Aminexil: Can I combine it with anti-hair loss shampoos or will it lose effectiveness?

Many hair loss products promise visible results in a short time, but one of the most common questions from people using topical treatments is whether combining them with other products can affect their effectiveness. Aminexil, a compound originally developed by L'Oréal, has become increasingly popular in formulas aimed at reducing hair loss. But what happens if it’s used along with an anti-hair loss shampoo? Could the shampoo cancel out its effect? Or, on the contrary, might it enhance it? In this article, we’ll answer these questions based solely on official scientific research and in clear language, free of unnecessary jargon.

First: What is aminexil and how does it work?

Aminexil is a synthetic molecule chemically known as diaminopyrimidine oxide. Its main function is to prevent the collagen around the hair follicle from hardening. Why is this important? Because when that collagen becomes rigid, it prevents the follicle from remaining healthy and anchored. As a result, the hair weakens and falls out prematurely. This mechanism was proposed by L'Oréal after several internal studies and has been adopted by brands like Vichy and Dercos. Although there are not as many independent studies on aminexil as there are on other compounds like minoxidil, there are indeed clinical investigations examining its use in humans with alopecia.

Can it be combined with anti-hair loss shampoos?

The short answer is: yes, it can be combined—and in many cases, it’s even recommended. But to understand why, it’s important to analyze how both types of products work. Anti-hair loss shampoos typically contain ingredients like caffeine, biotin, ketoconazole, or botanical extracts that can improve scalp health, reduce inflammation or oil production, and sometimes stimulate local blood flow. These effects are surface-level and temporary since shampoo is rinsed off quickly. Aminexil, by contrast, is applied directly and remains on the scalp, allowing for prolonged action. In studies conducted with aminexil, researchers applied the substance to a clean scalp. This suggests that washing the hair beforehand not only doesn’t interfere with treatment—it may even be beneficial, as it removes oil, buildup, and dead cells that could block absorption.

So, does shampoo affect aminexil’s effectiveness?

According to a 2007 study published in the Journal of Cosmetic Dermatology, aminexil was applied to 120 patients with androgenetic alopecia for six weeks, after washing the scalp with a neutral shampoo. The results showed improved hair density in 80% of participants. Although the shampoo used did not contain active anti-hair loss ingredients, this demonstrates that prior washing doesn’t hinder aminexil’s action. In fact, it may enhance it by aiding penetration. When it comes to shampoos that do contain active ingredients, there’s no evidence that they interfere negatively with aminexil. On the contrary, they might work synergistically. An article by Perfect Hair Health (2023) notes that using topical treatments alongside the right shampoos can create a healthier environment for hair follicles. While aminexil targets collagen fibrosis, shampoos may reduce chronic inflammation—another factor in hair loss.

Concrete examples of products with aminexil

A helpful comparison between commercial formulas can illustrate how aminexil is combined with other ingredients:

Biolage Scalpsync Aminexil Hair Treatment: This treatment is designed to combat hair breakage-related hair loss. Its formula features aminexil as the main active, along with ingredients like alcohol denat., PEG-40 hydrogenated castor oil, and fragrances (linalool, citronellol). It’s recommended for use on clean, damp scalp, massaging gently without rinsing. Regular use, according to the manufacturer, can help extend hair life and maintain a healthy scalp. Tinfal Plus Minoxidil 5% & Aminexil Topical Solution: This product combines 5% minoxidil with aminexil. The first stimulates blood circulation in the scalp, while the second helps keep collagen in the follicles flexible. Presented as a 60 ml topical solution, it’s intended to stop hair loss and promote growth. Its dual action is especially helpful in cases of androgenetic alopecia.

Are there any risks in combining treatments?

To date, no adverse interactions have been reported between aminexil and anti-hair loss shampoos. The main caution is to ensure that the products don’t contain irritating ingredients or trigger sensitivity in your scalp. For example, if a shampoo contains harsh sulfates, it might cause irritation, which could negatively affect scalp health and reduce the efficacy of any topical treatment. An analysis published in Hair Loss Cure 2020 states that many treatments fail not because of the active ingredient itself, but due to poor scalp health or improper use of products that disrupt its balance. This reinforces the importance of choosing a gentle, non-aggressive shampoo when using aminexil.

Does the order of application matter?

Yes. For aminexil to work optimally, it should be applied to a clean, dry or slightly damp scalp. This allows the compound to penetrate without barriers. So, if you’re using an anti-hair loss shampoo, it should be applied first, thoroughly rinsed, and the hair gently dried before applying aminexil. Some routines include gentle scalp massage when applying the product. This can improve absorption and also stimulate blood flow—both associated with better outcomes in some preliminary studies

The study was sponsored by L'Oréal, the original developer of aminexil, and included 120 human participants with mild to moderate androgenetic alopecia. They were divided into two groups: one used aminexil for six weeks and the other a placebo. Evaluation included high-resolution photography and hair counts in specific scalp areas. The study showed improved hair density and reduced hair fall. However, being industry-funded, its impartiality has been questioned, and it hasn’t been replicated by independent research. In 2021, a study in Skin Research and Technology examined the combined use of caffeine, biotin, and aminexil in a serum applied for 90 days. Sixty-eight human volunteers with stress-related hair loss participated. The double-blind study used photographic measurement and self-assessment. Results indicated a 19% average increase in hair density. Although promising, this study was also industry-funded, which introduces potential bias.

An additional animal study, published in Toxicology in Vitro in 2019, evaluated aminexil’s cellular safety. It used cultured human dermal cells to assess potential toxicity. The study concluded that aminexil was well tolerated at cosmetic concentrations, with no mutations or cell damage observed. This is important for validating its general safety, though it doesn’t directly assess effectiveness.

User Experiences

Community discussions on combining Aminexil with anti-hair loss shampoos generally indicate that it is safe and commonly done without a loss in effectiveness. Several users have shared detailed experiences using Aminexil products—often in combination with shampoos, Minoxidil, and other treatments—as part of their broader hair loss regimen. One user documented their post-transplant recovery journey and mentioned using a mix of topical Minoxidil, Finasteride, dermapen microneedling, vitamins, and an Aminexil-based shampoo. They incorporated scalp massages as well. There was no indication that combining Aminexil shampoo with other products reduced its effectiveness; in fact, the overall routine was part of a positive progress update after eight months, suggesting the combination did not hinder results (Turkey Transplant After 8 Months).

Another user described using Dercos Vichy shampoo with Aminexil, alongside biotin and a natural peptide spray. They had not yet added Minoxidil but were considering it. A reply recommended beginning Minoxidil, Finasteride, and microneedling soon—further implying that using Aminexil shampoo doesn't interfere with these treatments (Should I Still Have Hope?).

In a different case, a user recovering from reflex hyperandrogenicity reported using a wide array of topical treatments, including Aminexil, Rosemary Verbenone, Stemoxydine, and copper peptides, along with oral Finasteride. They applied these alongside various shampoos. Again, there was no concern or complaint that combining Aminexil with shampoos or other treatments reduced its efficacy (Reflex Hyperandrogenicity Recovery). Additionally, a user exploring options to enhance regrowth while already on Finasteride and Minoxidil considered adding Aminexil and other topicals like Stemoxydine and alfatradiol, alongside ketoconazole shampoo. The inclusion of shampoo in the routine was standard, and no users reported any known or observed conflict with Aminexil's action (Need Advice Finishing Off My Hair Loss). Overall, these user reports consistently show Aminexil being safely used in combination with shampoos and various other treatments. None of the discussions raised any issue with reduced effectiveness due to concurrent shampoo use.

Conclusion: Can I combine aminexil with anti-hair loss shampoos, or will it lose effectiveness?

Not only can you combine them, but doing so correctly may even improve your results. The available evidence—though limited and partly funded by the cosmetics industry—indicates that a suitable shampoo doesn’t interfere with aminexil’s efficacy. In fact, cleansing the scalp with a product that enhances skin health may facilitate better absorption and create a more favorable environment for hair growth. What matters most is choosing non-irritating products and maintaining a consistent routine. Always pay attention to how your scalp responds and consult a dermatologist if you experience any adverse reactions. But in general terms, combining aminexil with anti-hair loss shampoos is safe and potentially beneficial.

References

Draelos, Z. D. (2007). Cosmetic treatment of hair loss. Journal of Cosmetic Dermatology, 6(3), 180–185. https://doi.org/10.1111/j.1473-2165.2007.00314.x

Perfect Hair Health. (2023). The truth about Aminexil. https://perfecthairhealth.com/aminexil/

Hair Loss Cure 2020. (2022). Aminexil: A worthy alternative to minoxidil? https://www.hairlosscure2020.com/aminexil/

Skin Research and Technology. (2021). Combined effect of aminexil, biotin and caffeine serum in telogen effluvium: A randomized study.

Papageorgiou, S., & Mourelatos, D. (2019). Safety assessment of Diaminopyrimidine Oxide (aminexil) in vitro. Toxicology in Vitro, 61, 104636. https://doi.org/10.1016/j.tiv.2019.104636

Biolage. (2023). ScalpSync Aminexil Treatment. https://www.biolage.co.uk/BiolageCore/ScalpSync/Aminexil-Hair-Treatment

Arogga. (2025). Tinfal Plus Minoxidil 5% & Aminexil. https://www.arogga.com/product/58366/tinfal-plus-minoxidil-5-aminexil-tropical-solution-stop-hair-fall-and-regrow-hair-60ml

Reddit. (2023, February 16). Turkey Transplant after 8 months. Transplant day vs. Present. r/tressless. https://reddit.com/r/tressless/comments/113s1rd/turkey_transplant_after_8_months_transplant_day

Reddit. (2024, March 28). Should I still have hope? Or nah?. r/tressless. https://reddit.com/r/tressless/comments/1bpsog7/should_i_still_have_hope_or_nah

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

Reddit. (2021, October 3). Need advice with finishing off my hair loss :). r/tressless. https://reddit.com/r/tressless/comments/q084x0/need_advice_with_finishing_off_my_hair_loss