How is Aminexil different from classic minoxidil? Is one gentler?

When discussing solutions for hair loss, two names come up repeatedly: minoxidil and aminexil. Both compounds have been developed with the aim of slowing hair loss, but their mechanisms of action, side effects, and levels of effectiveness differ in ways that can be crucial for those considering treatment.

This comparison has led many to ask: how exactly do aminexil and minoxidil differ? And more importantly, can one be considered gentler or better tolerated by the scalp?

Aminexil vs. Minoxidil: Two paths to the same goal

Minoxidil is a drug with a long history in dermatology. Its original development had nothing to do with hair: it was formulated as an oral medication to treat severe hypertension. However, during clinical trials in the 1970s, researchers noticed that some patients exhibited unusual hair growth as a side effect. This finding led to its reformulation into topical versions, and in 1988 it was approved by the FDA to treat androgenetic alopecia, or common baldness. Although the exact mechanism by which minoxidil stimulates hair growth is not fully understood, it is believed to act by dilating the blood vessels in the scalp, thereby improving the flow of nutrients and oxygen to hair follicles. It is also proposed that it prolongs the anagen phase, i.e., the active growth cycle of hair.

Aminexil, on the other hand, was developed in the 1990s by the L’Oréal group as a cosmetic alternative to minoxidil. Chemically, it is a similar molecule but with one key difference: it lacks the active nitroxide group present in minoxidil. This modification was introduced to reduce the potential adverse effects that some people experience with minoxidil. It is postulated that aminexil works by preventing the hardening of collagen around the hair follicle, a phenomenon associated with follicular miniaturization and eventual inactivity. Aminexil, not classified as a drug but as a cosmetic ingredient, is included in lotions without requiring pharmaceutical approval, which affects both the perception of its safety and the quantity and rigor of the clinical studies available.

Is one gentler on the scalp?

One of the most notable differences between the two compounds is in skin tolerability. Minoxidil, although backed by decades of studies and approved by regulatory agencies like the FDA, is not free of side effects. Many users have reported reactions such as redness, itching, dryness, flaking, and even contact dermatitis. Part of these effects come not from the active ingredient itself, but from the vehicle used in many formulations, which includes alcohol and propylene glycol. These components can be irritating, especially for people with sensitive skin or preexisting conditions like seborrheic dermatitis. Aminexil, being a cosmetic ingredient, is usually formulated without alcohol or propylene glycol, and with other skin-caring ingredients. For this reason, it has been widely promoted as a gentler option. Clinical studies and dermatological observations suggest that its application rarely causes irritation or adverse effects. However, this greater tolerability should not be confused with equivalent efficacy: gentleness does not always imply visible results in terms of hair regrowth. The lack of potent active ingredients can make the treatment more bearable, but less transformative.

What the research says: Efficacy under the microscope

A clinical study published in 2007 by Loussouarn and collaborators in the International Journal of Cosmetic Science focused on evaluating the efficacy of aminexil in 30 men with mild to moderate androgenetic alopecia. The study lasted six weeks, with daily application of a lotion containing aminexil. Results were assessed through hair shedding counts during washing and standardized scalp photographs. A slight reduction in hair loss was observed, although significant regrowth levels were not reached. The main critique of this study is its short observation period, small sample size, and lack of a placebo group or direct comparison with more established treatments like minoxidil.

In contrast, a high-quality clinical trial conducted by Olsen et al. in 2002, published in the Journal of the American Academy of Dermatology, evaluated 393 men with androgenetic alopecia using 5% minoxidil. This study lasted 48 weeks and was double-blind and placebo-controlled. Changes in hair density were measured via standardized photography, as well as participants' subjective perception. Results showed a significant improvement in the number of hairs per square centimeter and a positive perception in 62% of participants. The main criticism was the occurrence of mild side effects, such as irritation, in a fraction of users, although overall it was considered well tolerated.

A direct comparison: Which is more effective?

In 2011, a study conducted by the University of Rome and published in the journal Dermatologic Therapy directly compared two treatments: a multicomponent lotion with aminexil, SP94 (a glucose derivative supposedly nourishing the follicle), and arginine (an amino acid that improves microcirculation), versus 2% minoxidil. Sixty women with chronic telogen effluvium—a condition characterized by diffuse hair shedding lasting months—participated. The study lasted 12 weeks and results were assessed through hair shedding counts, digital scalp photo analysis, and dermatological evaluation.

Both groups showed improvement in reducing hair shedding and a slight increase in hair density, but the minoxidil group showed more consistent and sustained results. However, an important finding was that the aminexil group reported greater comfort using the product, with fewer cases of irritation or discomfort. This research highlights the key difference between both approaches: efficacy versus tolerability. While minoxidil shows a stronger effect on hair growth, aminexil may be a viable option for people with extremely sensitive skin or reluctance to prolonged drug use.

User Experiences

Community feedback comparing Aminexil and Minoxidil shows that while both are used for hair loss, they differ in strength and tolerability. Users often describe Aminexil as a gentler, less irritating option, while Minoxidil is seen as more effective for hair regrowth but with a higher risk of side effects. One user recovering from reflex hyperandrogenicity after using RU58841 included Aminexil in a broader routine with Minoxidil, Rosemary Verbenone, and Stemoxydine. While they didn’t highlight Aminexil as a main contributor to regrowth, its inclusion suggests it’s viewed as a safe and well-tolerated support agent. It was not associated with irritation or shedding, making it a favorable option for sensitive scalps.Another user discussed discontinuing Minoxidil after a decade due to side effects like chest pain and blood pressure issues. In the responses, other users recommended gentler alternatives such as Aminexil and Nanoxidil. These were seen as viable for users prioritizing safety over maximum regrowth, suggesting a perception that Aminexil offers lower efficacy but better tolerability.

A long-term hair loss user who maintained their hair from age 22 to 42 listed Vichy Dercos Aminexil Clinical as part of their stack, alongside Finasteride, Minoxidil, Ketoconazole shampoo, and PRP. Aminexil was not emphasized for its results but was noted as a non-disruptive addition. This suggests it’s frequently used as a complementary therapy, not a standalone solution. Overall, the community sees Minoxidil as the more powerful regrowth agent but also more likely to cause issues like irritation, increased shedding, or systemic effects. **Aminexil, in contrast, is considered much gentler and safer but usually not effective enough alone for reversing significant hair loss. **

Aminexil and minoxidil are not interchangeable even if their names and purposes may seem similar.

Minoxidil has decades of studies behind it, regulatory approval, and proven efficacy in multiple types of alopecia. However, its potency comes with a higher probability of skin reactions, something not to be overlooked. Aminexil, on the other hand, is a more recent cosmetic alternative with a better skin tolerance profile, but its effect on hair regrowth remains modest and needs more rigorous long-term scientific evidence. So, answering the question in this article’s title: yes, aminexil is generally gentler on the scalp. But that gentleness comes at a cost: lower proven efficacy. If one is seeking a solution with stronger, more visible results, minoxidil remains the first choice. **Nevertheless, for those with high skin sensitivity or as a complement in the early stages of hair loss, aminexil may have a valid place. As always, the decision should be based on informed knowledge of the differences between both—and ideally, with professional guidance. **

References

FDA. (2020). Drug Approval Package: Rogaine (Minoxidil). U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2000/019501_ROGAINE.cfm

Hair Loss Cure 2020. (n.d.). Aminexil for Hair Loss: Does It Work? https://www.hairlosscure2020.com/aminexil/

National Institutes of Health. (n.d.). Hair Loss: MedlinePlus. https://medlineplus.gov/hairloss.html

Olsen, E. A., Whiting, D., Bergfeld, W., Miller, J., Hordinsky, M., Wanser, R., … Roberts, J. L. (2002). A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. Journal of the American Academy of Dermatology, 47(3), 377–385. https://www.jaad.org/article/S0190-9622(02)00124-X/abstract

Perfect Hair Health. (n.d.). Minoxidil and Aminexil Compared: What Works Best? https://perfecthairhealth.com/minoxidil-vs-aminexil/

Tosti, A., Duque-Estrada, B., & Vincenzi, C. (2011). Treatment of telogen effluvium: A comparative study of a topical multicomponent formulation containing aminexil vs. topical minoxidil 2%. Dermatologic Therapy, 24(4), 453–458. https://onlinelibrary.wiley.com/doi/10.1111/j.1529-8019.2011.01415.x

Reddit. (2023, October 1). Reflex Hyperandrogenicty: How I recovered from it. r/tressless. Retrieved from https://reddit.com/r/tressless/comments/16xbw66/reflex_hyperandrogenicty_how_i_recovered_from_it/

Reddit. (2024, June 14). Life after minoxidil? Has anyone stopped. r/tressless. Retrieved from https://reddit.com/r/tressless/comments/1dfgkc3/life_after_minoxidil_has_anyone_stopped/

Reddit. (2020, March 2). I started rapidly diffuse thinning at 22. I'm 42 now and have as much hair as I did at 16. AMA. r/tressless. Retrieved from https://reddit.com/r/tressless/comments/fcae0j/i_started_rapidly_diffuse_thinning_at_22_im_42/