You can start with one 500 mg pill a day, and depending on the degree of die-off it may cause, you can add another pill every day until you reach three or four pills a day. The number of pills is up to you. A total allicin potential of 4,000 mcg equals one garlic clove.
You’ll probably do better by taking the pills with a meal as it should help to lessen the aftertaste.
People who are taking blood-thinning or antiplatetlet medications or aspirin should avoid garlic.