I chelated on ALA alone, it worked at first very well, but after a few rounds things started going downhill. Not strong adverse reactions, just started getting increasingly foggy in head and lost concentration. The first ALA rounds had the opposite effect.

I didn't want to use DMSA, because I didn't see benefits from using it (I do not believe that chelating mercury alone will help much). Then when I finally got the connection to acetaldehyde and DMSA, I realized why people get benefits from using it.

http://onibasu.com/archives/am/203523.html

Never use anything like ALA, anti-oxidants etc. alone without having a proper aldehyde detoxer at hand. ALA also destroys candida, and it isn't particularly good at mopping up the candida toxins after that. I used molybdenum + pantothenic acid, which both support the aldehyde detox pathway. After having used these for a few weeks, I feel again very well. Brain fog lifted, adrenal problems are also much relieved etc.

Other options for acetaldehyde detox are succinic acid, and cysteine (NAC), which bind strongly to acetaldehyde. Both are more friendly to the liver than DMSA. NAC is also known to cause serious side-effects for some people, perhaps because of its ability to strongly bind to acetaldehyde. If you believe in the mercury theory, then you must use DMSA, but I don't so I get more options to treat myself.

Cysteine binds to acetaldehyde:
http://cebp.aacrjournals.org/cgi/content/abstract/15/1/146

Acetaldehyde is a fungal waste product that causes brain fog and metallic taste in mouth.

These are typically symptoms from taking acetaldehyde detox inhibiting drugs and then taking alcohol, making your body flooded with acetaldehyde (it deposits if not detoxed):

Flushing or blotching red rash (face, neck, thorax)
Sense of face and hand swelling
Diaphoresis
Palpitations/chest pain
Dyspnea/hyperventilation
Nausea/vomiting
Metallic taste!
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Headache
Vertigo/dizziness
Tingling paresthesias (perhaps due to hyperventilation)
Apprehension/sense of impending doom
Weakness
Hypertension
Hypotension (more severe poisoning, looked up this myself)
Tachycardia (occasionally dysrhythmias)