The Science of Sensitive Skin

Skin sensitivity is caused by a compromised stratum corneum allowing external irritants, allergens, and environmental stimuli to penetrate to the nerve-rich viable epidermis. The TRPV1 receptor (transient receptor potential vanilloid 1) on cutaneous sensory neurons mediates the stinging and burning sensation characteristic of sensitive skin. A healthy, intact lipid barrier prevents this penetration. The primary causes of acquired skin sensitivity are over-exfoliation, harsh cleansers, overuse of actives (retinoids, acids), UV damage, and stress-driven cortisol-mediated barrier impairment. True constitutional sensitive skin (as in rosacea or eczema) requires dermatologist management alongside topical protocol optimisation. (Misery L et al. PMID: 31199516)

The Sensitive Skin Active Hierarchy

Tier 1 — Always safe (start here): Centella asiatica (madecassoside, asiaticoside — anti-inflammatory, barrier repair), niacinamide 4% (lower than standard 10% — barrier support without potential flushing at high dose), ceramides, glycerin, squalane, hyaluronic acid, panthenol (vitamin B5 — wound healing and barrier support), allantoin.
Tier 2 — Introduce carefully one at a time: Azelaic acid 10% (anti-inflammatory, well-tolerated even in rosacea), niacinamide 10% (once tolerance confirmed), retinol 0.025% (lowest available concentration, every 3rd night initially), vitamin C (L-AA only if pH-tolerant; consider ascorbyl glucoside as gentler derivative).
Tier 3 — Approach with caution: AHAs and BHAs (start at lowest concentration, 1x/week maximum), high-strength retinoids, fragrance-containing products.

Ingredients to Avoid with Sensitive Skin

Fragrance (parfum): The single most common contact sensitiser in skincare. Includes essential oils — lavender, rose, citrus, eucalyptus are all common triggers despite natural origin.
Alcohol denat / SD alcohol: Disrupts barrier lipids and triggers TRPV1-mediated stinging in sensitised skin.
High-concentration physical exfoliants: Walnut shells, sugar scrubs — cause microtears and barrier disruption.
Sulfate cleansers (SLS, SLES): Strip SC lipid bilayer and significantly increase TEWL.
Menthol and camphor: TRPV1 and TRPM8 agonists — trigger nerve-mediated burning in sensitised skin despite the cooling sensation.
High-strength vitamin C (L-AA at low pH): The low pH required for L-ascorbic acid stability triggers stinging in compromised skin.

The SS Sensitive Skin Protocol

Phase 1 — Barrier Repair (weeks 1-4, no actives):
AM: Micellar water or cream cleanser — Hyaluron 3D Hydrator on damp skin — Ceramide moisturiser — Mineral SPF 50+
PM: Cream cleanser — Hyaluron 3D Hydrator — Ceramide moisturiser — Squalane seal
Zero actives, zero exfoliation, zero fragrance.

Phase 2 — Active Introduction (weeks 4-12, one at a time):
Week 5-6: Add Black Rice Niacinamide Concentrate AM only. Monitor 7 days before adding anything else.
Week 7-8: Add centella asiatica or azelaic acid 10% PM. Monitor.
Week 9-12: If tolerating well, introduce retinol 0.025% every 3rd night PM, sandwiched between HA serum and ceramide moisturiser.
Never introduce more than one new active per 2-week period.

Ongoing: Patch test every new product on the inner arm for 7 days before face application. Keep the routine minimal — fewer products means fewer potential triggers.

Results Timeline

Week 1-2: Stinging and reactivity reduce with barrier repair and active elimination.
Week 3-4: Skin feels more comfortable and less reactive to temperature and product application.
Month 2-3: Barrier function measurably restored, active tolerance improving.
Month 3+: Full active routine tolerated with continued maintenance.

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