Retinoids are the most evidence-backed topical ingredient in dermatology

Mechanism of action

Retinoids are derivatives of Vitamin A. They exert their effects by binding to nuclear receptors. Specifically, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which function as transcription factors, directly regulating gene expression in skin cells.

The downstream effects are broad: retinoids accelerate epidermal cell turnover (normalising the slower renewal of aged skin), stimulate fibroblast activity and collagen Type I production, inhibit MMP expression (reducing collagen degradation), and normalise melanocyte function (reducing hyperpigmentation). They also promote differentiation of keratinocytes, making them one of the most effective treatments for acne.

Prescription retinoids versus over-the-counter retinol

Active retinoic acid (tretinoin) binds directly to RARs. Retinol (the OTC form) requires two enzymatic conversion steps. First to retinaldehyde, then to retinoic acid before exerting its effect. Each conversion step introduces attrition: not all retinol is successfully converted, and the process is inefficient. Prescription-grade tretinoin is approximately 20× more potent than OTC retinol at equivalent concentrations, not because the molecule is different, but because it doesn’t require the conversion pathway.

How to use retinoids effectively

Initial dryness, peeling, and mild redness are expected with prescription retinoids and indicate the product is working. These are signs of accelerated cell turnover, the epidermis renewing faster than it is accustomed to. They typically resolve within 4 to 6 weeks as the skin adapts.

Start with the lowest available concentration, 2 to 3 nights per week, and increase frequency gradually. Apply to dry skin (wet skin increases penetration and irritation). A pea-sized amount for the whole face is sufficient. Follow with a fragrance-free moisturiser. Morning SPF is essential, because retinoids increase photosensitivity and their anti-ageing benefits are undermined by UV exposure.

Accelerated cell turnover in the early weeks can transiently worsen acne as follicular contents are expelled more rapidly. This typically resolves within 4 to 8 weeks and is a sign the product is working, not a reason to stop. Reducing frequency temporarily can manage the reaction without abandoning the treatment.

Using retinoids alongside clinical treatments

Retinoids should be paused for 3 to 5 days before and 5 to 7 days after microneedling, polynucleotide, or PRP treatments: their action on cell turnover and skin sensitivity increases the risk of excessive irritation in post-treatment skin. Full resumption can typically occur within a week.

Outside of treatment recovery windows, retinoids and clinical treatments are highly complementary, addressing skin quality at the topical and dermal levels simultaneously. Patients using consistent retinoids alongside periodic clinical treatments generally achieve better long-term outcomes than either approach alone.