Slugging involves applying a thick, occlusive layer, typically a petrolatum-based ointment, as the final step in a nighttime routine. This creates a physical barrier on the skin’s surface designed to prevent transepidermal water loss (TEWL), effectively locking in moisture and hydrating ingredients.
Retinol is a derivative of Vitamin A that works deep within the skin to promote cell turnover and boost collagen production, addressing concerns like fine lines and uneven texture. Combining these two steps is possible, but it requires a cautious and strategic approach to prevent significant skin irritation.
Why Slugging Over Retinol is Risky
The function of slugging is to create an airtight seal using occlusive ingredients like petroleum jelly. This barrier reduces the evaporation of water from the skin, but it also traps any ingredients applied underneath. When a potent active ingredient like retinol is applied before this occlusive layer, its penetration into the skin is significantly enhanced.
Retinol is slowly converted by the skin into its active form, retinoic acid, which causes the desired cellular changes. By trapping the retinol, the occlusive layer forces a higher concentration of the active ingredient to be absorbed over a shorter period. This accelerated penetration can overwhelm the skin’s tolerance, leading to a condition known as retinoid dermatitis. Symptoms include excessive redness, burning, peeling, and heightened sensitivity, which ultimately compromises the skin barrier.
How to Safely Combine Retinol and Slugging
Safely combining these two steps relies on “buffering” or “sandwiching” to mitigate the retinol’s potency before the occlusive barrier is applied. First, apply a simple, non-active moisturizer to clean skin. This acts as a protective base layer to dilute the retinol’s immediate impact and slow the rate of absorption, making the process gentler on the skin.
Next, apply the retinol product in a pea-sized amount and allow it to fully absorb. Wait approximately 20 to 30 minutes after the retinol application before proceeding to the slugging step. This waiting period allows the retinol to stabilize and begin its work without being immediately forced deeper by the occlusive layer.
The final step is to apply a thin layer of a non-comedogenic occlusive product, such as petroleum jelly. This application provides the necessary moisture barrier without creating an overly aggressive seal that could hyper-accelerate absorption. Apply the occlusive only to areas prone to dryness, such as the cheeks or neck, while avoiding sensitive areas like the corners of the nose or mouth.
When to Skip Slugging on Retinol Nights
Avoid combining slugging and retinol when using prescription-strength retinoids, such as tretinoin, or high-percentage over-the-counter retinols. The high potency of these formulas means enhanced penetration from an occlusive layer significantly increases the risk of severe irritation. New retinol users should also refrain from slugging until their skin has fully acclimated to the active ingredient, which typically takes four to six weeks of consistent use.
Slugging should also be skipped if the skin barrier is compromised or irritated. This includes nights when the skin is sunburned, actively flaring with eczema or rosacea, or experiencing excessive dryness and flaking. If the skin shows persistent warning signs like excessive burning, stinging, or new breakouts after combining the two steps, discontinue the practice immediately. Reserve slugging for nights when retinol is not used, allowing the occlusive to focus solely on barrier repair and hydration.