Can I use hyaluronic acid under petrolatum?

Why the combination makes sense

Hyaluronic acid is a humectant, meaning it attracts and retains water in the outer skin layer. Petrolatum, also called petroleum jelly, is an occlusive: it forms a surface barrier that reduces water evaporation. These are complementary jobs, and some moisturizers already combine humectants and occlusives. You do not need a separate hyaluronic acid serum if your moisturizer already supplies that ingredient.23

Despite its name, hyaluronic acid moisturizes rather than exfoliates. It does not do the same job as glycolic or salicylic acid. Hyaluronic acid and petrolatum are both useful ingredients for dry skin, including dryness during colder months.4

How to layer them

1. 1Wash gently, using lukewarm rather than hot water. Pat or blot your skin instead of rubbing it completely dry.
2. 2Apply your hyaluronic acid serum or moisturizer while your skin is still damp. Moisturizing immediately after washing helps retain the water already in the skin.
3. 3Finish with a small amount of petrolatum over the areas that need moisture retention. Smooth the ointment gently rather than rubbing vigorously, following the direction of hair growth.

Damp skin is especially useful here because plain petroleum jelly contains no water. Its job is to hold moisture in, so applying it after washing gives it moisture to retain rather than asking it to supply water itself.1

When should I use it?

Night is a practical choice because ointments are thick and greasy; a cream is easier to wear during the day. A shiny finish is part of using a greasy ointment, not evidence that your routine has achieved a higher rank. For slight dryness, a nighttime moisturizer can be enough. More severe dryness can need more frequent moisturizing, including after washing and whenever the skin feels dry or tight.35

What should I expect?

The aim is less dryness and better moisture retention, not exfoliation. Ointments provide longer lasting protection than lighter creams because of their higher oil content. Moisturizers have their greatest effect during the first six hours after application, so regular use matters more than treating one application as a permanent repair. There is no fixed number of days for this particular combination to resolve dryness.3

Who should be careful?

Occlusive moisturizers can aggravate acne, perioral dermatitis and folliculitis, which is inflammation around hair follicles. If these are problems for you, do not make an all over petrolatum layer your default. Sensitive skin can also react to fragrances, preservatives or other ingredients in the products underneath. Do not use ointments on weeping eczema.235

If you use a steroid cream or another treatment for a skin condition, leave 20 to 30 minutes between that treatment and an emollient. Ask your doctor which should go first rather than treating the medicine as another serum layer.5

Stop a product if an allergic rash develops. Speak to a pharmacist or clinician about persistent burning, stinging, inflamed follicles or worsening facial rashes, and seek medical advice for severe dryness. Keep emollient contaminated clothing and bedding away from flames and cigarettes. Use a clean spoon or spatula when taking ointment from a tub.35