Ingredient

Petrolatum

Petrolatum is petroleum jelly — the ingredient in Vaseline and in most plain healing ointments. It is the reference standard for sealing water into skin, and it costs almost nothing.
At a Glance

Petrolatum is a semi-solid mix of hydrocarbons that forms a physical seal over skin. It cuts water loss through the skin by more than 98%, better than any other single moisturizing ingredient, and it has one of the lowest allergy rates of anything you can put on your body. The catch is that it adds no water of its own — it only holds in what is already there, so it belongs on damp skin — and it is genuinely greasy, which is why most people use it overnight.

Key Facts

What It IsPurified semi-solid hydrocarbon from petroleum — the occlusive in Vaseline, Aquaphor and most plain ointments
Best ForCracked hands and heels, eczema, lips, eyelid dermatitis, wound aftercare, nappy rash, protecting skin around a treated area
Typical Strength100% as plain jelly, or 10–30% inside creams and ointments
Rx RequiredNo
Cost$2–$8 for a large tub. Branded ointments with added ingredients run $10–$20 and are rarely better

How It Works

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Petrolatum does not sink in, feed the skin, or repair anything. It sits on the surface and fills the gaps between the flat dead cells of the outer layer, forming a water-resistant film. Water that would otherwise evaporate out of the skin stays in. Measured in the lab, that drop in transepidermal water loss — water escaping through the skin — is over 98%, higher than lanolin, mineral oil, silicones or any plant oil. The trapped water then does the actual work: it lets the enzymes in the outer layer function, softens hardened scale, and gives the barrier the conditions to rebuild itself.

The film works in the other direction too. It keeps irritants, allergens and friction off skin that is raw, cracked or freshly treated. That is why it is the standard dressing after minor skin surgery, and why it beats antibiotic ointment for everyday wound care — it keeps the wound moist so it heals with less scarring, without the contact allergy risk that comes with neomycin and bacitracin. It has no antimicrobial action of its own. It simply does not get in the way.

What It Treats

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On eyelids, plain petroleum jelly is the default. It has no fragrance, no preservative and no realistic allergy risk, which is exactly what irritated lid skin needs.
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For hand dermatitis, petroleum jelly is the overnight treatment. It holds water in far better than a lotion and is the safest option on skin that is already irritated.
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For a seborrheic keratosis being rubbed by clothing, petrolatum acts as a barrier and settles the irritation. It has no effect on the growth itself.
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Petrolatum is the plain, cheap base layer of psoriasis care. It seals water into thickened plaques so they crack less and flake less, and it helps medicated creams spread and absorb.
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In cold sores, petrolatum stops the crust cracking during healing and reduces pain. It has no antiviral effect and does not shorten the outbreak.
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In lip licker's dermatitis, petrolatum works mechanically — it blocks saliva from reaching the skin and stops the lips feeling dry, which removes the trigger for the habit.
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Petrolatum is the most occlusive emollient option and is well suited to the dry, thickened lower-leg skin typical of nummular eczema. Best applied to damp skin.
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For striae, plain occlusive moisturizers are used for comfort and as the vehicle for daily massage. No emollient has been shown to prevent stretch marks on its own.
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For dry skin, petrolatum is the reference standard occlusive. It cuts water loss through the skin by more than any other over-the-counter ingredient, and it has no fragrance or common allergens.
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Petrolatum is the most occlusive barrier repair option there is, and it has no fragrance, preservatives or common allergens. It is a safe default when eczema skin is reacting to everything else.
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Petrolatum is a fragrance-free, preservative-free occlusive. In stasis dermatitis it is preferred over more complex moisturizers because contact allergy to cream ingredients is very common in this group.
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Petrolatum is the safest thing to put on skin that is reacting to everything else. It is close to inert and is often used as the negative control in patch testing.
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Petrolatum cuts water loss through damaged skin more than any other over-the-counter option, and it carries almost no risk of making the irritation worse.
Over the counter
Limited evidence
Petrolatum has no antibacterial action. In impetigo it is used purely as an occlusive to soften adherent crust so that a topical antibiotic can reach the base of the lesion.
Over the counter
Moderate evidence
Petrolatum keeps a wound bed moist and is as effective as topical antibiotics for clean minor wounds, without the sensitisation risk.
Over the counter
Moderate evidence
Petrolatum is an occlusive that holds water in the skin. For sunburn it belongs to the peeling and healing stage, not the hot first day or two, because it also holds heat in.

How to Use It

Apply it to damp skin
  • This is the one rule that matters. Petrolatum seals water in; it does not supply any. Put it on within about three minutes of a bath, shower or hand wash, while the skin is still slightly wet. On bone-dry skin, it seals in the dryness.
How much, and where
  • A thin layer is enough. Thicker does not seal better, it just transfers to your clothes. It earns its keep on the places that crack: heels, fingertips, knuckles, lips, elbows and shins. On the face most people use it only on dry patches, and acne-prone skin should keep it off the oily areas.
Overnight is the practical answer
  • It is greasy and it marks fabric, so most people apply it at bedtime. Cotton gloves over hands and cotton socks over feet make a large difference to cracked skin and keep it off the sheets.

Pairing & Conflicts

What to pair it with

Water first, then everything else, then petrolatum last. It is the top layer of a routine because nothing gets through it well. It pairs particularly well with humectants — glycerin, hyaluronic acid, urea — which pull water in while petrolatum stops it leaving. Over a prescription steroid or a topical antifungal it is fine, and it increases how much is absorbed, which is useful on thick skin but is worth mentioning to your doctor if you are using it on the face or in skin folds. It is the standard partner to hydrocortisone on eyelids and the standard aftercare for almost any procedure.

What not to mix

Do not apply it before a retinoid, benzoyl peroxide, acid or vitamin C — it blocks them. Put the active on first and let it absorb. Do not seal it under a dressing over infected skin, since a warm sealed environment suits bacteria. Do not use it with latex condoms or diaphragms, because oil-based products degrade latex. And do not use petroleum jelly as an internal lubricant, as it has been associated with bacterial vaginosis.

Side Effects

Petrolatum has one of the cleanest safety records of any topical ingredient. It is what dermatologists use as the negative control in patch testing, precisely because it so rarely reacts.

Common and expected
  • Greasiness, shine, and transfer onto clothes, sheets and phone screens. Clogged pores and small bumps in acne-prone people who apply it over oily areas of the face. Folliculitis — small itchy bumps around hairs — when it is applied thickly over hairy skin, particularly the chest and back. Blurred vision for a few minutes if it gets into the eye, which is uncomfortable and harmless.
Tell your doctor
  • An itchy rash where you applied it. True allergy to pure petrolatum is very rare, and when someone reacts to an ointment it is usually the lanolin, fragrance or preservative in it rather than the petrolatum. Also mention it if a wound you have been dressing becomes red, swollen, painful or starts producing pus, which means infection rather than an ointment problem.
Stop and get care
  • Increasing pain, spreading redness or fever around a wound. Any breathing problem in someone who has been using oily products in the nose, or in a child who has swallowed a large amount.

Who Should Avoid It

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There is almost nobody, which is unusual for this site. The genuine gates:

A burn that is still hot, fresh and blistered — cool it first and leave ointment off until it has settled.

An infected or pus-producing wound, until the infection has been treated.

People using latex condoms or diaphragms should not use it as a lubricant.

Acne-prone skin should keep it off the oily parts of the face and use it only on dry patches. That is a nuisance rather than a risk.

Petrolatum is safe in pregnancy, safe while breastfeeding — wipe it off the nipple before a feed — and safe on newborns. It is the standard first-line emollient for infant eczema and for nappy rash.

How Long Until It Works

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Petrolatum is one of the few things in dermatology that works the same day.

Within an hour. Skin feels less tight and less sore. Cracks stop stinging, because the film keeps air and water off exposed nerve endings.

Two to three days. Splits on fingertips and heels begin to close if you are applying it nightly to damp skin under gloves or socks. Crusts and thick scale soften.

One to two weeks. Rough, scaly skin looks and feels normal again. Chronic hand dermatitis takes longer, and needs the irritant removed as well.

When you stop. The benefit stops with it. Petrolatum manages dryness rather than curing it, so if the underlying cause — winter air, repeated hand washing, eczema, a medication — is still there, the dryness returns within days. That is not a failure of the product. That is what an occlusive is.

FAQ+
Does petrolatum suffocate the skin?No. Skin gets its oxygen from blood, not from air, and it does not breathe. Petrolatum is also not fully airtight — it slows water loss by about 98%, not 100%, and water vapour and gases still move through it. The idea that skin needs to "breathe" is marketing language, not physiology.
Is petroleum jelly a carcinogen?Cosmetic and pharmaceutical grade petrolatum is not. The concern comes from crude, unrefined petroleum residues, which do contain polycyclic aromatic hydrocarbons and are classified as carcinogenic. Fully refined USP or BP grade petrolatum has those removed, and refining standards are regulated on both sides of the Atlantic. Every jar sold in a pharmacy in the US, UK or EU is the refined kind.
Does it moisturize?Not in the way people mean. It contains no water and adds none. It seals in the water already in your skin, which is why applying it to damp skin makes such a difference and why applying it to bone-dry skin does very little.
Will it clog my pores?It can on acne-prone facial skin, though it tests as non-comedogenic and is used routinely on the face after procedures. In practice: use it on the dry patches, not across an oily T-zone.
Is it better than an expensive moisturizer?For sealing water in, yes — nothing beats it, at any price. What it does not do is add humectants, ceramides or anything that improves the skin's own function, so a good moisturizer with petrolatum on top beats either one alone.
Can I use it on my face every night?If your skin is dry, yes. This is what people mean by "slugging," and it works, particularly over a moisturizer on a damaged barrier. If you use a retinoid, apply the retinoid first and let it absorb before the petrolatum — sealing a retinoid in increases absorption and can cause irritation.
Is it safe for babies?Yes. It is a standard treatment for nappy rash and for infant eczema, and there is nothing in it to sting or to cause allergy. One thing it does not do: large trials found that applying plain emollients to newborns does not prevent eczema developing, despite earlier hope that it would.
Is it environmentally bad because it comes from petroleum?It is a by-product of oil refining rather than a driver of it, and it is used in tiny quantities. Plant-based alternatives such as shea, coconut oil and plant waxes have their own land and processing footprints, and none of them seal as well.
Should I use Vaseline or Aquaphor?Vaseline is 100% petrolatum and seals better. Aquaphor is about 40% petrolatum with lanolin and spreads more easily. Use Aquaphor when you want something less heavy, and plain Vaseline on eyelids, on lips, and any time skin has already reacted to a product — lanolin is a possible allergen and petrolatum essentially is not.