That vitamin and accutane are similar is fact and common knowledge. Not your discovery. And I've no idea why you feel the need to argue that point.
Correct one molecule can make a difference.
But the general rule of thumb in my pharmacy class is that we predict the actions of the drug based on the molecular structure. And it works pretty damn well most of, but not all, the time.
So here are the similarities between accutane and vitamin A:
1. Similar molecular structure.
2. Nearly identical efficacy in treating cystic acne. (At their respective doses.)
3. Both share many of the same side effects such as: birth defects, dry skin, depression.
Do I even need to go on? At this point you are just being ignorant if you aren't seeing similarity between accutane and vitamin A.
Furthermore, one must ask themselves. If taking a certain amount of an essential vitamin shows a statistically significant reduction in the illness, wouldn't the cause be referred to as a deficiency?
Edit: fixed some grammar mistakes
You were the one who began arguing that they weren't. What on earth are you smoking?