The benefits of AHA fruit acids for the skin

Written by: Kernel



Time to read 6 min

Fruit acids or AHAs - alpha hydroxy acids - are carboxylic acids that can be produced by fruits, hence their name fruit acids. Contrary to what their name might suggest, they are not aggressive for the skin and on the contrary have many benefits for it.

They are widely used in the cosmetic industry for chemical exfoliation products. Overall, they constitute an excellent anti-aging active ingredient for smoother and brighter skin.

1. What exactly are AHA fruit acids?

The name AHA fruit acids brings together several subcategories of acids, the six best known of which are: citric acid, glycolic acid, tartaric acid, mandelic acid, malic acid and lactic acid.

  • Citric acid:

Discovered in 1784 in lemons by the Swedish chemist Carl Wilhelm Scheele, citric acid is an acid of plant origin from citrus fruits and in particular lemons in which it is found in abundance at a rate of up to 8%. It can also be of synthetic origin. This acid is used in cosmetic and pharmaceutical products and in the food industry.

It has three main properties:

  • it is an acidifying agent used to regulate the pH: it is used to balance the pH of cosmetic products when the latter have a pH that is too basic. This property also allows it to fight against the proliferation of bacteria or fungi.
  • it is a chelating agent used to stabilize the appearance of cosmetic products
  • it is a masking agent which reduces or inhibits the odor of a cosmetic product

It is also used in bath products in combination with sodium bicarbonate for its effervescent properties allowing it to dissolve in water.

  • Glycolic acid:

Discovered in 1848 by the French chemist Auguste Laurent and then synthesized for the first time in 1851 by the chemists Nicolas Sokoloff and Adolph Strecker, glycolic acid is obtained from extracts of sugar cane, beets or grapes.

It is the smallest of the alpha hydroxy acids (AHA) with an excellent ability to penetrate the skin, which is why it is particularly used in skin care products and particularly in peels.

When glycolic acid is applied to the skin, it will act on the upper layer of the epidermis to loosen the lipid bonds between them and allow the elimination of dead cells. This action will help reduce acne by unclogging pores, fight against hyperpigmentation by eliminating dead cells containing melanin and reduce wrinkles by allowing cell renewal. Glycolic acid therefore helps improve the appearance of the skin by allowing it to renew itself and  to let the lower layer appear younger and brighter.

  • Tartaric acid:

Used since Antiquity for its properties to preserve wine, it was the Swedish chemist Carl Wilhelm Scheele who managed to extract it for the first time  wine tartar in 1769 using a process using sulfuric acid.

Tartaric acid is a compound existing in nature and present in many plants and fruits including grapes, which makes it the main acid in wine. It is used in the food, pharmaceutical and cosmetic industries.

It has lightening, anti-dark spots, anti-acne and anti-aging properties, making it an active ingredient of choice for treating skin with problems such as acne. It can also be used as a pH regulator or masking agent to reduce or inhibit product odor. It can be used alone or in combination with other alpha-hydroxy acids for increased effectiveness.

Tartaric acid has a higher molecular weight than other alpha-hydroxy acids, it will therefore penetrate the skin less deeply and will have a less irritating and less aggressive exfoliating action than these other acids such as glycolic acid for which it will constitute a good alternative for people who can't stand it.

  • Mandelic acid:

Mandelic acid was discovered in 1831 by German pharmacist Ferdinand Ludwig Winckler by heating amygdalin, an extract of the bitter almond, with hydrochloric acid. It is an active ingredient that can also be synthesized in the laboratory. Its name comes from the German “mandel” which means “almond”.

It is used in the pharmaceutical industry as an oral antibacterial and antibiotic and in the cosmetic industry as a component to perform chemical facial peels.

Just like tartaric acid, it has a higher molecular weight than other alpha-hydroxy acids such as glycolic acid and will therefore have a less profound action making it less irritating and less aggressive for the skin. It will constitute an alternative to other acids for skin that may be sensitive to this type of active ingredient. Its main properties allow it to be effective against wrinkles, acne and hyperpigmentation.

  • Malic acid:

Malic acid was discovered in 1785 by the Swedish chemist Carl Wilhelm Scheele in apple juice. Its name will be adopted after the word “malus” which is the Latin name for the apple tree after a proposal from the French chemist Antoine Lavoisier.

  • Lactic acid:

Lactic acid was discovered in 1780 by Swedish chemist Carl Wilhelm Scheele, it occurs naturally in the body and its name refers to the milk in which it is also found.

Lactic acid has an exfoliating action which facilitates the elimination of dead skin, plus it is perfectly suited to sensitive skin. It also helps promote collagen synthesis, maintain skin hydration and maintain its pH to keep it healthy and fight against bacteria that could proliferate and cause pimples and acne.

Malic acid is present in certain fruits such as rhubarb, strawberries, green apples or grapes and in most wines giving them all their tart taste. It also plays an important role in the synthesis of the ATP molecule which releases energy in the body.

In cosmetics, it is an exfoliating active ingredient like other alpha-hydroxy acids with anti-aging, anti-spot, anti-wrinkle and anti-acne actions. It also helps regulate the pH of cosmetic products, drinks, medicines and food supplements thanks to its acidifying properties.

2. What are the benefits of AHA fruit acids for the skin?

AHA fruit acids have several benefits for the skin:

  • A keratolytic and exfoliating action: AHA fruit acids are capable of breaking the bonds that are created between skin cells to loosen and eliminate dead cells, and promote desquamation of the skin. This will accelerate cell renewal and reveal a younger and brighter layer of skin. The depth of exfoliation of AHA fruit acids will depend on their molecular weights, the concentration used in the cosmetic product and the exposure time on the skin. The exfoliating action of AHA fruit acids will allow the skin to benefit from all their other benefits.

  • An anti-aging and anti-wrinkle and fine lines action: the use of AHA fruit acids over time helps reduce wrinkles and fine lines thanks to their action to increase the production of collagen which will firm the skin . Their moisturizing action also helps keep the skin hydrated.

  • Anti-acne action: AHA fruit acids help fight acne by eliminating dead skin cells. Dead cells can actually clog pores and make them clogged, which will lead to the accumulation of sebum and the proliferation of bacteria, both of which cause acne.

  • A lightening and anti-brown spot action: brown spots can be caused by acne scars or old age. AHA fruit acids will help fight against these spots, in fact they will reveal clearer skin after eliminating dead cells and promoting cell renewal.

  • They allow better absorption of facial care: AHA fruit acids increase the absorption and effectiveness of facial care products applied immediately after them thanks to their action to eliminate dead cells. Indeed, if too many dead cells are on the skin, other care products will not be able to penetrate the skin and their results will therefore be reduced.

AHA fruit acids in summary

AHA fruit acids are cosmetic active ingredients with numerous benefits for the skin, the six best known of which are: citric acid (lemon), glycolic acid (sugar cane, beets, grapes), tartaric acid ( wine), mandelic acid (almond), malic acid (apple) and lactic acid (milk). These active ingredients help exfoliate the skin and eliminate dead cells, fight against wrinkles, fine lines, acne and brown spots, and allow better absorption of cosmetic treatments applied to the skin after them.