Quick Comparison

NiacinamidePetrolatum (Vaseline)
Typical ConcentrationConcentrations: 2-10%. 5% is the most studied concentration and provides the best balance of efficacy and tolerability. Higher concentrations (10%) are available but may cause irritation in sensitive skin without proportional benefit. Apply morning and/or night.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.
ApplicationTopical (serum, moisturizer, toner). Water-soluble. Stable in formulation. Compatible with most actives.Topical (ointment, lip balm). Apply as final step to seal in moisture. Thin layer is sufficient.
Research Papers10 papers10 papers
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Mechanism of Action

Niacinamide

Niacinamide is converted to NAD+ via the Preiss-Handler pathway—essential for cellular respiration, DNA repair (PARP), and sirtuin regulation. In keratinocytes, it upregulates serine palmitoyltransferase and fatty acid elongases, increasing ceramide synthesis and strengthening the barrier. It inhibits melanosome transfer by downregulating protease-activated receptor-2 (PAR-2) on keratinocytes—brightening without tyrosinase inhibition. In sebocytes, it normalizes lipid synthesis and reduces sebum (possibly via AMPK). Niacinamide inhibits NF-kB translocation, suppressing IL-1beta, TNF-alpha, and IL-8. It inhibits phosphodiesterase, increasing cAMP and modulating keratinocyte differentiation. These multi-pathway effects explain broad efficacy across barrier repair, brightening, acne, and anti-aging.

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.

Risks & Safety

Niacinamide

Common

Very well-tolerated at 2-5%. Flushing/redness at concentrations above 5% in some individuals.

Serious

None documented.

Rare

Contact dermatitis (uncommon). Old advice to avoid combining with vitamin C is largely debunked at product pH levels.

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.

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