Adenosine: Is it true it works better for women than men? Why is that?

Adenosine has gained attention in the world of hair care as a promising active ingredient against hair loss. Its topical application has shown encouraging results in strengthening hair follicles and stimulating hair growth. But a question persists among researchers and consumers: does it work better in women than in men? Throughout this article, we will explore this question in depth, based exclusively on official and peer-reviewed research.

Adenosine is a molecule naturally produced by the human body. It is a nucleoside involved in essential cellular functions such as energy transfer and intercellular signaling.

It is especially known for its role in the production of ATP, the cell’s main energy source. However, its relevance in hair-related contexts lies in its ability to interact with specific receptors in the hair follicle. When applied topically to the scalp, adenosine binds to A2A receptors located at the base of the hair follicles. This binding triggers a cascade of biochemical signals that stimulate the anagen phase of hair growth, the active stage in which the follicle produces new hair. Unlike other molecules that simply delay hair loss, adenosine can improve the cellular environment surrounding the follicle, strengthening the hair root and contributing to a thicker hair shaft. It has also been observed that adenosine increases the production of certain growth factors, such as FGF-7, which support cellular proliferation in the follicle bulb. Additionally, it helps reduce the effects of follicular miniaturization—a process in which hair follicles progressively shrink and produce thinner hairs, typical in androgenetic alopecia.

Does adenosine work differently in men and women?

There is strong evidence suggesting that adenosine may indeed be more effective in women than in men when used to treat hair loss. This difference seems to stem, in part, from the way androgenetic alopecia manifests in each sex and from the distinct hormonal environments found in men and women. In general, androgenetic alopecia appears differently between the sexes. In men, it often starts with receding temples and hair thinning at the crown, eventually forming what is commonly known as baldness. In women, the hair loss pattern is more diffuse, with a progressive thinning at the top of the head, but without completely bald areas. This morphological difference could influence how each group responds to adenosine treatment.

A study published in 2008 in the Journal of the American Academy of Dermatology, conducted by Oura and colleagues, provided revealing data. It was a controlled clinical study comparing the effects of a 0.75% topical adenosine solution with minoxidil in patients with androgenetic alopecia. In the women’s group, adenosine produced more consistent clinical improvements, with less scalp irritation and a more positive subjective perception from users. While men also experienced benefits, their response was more irregular and less pronounced.

A key study to understand the gender difference

The study carried out by Oura and his team in Japan, published in 2008, is considered one of the cornerstones in asserting that adenosine has a better response in women. This clinical trial was designed to evaluate the efficacy and safety of a hair solution containing adenosine in Japanese women diagnosed with androgenetic alopecia. It was a randomized, double-blind study, meaning neither the participants nor the researchers knew who was receiving the active treatment.

Over twelve months, the 102 participating women applied the adenosine solution daily to the scalp. Progress was evaluated using standardized medical photographs, dermatologists’ scores, and satisfaction surveys completed by the patients themselves. At the end of the study, 83% of participants reported a visible improvement in hair density and thickness. A significant reduction was also documented in areas of hair thinning, based on comparative clinical images. Although the study was well received and provided valuable evidence, it is not without limitations. First, it focused exclusively on Japanese women, which may limit its applicability to women of other ethnicities or lifestyles. Second, it did not evaluate hormonal markers or genetic predisposition, which could also influence treatment response. Additionally, the comparison was made against minoxidil and not a placebo, leaving the question of how effective adenosine is on its own.

The influence of the female hormonal environment

One of the most plausible explanations for why adenosine seems more effective in women relates to hormonal influence. Androgenetic alopecia, especially in men, is strongly associated with the action of a hormone known as dihydrotestosterone, or DHT. This is a more active form of testosterone that tends to shrink hair follicles in sensitive areas of the scalp, eventually halting hair production. In women, DHT can also contribute to hair loss, but its impact is more moderated by the action of hormones like estrogen and progesterone. Moreover, the expression of DHT receptors and their distribution across the female scalp differs considerably from that of men. As a result, women tend to experience more diffuse hair loss without completely bald areas.

Adenosine does not act on sex hormones nor inhibit DHT like other pharmacological treatments. Its mechanism focuses instead on improving the cellular environment of the follicle, supporting hair growth from a local rather than a hormonal perspective. This could explain why women, who face less intense hormonal pressure from DHT, may benefit more from adenosine use, since their follicles still retain regenerative capacity that can be stimulated by this molecule.

What recent studies say about adenosine

In 2015, a review published in the journal Dermatology and Therapy analyzed relevant clinical trials on the use of adenosine in treating different types of alopecia. This review, conducted by Koyama and other researchers, compiled and evaluated data from studies carried out between 2001 and 2014. Although both male and female studies were included, the authors noted more consistent positive results reported by women. In trials where adenosine was used for at least six months, women showed significant improvements in hair thickness and quality, along with good product tolerance. Clinical evaluations by dermatologists, high-resolution photographic imaging, and subjective satisfaction reports were the main assessment methods. Despite its value, this review also has limitations. The heterogeneity among the included studies—that is, differences in dosage, frequency of application, and evaluation criteria—prevents entirely fair comparisons. Moreover, the review did not delve into hormonal analysis or possible ethnic differences among participants. Still, the general consensus is that adenosine has more consistent treatment outcomes in women than in men.

The stance of health authorities and expert sites

To date, the FDA (U.S. Food and Drug Administration) has not approved adenosine as an official medical treatment for androgenetic alopecia. However, countries such as Japan and South Korea have authorized its use in over-the-counter cosmetic and therapeutic products based on locally generated clinical evidence. Specialized websites like Perfect Hair Health, which reviews hair health studies from a scientific and critical standpoint, highlight that adenosine has shown effects similar to minoxidil, but with fewer side effects. According to this platform, many users find adenosine to be a more tolerable option, especially those who have experienced irritation or palpitations with minoxidil. Meanwhile, the site Hair Loss Cure 2020 has also collected reports and studies on adenosine use, noting that although it is not FDA-approved, the research behind its use is substantial and shows a positive trend, particularly in women with moderate hair thinning.

User Experiences

Community feedback from Tressless suggests that adenosine is viewed as a moderately effective hair loss treatment with potentially better responses in women than in men, particularly when compared to more established treatments like minoxidil.

In a 2023 thread titled “Adenosine vs. Minoxidil, experiences/thoughts?”, users shared that while adenosine may not be as potent as minoxidil, it tends to have a more favorable side effect profile. Some male users noted that they saw results in terms of hair texture and minor thickening but did not achieve regrowth comparable to what they experienced with minoxidil. One user highlighted that adenosine might act more gently and be a decent option for those who cannot tolerate minoxidil’s side effects such as irritation or increased shedding.

Female users, especially those with early-stage hair thinning or female pattern hair loss (FPHL), were more positive in their reports. In discussions referencing studies and personal use, women described adenosine-based products like Shiseido Adenovital and other Asian-market formulations as contributing to visible hair thickening over time. A popular thread noted that adenosine is particularly well-tolerated among women, with little to no irritation, making it a viable long-term treatment, especially for those not using hormonal options like spironolactone or finasteride. Another discussion examined the combination of adenosine and caffeine in a liposomal gel. Some users speculated that since caffeine is an adenosine receptor antagonist, it might reduce the efficacy of adenosine, although others felt any potential conflict is minor in practical use. Still, there was no definitive consensus, and users seemed to rely on personal experimentation.

Lastly, a 2018 community post comparing topical adenosine (0.75%) to minoxidil (5%) found that patient satisfaction was somewhat higher with adenosine early in treatment due to quicker perceived results and fewer side effects, although long-term regrowth was still superior with minoxidil. The lower availability of adenosine-containing products, especially outside Asia, was a common complaint, with users in the UK and USA asking where to purchase effective formulations without importing them. Overall, the Tressless community suggests that adenosine may be more effective for women, likely due to their better tolerance of the compound and possibly differing follicular response mechanisms. However, men often find its benefits modest unless combined with other treatments.

Conclusion: Does adenosine work better in women than in men?

Based on existing studies and current knowledge, the answer is yes. Adenosine appears to be more effective in women, particularly those with early to moderate stages of androgenetic alopecia. This is partly due to the less aggressive hormonal environment compared to that of men, as well as the more diffuse pattern of hair loss seen in women.

Adenosine offers an alternative with a low side-effect profile, making it especially appealing for those seeking options beyond minoxidil or hormonal treatments. Although the evidence is promising, further research is needed in diverse populations, with larger sample sizes and studies comparing results directly with placebos. Nevertheless, what we know so far justifies its inclusion as a potentially effective tool—especially for women.

References

Koyama, J., Fujimoto, M., & Oura, H. (2015). Clinical Utility of Adenosine in Androgenetic Alopecia. Dermatology and Therapy, 5(4), 331–340. https://doi.org/10.1007/s13555-015-0092-5

Oura, H., Iino, M., & Fukuzumi, T. (2008). Clinical efficacy of topical adenosine in the treatment of androgenetic alopecia in Japanese women. Journal of the American Academy of Dermatology, 59(5), 884–886. https://doi.org/10.1016/j.jaad.2008.06.043

Perfect Hair Health. (n.d.). Adenosine for Hair Growth: What the Science Really Says. Retrieved from https://perfecthairhealth.com/adenosine-hair-growth/

Hair Loss Cure 2020. (n.d.). Adenosine for Hair Growth. Retrieved from https://www.hairlosscure2020.com/adenosine-hair-loss/

U.S. Food & Drug Administration. (n.d.). Drugs@FDA: FDA-Approved Drugs. Retrieved from https://www.accessdata.fda.gov/scripts/cder/daf/ Reddit. (2023, August 7). Adenosine vs. Minoxidil, experiences/thoughts? https://reddit.com/r/tressless/comments/15l0eeu/adenosine_vs_minoxidil_experiencesthoughts/

Reddit. (2023, July 25). Is Adenosine + caffeine good combo or does caffeine cancels Adenosine affect? https://reddit.com/r/tressless/comments/1591f7d/is_adenosine_caffeine_good_combo_or_does_caffeine/

Reddit. (2018, June 28). Comparison of the efficacy of topical minoxidil 5% and adenosine 0.75% solutions on male androgenetic alopecia and measuring patient satisfaction rate. https://reddit.com/r/tressless/comments/8ui60m/comparison_of_the_efficacy_of_topical_minoxidil_5/

Reddit. (2022, August 13). Does anyone know where to buy adenosine shampoo or conditioner in the UK? https://reddit.com/r/tressless/comments/wnm3wf/does_anyone_know_where_to_buy_adenosine_shampoo/

Reddit. (2023, May 29). Anyone tried topical adenosine? https://reddit.com/r/tressless/comments/13v3468/anyone_tried_topical_adenosine/