Slugging

Slugging is the practice of applying a thin layer of an occlusive product, most often petrolatum, as the final step of an evening routine to seal in the layers beneath it. The name refers to the glossy, slick film left on the skin overnight. The goal is to reduce transepidermal water loss so that skin retains more moisture by morning.

An occlusive does not add water to the skin; it forms a physical barrier that slows evaporation. For this reason slugging works best over hydrating steps, such as a humectant serum and a moisturiser, rather than on bare skin. It is often favoured by people with dry, dehydrated, or compromised-barrier skin, and during cold or low-humidity conditions.

The method is not suited to everyone. Because the occlusive traps whatever is underneath, applying it over strong actives such as retinoids or acids can increase their intensity and the risk of irritation, so those are generally best kept to separate nights. Slugging can feel heavy and may not suit acne-prone or fungal-acne-prone skin, since occlusion and certain ingredients can aggravate congestion or feed Malassezia. Using non-comedogenic products, keeping pillowcases clean, and reserving the technique for nights that call for it help. Anyone with active breakouts or a persistent skin condition should adjust accordingly or consult a clinician.