Some anti-ageing ingredients have more evidence than others that they actually work. Retinol is one. It's derived from vitamin A and can increase cell turnover and encourage the production of collagen, improving the appearance of sun damage, lines, acne, scars and dark spots, evening out skin tone and smoothing texture. Essentially, it's the closest thing to a skincare miracle you'll find.
The only disadvantage is that overuse can cause dryness and irritation, and some sensitive skins may not be able to tolerate it. You can use a retinol every day, if your skin can cope with it - vary your usage to see what works for you - and they're safe to be used in conjunction with an acid exfoliator.
And they're not only suitable for mature skin: we recommend catching early signs of ageing early and starting with regular retinol use in your late 20s or early 30s. It can also make skin more sensitive to sunlight, so best use at night and make sure to follow up with your usual SPF cream in the morning.
Indeed Labs Retinol Reface Skin Serum: £19.99, Boots
Indeed Labs' offering is fragrance-free and a thin cream in consistency, so it doesn't have the nourishing feel of many, but, as often with the brand, it gives results that match products five times the price.
A great place to start if you're new to retinols and want a fair price - good results entry product.
Beauty Pie Super Retinol Ceramide-Boost Anti-Aging Face Serum: £80, Beauty Pie
Beauty Pie's Super Retinol serum is very well reviewed, and a look at the ingredients list quickly tells us why: as well as the titular retinol, it features moisture-magnet hyaluronic acid, exfoliating lactic acid and ceramides to support the skin barrier and improve elasticity.
No wonder our tester saw a change in the appearance of lines, plus skin brightness, smoothness and plumpness within a week.
Kate Somerville +Retinol Firming Eye Cream: £72, Kate Somerville
Cult US skincare brand Kate Somerville finally launched in the UK this year and we were so very glad. The retinol offering is slightly different as it's specifically an eye cream, which leaves the under-eye area soft and smooth, and dramatically reduced make-up visibly settling into our tester's fine lines.
We're not entirely convinced the old metal under-eye applicator thing isn't just a gimmick, but it feels good regardless.
The Ordinary Advanced Retinoid 2%: £8, Cult Beauty
The Ordinary is sweeping the press at the moment because of its focus on clinically proven ingredients with minimal fuss and therefore extraordinarily low prices.
This approach means that the brand's thin, milky retinol doesn't feel luxurious or nourishing to the skin, however, it does deliver line-reducing, smoothing results for less than a tenner.
LixirSkin Night Switch Retinol 1%: £28, LixirSkin
We're total suckers for LixirSkin's eminently Instagrammable millennial pink minimalist range.
The Retinol Night Switch is designed to be added to the brand's Universal Emulsion, but really can be mixed with any moisturiser to give it a retinol boost for smoother skin and better moisture retention after one use.
La Roche-Posay Redermic Anti-Ageing Concentrate Intense: £29.50, Escentual
Compared to a lot of retinol products, which are notoriously expensive, La Roche-Posay's delivers great results without the matching price tag.
Our tester's skin was having a small crisis - dehydrated, rough and breaking out - but this sorted it right out within three weeks of daily use, with zero irritation.
Murad Retinol Youth Renewal Night Cream: £65, Murad
There is not a single dud product in the extensive Retinol range from the US dermatological brand.
This is a night cream that isn't super heavy or oily, and skin is silky, fresh and looks well-rested in the morning. Plus, our tester's usually sensitive skin didn't show any signs of redness or irritation.
REN Bio Retinoid Anti-Ageing Cream: £45, REN Skincare
REN's Bio Retinoid (a moisturiser rather than a serum or oil) is a winning combo of mid-range price, minimal fuss and very good results.
Our tester's mature skin felt firmer and brighter and she saw an improvement in the lines around her brow and mouth.
Sunday Riley Luna Sleeping Night Oil: £45, Cult Beauty
Despite the slightly alarming blue colour of this oil, our tester found this had remarkable effects on acne scars after just two weeks of use (the brand aims to create products that show results quickly) and it also reduced the frown line between her eyebrows.
The oil formula is excellent for nourishing dry skins and doesn't strip any natural moisture.
Zelens Power A High Potency Vitamin A Treatment Drops: £120, John Lewis
Our tester found that this smelled fantastic - lightly fragranced and not at all overpowering - and the pipette is easy to control to dispense the small amount necessary, cutting out waste.
Skin was smoother and reduced more pronounced lines, but everyday use caused irritation after a couple of weeks, so we recommend limiting use to three times a week.
If you're coming to retinol with no previous experience, start with Indeed Labs - it scores highly across the board and comes at a give-it-a-go-friendly price too.