Table of Contents
Azelaic Acid, officially nonanedioic acid, is a white crystalline solid with a melting point of 106.5 ° C. It takes place naturally in grains such as wheat, rye, and barley and is produced industrially by ozonolyzing oleic acid. Some plants launch azelaic acid as a “distress flare” to signal cells to activate their defenses against assaulting pathogens. [2]
Background
Azelaic acid is a saturated dicarboxylic acid discovered naturally in wheat, rye, and barley. It is likewise produced by Malassezia furfur, likewise referred to as Pityrosporum ovale, which is a types of fungi that is typically found on human skin. Azelaic acid is effective versus a variety of skin conditions, such as moderate to moderate acne, when applied topically in a cream solution of 20%. It works in part by stopping the growth of skin germs that cause acne, and by keeping skin pores clear. Azelaic acid’s antimicrobial action might be attributable to inhibition of microbial cellular protein synthesis.
Mechanism of action
The specific mechanism of action of azelaic acid is not known. It is believed that azelaic acid manifests its anti-bacterial effects by hindering the synthesis of cellular protein in anaerobic and aerobic germs, especially Staphylococcus epidermidis and Propionibacterium acnes. In aerobic bacteria, azelaic acid reversibly hinders several oxidoreductive enzymes including tyrosinase, mitochondrial enzymes of the respiratory chain, thioredoxin reductase, 5-alpha-reductase, and DNA polymerases. In anaerobic germs, azelaic acid impedes glycolysis. Along with these actions, azelaic acid also improves acne vulgaris by normalizing the keratin process and reducing microcomedo development. Azelaic acid might work against both irritated and noninflamed lesions. Particularly, azelaic acid lowers the thickness of the stratum corneum, shrinks keratohyalin granules by decreasing the quantity and circulation of filaggrin (a component of keratohyalin) in skin layers, and decreases the number of keratohyalin granules. [3]
Metabolic process
Generally excreted the same in the urine however undergoes some b-oxidation to much shorter chain dicarboxylic acids.
Path of removal
Azelaic acid is primarily excreted unchanged in the urine, however goes through some ß-oxidation to much shorter chain dicarboxylic acids.
Half-life
The observed half-lives in healthy subjects are approximately 45 minutes after oral dosing and 12 hours after topical dosing, suggesting percutaneous absorption rate-limited kinetics. [3]
Properties
Azelaic acid is soluble in hot water, alcohol and organic solvents.
Azelaic acid is used in the manufacture of adhesives and sealant chemicals; lubes and lube additives; paint and coating ingredients, and plasticizers. [4]
Benefits
A single system of action has not been recognized to explain the impacts of azelaic acid on the skin. It helps scavenge reactive oxygen types, minimizes expression of kallikrein-5 (KLK-5) and pro-inflammatory cathelicidins such as LL-37, as well as hinders toll-like receptor 2 (TLR-2). In addition, it hinders the pigment producing enzyme tyrosinase, has comedolytic residential or commercial properties, and might reduce epidermal hyperkeratinization. While the 15% gel formulation is FDA approved for the treatment of rosacea, a different 20% cream solution (Azelex, Allergan) is indicated for the treatment of acne. Both formulations bring a pregnancy category B ranking.
Azelaic Acid for Rosacea
The 15% gel solution of azelaic acid is FDA approved to deal with the papules and pustules of moderate to moderate rosacea. While the 15% gel has a lower concentration of azelaic acid compared to the 20% cream, advances in formula innovation provide the gel greater cutaneous biovailability. While the indicator is for use of azelaic acid 15% gel twice daily, a research study subsequent to its approval demonstrated equivalent efficacy of when compared to two times everyday application.
Current information recommend unusual over-activity of the innate body immune system as a major contributor to the pathophysiology of rosacea. Excess skin antimicrobial peptides (e.g., cathelicidins) and stimulation of TLR-2 both play substantial roles. Cathelicidins are processed by serine proteases (e.g., KLK-5) into pro-inflammatory peptides, such as LL-37. Overactivity of KLK-5 leads to a high level of cathelicidin processing into peptides with greater pro-inflammatory properties than anti-bacterial homes. This imbalance promotes angiogenesis and chronic skin inflammation. Topical application of azelaic acid 15% gel has actually been shown to reduce skin serine protease activity and help reverse these changes.
Azelaic Acid for Acne
TLR-2 over-activity plays a role in the pathogenesis of acne. Propionibacterium acnes itself has actually been shown to promote TLR-2 activity, leading to skin inflammation and comedogenesis. Topical retinoids are a staple in treating acne not just because of their ability to stabilize follicular hyperkeratinization however also due to their anti-inflammatory homes. Similar to its mechanism of action in dealing with rosacea, azelaic acid’s ability to inhibit TLR-2 activity helps describe its efficacy in dealing with acne vulgaris. The use of azelaic acid 15% gel is considered off label for the treatment of acne vulgaris. Many specialists may utilize it off-label for acne as part of a mix therapy for patients who can not tolerate topical retinoids, those who likewise suffer from hyperpigmentation, and for women who are pregnant or breastfeeding (as it is pregnancy category B).
Azelaic Acid for Hyperpigmentation
Post-inflammatory coloring medically manifests as dark spots in locations of skin that formerly were inflamed, be it from acne or another inflammatory dermatosis. While not improved for this sign, azelaic acid is typically used off-label to treat pigmentation. One clinical trial demonstrated 15% azelaic acid gel to be both efficacious and safe in dealing with hyperpigmentation connected with acne for 16 weeks. This effect may be described by two residential or commercial properties of the drug. First, azelaic acid is known to hinder the enzyme tyrosinase, which is required for the production of melanin.3 2nd, its role as an anti-inflammatory may be advantageous too. When active acne sores (e.g., papules and pustules) willpower, evidence shows that the skin in these locations still have subclinical inflammation.14 While this has been shown in acne scars, the same might likewise be true in cases of persistent erythema and coloring. More research is needed to corroborate this theory, however.
Having a drug that effectively deals with a condition helps us much better understand that condition, as we find the system by which the drug works. Just as biologics have shed light on the pathogenesis of psoriasis, research study into the system of action of azelaic acid has significantly enhanced our understanding about the pathogenesis of rosacea, specifically the function of an over-active inherent immune system. A greater understanding of the illness equates to better treatment algorithms and patient outcomes, and eventually this assists affect the future of drug development. [5]
Blackheads
The anti-bacterial qualities of azelaic acid aid to prevent the development of both white and blackheads, by eliminating the skin bacteria that can result in areas. It also inhibits the production of keratin skin cells, which can block pores and sebaceous glands and develop oily build-ups (leading to blackheads).
Finacea Gel vs. Skinoren Cream: What’s the primary distinction?
Finacea Gel and Skinoren Cream are both skin medications. Each works at treating acne, but there are some distinctions in between the two, with the key one being that Skinoren Cream consists of more azelaic acid than Finacea Gel.
Below, we have actually highlighted the essential distinctions in between Finacea Gel and Skinoren cream:.
Skinoren Cream is more powerful: it’s 20% azelaic acid, while Finacea Gel is 15%.
Skinoren Cream treats all acne: Finacea Gel is only for moderate to moderate acne.
Finacea Gel treats rosacea: it’s a milder treatment, that makes it OK for rosacea.
As both consist of comparable ingredients, they can trigger comparable side effects.
More about Finacea Gel
Finacea Gel is a prescription-only gel used to deal with rosacea. It’s 15% azelaic acid, which offers it anti-inflammatory effects and permits it to decrease the inflammation and swelling of rosacea.
Finacea likewise lowers the body’s natural production of keratin cells. This prevents keratin cells from blocking pores and sebaceous glands (the small glands in your skin which launch sebum), relieving rosacea symptoms such as bumps, areas, papules, and pustules.
More about Skinoren Cream
Skinoren cream likewise includes the active ingredient of azelaic acid, but in a higher concentration. It’s 20% azelaic acid where Finacea Gel is a weaker 15%.
The powerful azelaic acid in Skinoren works in 2 methods to fight acne: by reducing the growth of pore-blocking keratin cells, and by killing the germs connected with acne. A common skin germs called propionibacterium feeds upon the sebum produced by the skin, creating waste products and fatty acids that aggravate acne signs and irritate the skin.
By unblocking pores and glands and killing propionibacterium, Skinoren minimizes acne and permits your skin to heal naturally.
Although Finacea Gel is generally utilized for rosacea, and Skinoren cream is mainly utilized for acne, the two treatments can often be recommended for the other skin problem. It all depends on the situation, however given that each item is prescription-only, there shouldn’t be any confusion about what to use. [6]
How Do You Use Azelaic Acid?
Azelaic acid is applied topically and it’s available in creams, foams and gels.
Many dermatologists advise that whichever form you select, the strength should sit somewhere in the 15% to 20% range.
Over the counter products containing a smaller sized dosage of azelaic acid are offered as well, although for finest results a prescription is normally needed.
The majority of topical representatives require you to use them twice a day to clean, dry skin (masks consisting of azelaic acid should be utilized less regularly).
Below we have actually put together a detailed skincare regimen to reveal you how to incorporate azelaic acid into your routine.
Step One
Wash your confront with your everyday cleanser and pat the skin dry. If you utilize a toner, apply it after this first step.
It is necessary not to skip this action since the cleaner your skin is, the more likely it is to soak up other treatments.
Step 2
Next apply your azelaic acid cream, gel or cream.
If you have sensitive skin, we recommend starting with a single application every other day. As your skin changes, you can utilize the product more frequently.
Additionally, perform a patch test on the back of your arm before using your foam, cream, or gel to more sensitive areas such as your face or neck, where the skin is thinner.
You ought to likewise wait about 15 minutes for the item to take in to prevent smearing. This is specifically important if you’re using it as a spot treatment to fade darker areas.
If you’re utilizing azelaic acid as a spot treatment, do not use it all over the face. This is because you’ll run the risk of fading the skin in unneeded areas.
Step Three
After letting the azelaic acid take in, use your moisturizer as usual. It’s likewise important not to stint sunscreen.
When using azelaic acid, the skin tends to end up being more susceptible to ecological damage.
This indicates that not using sun security can reverse all of the benefits of azelaic acid, because sun damage can cause hyperpigmentation and melasma.
Step Four
It’s safe to apply makeup after the azelaic acid cream, foam or gel has actually dried totally.
Do not bandage or cover the area unless your skin doctor has instructed you to do so.
When not in use, shop your azelaic acid at room temperature level and away from direct light.
This is since excessive direct exposure to light can trigger azelaic acid to destabilize and break down.
A Note about AHA and BHAs
Alpha-hydroxy acids (AHAs) and beta-hydroxy acids (BHAs) are used to treat skin conditions like acne.
The most typical kinds of these acids include salicylic acid, glycolic acid, and lactic acid.
AHAs are more aggressive exfoliants than azelaic acid, that makes them more efficient in dealing with sun damage and combating signs of aging. They are also a popular option for people seeking to improve their skin’s texture.
BHAs resemble AHAs, except they have antibacterial homes. This is terrific for dealing with acne since it kills hazardous germs that can possibly infect blemishes.
Although you’ll see faster results by utilizing BHAs, they are most likely to trigger severe side effects like rashes or blistering.
In comparison to AHAs and BHAs, azelaic acid is a gentler treatment with fewer negative effects.
Nevertheless, some dermatologists caution against combining azelaic acid with salicylic acid or other beta-hydroxy acids since it might cause excessive dryness and irritation.
For those who have oily or mix skin, treating your acne with azelaic and salicylic acid can be particularly efficient. [7]
Forms of Azelaic Acid
You can get azelaic acid as a:.
- Gel
- Foam
- Cream
- Tablet
Prescription kinds have 15% to 20% azelaic acid, but over-the-counter versions have much less. [8]
Azelaic Acid’s Role as an Inhibitor of 5α-Reductase Activity
5α-reductase is an enzyme that changes testosterone into another androgen, dihydrotestosterone (DHT) (5 ). DHT is five times as potent as testosterone. It plays a crucial role in the development of males’s sexual qualities, including the development of hair on the chin, back, and chest.
Oddly, DHT is likewise destructive to the development of hair on the scalp. To put it simply, it has the exact opposite impact on the scalp compared to the remainder of the body. This makes it an essential particle in male pattern baldness.
DHT is associated with male pattern baldness.
Hence, finding particles that inhibit the action of 5α-reductase is of fantastic interest to pharmaceutical companies and skin doctors focusing on hair regrowth.
A 1988 research study released in the British Journal of Dermatology utilized an in vitro assay to evaluate the results of zinc and azelaic acid on 5α-reductase activity in human skin.
In the experiment, Dr. Stamatiadis and his research study group determined that azelaic acid could totally hinder 5α-reductase activity in vitro (in a petri dish). Much more intriguing, when azelaic was integrated with zinc sulfate, the inhibition was even more powerful.
Dr. Stamatiadis concluded that the mix of these 2 substances might potentially treat androgen-related ailments.
Azelaic Acid and Alopecia Areata
Alopecia Areata (AA) is a kind of hair loss that is autoimmune in nature. For factors that are not clear, the body’s immune cells assault the follicles. The result is distinct, completely bald spots. These can appear anywhere on the scalp, and frequently on other parts of the body.
The FDA has not currently authorized any medications for AA. As a result, medical professionals recommend different medications off-label.
Can Azelaic Acid Treat AA?
Alopecia areata is the scientific term for patchy baldness.
In a pilot study concerning azelaic acid’s possible usage in managing area baldness, Dr. Sasmaz and Dr. Arican performed an experiment comparing azelaic acid to anthralin.
Azelaic acid has actually been utilized to treat this condition in the past. Until this research study came out, nevertheless, there were no controlled studies to evaluate its effectiveness.
Anthralin is a proven topical treatment for the management of alopecia location. This makes it a good standard to compare the efficiency of novel treatments.
The Study Protocol
In the experiment, Dr. Sasmaz and Dr. Arican recruited 31 topics with irregular alopecia location. None of these subjects had used any alopecia treatments within at least the past month. The researchers then arbitrarily assigned the clients into one of two groups.
The first group applied 20% azelaic acid cream to the affected portion of the scalp daily for 12 consecutive weeks.
The 2nd group used 0.5% anthralin cream to the afflicted portion of the scalp daily for 12 successive weeks. Afterward, there was an 8-week follow-up throughout which patients applied no cream. The objective of this follow-up was to see whether the clients could preserve their treatment results.
All research study participants finished the experiment as advised. There were no major negative effects.
Outcomes
At the end of this 20 week period, Dr. Sasmaz and Dr. Arican carried out a scientific evaluation on each participant.
Throughout this assessment, each of the subject’s scalps was granted a Terminal Hair Regrowth Score on a scale from 0 to 2. On this scale, a 0 showed an inadequate action, a 1 a partial response, and a 2 a total reaction. At week 20, the Average Terminal Hair Re-growth Scores were as follows:.
Azelaic acid group
1.27 (Margin of Error: +/- 0.9).
Anthralin group
1.37 (Margin of Mistake: +/- 0.8).
Thus, subjects in either treatment arm had broadly comparable outcomes. The Typical Terminal Regrowth Scores were both over 1, revealing total sufficient reaction to treatment.
In fact, 53.3% of cases in the azelaic acid cream group and 56.2% of cases in the anthralin group had a complete action. In addition, topics with a total reaction had no new bald patches establish during the study duration. This suggests the azelaic acid treatment could help manage the condition beyond the cured area.
Dr. Sasmaz and Dr. Arican concluded that azelaic acid could be a reliable topical treatment for irregular alopecia areata.
This study is not without its faults, however. Dr. Sasmaz and Dr. Arican used a fairly small sample size in their experiment. In addition, there was no reported follow-up for the research study to assess the long-term results of treatment. Some researchers have even questioned the use of anthralin as a contrast tool, due to an absence of certainty in its usefulness.
Azelaic Acid and Androgenetic Alopecia?
To date, there is no published research study on the efficiency of azelaic acid against male androgenetic alopecia (AGA). Having stated that, the substance inhibits DHT, at least in vitro. This makes it an in theory helpful treatment choice.
This has actually not stopped many men with hair loss from integrating it into their baldness treatment regimen. Numerous report positive outcomes, while others state it made no difference in their loss of hair.
The absence of standardized treatment routines is a problem. There are no standards on what strength to use, how typically, or in combination with what other active components.
Usually, users try formulas consisting of in between 10-15% azelaic acid.
How to Experiment With Azelaic Acid Yourself
Because there are promising outcomes linking azelaic acid to a drop in DHT levels and a reduction of alopecia areata symptoms, it might be worth your while to try this item out on your own.
It is recommended that you include azelaic acid to your normal regime instead of replacing it as a treatment. This holds true specifically if you are using an FDA-approved hair item such as Minoxidil or Propecia. There are a range of topical products you can purchase which consist of azelaic acid:.
Scalp creams and conditioner for alopecia consisting of azelaic acid.
- The FDA-approved acne creams discussed earlier
- Shops offering natural supplements often have vials consisting of azelaic acid
- Apply the cream or other topical service daily for the best outcomes. [9]
Azelaic acid adverse effects
Azelaic acid can trigger adverse effects, including:.
- burning or tingling on your skin
- peeling skin at the site of application
- skin dryness or redness
Less-common side effects consist of:.
- blistering or flaking skin
- inflammation and swelling
- tightness or pain in your joints
- hives and itching
- fever
- trouble breathing
If you experience any of these adverse effects, stop using azelaic acid and see a medical professional.
It’s constantly important to wear sunscreen when you go outside, but be especially mindful to use SPF items when you’re using azelaic acid. Given that it can thin your skin, your skin is more delicate and prone to sun damage.
How azelaic acid compares with other treatments
Azelaic acid isn’t for everyone. The effectiveness of the treatment may depend on your:.
- signs
- skin type
- expectations
Given that it works slowly, azelaic acid is frequently recommended along with other forms of acne treatment.
According to older research, azelaic acid cream might be as reliable as benzoyl peroxide and tretinoin (Retin-A) for the treatment of acne. While azelaic acid outcomes resemble those of benzoyl peroxide, it’s also more expensive.
Azelaic acid also works more gently than alpha hydroxy acid, glycolic acid, and salicylic acid.
While these other acids are strong enough to be utilized by themselves in chemical peels, azelaic acid isn’t. This suggests that while azelaic acid is less likely to irritate your skin, it likewise needs to be used regularly and offered time to take effect. [10]
Azelaic acid topical dosing information
Usual Grownup Dosage for Acne:
20% Cream Formulations: Apply a thin layer to the affected location( s) 2 times a day
Remarks:
- The afflicted area( s) should be carefully cleaned and patted dry prior to application.
- This drug ought to be gently but thoroughly rubbed into the affected location( s) in the morning and night.
- The duration of therapy is based upon the client and the intensity of the acne.
- Improvement in patients with inflammatory sores usually happens within 4 weeks.
Usage: Topical treatment of mild-to-moderate inflammatory acne vulgaris
Normal Adult Dose for Acne Rosacea:
15% Gel/Foam Formulations: Use a thin layer to the affected location( s) 2 times a day
Comments:
- The afflicted location( s) need to be carefully washed and dried prior to application with an extremely moderate soap or soapless cleansing cream.
- This drug must be gently but completely rubbed into the affected areas in the morning and night.
- Clients may use cosmetics once the treatment has dried.
- Patients ought to be reassessed if enhancement is not observed after completing 12 weeks of treatment.
- For clients using foam formulations, the tiniest amount of foam need to be used to properly cover the afflicted location( s) with a thin layer.
Usage: Topical treatment of the inflammatory papules and pustules of moderate to moderate rosacea
Typical Pediatric Dose for Acne:
12 years and older:
20% Cream Formulas: Apply a thin layer to the affected area( s) 2 times a day
Comments:
- The afflicted location( s) need to be carefully washed and patted dry prior to application.
- This drug needs to be carefully however thoroughly massaged into the affected area( s) in the morning and night.
- Enhancement in clients with inflammatory lesions normally occurs within 4 weeks.
Use: Topical treatment of mild-to-moderate inflammatory acne vulgaris [11]
What other drugs interact with azelaic acid?
If your doctor has directed you to utilize this medication, your medical professional or pharmacist might already know any possible drug interactions and might be monitoring you for them. Do not start, stop, or change the dose of any medicine before contacting your doctor, health care supplier or pharmacist first.
- Azelaic Acid has no recognized extreme interactions with other drugs.
- Azelaic acid has no recognized major interactions with other drugs.
- Azelaic acid has no known moderate interactions with other drugs.
- Azelaic acid has no known moderate interactions with other drugs.
This file does not consist of all possible interactions. For that reason, prior to utilizing this product, inform your medical professional or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your physician and pharmacist. Consult your doctor if you have health concerns or concerns. [12]
FAQs
Who Should Utilize Azelaic Acid and Who Should Not?
Azelaic acid is a safe skin care ingredient that has widespread compatibility with all skin types, and is usually well-tolerated, even by those with delicate skin.
Who could take advantage of azelaic acid?
Azelaic acid is especially useful for those with blemished skin and/or those with unequal tone and bumpy texture. It can also be used to relax level of sensitivity.
Who should keep away from azelaic acid?
Negative reactions and side effects to azelaic acid are not typical, but similar to any skin care ingredient, if you experience indications of irritation, stop usage or experiment with applying less frequently (once every other day, for example).
How Does Azelaic Acid Compare to Alpha Hydroxy Acids (AHAs) or Salicylic Acid (BHA)?
AHA, BHA, and azelaic acid share similarities, but likewise some fascinating differences. Although azelaic acid can exfoliate skin when appropriately created, it does not exfoliate the same way or with the very same level of effectiveness as components like glycolic acid and lactic acid (AHAs) or salicylic acid (BHA).
On the other hand, azelaic acid offers fringe benefits that AHA and BHA components do not provide, particularly when it concerns enhancing a significantly irregular skin tone and skin sensitivity issues.
Can you utilize them together? Yes, in fact, this combination can be ideal for resolving the look of numerous skin issues, from bumps to irregular complexion to age-related issues you might be struggling with.
Can I Utilize Vitamin C and Azelaic Acid Together?
Yes, you can use vitamin C and azelaic acid items together– these active ingredients complement one another. Utilizing them together might accelerate the results for night skin tone and fading marks by targeting the issue via multiple pathways.
What Should You Not Blend With Azelaic Acid?
Azelaic acid items can be used along with all kinds of skin care items, and there isn’t research study revealing it’s an issue to utilize along with other powerhouse active ingredients. Of course, if you’re utilizing a prescription version, consult with your doctor on how to work it into your skin care regimen. [13]
Precautions
It is very important that your doctor check your progress at regular gos to for any undesirable effects that might be caused by this medicine.
If your acne does not improve within 4 weeks, or if it becomes worse, check with your doctor.
If your rosacea does not enhance within 12 weeks, or if it becomes worse, contact your medical professional.
Hypopigmentation might happen while you are using this medicine. Check with your doctor right now if your skin color is lighter in the treated areas, particularly if you have dark skin.
This medication may trigger allergic reactions, consisting of angioedema, which can be life-threatening and require instant medical attention. Consult your doctor immediately if you have itching skin, difficulty breathing, or big, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs after using this medication.
This medication may trigger skin responses. Check with your physician immediately if you have a skin rash, burning, dryness, inflammation, peeling, stinging, swelling, or inflammation on the skin. [14]
The bottom line
Azelaic acid is a naturally occurring acid that’s milder than some more popular acids used to treat acne.
While the outcomes of treatment with azelaic acid may not be obvious right now, there is research that points to this component as efficient.
Acne, irregular skin tone, rosacea, and inflammatory skin conditions have all been shown to be efficiently treated with azelaic acid. Just like any medication, follow the dosing and application directions from your medical professional carefully. [15]
Referrals
- https://www.merriam-webster.com/medical/azelaic%20acid
- https://www.acs.org/content/acs/en/molecule-of-the-week/archive/a/azelaic-acid.html
- https://go.drugbank.com/drugs/DB00548
- https://thechemco.com/chemical/azelaic-acid/
- https://practicaldermatology.com/articles/2013-mar/new-insights-into-azelaic-acid
- https://www.theindependentpharmacy.co.uk/rosacea/guides/azelaic-acid-benefits
- https://navamd.com/face-forward-blog/all-about-azelaic-acid
- https://www.webmd.com/skin-problems-and-treatments/what-to-know-about-azelaic-acid-skin
- https://www.hairguard.com/azelaic-acid/
- https://www.healthline.com/health/azelaic-acid-acne#alternative-treatments
- https://www.drugs.com/mtm/azelaic-acid-topical.html
- https://www.rxlist.com/consumer__azelaic_acid_azelex_finacea/drugs-condition.htm
- https://www.paulaschoice.com/expert-advice/skincare-advice/ingredient-spotlight/azelaic-acid-for-skin.html
- https://www.mayoclinic.org/drugs-supplements/azelaic-acid-topical-route/precautions/drg-20062084
- https://www.healthline.com/health/azelaic-acid-acne
