I think they are pretty much the same in terms of effectiveness (both contain the same active ingredient Tretinoin), but Retin A Micro is less irritating than Retin A in the same strength. You can apply Retin A Micro immediately after you wash your face, but you have to wait 20-30 minutes for Retin A.

Retin A is available in 3 different forms - cream, gel and liquid. But I think Retin A Micro is only available in the gel form.

From what I understand, Retin A micro and Retin A both contain the same active ingredient, tretinoin. But the difference with retin a micro is that it uses microscopic particles called microspheres. The spheres hold the tretinoin in reserve, and lets the skin absorb tiny amounts of it over time. They do this so people who use the medication experience less irritation.

I'm not sure why you have to wait 20-30 minutes after you wash your face to apply retin a. I think it's cuz you have to wait for all the water to dry. Retin A micro users don't have to wait because the micro gel is water based.