was isolated from apple juice for the first time in 1785 by Karl Wilhelm Scheele and is more than just a name. However malic acid is not just extracted from apples and can also be found in most unripe fruits from quinces to grapes, barberries, rowan berries and gooseberries. It is extracted using a biotechnological process. The riper the fruit, the lower its malic acid content. In nature, the sour flavour of the acid ensures that the unripe fruit is not eaten by animals before it is ready. As the malic acid content decreases during the ripening process, the sugar content of the fruit automatically increases. Malic acid is one of the components responsible for the exfoliating effect of the gel mask.

is known as the superstar of the fruit acids because it has the smallest molecule size, can penetrate easily into the skin and is particularly effective as a means of exfoliation. Glycolic acid is classed as a fruit acid due to its natural occurrence. It is primarily found in grapes, sugarcane juice and sugar beets but also occurs in rosemary and the leaves of grape vine.

is predominantly extracted from lemon juice. It can be found in apples, pears, sour cherries, raspberries, blackberries, redcurrants, conifers, fungi, tobacco leaves, wine and even milk. It was first identified by alchemists under a different name in the 9th century but was isolated and named citric acid by Karl Wilhelm Scheele in 1784. It is colourless and water-soluble.

was also first documented as such by Scheele. It was previously assumed that the tartar, i.e. salt, was the actual acid and this was known as the spirit of the wine. In nature, tartaric acid occurs in numerous plants and fruits such as the dandelion and sugar beet and, of course, grapes. In cosmetics, it is an intensive and effective component of fruit acid exfoliation.