What it's normally used for
Acetyl L-Carnitine is used for heart-related conditions. Some clinical trials show that Acetyl L-Carnitine can be used with conventional treatment for angina, reducing the need for medicine, and improves the ability of those with angina to exercise with no chest pains or discomfort. Some studies have shown that taking Acetyl L-Carnitine after having a heart attack decreases the odds of having another heart attack later.
Carnitine has been used to reduce fatigue and also serve as an appetite suppressant.
What it does for Lucid Dreaming
Acetyl L-Carnitine is known for generating vivid dreams, and it helps increase the amount of Acetylcholine within the brain.
My own results
I take Acetyl L-Carnitine before bed and get more vivid, and possibly longer.