I started at 50 mcg a day and slowly worked it up to 200 mcg a day. I've been on for maybe a week, but I don't feel any different. They are small white circles scored into quarters, and they have "100" on them.
Did they come in a bottle? Chances are they are real... there really isnt a market for fake thyroid meds since they are so easy to get your hands on and are not a scheduled med.