I figured that 20 drops is equal to about 50mg. That's 50,000 mcg. Maybe a little more.
Considering I didn't have any health issues to address I started with 20 drops day one. For the first week my teeth hurt and I felt head pressure and some disorientation.
You might want to start a lot lower than I did. Maybe start with 5mg and see how you do. Then up your dosage by 5mg until you feel side effects and hold there until they go away.
From what I read, 50mg a day is good for maintenance. I mostly take 50mcg every day. I also read that for therapeutic, like really trying to deal with a particular health issue uses 100mg is best to take for a month or 3 then switch back to 50mg.