If you're after beautiful skin then you need to know about AHAs.
You see, these clever little guys, give skin a noticeably younger and more fresh appearance and in very little time.
"These acids basically gobble up dead skin cells that make older skin in particular seem lacking in vibrancy," says beauty expert Sali Hughes, author of Pretty Honest (Harper Collins).
"They also help spots, enlarged and clogged pores and strip away the cells collected around and exacerbating the appearance of fine lines."
Clearly we want them in our lives and most definitely our skincare regimes but what are AHAs exactly and how do they work?
Skincare expert Paula Begoun, creator of the beauty brand Paula's Choice, explains it like this.
"As we age, and because our skin is subject to unprotected sun exposure, skin’s surface gradually stops shedding as quickly and evenly as it did when we were younger," says Paula.
"This leads to a constant buildup of dry-looking, dull, rough, uneven skin."
But AHAs can ease, if not altogether erase, this problem. And this is how.
Basically AHAs (Alpha Hydroxy Acids) work in two ways. In low concentrations (less than three per cent) they're excellent water-binding agents meaning they hydrate skin.
At concentrations of more than four per cent, and in a base with an acid pH of three to four, they can exfoliate skin cells by breaking down the substance in skin that holds skin cells together.
The most effective versions of this amazing ingredient are glycolic acid and lactic acid.
Malic, citric and tartaric acid may also be effective but there's not as much research showing this to be the case.
Glycolic and lactic however - absolute winners, says Paula.
Obviously they are awesome, but AHAs are not to be played about with. In fact, you should start using them gradually applying every third day or so you can see how your skin reacts. If all goes well, you should be able to settle into an every second or third day routine.
Also - always follow the instructions on the product itself. They're there for a reason!
And one last word of warning - if you use an AHA you must also wear sunscreen every day.
"This is absolutely essential as newly exposed skin cells will be more susceptible to irritation and long-term damage," adds Sali.