Acetylcholine is a neurotransmitter, which means that it helps nerves communicate. It is used in the central nervous system (which is made up of the brain and spinal cord) and the peripheral nervous system (all other nerves). It is responsible for activating muscles and for control of the brain's "reward" system. It is also used by the hippocampus, which is the part of the brain that is responsible for making memories.
Amino acids. Acetyl-N-Carnitine is a kind of amino acid that is able to increase the production of acetylcholine by donating a small molecule called acetyl (which is made up of two carbons atoms, three hydrogen ones, and an oxygen atom) to another compound, which is known as choline. Once choline receives this acetyl molecule, it becomes acetylcholine (hence the name). Taurine, another amino acid, has been shown to increase the levels of acetylcholine in the hippocampus, which is a part of the brain. Both amino acids are readily available as supplements in health stores.
Hormones. Dehydroepiandrosterone (also known as DHEA) can increase the release of acetylcholine in the hippocampus. Another hormone, pregnenolone, has a similar effect. Both of these require prescriptions, but they can be prescribed by doctors who specialize in anti-aging medicine.
Anti-aging drugs. This include dimethylaminoethanol (DMAE) which is a drug that slows the breakdown of choline in tissues outside fo the brain. As a result, more choline is available to be turned into acetylcholine. Another drug, pyroglutamate, is also able to increase acetylcholine production by enhancing the production of other chemicals that cause more acetylcholine to be made. Again, these drugs are available via prescription.
Vitamins. Certain B vitamins are critical for the synthesis of acetylcholine, and a deficiency in them can cause decreased acetylcholine production. These include vitamin B1, B5, and B12. All of these are readily available as supplements. To increase your intake of these, take a B vitamin supplement, available at most drug stores and health food stores.
Supplements. These include the herb ginkgo biloba, which stimulates the brain's adsorption of acetylcholine, and the lipid phosphatidylserine, which aids in the production and release of acetylcholine into the brain. Both of these compounds are available at health food stores.