Quick Comparison
| EGF (Epidermal Growth Factor) | Vitamin C (L-Ascorbic Acid) | |
|---|---|---|
| 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. | L-Ascorbic Acid: 10-20% at pH 2.5-3.5. Start with 10% if new to vitamin C. Apply in the morning under sunscreen for photoprotective synergy. The SkinCeuticals CE Ferulic formula (15% L-AA + 1% vitamin E + 0.5% ferulic acid) is the most studied and copied formulation. |
| Application | Topical (serum, cream, ampoule). Apply to clean skin. Temperature-sensitive — some products require refrigeration. | Topical (serum, usually water-based). Apply to clean, dry skin in the morning before sunscreen. Store in cool, dark place. Discard when it turns dark yellow or brown. |
| 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.
Vitamin C (L-Ascorbic Acid)
L-Ascorbic acid donates electrons to scavenge reactive oxygen species (superoxide, hydroxyl radical, singlet oxygen) and reactive nitrogen species from UV, pollution, and metabolism—preventing oxidative damage to lipids, proteins, and DNA. It inhibits tyrosinase (copper enzyme catalyzing tyrosine to L-DOPA to dopaquinone) through copper chelation and competitive inhibition. Ascorbate is an essential cofactor for prolyl and lysyl hydroxylase—enzymes that hydroxylate collagen residues for triple-helix formation and lysyl oxidase crosslinking. Vitamin C regenerates oxidized vitamin E, creating a sustained redox cycle. Ferulic acid stabilizes both vitamins; the CE Ferulic combination provides 4-8x greater photoprotection than vitamin C alone. Penetration requires pH 2.5-3.5.
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.
Vitamin C (L-Ascorbic Acid)
Common
Tingling/stinging on application (due to low pH), oxidation of product (turns yellow/brown — discard when this happens).
Serious
None.
Rare
Contact dermatitis, especially with oxidized product. May cause temporary orange staining of skin at high concentrations.
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.
Vitamin C (L-Ascorbic Acid) →
The most potent topical antioxidant with strong clinical evidence for brightening, anti-aging, and photoprotection. L-Ascorbic Acid is the pure, active form that directly neutralizes free radicals, inhibits melanin production, and stimulates collagen synthesis. The challenge is formulation — it is notoriously unstable and must be at low pH (2.5-3.5) for skin penetration, which can cause irritation.