“Strength is an area where caution and individualisation are important”, the expert stresses. “Strength is one of the most misunderstood aspects of retinoid use. What matters is not only the percentage printed on the label, but also the form of vitamin A being used and how many conversion steps it must take before becoming biologically active as retinoic acid.
“An additional consideration is the process of retinization (the period of adjustment when the skin first encounters retinoids and responds with dryness, peeling, redness or sensitivity as cell turnover accelerates and the barrier adapts). This phase can last several weeks and is often the point at which people give up, mistaking it for an allergic reaction rather than a predictable biological response. The choice of strength therefore has to balance efficacy with tolerability – if it’s too weak, and results will be slow; too strong, and the irritation of retinization can make it impossible to continue. The goal is always to find a formulation and concentration that can be used consistently”.
He details the following as a rough guide:
“Retinyl esters (e.g. retinyl palmitate, which is often used in introductory products) need three conversions and are therefore the weakest and most gentle. Retinol, the most common form in over-the-counter (OTC) products, requires two conversions before becoming active, as mentioned above, making it moderately effective but still well tolerated by most skin types. Retinaldehyde sits just one step away from retinoic acid, meaning it is significantly stronger than retinol at the same percentage, though also more likely to cause irritation if introduced too quickly. At the far end of the spectrum is tretinoin (retinoic acid itself), available only on prescription in the UK, which acts immediately without conversion and is correspondingly powerful, but also prone to side effects if the skin is not acclimatised.
“Because of this hierarchy, percentages are not directly comparable across the different forms. A cream containing 0.1% retinaldehyde, for example, is far stronger in practice than a 0.1% retinol formulation. For beginners, I usually recommend starting with a low-strength retinol, often between 0.1% and 0.3%, used only a few nights a week at first. As the skin develops tolerance, this can be increased to 0.5% or even 1% if required. Those with acne or more significant photo-damage may benefit from retinaldehyde or prescription retinoic acid, but these are best introduced with medical guidance. Ultimately, the best strength is the one you can use consistently over months and years, because the cumulative effect of steady use is far more valuable than chasing high concentrations that your skin cannot comfortably tolerate.
“This being said, newer molecules like Granactive Retinoid (hydroxypinacolone retinoate, HPR) offer something unique to avoid the retinization effects. Found in my Good Night cream at 0.2%, it binds directly to the skin’s retinoid receptors without needing conversion, so in effect it delivers the potency of a retinaldehyde-level system but with dramatically less irritation. What makes my Good Night cream unusual is that the retinoid isn’t working in isolation as it’s combined with niacinamide, an azelaic acid derivative, PHAs, peptides and humectants to further reduce the retinization effects. Together, these actives buffer the potential for irritation, reduce redness, reinforce the barrier and even aid penetration, meaning the skin can tolerate a strength of retinoid that would normally be considered ‘advanced’ from the outset. This allows people to access the benefits of a high-performing retinoid (improved tone, reduced pigmentation, refined pores and collagen stimulation) without going through the uncomfortable phase of peeling, redness and sensitivity. The end result is that you can start strong and stay consistent, which is the single most important factor in achieving results with retinoids”.
