Antiviral reader Patrick wrote in to us because of the “constant claims” he sees on social media “that retinol (vitamin A) and related compounds help to keep skin youthful”.

To examine whether retinol really is the “road to ultimate youthful skin”, as one TikTok video claims, we turned to Dr Natalia Spierings, a consultant dermatologist and skin cancer surgeon in London with a reputation for her evidence-based, no-nonsense approach to skincare.

She conducted a systematic review – a type of study which involves analysing the quality of evidence and conclusions from the existing research to provide a comprehensive overview of the evidence – into the efficacy of over-the-counter vitamin A products.

It’s important to distinguish between the terms used in product claims. Vitamin A is a nutrient essential for cell division, immune function and vision.

The term “retinoid” is the umbrella term used for all of the chemical compounds that are natural or synthetic derivatives of vitamin A, says Dr Deshan Sebaratnam, a dermatologist and conjoint associate professor at the University of New South Wales.

“This group of compounds regulates cellular proliferation [growth and division] and collagen production,” he says.

Retinol and retinaldehyde are specific over-the-counter retinoids, Sebaratnam says, while retinoic acid (tretinoin) and synthetic retinoids (like trifarotene and adapalene) require prescriptions from a doctor in........

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