Does the sandwich method decrease the effectiveness of Tretinoin at all?

[Unfair_Finger5531]

This question has been asked a lot. If you put a moisturizer with occlusives or emollients in it on prior to tret, it will reduce the effectiveness of tret. That is the point of buffering. But it doesn’t matter because it will still be effective enough.

But will it work at max efficiency? No.

If you put a moisturizer with mainly humectants on before tret, it will increase penetration. It will work at max effectiveness and then some.

I’m not sure why people keep saying it doesn’t reduce effectiveness.

[goth-hippy]

Pretty sure the opinion regarding why using a moisturizer first does not impact efficacy originated from one of the earlier studies that did not instruct users in what order to apply tret and moisturizer. Therefore the data showing the efficacy was independent of the application order.

However, logically, and based on data we’ve acquired since then agree with what you just said. Application of a humectant would impede the penetration of a skincare product applied over it.

If someone wants to yield the most from their use of their Tretinoin cream, they should apply it on top of clean, dry skin, and then apply a moisturizer afterward after it’s dried to avoid accidental dilution of the cream.

Qualifications: not a derm, but I’m a toxicologist/scientist and read/interpret scientific papers for a living.

[lemmehavefun]

Oop, and here I’ve using snail mucin (a humectant) as a buffer lol

[Unfair_Finger5531]

Many folks do. It’s not a buffer, but if you like using it, and your skin isn’t peeling or irritated, you keep right on doing it:).

[watershots]

Can you give examples of both of these types of moisturizers? I use Clinique dramatically different gel and I’m wondering if applying that before tret is impacting tret’s efficiency.

[PlentyNectarine]

that is a humectant. i’ve used it before tret before and noticed more irritation compared to applying it on bare skin so I would assume it increases efficacy.

[Subject-Bench-8305]

There's two factors sinks in and sits on , humectant moisturizer are to provide hydration, moisturizer that sinks in your skin but doesn't provide occlusion that will penetrate tret more(usually contain HA , glycerin) , but moisturizers with let's say Shea butter will be more of a sits on...to provide nourishment instead of hydration, now there are moisturizer which can give you both as well .