released by the parasympathetic nervous system.

In 2015, a large German study found 29% of ME/CFS patients had elevated autoantibodies to M3 acetylcholine receptors. A 2016 Australian study found that ME/CFS patients had significantly greater numbers of single nucleotide polymorphisms associated with the gene encoding for M3 acetylcholine receptors.

Anecdotally, some patients have tried Mestinon, an acetylcholine reuptake inhibitor used to treat myasthenia gravis, with some success.