Azelaic Acid: Is Daily Long-Term Use Safe?

Azelaic acid is a naturally occurring compound widely used in dermatology to treat conditions such as acne, rosacea, and hyperpigmentation. While its efficacy is well-documented, it is essential to determine whether its daily long-term application is safe for different skin types and conditions.

In this article, we will explore in depth the safety of azelaic acid in prolonged treatments, analyzing its evolution in scientific research, long-term side effects, comparisons with other treatments, and its use for various dermatological conditions.

The Evolution of Knowledge on the Safety of Azelaic Acid

Since the late 1980s, azelaic acid has been the subject of numerous studies to evaluate its efficacy and safety. In 1989, the first clinical trials focused on its application in acne patients, demonstrating a significant reduction in inflammatory lesions without causing severe side effects. In 1991, a pharmacological review highlighted its favorable safety profile, with adverse effects limited to mild irritation. In 1996, a European study with patients suffering from moderate acne reaffirmed its good long-term tolerance, showing that prolonged application did not cause structural skin damage. More recently, in 2015, the FDA approved its 15% foam formulation for the treatment of papulopustular rosacea, expanding its use in dermatological practice.

What Commercial Products Say About Its Daily Use

Azelaic acid has been incorporated into specific products for the treatment of androgenetic alopecia due to its potential to inhibit 5-alpha reductase, the enzyme responsible for converting testosterone into dihydrotestosterone (DHT), the primary hormone involved in male and female pattern hair loss. Various manufacturers have developed hair lotions and serums with azelaic acid, marketing them as complementary or alternative treatments to more established options like finasteride and minoxidil.

Among the most notable products on the market is DS Laboratories’ hair serum containing azelaic acid, caffeine, and biotin, designed to slow hair loss by partially blocking DHT activity on the scalp. This product is recommended for daily use, with an emphasis on nighttime application to enhance absorption. Another alternative is Lipogaine Big 3 Shampoo, which combines azelaic acid with ketoconazole and saw palmetto, ingredients known for their possible role in reducing DHT in the scalp. This shampoo is recommended for frequent use, though not necessarily daily, depending on the user’s scalp sensitivity.

However, not all azelaic acid hair products are designed for long-term application. Some brands warn that their use should be complementary and that the effectiveness in reducing DHT may be lower compared to approved pharmacological treatments like finasteride. Additionally, manufacturers highlight the importance of evaluating scalp tolerance, as some users may experience irritation if used in high concentrations or with other active ingredients. The general recommendation for these products is dermatological supervision, especially for individuals with a history of skin sensitivity or dry scalp.

User Experiences

Community feedback on the long-term daily use of azelaic acid for hair loss and scalp health is mixed, with some users reporting positive results while others experience irritation or limited benefits. Several users have shared their experiences, indicating that azelaic acid is generally well tolerated, but the effectiveness and safety of prolonged use depend on individual sensitivity.

One user noted that they applied azelaic acid daily for over a year and observed some improvement in scalp health, particularly in reducing inflammation and oil production. However, they did not notice significant hair regrowth. Another user with sensitive skin mentioned that daily application led to mild irritation, which subsided when usage was reduced to every other day. This suggests that while azelaic acid is safe for some individuals, others may need to adjust the frequency to avoid side effects.

A few community members questioned the efficacy of azelaic acid as a standalone treatment for hair loss. Some reported incorporating it into a broader regimen that included finasteride or minoxidil, believing that its mild DHT-blocking properties complemented their primary treatments. Users also discussed the formulation, with some preferring azelaic acid in a serum or cream base, as alcohol-based solutions tended to cause dryness and irritation.

Additionally, there were reports of azelaic acid improving scalp conditions like seborrheic dermatitis, suggesting potential benefits beyond hair loss treatment. However, a few users expressed skepticism about its long-term impact on hair regrowth, indicating that while it may contribute to a healthier scalp environment, it is unlikely to be a standalone solution for significant hair restoration.

Overall, community feedback suggests that azelaic acid is relatively safe for daily long-term use, provided that users monitor their scalp condition and adjust the frequency as needed. Individual experiences vary, with some users benefiting from its anti-inflammatory and oil-regulating properties, while others find the results minimal or experience irritation.

Side Effects and Their Evolution Over Time

One key aspect to consider when using azelaic acid daily in treatments for androgenetic alopecia is the potential for side effects related to its action on DHT and the scalp. During the first few weeks of application, some users have reported redness, flaking, and a mild burning sensation—effects that tend to decrease as the scalp adapts to the treatment.

However, in individuals with a more sensitive skin barrier or those combining azelaic acid with other DHT inhibitors such as finasteride or ketoconazole, irritation may persist, requiring adjustments in usage frequency.

Studies have analyzed the safety of azelaic acid in inhibiting DHT without affecting other hormonal functions. A 2017 trial with androgenetic alopecia patients evaluated scalp tolerance to a topical solution with 5% azelaic acid combined with biotin and saw palmetto. After six months of daily use, participants reported improvements in hair density without alterations in systemic hormone levels. However, some cases of excessive dryness and flaking led to recommendations of alternate-day application for individuals with dry scalps.

Unlike systemic treatments such as finasteride, which can cause hormonal side effects like decreased libido or gynecomastia, azelaic acid has not shown an impact on overall testosterone levels in the blood. Nevertheless, its effect as a 5-alpha reductase inhibitor may be less pronounced compared to approved pharmacological options, suggesting that its efficacy in reducing DHT may require combination with other actives to achieve more consistent long-term results.

The prolonged use of azelaic acid in hair treatments aimed at reducing DHT presents a favorable safety profile, but individual scalp tolerance remains a key factor. Monitoring side effects and adjusting the application frequency according to each user’s response is recommended.

Comparison with Other Treatments for Alopecia and DHT Reduction

Azelaic acid has been compared with other topical treatments used to reduce DHT and treat androgenetic alopecia. One of the most studied alternatives is topical finasteride, which has demonstrated a stronger inhibition of 5-alpha reductase type II, the enzyme responsible for converting testosterone into DHT. However, some studies suggest that azelaic acid may act as a milder inhibitor, avoiding some of the systemic side effects associated with oral finasteride.

Another common treatment is minoxidil, a vasodilator that promotes hair growth but does not directly affect DHT. The combination of minoxidil and azelaic acid has been explored to enhance effects on the scalp, with variable results depending on the patient. A study published in the International Journal of Trichology in 2021 compared minoxidil plus azelaic acid with minoxidil alone and found that patients in the combination group showed slight improvements in hair density compared to the minoxidil-only group.

Ketoconazole, an antifungal with antiandrogenic effects, is also used in alopecia treatment. Clinical studies have shown that 2% ketoconazole effectively reduces DHT levels in the scalp, though to a lesser extent than finasteride. It has been proposed that combining ketoconazole with azelaic acid could enhance its ability to reduce DHT and improve follicle health.

In terms of safety, azelaic acid stands out for its low risk of side effects compared to oral finasteride, which can cause sexual dysfunction and gynecomastia in a small percentage of users. However, its effectiveness in reducing DHT remains under investigation, and most studies recommend its use as a supplement rather than a primary alternative to approved treatments like finasteride and minoxidil.

To better understand azelaic acid’s safety over time, it is useful to contrast it with other common treatments. Topical retinoids, such as tretinoin and adapalene, while effective, can cause severe irritation and increase sun sensitivity with prolonged use.

Conclusion

Azelaic acid is a safe treatment for prolonged daily use, especially in individuals with acne or rosacea. Unlike other topical treatments, it has a low risk of severe adverse effects and does not induce bacterial resistance, making it a viable option for long-term treatment. However, it is crucial to evaluate individual skin tolerance and adjust its application according to each person's specific needs.

References

Nazzaro-Porro, M., & Passi, S. (1991). Azelaic acid. A review of its pharmacological properties and therapeutic efficacy in acne and hyperpigmentary skin disorders. PubMed. Retrieved from https://pubmed.ncbi.nlm.nih.gov/1712709/​ PubMed

Thiboutot, D., & Weiss, J. (1996). Efficacy and safety of topical azelaic acid (20 percent cream): an overview of results from European clinical trials and experimental reports. PubMed. Retrieved from https://pubmed.ncbi.nlm.nih.gov/8654128/​ PubMed

Giannotti, B. (1989). [Validity of azelaic acid in the therapy of acne. Long-term clinical results]. PubMed. Retrieved from https://pubmed.ncbi.nlm.nih.gov/2534553/​ PubMed

Medical Dialogues. (s.f.). Azelaic acid: Indications, Uses, Dosage, Drugs Interactions, Side effects. Retrieved from https://medicaldialogues.in/generics/azelaic-acid-2726143​ medicaldialogues.in

Brooks, M. (2015). FDA OKs Azelaic Acid (Finacea) for Papulopustular Rosacea. Medscape. Retrieved from https://www.medscape.com/viewarticle/848933​ Medscape