Yes, another wonder ingredient in the grooming game. It is only sensible that one greets an elixir of youth with a smidge of skepticism. After all, the hyperbole that propels the skincare industry is rarely matched by irrefutable science. Far too often, minor improvements morph into miracles when recounted through the megaphones of marketing departments.

Alas, only a handful of ingredients have ever lived up to the hype. The latest one you need to know about is retinol, a derivative of vitamin A that has become the gold standard in anti-ageing. You may know it by other names, including Retin-A, tretinoin (the prescription version), retinyl palmitate (the weakest version) or by the catch-all term “retinoids”.  A jack-of-all-trades – and, unusually, a master of them all, too – retinol possesses the ability to correct, smooth and regenerate skin. It can dramatically reduce fine lines, clear acne and diminish the appearance of sun damage and pigmentation. As an added bonus, it’s an antioxidant. It’s also supported by research showing that it can jumpstart the production of collagen.

“Done right, retinol is a very, very powerful tool and applicable to everyone,” says dermatologist Dr Dennis Gross. “Anyone who is serious about anti-ageing, whether it be preventative or restorative, should have retinol in their anti-ageing routine.”

There is, of course, a catch. The complexity and strength of retinol tends to mystify consumers who, in turn misuse the ingredient. Even at low concentrations, over-the-counter retinol is far from user-friendly and can cause temporary bouts of peeling, dryness, irritation, redness and sensitivity. Some experts believe that this is simply the price of admission for (what will eventually become) ageless skin. According to Dr Gross, it doesn’t have to be that way. We unpack the nuts and bolts of retinol so that you can harness its power without looking like a Sith Lord.

At some point in your late twenties, communication between skin cells takes a nosedive and the production of new cells begins to slow down. This, dear reader, is the root of all cosmetic ageing.

Retinol is the intransigent interventionist that pushes its way into the conversation and forces errant skin cells to start behaving in a more functional manner. With improved communication comes new cells, which, in turn, create younger, clearer skin. This is the “Benjamin Button” effect that makes retinol so popular. You don’t have to wait for signs of ageing to become apparent before you start using retinol. But, given that things tend to go awry in the run up to 30, we’d recommend using a low concentration sooner rather than later.

Only a fool would walk into a gym on his first day and start bench-pressing double his bodyweight. As any PT worth their salt will tell you, beginners require a period of consistent training before they start piling on the 45lb plates. The same logic applies here.

Over-the-counter retinol comes in different concentrations – anywhere from 0.1 per cent to one per cent – and starting out with the highest percentage you can find is not going to end well.

“If retinol is too strong, or it’s not buffered with an ingredient such as ferulic acid, it will irritate the skin and make the whole routine counterproductive,” says Dr Gross. “Yes, your skin will heal, but once it has become inflamed, it will create free radicals. And free radicals are the enemies of anti-ageing,” he warns.

Dr Gross discards the idea of shopping for retinol by concentration altogether. “People seem to think that if they buy a strong retinol product, they’ll get more value for money and better results,” he says. “This is simply not true. The optimal concentration is not necessarily the highest concentration. You only need enough retinol to coat the cell receptors.”

His sentiment is mirrored by the research. Studies demonstrate that you’ll get the same results from using a lower strength (0.01 per cent to 0.1 per cent) retinol as you would with a formula of moderate strength (0.04 per cent to 0.1 per cent). The only variable here is time and, given the possible side effects, it’s worth remembering that slow and steady will always win the race.

“If you are a first-time retinoid user, or know your skin is sensitive, an over-the-counter retinol is a good place to start,” says Dr Gross. The general advice is to start small and then increase frequency as the skin acclimatises. For example, begin with one application of a low concentration for one week, two applications for week two and three for week three.

At that point, check in with your skin and, if you don’t have any side effects, you can commit to it every other night. If you notice your skin has become sensitised, dial it back a notch and go back to the previous week’s dosage. The thinking here is that by going up in gradations you will mitigate any side effects and build tolerance over months, even years.

As per the doctor’s advice, the percentage is not the goal. If you’re doing well and seeing results from a low to moderate strength over-the-counter product then stay there instead of automatically “upgrading” to a prescription-strength formula.

We’ve always advocated the use of active products overnight as this is when skin metabolism is at its highest and your cells aren’t preoccupied with defending themselves from UV rays and pollution. And while retinol can be used during the day, it’s worth noting that the ingredient is photosensitive. This means it reacts with sunlight and loses its potency, all the while making your skin more prone to irritation. If you must use retinol during the day, always be sure to apply a strong, broad-spectrum sunblock afterwards.