What Retinoids Are
Retinoids are derivatives of Vitamin A. They bind to retinoic acid receptors in skin cells, triggering processes including accelerated cell turnover, collagen stimulation, normalised skin cell cycling, and reduced sebum production in acne-prone skin.
The retinoid family from lowest to highest potency: retinyl esters, retinol, retinaldehyde, adapalene, tretinoin. Over-the-counter products contain retinol or retinyl esters; prescriptions contain tretinoin or adapalene (adapalene 0.1% is OTC in the US).
The Evidence Base
Retinoids are the most evidence-backed anti-ageing ingredient class available. Multiple controlled trials demonstrate that tretinoin reduces fine lines, improves skin texture, and increases epidermal thickness with consistent use over 3 to 12 months. A 2007 study in the Archives of Dermatology found that topical retinol significantly improved fine wrinkles in elderly subjects after 24 weeks. Retinoids are also first-line treatment for acne in dermatology guidelines.
Retinol vs Retinoids: Which Strength?
For first-time users, start with low-concentration OTC retinol (0.025 to 0.05%). Prescription tretinoin is significantly more potent. Adapalene 0.1% (US OTC as Differin) is a strong option for acne-prone skin with better tolerability than tretinoin.
General progression: start with 0.025% retinol, increase to 0.05%, then 0.1%, then consider prescription strength if needed. Each step should be stable for 8 to 12 weeks before advancing.
How to Start Safely
The correct introduction approach: start once per week for 2 to 4 weeks, then twice weekly, then every other night. Apply to dry skin (damp skin increases absorption and irritation). For sensitive skin, apply moisturiser before retinol (sandwich method). Apply at night only. Use SPF every morning without exception. See our SPF guide.
Managing Side Effects
Initial redness, flaking, tightness, and increased breakouts (purging) are expected and represent adaptation, not allergy. Reduce frequency if irritation is significant. Increase barrier support with a richer moisturiser. Avoid other actives on the same nights. Purging resolves within 4 to 6 weeks as cell turnover clears congested pores.
Who Should Avoid Retinoids
Retinoids are contraindicated during pregnancy and not recommended during breastfeeding. Anyone pregnant, planning to conceive, or breastfeeding should consult a GP or dermatologist before use. Those with rosacea, severely compromised skin barriers, or active eczema should approach retinoids with caution and ideally dermatologist guidance. See our eczema guide.
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