Exfoliation with fruit acid: Gentle beautifier for the skin

Smiling woman with radiant facial skin holds half lemon in front of her face with right hand

At first glance, the two terms "acid" and "skin care" don't quite seem to go together - but don't worry, the acids we're talking about here consistently mean well for your skin. First and foremost, these include the various fruit acids. They occur naturally in many plants and their fruits. How do they work and can they smooth wrinkles?

Effect and application

In skin care, fruit acids are used as active ingredients because of their exfoliating properties:

 "Exfoliation" refers to the body's own continuous renewal of the skin. This process can be promoted and accelerated by integrating mild exfoliating products into daily skin care. Almost every skin type benefits from this, because exfoliation keeps the cells of the epidermis young and resistant. This prevents wrinkles and helps to reduce them. 

But be careful: very dry or stressed skin should first be brought back into balance before the skin's own renewal is given a helping hand.

In domestic skin care, two entirely different types of products share the term "exfoliation":

  • Mechanical peels, also known as face scrubs, basically work like sandpaper on the skin: they smooth the skin's surface mechanically and have no place in daily skin care. They are sporadic intensive care.
  • Domestic exfoliation with the help of fruit acids or enzymes, on the other hand, is much gentler on the face than the term "chemical peeling" suggests, under which they also operate. It is actually reserved for treatments at the beautician or dermatologist, because there significantly higher concentrations are used. 

So, this article is about exfoliation with fruit acid or enzymes. They also loosen the loose skin flakes on the skin surface. But this happens much more gently than with the mechanical variant, because fruit acids and enzymes can not cause micro-injuries compared to mechanical peels and there is no abrasive feeling during application. 

In addition, quasi as a bonus, the chemical helpers also fulfill other tasks:

  1. They increase the skin's ability to retain moisture.
  2. They have an antibacterial effect.
  3. They stimulate cell division in the dermis.

Fruit acid: The pH value is important

However, a certain degree of caution is also required with fruit acids, as it depends on the concentration of the acid used and its bioavailability. The latter is the higher, the lower the pH value of the fruit acid product (e.g. fruit acid cream, serum etc.) is: at a pH value below 4 the effect is relevant, below 3.5 it can already become challenging for the untrained skin. Ultimately, each skin reacts individually, especially since each fruit acid has its own special properties.

Fruit acids at a glance

Alpha fruit acids (AHA)

The alpha-fruit acids, also abbreviated AHA (from the English term "alpha-hydroxy acids"), include, for example, the following representatives:

  • CITRIC ACID (citric acid)
  • GLYCOLIC ACID (glycolic acid or glycolic acid)
  • LACTIC ACID (lactic acid)
  • MANDELIC ACID (Mandelic Acid)

They are used for (more or less) regular exfoliation of the skin. In doing so, the fruit acids proceed much more mildly than mechanical rubbing grains. They carefully dissolve the cell cement in the uppermost horny layer, which prevents the long-dead skin flakes from falling off on their own. In this way, they make room for new, fresh skin cells on the face, accelerating natural skin renewal. 

Is there an anti-aging effect?

Exfoliated skin consists of proportionally more "fresh" skin cells on its surface, so it is moister and plumper. This makes the skin appear rosier. 

Since fewer dead corneal flakes protrude from the surface, the light is also reflected more evenly. This not only provides the longed-for "glow" in the face, but also helps with makeup: it can be applied better and lasts longer.

But the effect is far from superficial: its peeling effect and the resulting thinning of the horny layer activate the basal layer to produce new cells. These can tighten the skin overall and smooth wrinkles.

Research shows that glycolic acid is able to increase vitality and cell division activity by more than 40 percent, ultimately even making the epidermis thicker.

The four most common fruit acids and their effects

The fruit acids listed above are the most commonly used. 

  • Glycolic acid has the smallest molecules, which allows it to penetrate very quickly through the skin layers, but in higher concentrations it can also cause irritation.
  • The molecules of lactic acid are larger, those of mandelic acid even significantly larger. It is virtually the "fat bumblebee" among the alpha-fruit acids, so it penetrates the cornea particularly slowly. This may sound like a disadvantage, but it is particularly recommended for sensitive skin, as it leads to less irritation. 
  • Mandelic acid has other special features: It has an anti-inflammatory and antibacterial effect, which is why it can lead to a significant improvement in the appearance of the skin, especially in the case of impurities. It is the only one of the alpha-fruit acids that is lipophilic, which is why it penetrates well into the skin layers. 

AHAs are effective in concentrations as low as 3 percent, and dosages of up to 15 percent are possible in over-the-counter products and are not uncommon. The higher concentrations require careful familiarization and are also not necessary for regular stimulation of the skin's own exfoliation, but rather reserved for the targeted treatment of impurities.

Beta fruit acid (BHA)

When we talk about beta fruit acid (the abbreviation BHA here stands for the English term "Beta Hydroxy Acids"), we are specifically referring to only one: salicylic acid. It is an extremely popular acid and may even be found in your medicine cabinet in a similar form. This is because ASA, i.e. Aspirin®, is made from acetylsalicylic acid.

Salicylic acid, like the alpha representatives, is keratolytic, i.e. it dissolves horns (from a concentration of about 1 percent). In addition it acts 

  • antibacterial, 
  • anti-inflammatory, 
  • moisture retaining and even 
  • skin soothing, 

because it has analgesic properties similar to its relative in tablet form. 

Salicylic acid helps against impure skin

Since it is fat-loving, it penetrates particularly well into the epidermis, but especially into the pore. There accumulated sebum, also known as blackheads, dissolves the salicylic acid wonderfully. Therefore, it is very popular in facial cleansers and tonics, especially for blemished skin. Salicylic acid can also help with rosacea, a chronic inflammatory skin disease.

Products against impurities should contain at least one percent salicylic acid, because lower concentrations only act as a preservative for the product but have no significant effect on the skin. EU legislation allows up to two percent salicylic acid for over-the-counter products.

Until now, salicylic acid was considered by product developers to be a comparatively inconvenient fruit acid: namely, it is relatively difficult to dissolve in its original form. Modern formulations therefore use pre-dissolved forms of salicylic acid. The persistent myth that a BHA product must have a strongly acidic pH of less than 4 to be effective has been scientifically disproved for many years. 

Today we know: Due to the size and oily structure of its molecules, salicylic acid is significantly less sensitive to somewhat higher pH values than previously assumed. This enables mild, since pH skin-friendly formulations with BHA.

Poly-fruit acids (PHA)

Poly-fruit acids are also referred to as "second generation alpha-fruit acids" because they are said to have similar properties while being milder and more tolerable than most AHAs due to their larger molecules. In cosmetic formulations (or a cream), mainly

  • GLUCONOLACTONE 
  • LACTOBIONIC ACID

to find. PHAs have been in use in the USA for many years; they are still comparatively rare in European products. In the case of AHAs, however, mandelic acid is on a par with PHAs in terms of tolerability due to its similar structure.

Azelaic acid inhibits inflammation

This acid does not belong to the fruit acids, but to the so-called dicarboxylic acids. It is found in its natural form in whole grains and is also part of the microbiome on our skin - an interesting combination. Azelaic acid only appeared on the radar of skin care fans a few years ago. 

Until then, it was more familiar to acne patients, because its spectrum of action is literally tailor-made for acne-plagued skin: azelaic acid inhibits inflammation, dissolves keratinization in the pore and acts very efficiently against the acne-triggering Propionibacterium acnes. Studies have shown that after just one application, azelaic acid manages to deprive acne bacteria of food and literally starve them out.

The biological process behind it also works for other conditions, which is why azelaic acid has also been proven to treat rosacea, psoriasis, and even melasma (hyperpigmentation). The exciting thing is that azelaic acid manages all of this not just a little bit, but really well. 

Azelaic acid is a multifunctional skin improver and is quite mild and tolerable. However, a slight stinging sensation or temporarily increased skin dryness is possible. Another plus point is that azelaic acid does not reduce the skin's light callosity, i.e. its physical self-protection against UV radiation.

In the list of ingredients you will find the classic azelaic acid as AZELAIC ACID. Its sister, which is coupled with glycerin and thus more soluble, is called POTASSIUM AZELOYL DIGLYCINATE.

Cosmetic acids at a glance:

The graph summarizes the differences of the 4 types of cosmetic acids.
Alpha fruit acids (AHA) and their milder relatives, poly fruit acids (PHA), have exfoliating and moisturizing properties. Salicylic acid (BHA) also removes excess corneal flakes, but does this before in the pores due to its oil solubility. Azelaic acid additionally brings brightening properties.

What does fruit acid do for my skin?

Compared to mechanical peeling, exfoliation with fruit acids or enzymes is not an ad hoc measure for immediate anti-aging or smoother skin, as results often require several applications. Fruit acids should rather be considered as a regular training for skin renewal, especially since they may require some time to get used to. In return, the results are more comprehensive, as in addition to their smoothing and moisturizing properties, AHAs can also soften blemishes and cleanse (and thus visually shrink) pores from the inside. This can improve the overall appearance of the skin.

The latter is mainly reserved for salicylic acid, as it is fat-soluble and therefore penetrates the sebum in the pore. It is a so-called beta fruity acid (BHA), whose horny dissolving properties are somewhat weaker than those of the AHAs. Its strength lies primarily in clearing clogged pores; as an active ingredient, e.g. in a cream or serum, it is also extremely mild.

The most important plus point of AHAs is that, when used regularly, they stimulate collagen formation, thus making the skin thicker. However, the opposite initially applies to the top layer, the callus. As with all peeling variants, it becomes somewhat thinner. Therefore, UV protection is enormously important with regular exfoliation, as the skin's own protection time is shortened. You must always apply sunscreen - not only in summer!

Fruit acid is available as an active ingredient in various dosage forms:

  • Fruit acid cream
  • Peeling 
  • Serum
By the way, our first product was the Face Serum. The 10 percent mandelic acid as well as the contained niacinamide and 6 moisture-binding substances still make it one of our most highly effective classics.