The claim
Locks in hydration, repairs the barrier, and wakes you up with 'glass skin'.
What the evidence says
Petrolatum is the best-studied occlusive in dermatology; it cuts water loss sharply and even triggers barrier-repair signaling. The trend simply applies a standard recommendation for dry or irritated skin to everyone, including oily, acne-prone faces, where an all-over occlusive can trap sebum and actives.
Who should skip it
Active acne, fungal acne, or very oily skin over the whole face; anyone still adjusting to a new retinoid or acid, which slugging can drive deeper.
What to do instead, or as well
Slug selectively: lips, cheeks, hands, heels, and post-procedure skin, over a moisturizer rather than instead of one.
Sources on file
These links support the claims above. Reviewed September 1, 2026.