Quick Comparison
| Petrolatum (Vaseline) | Urea | |
|---|---|---|
| Typical Concentration | Apply thin layer over damp skin or over other skincare products. Can be used as 'slugging' (applying all over face at night). Safe for daily use. Especially effective over retinoids to buffer irritation. | Moisturizing: 2-10%. Mild exfoliation: 10-20%. Strong keratolytic: 20-40%. For face: stay at 5-10%. For body rough patches: 10-20%. For calluses/severely rough skin: 40%. Apply to damp skin and seal with cream. |
| Application | Topical (ointment, lip balm). Apply as final step to seal in moisture. Thin layer is sufficient. | Topical (cream, lotion, gel). Apply to damp skin. Eucerin and CeraVe have well-known urea-containing lines. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
Petrolatum (Vaseline)
Petrolatum is a mixture of long-chain saturated hydrocarbons (C16-C32) that forms a semi-occlusive film—reducing transepidermal water loss (TEWL) by up to 99%. It penetrates intercellular spaces of the stratum corneum, filling gaps in the lipid lamellae and creating a hydrophobic barrier. This occlusive environment raises stratum corneum water content, activating endogenous repair: upregulation of antimicrobial peptides (defensins, cathelicidin LL-37), lamellar body secretion, and barrier lipid synthesis. The stratum corneum obtains oxygen from dermal circulation, not the atmosphere. Studies demonstrate accelerated wound healing and barrier recovery, contradicting infection myths.
Urea
At low concentrations (<10%), urea acts as a humectant — small molecule (60 Da) absorbing into stratum corneum, drawing water via hydrogen bonding to carbonyl and amine groups. Part of endogenous NMF (filaggrin degradation products with amino acids, lactate), highly biocompatible. Integrates into corneocyte envelope, supports aquaporin-3 water transport. At higher concentrations (>10%), denatures keratin (K1, K10) by disrupting hydrogen bonds in alpha-helical structure and disulfide bridges in cornified envelope, causing corneodesmosome degradation and desquamation. Keratolytic via direct protein denaturation, not enzymatic. Dual mechanism — humectant at low dose, keratolytic at high — versatile for hydration and hyperkeratotic conditions (psoriasis, keratosis pilaris).
Risks & Safety
Petrolatum (Vaseline)
Common
Greasy feel. May trap bacteria if applied over unwashed skin (cleanse first).
Serious
None when using cosmetic-grade/USP petrolatum.
Rare
Allergic reaction is extremely rare. Concerns about contamination (PAHs) apply only to industrial-grade, not cosmetic-grade petrolatum.
Urea
Common
Stinging on broken or irritated skin (more likely at higher concentrations).
Serious
None.
Rare
Contact dermatitis (uncommon).
Full Profiles
Petrolatum (Vaseline) →
The most effective occlusive ingredient available — petrolatum reduces transepidermal water loss (TEWL) by 99%. Despite misconceptions, it does not clog pores and does not prevent skin from 'breathing.' Dermatologists recommend it universally for barrier repair, wound healing, and locking in moisture. It is the standard against which all other moisturizing ingredients are measured.
Urea →
A natural component of the skin's Natural Moisturizing Factor (NMF) that serves as both a humectant and a keratolytic depending on concentration. At low concentrations (2-10%), urea hydrates by drawing water into the stratum corneum. At higher concentrations (20-40%), it breaks down keratin protein, making it a powerful treatment for rough, thickened, or keratotic skin conditions like keratosis pilaris, calluses, and psoriasis.