Tretinoin

Tolerability and safety

Working concentrations

0.025–0.1% (prescription drug)

Irritation potential

High

Allergen risk

Low

Pregnancy

Avoid

Suitable for

Normal, Combination, Oily

Use with caution

Sensitive, Dry

For sensitive skin

Retinoid dermatitis (peeling, redness, burning) is a normal adaptation response. Short-contact method (apply for 30 min, then rinse) helps reduce irritation.

How to introduce

Start at 0.025% every other day, gradually transitioning to daily use. Adaptation takes 6–12 weeks.

About this ingredient

Tretinoin (all-trans retinoic acid) is the most active topical form of vitamin A. Spanish pharmacies dispense it on prescription (Retirides, Vitanol-A; in the US – Retin-A, Tretinoin Crema). The gold-standard topical treatment for acne and photoageing since 1971, when the FDA approved Retin-A. Mechanism. Binds nuclear receptors RAR-α, β, γ. Speeds keratinocyte differentiation, normalises follicular keratinisation (resolves comedones), suppresses sebaceous gland output, stimulates fibroblasts to produce type I and III collagen, suppresses MMP-1 collagenase. Effects on wrinkles and pigmentation are documented after 6-12 months of use. Where applied. Creams and gels 0.025-0.1% for acne (Retirides, Tretinoin Crema), photoageing, melasma, post-acne scars. In Spain it is prescription-only (dermatologist or family physician). Ready-made regimens often combine it with hydroquinone and hydrocortisone (the Kligman trio for melasma). Evidence base. Meta-analyses (Riahi 2016, Mukherjee 2006) confirm a 40-70% reduction in inflammatory and non-inflammatory acne lesions over 12 weeks and improvement of photoageing (fine wrinkles, texture, pigmentation) over 24-48 weeks. Effects are maintained with 1-2 applications per week. Side effects and retinoid dermatitis. Burning, peeling, erythema and dryness occur in 60-80% of patients in the first 2-4 weeks. Solutions: sandwich method (moisturiser + retinoid + moisturiser), start at 0.025% every other day, ramp up slowly. SPF 50 is mandatory because of photosensitisation. Safety. Topical systemic absorption is minimal (<2%), but it is contraindicated in pregnancy and lactation due to pharmacokinetic kinship with systemic retinoids (isotretinoin, acitretin), which are teratogenic. FDA pregnancy category C; AEMPS and EMA recommend stopping at least 1 month before conception and avoiding it throughout pregnancy and lactation. Alternatives in pregnancy: azelaic acid, niacinamide, glycolic acid. Suited for. Inflammatory and comedonal acne, photoageing (fine lines, pigmentation, dullness), melasma, post-acne scars. Not for rosacea or perioral dermatitis (worsens inflammation).

Frequently asked questions