I understand how confusing it is to understand the different forms of vitamin A and how one could be FAR superior to another! I want to explain this again but in a different way.
Retinol (with an O) can be converted into Retinal (with an A). Retinal is also known as Retinaldehyde. This is 1000x more potent than Retinol. Retinaldehyde can be converted into Retin-A. Retin-A is also known as Retinoic Acid. This is EQUALLY as potent as Retinaldehyde.
This chain may NOT be converted backwards.
Once you understand the above … I will add to it …
Retinaldehyde is a form of Vitamin A that is already stored in your body thus your body accepts and recognizes it. This is not true of Retin-A.
Therefore when you apply Retin-A on your skin, your body will utilize what it can to use it (for example to create collagen) but the excess will simply “sit” on the skin thus damaging it and causing it to be sun sensitizing and irritating.
When you apply Retinaldehyde, however, your skin will use what it needs (for example convert into Retin-A to to create collagen) and the excess will be STORED for future use because your body ALREADY stores and recognizes it. And because Retinaldehyde is EQUALLY as potent as Retin-A and IS NOT irritating as Retin-A, there really is no comparison.
So remember that Retinaldehyde can always convert into Retin-A but Retin-A cannot convert back – thus the excess is nothing more than an IRRITANT and actually DAMAGING to the skin.
I only treat skin and provide high quality products containing Retinaldehyde….never retinol or retin-A!