What Is Slugging, Exactly?
Slugging is where you apply a lot of petroleum jelly — commonly Vaseline — on your face to lock in moisture and keep it protected during harsh conditions like winter and when your skin is dry.
Petroleum jelly is what's called an occlusive. Occlusives are basically ingredients that seal up the skin and keep water from evaporating. Common occlusives used in skincare are oil-derived like petroleum jelly or mineral oil, waxes like beeswax, as well as silicones and lanolin.
Occlusives work by forming a waterproof barrier over your skin when you slather it on. The outer surface of your skin, the stratum corneum, normally functions as a waterproof barrier to keep water in. However, when you have dry skin, this barrier is compromised or is just not up to the task — such as in cold winter — so petroleum jelly reinforces this barrier.
Why Slugging Falls Short
I tried some slugging myself and noticed two major drawbacks.
What the Research Actually Shows
That's why I was excited when my team came across a paper published by Soma and colleagues in the International Journal of Dermatology in 2005 — because it included a direct comparison between petroleum jelly and niacinamide-based moisturization.
This study was conducted in patients with atopic dermatitis, commonly known as eczema. These patients have a very compromised skin barrier and consequently, very dry skin. Those of you who don't have eczema but have sensitive skin or dry skin likely also have a compromised skin barrier, just to a lesser degree.
Though both improved immediate skin dryness, as time went on the niacinamide moisturizer was much better at hydration than petroleum jelly — even in patients with very dry, damaged skin barriers. This suggests a lightweight niacinamide moisturizer is superior to a heavy occlusive like Vaseline for long-term skin hydration.
Why Niacinamide Is Better
Niacinamide, though it is a vitamin, will increase ceramide, fatty acid, and cholesterol production in your skin. Ceramides, fatty acids, and cholesterol are the natural lipids that form your natural skin barrier — so niacinamide strengthens your skin barrier from the inside out.
You can also apply a moisturizer that contains these natural lipids directly onto your skin. These natural lipids are called occlusive emollients — your skin can absorb these ingredients into your skin barrier to fortify it, making them a better alternative to petroleum jelly as well.
What to Do Instead
Slugging might be a decent quick fix, but if you want to improve, repair, and fortify your natural skin barrier with longer lasting results, you might see much better results with niacinamide-infused products.
You could try a niacinamide serum followed by a lightweight cream that has ingredients with both occlusive and emollient properties, or a lightweight cream that has niacinamide listed as an ingredient. These options are better for your skin — and likely feel much better than slathering Vaseline all over your face.
- Soma Y, Kashima M, Imaizumi A, Takahama H, Kawakami T, Mizoguchi M (2005). "Moisturizing effects of topical nicotinamide on atopic dry skin." Int J Dermatol 44:197–202.
