The 20 Most Influential Hair Research Studies of 2025
A Comprehensive Review of the Year's Groundbreaking Findings in Hair Loss Treatment and Research
Based on Dr. Donovan's Year-End Webinar | December 29, 2025
Based on Dr. Donovan's Year-End Webinar | December 29, 2025
As we close out 2025, it's an opportune time to reflect on the remarkable advances in hair research that have emerged this year. From groundbreaking insights into minoxidil dosing and delivery methods to new understandings about the connections between systemic health and hair loss, 2025 has been a pivotal year for both clinicians and patients navigating the complex landscape of hair disorders.
Dr. Donovan, a leading figure in hair loss research and treatment, recently presented his annual review of the 20 most influential hair research studies of the year. This comprehensive webinar covered seven major categories of hair research, each containing studies that will likely shape clinical practice and patient care for years to come.
In this article, we'll explore the key findings from each of these studies and discuss their practical implications for anyone dealing with hair loss or those professionals treating it.
Section 1: Minoxidil-Related Studies
Minoxidil remains one of the most widely used treatments for hair loss, and 2025 brought several important studies examining dosing strategies and delivery methods that could refine how we use this medication.Oral Minoxidil: Is 2.5 mg as Effective as 5 mg?
Study: Fonseca LPC et al. "Oral minoxidil 2.5 mg versus 5 mg for male androgenetic alopecia: A double-blind randomized clinical trial." Journal of the American Academy of Dermatology, 2026;94(1):316-317.This double-blind randomized clinical trial addressed a question that has long been debated in clinical practice: whether the higher 5 mg dose of oral minoxidil provides meaningfully better results than the lower 2.5 mg dose for male pattern hair loss. The findings have significant implications for treatment protocols, as lower doses may offer comparable efficacy with potentially fewer side effects such as hypertrichosis (unwanted hair growth) and fluid retention.
The "Dread Shed" Phenomenon: Myth or Reality?
Study: Bi L et al. "Whether the transient hair shedding phase exist after minoxidil treatment and does it predict treatment efficacy?" Journal of Dermatological Treatment, 2025;36(1):2480739.Anyone who has started minoxidil treatment has likely heard about—or experienced—the so-called "dread shed," a period of increased hair shedding that occurs in the early weeks of treatment. This retrospective study in androgenetic alopecia patients examined whether this transient shedding phase actually exists and, importantly, whether experiencing it predicts better treatment outcomes. This research helps set realistic expectations for patients beginning treatment and may help identify early responders.
Sublingual vs. Oral Minoxidil: A New Delivery Method
Study: Sanabria B et al. "Sublingual Minoxidil 5mg versus Oral Minoxidil 5mg for male androgenetic alopecia: A double-blind randomized clinical trial." Journal of the European Academy of Dermatology and Venereology, 2025;39:e700-e702.This innovative study compared sublingual (under-the-tongue) administration of minoxidil with traditional oral dosing. Sublingual delivery bypasses first-pass metabolism in the liver, potentially leading to different pharmacokinetics and possibly improved efficacy or reduced side effects. This research opens new possibilities for optimizing minoxidil delivery in clinical practice.
Long-Term Benefits: Continued Improvement Beyond Year One
Study: Kushnir-Grinbaum D et al. "Continued year-on-year improvement in hair density with systemic minoxidil in women with female pattern hair loss: A case series." Journal of the American Academy of Dermatology, 2025;93(1):279-280.While many studies focus on short-term results, this case series documented continued year-on-year improvement in hair density among women using systemic minoxidil for female pattern hair loss. This finding is encouraging for patients who may wonder whether the benefits plateau after the first year of treatment—the evidence suggests that continued use can lead to ongoing improvements.
Section 2: Antiandrogen-Related Studies
Antiandrogen medications, including 5-alpha reductase inhibitors like finasteride and dutasteride, are cornerstone treatments for androgenetic alopecia. The 2025 research addressed important safety questions and explored new dosing strategies.5-Alpha Reductase Inhibitors and Gynecologic Safety
Study: Singal A et al. "Exposure to 5-Alpha Reductase Inhibitors and Spironolactone Is Not Associated With Increased Odds of Gynecologic Tumors in a Large Cohort Study of Patients With Alopecia." International Journal of Dermatology, 2025;64:2131-2133.This large cohort study provided reassuring data for women using antiandrogen medications for hair loss. The research found no association between exposure to 5-alpha reductase inhibitors or spironolactone and increased risk of gynecologic tumors. This finding helps address concerns that have limited the use of these potentially effective treatments in women.
Breast Health Outcomes in Women on 5-Alpha Reductase Inhibitors
Study: Venkatesh T et al. "Analysis of breast health outcomes in women on oral 5-alpha reductase inhibitors: A single-center retrospective cohort study." Journal of the American Academy of Dermatology, 2025;92(1):163-164.Complementing the previous study, this research specifically examined breast health outcomes in women taking oral 5-alpha reductase inhibitors. As these medications continue to gain traction for treating female pattern hair loss, understanding their long-term safety profile becomes increasingly important. This study contributes valuable real-world data to inform clinical decision-making.
Intermittent Dutasteride: A New Dosing Paradigm?
Study: Sereepanpanich V et al. "Efficacy and safety of twice- or thrice-weekly dutasteride versus daily finasteride in men with androgenetic alopecia: A randomized, investigator-blinded, active-controlled, parallel-group pilot study." JAAD International, 2025;23:69-76.This pilot study explored whether intermittent dosing of dutasteride (two or three times weekly) could match the efficacy of daily finasteride. Given dutasteride's longer half-life, less frequent dosing could reduce medication burden and potentially side effects while maintaining therapeutic benefits. This approach could offer patients more flexible treatment options.
Section 3: Telogen Effluvium
Telogen Effluvium as a Precursor to Pattern Baldness
Study: Asfour L et al. "You cannot go bald without first losing your hair: telogen effluvium is a precursor to, prerequisite for and potentially an incitant to common baldness in men." Clinical and Experimental Dermatology, 2025;00:1-6.This provocative study challenges conventional thinking about the relationship between telogen effluvium (diffuse, often stress-related shedding) and androgenetic alopecia (pattern baldness). The researchers argue that telogen effluvium may not just be a separate condition but could actually be a precursor, prerequisite, and potential trigger for the development of pattern baldness in men. This conceptual framework has important implications for how we understand and treat hair loss progression.
Section 4: GLP-1 Receptor Agonist-Related Hair Loss
Hair Loss and Weight Loss Medications: What's the Connection?
Study: Burke O et al. "Glucagon-like peptide-1 receptor agonist medications and hair loss: A retrospective cohort study." Journal of the American Academy of Dermatology, 2025;92(5):1141-1142.With the explosive popularity of GLP-1 receptor agonists like semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) for weight loss and diabetes management, concerns about hair loss as a potential side effect have emerged. This retrospective cohort study examined the association between these medications and hair loss, providing important data for the millions of patients now using these drugs. Understanding whether hair loss is directly medication-related or secondary to rapid weight loss and nutritional changes is crucial for patient counseling and management.
Section 5: Alopecia Areata
Alopecia areata, an autoimmune condition causing patchy hair loss, was the subject of several important 2025 studies that expanded our understanding of its causes, associations, and treatment options.Early Antibiotics and Pediatric Alopecia Areata Risk
Study: Kim SR, Park SH, Koh S-J, Park H. "Association of infantile antibiotic exposure and its changes with pediatric alopecia areata." Journal of Investigative Dermatology, 2025;145:188-190.This study explored the intriguing connection between early-life antibiotic exposure and the development of alopecia areata in children. As we learn more about the gut microbiome's role in immune function, understanding how antibiotic-induced dysbiosis might contribute to autoimmune conditions becomes increasingly relevant. This research adds to the growing body of evidence connecting gut health to hair health.
The Gut-Skin Connection: Microscopic Colitis and Alopecia Areata
Study: Hirpara M, Greene R, Chapman M, Albers CG, Mesinkovska N. "Microscopic colitis in alopecia areata: A gut-skin connection beyond the follicle." JAAD International, 2025;23:55-57.Building on the gut-skin axis theme, this study identified an association between microscopic colitis—an inflammatory bowel condition—and alopecia areata. This finding reinforces the concept that alopecia areata is not simply a hair follicle disease but part of a broader systemic immune dysregulation that can manifest in multiple organ systems.
Oral Minoxidil for Alopecia Areata
Study: Kalil L, Valido K, Peterson D, King B. "Oral minoxidil treatment of alopecia areata." Journal of the American Academy of Dermatology, 2025;93(4):1099-1101.While JAK inhibitors have revolutionized alopecia areata treatment, oral minoxidil offers a potentially more accessible and affordable option. This study examined the efficacy of oral minoxidil specifically for alopecia areata, providing data that could expand treatment options for patients who may not have access to or tolerate JAK inhibitors.
JAK Inhibitors and Pregnancy: A Clinical Challenge
Study: Ogbutor C, Chen L-C, Kalil LL, et al. "Discontinuation and restart of Janus kinase inhibitors due to pregnancy in alopecia areata: a case series." International Journal of Women's Dermatology, 2025.As JAK inhibitors become standard treatment for severe alopecia areata, managing these medications around pregnancy presents a clinical challenge. This case series documented the outcomes of women who discontinued JAK inhibitors due to pregnancy and subsequently restarted treatment, providing valuable guidance for managing this increasingly common clinical scenario.
Section 6: Seborrheic Dermatitis
Seborrheic Dermatitis and Systemic Associations
Study: Meng S, Berna R, Hoffstad O, Takeshita J, Shin D, Chiesa Fuxench ZC, Margolis DJ. "Epithelial Barrier Diseases Among Adult Patients With Seborrheic Dermatitis." JAMA Dermatology, Published online November 5, 2025.This JAMA Dermatology study examined the relationship between seborrheic dermatitis and other epithelial barrier diseases. Seborrheic dermatitis, while often dismissed as simply "dandruff," can significantly impact scalp health and may contribute to hair concerns. Understanding its associations with other barrier dysfunction conditions helps contextualize it within broader patterns of immune and barrier-related diseases.
Section 7: Scarring Alopecias
Scarring alopecias, conditions where hair follicles are permanently destroyed, represent some of the most challenging hair disorders to treat. The 2025 research brought new insights across multiple types of scarring hair loss.Lichen Planopilaris: Doxycycline Dosing Strategies
Study: Needle C et al. "Efficacy and tolerability of low-dose versus high-dose doxycycline in the management of lymphocytic scarring alopecias." Journal of the American Academy of Dermatology, 2025;92(6):1431-1433.Doxycycline, with its anti-inflammatory properties beyond its antibiotic effects, is commonly used for lymphocytic scarring alopecias like lichen planopilaris. This study compared low-dose versus high-dose regimens, helping clinicians optimize treatment while minimizing side effects such as gastrointestinal upset and photosensitivity.
Frontal Fibrosing Alopecia: Affluence, Not Race, as Risk Factor
Study: Wyche J et al. "Odds of developing frontal fibrosing alopecia more closely tied to affluence than race: A retrospective cohort study." Journal of the American Academy of Dermatology, 2025;93(3):830-831.This thought-provoking study challenged previous assumptions about who develops frontal fibrosing alopecia (FFA). The research found that affluence was more closely associated with FFA risk than race, suggesting that environmental exposures common among higher socioeconomic groups—potentially cosmetic products, fragrances, or other lifestyle factors—may play a role in disease development. This finding redirects research attention toward modifiable environmental risk factors.
Topical JAK Inhibitor for Frontal Fibrosing Alopecia
Study: Martin A, Shokrian N, Kelley KJ, Correa da Rosa J, Del-Duca E, Bissonnette R, et al. "Randomized Controlled Trial of the Topical JAK Inhibitor Delgocitinib Cream in Patients with Frontal Fibrosing Alopecia." Journal of Investigative Dermatology, 2025.This randomized controlled trial tested delgocitinib cream, a topical JAK inhibitor, in patients with frontal fibrosing alopecia. Topical JAK inhibition could offer the benefits of this class of medications while minimizing systemic exposure and potential side effects. The results of this trial could open new treatment avenues for this challenging condition.
Central Centrifugal Cicatricial Alopecia and Insulin Resistance
Study: Wyche J, Aguh C. "Homeostasis model assessment of insulin resistance enhances detection of insulin resistance in younger patients with central centrifugal cicatricial alopecia." Journal of the American Academy of Dermatology, 2025;93(6):1599-1600.Central centrifugal cicatricial alopecia (CCCA) primarily affects women of African descent, and emerging research has linked it to metabolic dysfunction. This study demonstrated that the HOMA-IR calculation (a measure of insulin resistance) is more effective at detecting metabolic dysfunction in younger CCCA patients than standard measures. This finding supports a more holistic approach to CCCA treatment that addresses underlying metabolic factors.
Hair Transplantation in Folliculitis Decalvans
Study: Cova-Martín R et al. "Hair transplantation in folliculitis decalvans: Outcome description in a multicentre series of 11 patients." Journal of the European Academy of Dermatology and Venereology, 2025;39:e845-e849.Hair transplantation in the setting of scarring alopecia has traditionally been approached with caution due to concerns about disease reactivation. This multicenter case series documented outcomes of hair transplantation in patients with folliculitis decalvans, providing evidence that carefully selected patients can achieve successful results. This expands surgical options for patients whose disease has been adequately controlled.
Dissecting Cellulitis and Cardiovascular Risk
Study: Patel D, Thakker S, Olagun-Samuel C, et al. "Long-term cardiovascular morbidity in dissecting cellulitis: A propensity-matched TrinetX cohort study." Journal of the American Academy of Dermatology, 2025;93(6):1614-1616.This large cohort study revealed an association between dissecting cellulitis of the scalp and increased long-term cardiovascular morbidity. As dissecting cellulitis is an inflammatory condition, this connection aligns with what we understand about systemic inflammation and cardiovascular risk. The finding underscores the importance of addressing overall health, not just hair concerns, in patients with this condition.
Looking Ahead: Implications for 2026 and Beyond
The 20 studies highlighted in Dr. Donovan's 2025 year-end review reflect several important themes in hair research:Optimization of existing treatments: Studies on minoxidil dosing, delivery methods, and antiandrogen scheduling demonstrate that we continue to refine how we use established therapies to maximize efficacy and minimize side effects.
The systemic nature of hair disorders: From gut-skin connections to metabolic dysfunction and cardiovascular risk, hair loss is increasingly understood as reflecting broader health status rather than being purely a cosmetic concern.
Safety reassurance: Multiple studies provided reassuring long-term safety data for commonly used treatments, helping patients and clinicians make more informed decisions.
Environmental and lifestyle factors: Research linking conditions like FFA to affluence and examining the impact of GLP-1 agonists highlights how our modern environment and treatment choices affect hair health.
As we enter 2026, these studies will shape clinical practice and open new research directions. For patients dealing with hair loss, the message is hopeful: the field continues to advance, with more treatment options, better understanding of underlying causes, and increasingly personalized approaches to care.
AGA
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