The Science Behind Vitamin A Derivatives in Skincare

Last updated: 9 August 2026

Vitamin A derivatives, collectively known as retinoids, are arguably the most extensively researched and evidence-supported class of active ingredients in dermatology. From prescription tretinoin to over-the-counter retinol, these compounds have demonstrated remarkable effects on skin ageing, acne, pigmentation, and overall skin quality. Practitioners consider retinoid therapy a cornerstone of any evidence-based skincare programme and guide patients through the often-confusing landscape of vitamin A options.

Understanding the retinoid family

All retinoids ultimately work by binding to retinoic acid receptors (RARs) and retinoid X receptors (RXRs) in skin cells, modifying gene expression to influence cell behaviour. However, different forms of vitamin A must undergo varying degrees of conversion before they can activate these receptors, which directly affects their potency and irritation potential:

• Tretinoin (retinoic acid)the active form that binds directly to receptors; prescription-only in the UK. The gold standard for anti-ageing with the most extensive clinical evidence.
• Adapalenea synthetic retinoid that binds selectively to specific receptor subtypes; prescription-only but better tolerated than tretinoin. Originally developed for acne.
• Tazarotenethe most potent topical retinoid; prescription-only, used for resistant acne and psoriasis.
• Retinolthe most common over-the-counter form; requires two-step conversion in the skin (retinol to retinaldehyde to retinoic acid), making it 10-20 times less potent than tretinoin.
• Retinaldehyde (retinal)requires only one conversion step; more potent than retinol but gentler than tretinoin. Gaining popularity as the “Goldilocks” retinoid.
• Retinyl palmitate and retinyl acetatethe weakest forms, requiring three conversion steps; found in many cosmetic products but with limited clinical evidence for anti-ageing efficacy.
• Hydroxypinacolone retinoate (HPR/granactive retinoid)a newer ester that binds directly to retinoid receptors without conversion. This offers retinoic acid-like effects with reduced irritation.

How retinoids transform skin

The effects of retinoids on skin are comprehensive and well-documented in the dermatological literature. A seminal review in the Journal of the American Academy of Dermatology catalogued their multiple mechanisms of action:

• Collagen stimulationretinoids increase procollagen gene expression, directly stimulating the production of types I and III collagen
• Collagen protectionthey inhibit matrix metalloproteinases (MMPs) that break down existing collagen
• Epidermal renewalaccelerated cell turnover replaces damaged surface cells with healthier ones
• Pigmentation regulationretinoids inhibit tyrosinase activity and accelerate melanin dispersal, improving hyperpigmentation
• Pore size reductionnormalisation of keratinisation prevents pore blockage and reduces apparent pore size
• Acne treatmentretinoids are comedolytic (prevent blocked pores), anti-inflammatory, and reduce sebum production
• Angiogenesisimproved dermal blood supply contributes to a healthier complexion
• GAG synthesisincreased production of glycosaminoglycans (including hyaluronic acid) improves skin hydration

The clinical evidence

The evidence base for retinoid therapy is exceptionally strong. Key findings include:

• A 2019 systematic review in British Journal of Dermatology confirmed that tretinoin produces statistically significant improvements in fine wrinkles, rough texture, and hyperpigmentation after 12-24 weeks of use
• Long-term studies spanning up to four years demonstrate that tretinoin continues to improve skin structure without loss of efficacy or tachyphylaxis
• Histological studies show measurable increases in epidermal thickness, dermal collagen density, and new blood vessel formation after retinoid therapy

Starting retinoid therapy

The retinisation period, the initial adjustment phase when the skin adapts to retinoid use, is the primary reason many patients abandon retinoid therapy prematurely. Symptoms including dryness, peeling, redness, and increased sensitivity typically last two to six weeks. A careful approach to minimising retinisation includes:

1. Start lowbegin with a low concentration (retinol 0.25-0.5% or retinaldehyde 0.025%)
2. Go slowapply every third night for the first two weeks, then every other night, then nightly as tolerated
3. Buffer if neededapply moisturiser before the retinoid (“sandwiching” technique) to reduce irritation
4. Pea-sized amounta small quantity is sufficient for the entire face
5. Avoid sensitive areas initiallyapply around the eyes, mouth corners, and nostrils only once tolerance is established
6. Support with barrier careuse ceramide-rich moisturisers, gentle cleansers, and niacinamide to support barrier function during the adjustment period
7. Absolute daily SPFretinoids increase photosensitivity; SPF 30+ is mandatory

Retinoids and aesthetic treatments

We consider retinoid therapy complementary to professional treatments. However, timing is important:

• Before treatmentsretinoid use may need to be paused 3-7 days before chemical peels, laser, or microneedling to avoid excessive sensitivity
• After treatmentsresume retinoid use only when the skin has fully recovered, typically 5-14 days post-procedure depending on the treatment intensity
• Long-term combined effectconsistent retinoid use between treatment courses enhances and prolongs professional treatment results

Choosing the right retinoid

Our general recommendations based on skin type and goals:

• Sensitive or retinoid-naive skinstart with retinaldehyde 0.025% or retinol 0.25%
• Normal skin, anti-ageing focusretinol 0.5-1% or retinaldehyde 0.05-0.1%
• Resilient skin, advanced anti-ageingprescription tretinoin 0.025-0.05%
• Acne-prone skinadapalene 0.1-0.3% (prescription) or retinol combined with salicylic acid
• Very sensitive or rosacea-prone skinHPR (hydroxypinacolone retinoate) or encapsulated retinol

Frequently asked questions

At what age should I start using retinoids?
For anti-ageing purposes, the mid-to-late twenties is an excellent time to begin, as collagen production starts declining around age 25. For acne management, retinoids can be used from the teenage years under medical guidance. There is no upper age limit, retinoids produce measurable benefits at any age.

Can I use retinoids during pregnancy?
No. Oral retinoids are a known teratogen, and whilst the risk from topical retinoids is theoretical, all retinoid use is contraindicated during pregnancy and breastfeeding as a precautionary measure. Safe alternatives include azelaic acid, niacinamide, and vitamin C.

Why does my skin look worse when I first start retinoids?
The initial “purging” phase occurs because retinoids accelerate cell turnover, bringing existing microcomedones (tiny blocked pores) to the surface faster than normal. This temporary worsening typically resolves within four to six weeks and is followed by clearer, smoother skin.

Can I use retinoids with other active ingredients?
Retinoids combine well with niacinamide, hyaluronic acid, and peptides. They should be used cautiously alongside AHAs, BHAs, and vitamin C, as combining multiple actives can increase irritation. Your practitioner can design a schedule that incorporates all beneficial actives without overwhelming the skin.