Do you like sandwiches? How about a sandwich made of skincare!? Sounds delicious to me!
The term moisture sandwich, at least when referring to skincare (haha) simply refers to product layering.
Don't worry, its not a new concept, just a different way of thinking about virtually the same concept as any other product layering system, like how I recommend to layer products as you layer winter clothing or as the concept of "slugging".
(I have an Instagram post about both of those, so they'll likely pop up here as well!)
Think of the objective of your skincare as two fold: trying to "trap" certain ingredients but also helping with product penetration.
So let's build this sandwich!
So, your skin would be one piece of bread, your humectant-rich serums like Everlasting, a mist like Petrichor, or even tap water (and any combination thereof) would be the sandwich ingredients, and a heavier, occlusive-rich layer (such as a balm, heavier oil or cream) would be the top piece of bread. Mmm, delicious face!
The idea is to "trap" what's in the bread to make it work better, and keep it from evaporating.
So with Stark, your sandwich could be:
Bread: Cleansed, damp skin
Ingredient 1.: Everlasting (keep skin damp!) , spritz of water or Petrichor. Do not use anything irritating.
Ingredient 2: Other serums, facial oil (light), soothing ingredients.
Bread: Facial oil (heavier), sunscreen or a balm (Aurora) or heavier oil-serum like Midnight.
At night, you can definitely use a heavier hand when building up the sandwich, especially with your final layer, which can go heavy on the occlusive if you have dry skin.
For oily skin, you could do an open-face sandwich, so to speak, and not worry about that final piece of "bread" being anything too heavy. You might not need a balm at night, or heavier oil.
Do not do this with acid treatments or retinols. I akin this to trapping an angry scorpion in a sandwich, with no way out. Sting-city!
The benefits will be increased skin hydration and better product penetration which will result in a more natural glow, and fine lines disappearing (within reason, this isn't a miracle sandwich after all... and keep in mind that with skincare, there's no miracles, just consistency).