Lactic acid – always the bridesmaid for the more hyped glycolic acid – is my first choice of alpha hydroxy acid for all manner of reasons. It exfoliates without stripping or stinging (its bigger molecule size makes it particularly well tolerated by even sensitive skins), can stimulate collagen and ceramide production to firm, plump and protect mature skins, has antibacterial properties for more problematic ones, and binds with water to keep every type more hydrated. Lactic also imparts an unmistakable glow to the complexion and deflakes rough areas brilliantly.

I’ve always loved it, but have rarely been so spoilt for choice. Beauty Pie’s new Youthbomb Extreme Retinal Triple Renewal Serum (£49 to members) is their best formula in some time, which goes some way to justify its high (for Beauty Pie) price point.

The creamy serum contains niacinamide, two potent retinoids, hyaluronic acid, ceramides and plenty of other good stuff, but I was particularly pleased to find lactic acid in the mix, and felt its smoothing effects on my skin. Although consumer lactic acid products are safe during pregnancy, retinoids in any strength are not, so skip this one if expecting.

Fine at any time is Clinique’s Moisture Surge Active Glow Serum, my most-used morning serum of the past 18 months. This combines my skin’s favourite trio: glycerin, vitamin C and lactic acid, for instant glassy moisture, glow and evenness, and at £44, it’s fairly priced in relation to the rest of the market.

If your budget is lower, try Brightening Serum (£12.99) from the consistently great Byoma. This adds a dash of lactic to its fine-textured, hydrating serum that’s suitable for oilier types.

If you’re content with your existing skincare lineup and would like to incorporate lactic acid without having to bench a favourite product, a tonic is an easy slot-in. Paula’s Choice is famous for its liquid exfoliants and 6% Mandelic + 2% Lactic Acid (£14) is its gentlest. Just sprinkle into palms or sweep over skin with a cotton disc and proceed with the rest of your routine.

Lactic is particularly good on the body, especially if you have flaky skin prone to those small, hard micro-bumps (keratosis pilaris) on your thighs and upper arms. There are several good lotions available, but First Aid Beauty’s KP Smoothing and Brightening Body Lotion (£30), which has a decent 10% of lactic acid (aim for 5-10% generally), stands out for best disguising the sour milk pong of its competitors.