Petroleum jelly is widely used for treating minor scrapes and protecting chapped lips. Its effectiveness in creating a barrier on the skin is recognized in both home remedies and clinical settings. Despite decades of use and endorsement by dermatologists, its origin as a byproduct of petroleum refining often sparks public concern regarding its safety. Determining if this common substance is harmful requires an objective look at its composition, its function on the skin, and the specific circumstances where its use may pose a risk.
Composition and Purity Standards
Petroleum jelly, also known as petrolatum, is a semi-solid mixture of hydrocarbons derived from crude oil. The raw material is a byproduct of the oil refining process, a fact that contributes to the widespread safety concerns. However, the commercial-grade product undergoes a rigorous process of distillation, extraction, and purification to remove impurities.
The primary safety concern involves polycyclic aromatic hydrocarbons (PAHs), which are carcinogens naturally found in crude oil. To ensure safety, cosmetic and pharmaceutical grades must meet strict purity standards, such as those set by the United States Pharmacopeia (USP). This refinement process removes PAHs to a level that makes the final product chemically inert and non-toxic for topical application. High-grade, fully refined “white petrolatum” is the standard used in personal care.
Primary Function: The Occlusive Barrier
The mechanism by which petroleum jelly works is called occlusion, which involves creating a physical, water-tight barrier on the skin’s surface. This barrier is highly effective due to the product’s hydrophobic nature, meaning it repels water. Petroleum jelly does not directly add moisture; instead, it prevents the evaporation of existing moisture, a process known as transepidermal water loss (TEWL).
It is considered one of the most effective occlusive agents available, capable of reducing water loss by up to 98%. By sealing in moisture, the product helps to hydrate the outermost layer of the skin, promoting faster healing and strengthening the skin barrier function. This property makes it highly beneficial for healing minor scrapes, protecting raw or chapped skin, preventing diaper rash, and aiding in post-procedure care.
Specific Concerns and Situations to Avoid
While purified petroleum jelly is generally safe, its occlusive nature necessitates caution in certain scenarios.
Skin Impurities and Acne Risk
The product is scientifically classified as non-comedogenic, meaning it does not clog pores from within. However, its heavy barrier can trap surface impurities like dirt, dead skin cells, or sebum if the skin is not thoroughly cleansed before application. For individuals with very oily or acne-prone skin, this trapping of debris can lead to breakouts, which is why a patch test or minimal use may be recommended on the face.
Respiratory Risks
Exogenous lipoid pneumonia is a rare risk, occurring when lipid-based substances are aspirated into the lungs. Petroleum jelly can cause this condition if applied heavily around or inside the nostrils, especially in infants, or if used chronically as a nasal moisturizer and accidentally inhaled. The oily particles accumulate in the air sacs of the lungs and cause inflammation.
Wound Care Limitations
The occlusive effect is a disadvantage in specific wound care situations. Petroleum jelly should not be used on deep puncture wounds, animal bites, or wounds that show signs of infection, as the barrier can seal in bacteria and impede drainage or healing. Applying the substance to a severe, fresh burn should be avoided because its heat-trapping property can hold residual warmth in the tissue, potentially worsening the injury. It is only appropriate for minor, superficial burns after the initial cooling period, once the wound is clean and starting to heal.