Quick Comparison
| Adapalene | Centella Asiatica | |
|---|---|---|
| Typical Concentration | OTC: 0.1% gel, apply pea-sized amount once nightly to clean, dry skin. Prescription: 0.3% gel for more resistant acne. Can be applied to slightly damp skin with less irritation than tretinoin. Results visible at 8-12 weeks. | Used in various forms: full extract, TECA (Titrated Extract of Centella Asiatica — a standardized blend of the four key actives), or individual compounds. Concentrations vary widely (0.1-5% of active compounds). Apply morning and/or night. Safe for daily use on all skin types. |
| Application | Topical (gel, cream, lotion). More stable than tretinoin — can tolerate some benzoyl peroxide layering (Epiduo combines both). | Topical (serum, cream, toner, mask). TECA or pure centella extract preferred over whole plant extract for consistency. |
| Research Papers | 8 papers | 10 papers |
| Categories |
Mechanism of Action
Adapalene
Adapalene selectively binds RAR-beta and RAR-gamma (minimal RAR-alpha affinity), reducing inflammatory signaling compared to pan-RAR agonists. It normalizes follicular epithelial differentiation and reduces corneocyte cohesion in the pilosebaceous unit, preventing microcomedo formation. Adapalene inhibits AP-1 transcription factor (c-Fos/c-Jun dimerization), suppressing IL-6, TNF-alpha, and neutrophil chemotaxis. It promotes comedolysis by accelerating desquamation of existing comedones. For anti-aging, it stimulates fibroblast collagen I and III via RAR-beta/gamma, with comparable efficacy to tretinoin. Its lipophilic naphthoic acid structure confers superior follicular penetration and light stability.
Centella Asiatica
The four key triterpenoid saponins—madecassoside, asiaticoside, madecassic acid, and asiatic acid—exert distinct but complementary mechanisms. Madecassoside and asiaticoside are anti-inflammatory: they inhibit NF-κB nuclear translocation and IκB kinase activity, reducing TNF-α, IL-6, and IL-1β production in keratinocytes and dermal cells. Madecassic acid and asiatic acid (the aglycone forms) stimulate type I and III collagen synthesis in fibroblasts by upregulating collagen gene expression and procollagen production. All four compounds promote wound healing by stimulating angiogenesis via VEGF (vascular endothelial growth factor) upregulation, fibroblast proliferation and migration, and extracellular matrix remodeling. Centella extracts also increase superoxide dismutase (SOD) and catalase activity in skin cells, enhancing endogenous antioxidant defense. The triterpenes may modulate TGF-β and Smad signaling. TECA (Titrated Extract of Centella Asiatica) standardizes these actives for consistent clinical efficacy.
Risks & Safety
Adapalene
Common
Dryness, peeling, redness — generally less than tretinoin. Initial purging for 4-6 weeks.
Serious
Avoid in pregnancy (retinoid class).
Rare
Allergic contact dermatitis, severe peeling.
Centella Asiatica
Common
Very well-tolerated. Occasionally mild tingling.
Serious
None documented.
Rare
Allergic contact dermatitis (uncommon). Purified extracts are less likely to cause reactions than crude extracts.
Full Profiles
Adapalene →
A third-generation synthetic retinoid originally developed for acne that has significant anti-aging benefits. Adapalene is more stable than tretinoin (resistant to light and oxygen degradation) and better tolerated because it selectively binds to RAR-beta and RAR-gamma receptors rather than all three subtypes. The 0.1% concentration became available OTC in 2016 (Differin), making it the most accessible prescription-strength retinoid.
Centella Asiatica →
Also known as Cica, Gotu Kola, or Tiger Grass, Centella Asiatica is an herb used in traditional medicine for wound healing that has become one of the most popular soothing ingredients in Korean and global skincare. Its active compounds (madecassoside, asiaticoside, madecassic acid, asiatic acid) reduce inflammation, stimulate collagen production, and accelerate wound healing. Essential for sensitive and compromised skin.