I've heard a plastic surgeon (and a cosmetic dermatologist) say, that if you want to maximise the anti-aging benefits of Retin-A. You should use the 0.1% strength, and once you can tolerate it. You should apply it twice a day.
They say the results will be much better, than using an anti-oxidant (C E Ferulic) in the morning and Retin-A in the evening.
They also go onto say, that the increased sun sensitivity won't be a problem as long as you use a sunblock.
Your thoughts ?
Tretinoin is not stable in daylight. I believe it is the yellow light that breaks it down. That´s why older skin is vitamin A deficient, the daylight downregulates the RARs and destroys the retinoic acid (vitamin A).
But sure if you have rhinoceros skin you can apply a retinoid (preferably the synthetic ones, adapalene or tazarotene as theyre more stable) OVER your C serum. But there´s no studies that show greater effect beyond 0.1% once daily. Actually, 0.025% and 0.1% were equally as effective in one study.
The higher % will give results faster (and much more irritation), it will be more like a peel where you look awful for 7-10 days and then look great after you´ve "healed" your skin barrier. There´s a peel made by Skinmedica that combines retinoic acid with AHAs.
But over time 0.025 to 0.1% once daily is fine. Use to tolerance. If that´s twice a day for you, fine, but don´t use it instead of topical C, layer it in that case.
Edited by Fredrik, 09 July 2008 - 05:13 PM.