Azelaic Acid against Acne and Hair Loss
Azelaic acid is a saturated dicarboxylic acid, naturally occurring in wheat, barley, rye and olive oil (especially in rancid oil). Interest in this substance - produced in significant quantities by the fungus Malassezia furfur, which normally resides on human skin - derives from some characteristics particularly useful in dermatology.
Azelaic acid, in fact, has a depigmenting and inhibitory activity against 5-alpha-reductase. As such, it is used topically - at a concentration of 20% - in products intended for the treatment of hair loss on an androgenetic basis. In addition to this, azelaic acid has also been shown to be effective in treating other ailments, such as acne and melasma.
Azelaic acid is a compound with numerous properties and, for this reason, it is widely and effectively used in the dermatological field.
More specifically, azelaic acid has:
- Antibacterial properties.
- Inhibitory activity against keratinocyte proliferation.
- Anti-inflammatory and anti-radical activity.
- Depigmenting action.
As mentioned, by virtue of its numerous properties, azelaic acid is used in the treatment of various skin disorders and is also used to combat hair loss.
The anti-acne activity of azelaic acid probably derives from its bacteriostatic and bactericidal action against microorganisms that settle the superficial layers of the epidermis, causing skin lesions characteristic of acne vulgaris ( Propionibacterium acnes).
This bacteriostatic and bactericidal action is due to the inhibitory activity of azelaic acid against enzymatic systems essential for the activation of the mitochondrial respiratory chain and for the synthesis of nucleic acids and proteins.
In addition to the aforementioned actions, azelaic acid has demonstrated an activity radical scavenger (anti free radicals), potentially useful from an anti-aging point of view, but also valuable for counteracting the inflammatory phenomena that accompany acne.
Azelaic acid normalizes the processes of epidermal differentiation and inhibits the proliferation of keratinocytes, leading to a reduction in the content of free fatty acids in the lipids of the skin surface. This characteristic contributes to enhancing the anti-acne and anticomedogenic action, since it significantly reduces the density of colonization of the Propionibacterium acnes.
For all these reasons, azelaic acid is still considered one of the first drugs used in modest forms of acne.
Although the causes of rosacea have not yet been fully clarified, it is believed that inflammatory processes still play a fundamental role in this pathology.
Thanks to its interesting anti-inflammatory properties, azelaic acid has proved very useful in the treatment of rosacea.
In detail, the effectiveness of azelaic acid in this area is due to its ability to modulate the inflammatory response at the level of keratinocytes through a series of mechanisms, such as:
- The inhibition of pro-inflammatory cytokine synthesis;
- The inhibition of the release of reactive oxygen species (free radicals or ROS) by neutrophils;
- A "scavenger" action of free radicals already formed (radical scavenger).
As a depigmenter
Azelaic acid exerts an inhibitory action against tyrosinase, the key enzyme for the synthesis of melanin; in this sense, it is active above all at the level of hyperactive melanocytes, while sparing normal ones. As such, it is widely used in the treatment of melasma.
Against hair loss
It is well known that androgenetic alopecia, the most common cause of hair "loss" in both men and women, is linked to the action of androgens in a genetically predisposed terrain. In this sense, the follicular concentration of the 5-alpha-reductase enzyme, which converts testosterone into dihydrotestosterone, the main culprit in the genesis of baldness, plays a leading role. Stamatiadis studies et al. have shown how in vitro azelaic acid has a very strong inhibitory activity against the 5-alpha-reductase enzyme; this effect is not direct (as in the case of progesterone), but derives from the inhibition of NADP reductase with blocking of the production of NADPH (key coenzyme of 5-alpha-reductase). Consequently, at the level of the hair bulb, the metabolic fate of testosterone is no longer oriented towards the synthesis of dihydrotestosterone, but towards the oxidation to androstenedione and estrone (the latter with a positive activity on the health of the hair).
The association with pyridoxine and zinc appears to potentiate the effects of azelaic acid in vitro.
Against skin aging
By virtue of its action against free radicals - therefore its antioxidant properties - it is believed that azelaic acid can be an effective anti-wrinkle and anti-aging remedy.
Generally, when used as an anti-wrinkle and anti-aging treatment, azelaic acid is part of a creamy or oily formulation. However, in these cases, its concentration must necessarily be lower than that used to combat the aforementioned disorders, in order to avoid unpleasant adverse reactions.
In fact, in anti-aging treatments, the concentration of azelaic acid should be around 3%, against the 10-20% present in products for medical-dermatological use.
Despite being an active principle that is normally well tolerated, azelaic acid is however not free from inducing side effects. For this reason, its use should only be carried out on the advice of the doctor and under his supervision.
The main side effect induced by azelaic acid is skin irritation which may be associated with:
- Skin dryness.
In the most serious cases - and, above all, in the case of improper and / or excessive use of azelaic acid - real burns can also occur at the area of application.
Other side effects include:
- Burning or pain at the application site;
- Skin rashes;
- Loss of sensation in correspondence of the treated area;
- Exfoliation of the skin at the application site;
- Depigmentation of the treated area (this is to be considered an undesirable effect when azelaic acid is used in the treatment of acne and rosacea, while it represents a desired effect when used against melasma).
Finally, in sensitive subjects, the use of azelaic acid can cause allergic and sensitization reactions.