The main difference is the speed in which results can be seen. Retinal has an increased absorption and exfoliation rate, which will result in a more even complexion, a definite selling point. It also has been clinically proven to work up to 11 times faster than retinol. Retinal is the closest thing you can get to prescription-strength vitamin A. The one downside is that with its extreme efficacy, there is a possible chance of temporary skin flaking, redness and sensitivity as it helps transform the skin from unhealthy to healthy; however, compared to its cousin the prescription retinoid, it is much more tolerable.