Quick Comparison
| EGF (Epidermal Growth Factor) | Retinaldehyde | |
|---|---|---|
| Typical Concentration | Concentrations vary by product (typically measured in ppm or sh-oligopeptide-1 percentage). Applied once or twice daily. Best used after procedures or on aging skin. Apply before oils/occlusives. Store in refrigerator for stability. | Concentrations: 0.025-0.1%. Start at 0.025% every other night. More effective than retinol at equivalent concentrations but less irritating than tretinoin. Products are less common and more expensive than retinol. |
| Application | Topical (serum, cream, ampoule). Apply to clean skin. Temperature-sensitive — some products require refrigeration. | Topical (serum, cream). Apply at night. Less stable than retinol — requires careful formulation. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
EGF (Epidermal Growth Factor)
EGF binds EGFR/ErbB1 on keratinocytes and fibroblasts, triggering dimerization and autophosphorylation. Activates MAPK/ERK (Ras-Raf-MEK-ERK) and PI3K/AKT pathways, promoting proliferation, migration (actin reorganization, focal adhesion turnover), and differentiation. Upregulates cyclin D1, inhibits p27. Stimulates fibroblast collagen types I/III and hyaluronic acid via HAS2. In wound healing, accelerates re-epithelialization via keratinocyte migration and reduces scarring via TGF-beta modulation. For anti-aging, promotes cellular renewal and extracellular matrix production. Theoretical cancer concern from EGFR's growth role — topical EGF has not been shown to penetrate to basal layer or systemic circulation significantly.
Retinaldehyde
Retinaldehyde is converted to retinoic acid by retinaldehyde dehydrogenase (RALDH) in a single enzymatic step within keratinocytes and fibroblasts. This makes it more potent than retinol (which requires alcohol dehydrogenase then RALDH) but less irritating than tretinoin (the active form). The single-step conversion produces a more controlled retinoic acid flux, reducing RAR-mediated irritation while still activating collagen synthesis, normalizing keratinocyte differentiation, and inhibiting matrix metalloproteinases. It uniquely has direct antimicrobial activity against Cutibacterium acnes through disruption of bacterial membrane integrity and interference with bacterial fatty acid metabolism — no other retinoid has this property. Clinically, this dual mechanism addresses both acne pathogenesis and photoaging.
Risks & Safety
EGF (Epidermal Growth Factor)
Common
Very well-tolerated.
Serious
Theoretical concern about promoting growth of pre-existing skin cancers (unproven but debated).
Rare
Mild irritation.
Retinaldehyde
Common
Dryness, peeling, mild redness — less than tretinoin but more than retinol.
Serious
Avoid in pregnancy (retinoid class).
Rare
Contact dermatitis.
Full Profiles
EGF (Epidermal Growth Factor) →
A signaling protein that stimulates cell growth, proliferation, and differentiation. In skincare, EGF promotes wound healing, skin renewal, and collagen production. Originally used in medical wound care and post-laser recovery, it has become popular in Korean skincare for anti-aging. It is one of the few growth factors with evidence for topical skincare efficacy.
Retinaldehyde →
The immediate precursor to retinoic acid, sitting between retinol and tretinoin in both potency and the conversion chain. Retinaldehyde requires only one enzymatic step to become active (vs two for retinol), making it significantly more effective than retinol while remaining available OTC. It also has direct antibacterial activity against C. acnes — unique among retinoids.