I’ve told this story before: when I met the head scientist at Avon last year and asked her what had been the most important skincare breakthrough in the last 15 years or so, she said glycolic acid. Now I have just come across something that claims to be the next generation of alpha hydroxy acids (the family in which glycolic belongs), polyhydroxy acid (PHA).

Next generation implies that PHAs would be superior to AHAs and that is supposed to be the case. What excites me is the claim that, unlike AHAs, PHAs do not increase sensitivity to the sun (you know how I feel about sunscreen). And what’s more, PHAs do a lot more than the exfoliating effects of glycolic; they are an antioxidant. In fact, the maker of PHA, a company called Neostrata suggest that you test this out at home using a banana skin – PHAs will inhibit the oxidation of browning skin. So I did....

In the interests of science, I have just sacrificed a perfectly good (if slightly under-ripe) banana. I smeared two strips of banana skin  (one inside and one outside) with a cream called Exuviance Age Reverse Night Lift, one of four new products that Neostrata has launched and which feature PHAs. Of course, I have an au natural strip of skin as the control.

While we leave them to go brown (or not), I’ll tell you more about PHAs, Neostrata and Exuviance Age Reverse. Neostrata was founded by Dr Drs. Eugene Van Scott and Ruey Yu. They claim to have discovered the role of AHAs in skincare in the first place.  I suppose we should expect the founding father’s of the lunchtime peel to come up with ‘a new and improved’, but I’d like to see some claims made for PHAs that are independent of Neostrata. Nonetheless, those claims are definitely intriguing and this could be one acid worth dropping.

PHAs include lactobionic acid, galactose and gluconic acid. (and another variation called bionic acids) apparently “chelate or trap oxidation-promoting metals in skin”. Not only do they not increase sensitivity to the sun, they also help protect cell lipids and membranes from UV damage. Furthermore,  they may also help to preserve the skin's elasticity by preventing an increase in the enzyme elastase. And we aren't done yet. PHAs/bionic acids inhibit MMP enzymes in skin, which are responsible for all the things we are trying to prevent such as wrinkles, sagging and broken veins.

And you get all of this without any irritation. Nary a tingle. This, too, is a notable improvement on glycolic acid, which must be used in a lowish concentration (around 5%) by those of us with sensitive skins. This is because PHAs have a larger molecule size than AHAs.

Exuviance Age Reverse Night Lift ($68) has the PHA gluconolactone and maltobionic acid. In addition, it has Matrixyl 3000, the collagen-boosting peptides, vitamins A, E and C, and the antioxidant botanicals, grape, acai, billberry and pomegranate. As well as shea, there are gentle emollients such as hydrogenated polydecene and fragrances deemed to be harmless such as methyldihydrojasmonate. Slightly undermining the appeal of Night Lift are some silicones and other fillers plus a few possible irritants such as ammonium hydroxide and ethylene brassylate, chlorphenesin and phenoxyethanol.

As for the banana skin test, well Exuviance Night Lift didn't do that great. Granted that it is not a pure PHA, but gluconolactone is the second ingredient. After a couple of hours, the untreated banana skin shows deeper oxidation in patches and overall looks drier, slightly shriveled. The  (inner) skin smeared with night cream looks MUCH more hydrated, but is showing signs of oxidation – less deeply than the control - but almost uniformly. The outer skin smeared with cream looks as fresh as a daisy. (Adendum: the next day, the control skin looked much the same, while the cream smeared skin was brown all over).

See our Five Best with polyhydroxy acid

See all our FIVE BEST recommendationsincluding Five Best for sagging skin, Five Best with vitamin C and Five Best eye creams.

Ingredients in Exuviance Age Reverse Night Lift:

Aqua (Water), Gluconolactone, Glyceryl Stearate, Butyrospermum Parkii (Shea Butter), Isononyl Isononanoate, Maltobionic Acid, Glycerin, Cyclopentasiloxane, Butylene Glycol, Glycolic Acid, Hydrogenated Polydecene, Stearyl Alcohol, Ammonium Hydroxide, Dimethicone, PEG-100 Stearate, Propylene Glycol, Cetyl Alcohol, Palmitoyl Oligopeptide, Palmitoyl Tetrapeptide-7, Tocopheryl (Vitamin E) Acetate, Tetrahexyldecyl Ascorbate (Vitamin C Ester), Retinyl (Vitamin A) Palmitate, Rosa Damascena Flower Oil, Euterpe Oleracea (Acai) Fruit Extract, Punica Granatum (Pomegranate) Extract, Vaccinium Angustifolium (Blueberry) Fruit Juice, Vitis Vinifera (Grape) Seed Extract, PEG-75 Stearate, Ceteth-20, Steareth-20, Magnesium Aluminum Silicate, Xanthan Gum, Triethyl Citrate, Methyldihydrojasmonate, Ethylene Brassylate, Disodium EDTA, Sodium Bisulfite, Pentaerythrityl Tetra-di-t-Butyl Hydroxyhydrocinnamate, Chlorphenesin, Phenoxyethanol, Capryl Glycol, CI 17200 (Red 33), CI 61570 (Green 5)