A retrospective review of 178 patients published in the Journal of the American Academy of Dermatology in April 2026 found that low-dose oral minoxidil (LDOM) produces measurable improvements in frontal hair density within the first 3–6 months of treatment — but that the response plateaus at that point, with no statistically significant further gains detected through 36 months of follow-up.1
About the Study
The study, titled Time to Maximal Response with Low-Dose Oral Minoxidil in Clinical Treatment of Androgenetic Alopecia, was co-led by Archie Spindler and Derek Maas from the New York University Grossman School of Medicine, alongside collaborators Isabella Zappi, Margaret Cote, Esha Patel, Sarah Go, Jolie Kantor, Jerry Shapiro, and Kristen I. Lo Sicco.1
The researchers conducted a retrospective review of patients with androgenetic alopecia (AGA) who received LDOM at NYU between January 2020 and October 2025. The cohort included 178 patients who had at least one baseline and one follow-up frontal hair measurement on record. The median follow-up period was 18 months.
Study Design
Retrospective cohort review conducted at New York University Grossman School of Medicine, analysing real-world clinical data from patients treated between January 2020 and October 2025.
Patient Cohort
178 patients with androgenetic alopecia who received low-dose oral minoxidil and had at least one baseline and one follow-up frontal hair measurement available for analysis.
Follow-Up Intervals
Patients were assessed at three structured follow-up windows: 3–6 months, 6–12 months, and 12–36 months post-treatment initiation. Median follow-up duration was 18 months.
Key Findings
The study's central finding was that the therapeutic response to LDOM follows a front-loaded trajectory. Measurable increases in frontal hair density were documented within the first 3–6 months of treatment, consistent with the known anagen-phase stimulatory effect of minoxidil. Critically, however, no statistically significant additional hair density gains were observed at either the 6–12 month or 12–36 month follow-up intervals.1
Hair growth with low-dose oral minoxidil appears to peak by 6 months — not to decline, but to stabilise. Patients who are responding at 6 months are effectively seeing their best result, maintained long-term.
This plateau does not represent treatment failure. Patients who responded by 6 months maintained that improvement through the 36-month observation window, indicating that LDOM provides durable stabilisation of hair density rather than progressive cumulative gain. The implication is that the drug's primary value — in terms of new hair growth — is concentrated in the first treatment cycle.
Low-dose oral minoxidil commenced. Some patients experience a transient telogen effluvium (initial shedding) as follicles are recruited from resting to active growth phase — a normal and self-limiting response.2
Measurable improvements in frontal hair density documented in the NYU cohort. This 3–6 month interval represents the most clinically meaningful period of new hair growth with LDOM — the primary window for objective treatment response assessment.1
No statistically significant additional hair density gains detected beyond the 6-month mark. Treatment benefit is maintained rather than amplified. This stabilisation phase still represents a clinically meaningful outcome — the gains made are preserved.1
Continued measurement to 36 months confirmed no significant further improvement over the 6-month baseline response. LDOM functions as a maintenance therapy sustaining the initial growth response rather than producing cumulative gains over years.1
Clinical Implications
These findings carry direct relevance for how clinicians counsel patients commencing LDOM therapy. Several practical points emerge from the data.
Set Realistic Timelines
Patients should be counselled that the 3–6 month window is when they are most likely to see new hair growth. If significant improvement has not occurred by 6 months, extending treatment in the hope of further gain may not be warranted without reassessment.1
Plateau Is Not Failure
The absence of further growth after 6 months does not mean the treatment has stopped working. Stabilisation — preventing ongoing loss and maintaining the gains achieved — remains a clinically meaningful endpoint in androgenetic alopecia management.3
Assess Response at 6 Months
The 6-month mark is the optimal clinical review point to evaluate whether LDOM has delivered meaningful benefit. Standardised photography and trichoscopic measurement at this interval allows an objective and timely treatment assessment.1,4
Maintenance Matters
Cessation of minoxidil — oral or topical — typically results in shedding of the regrown hair within 3–6 months as follicles return to their previous miniaturisation trajectory. The gains made by 6 months require continued treatment to be sustained.2,5
Why Oral Minoxidil Behaves This Way
The plateau pattern observed is biologically consistent with what we understand about minoxidil's mechanism of action. Minoxidil — whether oral or topical — works primarily by prolonging the anagen (growth) phase of the hair cycle and recruiting telogen follicles back into active growth.5 Once this recruitment and cycle prolongation has occurred across the susceptible follicular population, there are no additional follicles to stimulate. The drug has achieved its effect on the available pool.
This is fundamentally different from the mechanism of 5α-reductase inhibitors such as finasteride or dutasteride, which continue to act on the androgen pathway over time and may show more progressive improvement over 12–24 months as miniaturised follicles gradually reverse their trajectory.3 For patients where early, measurable growth is the priority, LDOM's front-loaded response profile may be an advantage. For those expecting cumulative gains over years, this data recalibrates that expectation.
Study Limitations
The authors appropriately acknowledged several limitations that should be considered when interpreting these findings.
| Limitation | Clinical Consideration |
|---|---|
| Retrospective design | No randomisation or control group; results reflect real-world use but cannot exclude confounding variables |
| Unequal follow-up group sizes | Potential attrition bias — patients who discontinued or were lost to follow-up may have had different outcomes |
| Single measurement site | Frontal scalp measurements may not reflect vertex or temporal response, which can differ in androgenetic alopecia |
| Adherence unverifiable | Patient compliance with daily oral dosing could not be confirmed from clinical records |
Read the Full Article
The full study is published as a brief report in the Journal of the American Academy of Dermatology and is available via the link below.
Conclusion
This NYU retrospective review provides useful real-world data on the treatment timeline for low-dose oral minoxidil. The principal takeaway is that LDOM's hair growth benefit is concentrated in the first 3–6 months, followed by a durable plateau — not progressive cumulative gain. For clinicians, this reinforces the importance of early, objective response assessment at the 6-month mark and clear patient communication about what continued treatment achieves: preservation of improvement rather than ongoing regrowth. As with all alopecia pharmacotherapy, the treatment is a commitment to long-term maintenance of the result it delivers.
References
- Spindler A, Maas D, Zappi I, et al. Time to maximal response with low-dose oral minoxidil in clinical treatment of androgenetic alopecia. J Am Acad Dermatol. 2026. doi:10.1016/j.jaad.2026.04.019
- Suchonwanit P, Thammarucha S, Leerunyakul K. Minoxidil and its use in hair disorders: a review. Drug Des Devel Ther. 2019;13:2777–2786.
- Gupta AK, Talukder M, Venkataraman M, Bamimore MA. Minoxidil: a comprehensive review. J Dermatolog Treat. 2022;33(4):1896–1906.
- Randolph M, Tosti A. Oral minoxidil treatment for hair loss: A review of efficacy and safety. J Am Acad Dermatol. 2021;84(3):737–746.
- Penha MA, Shapiro J, Lartey RT, et al. Oral minoxidil versus topical minoxidil for male androgenetic alopecia: a randomized clinical trial. JAMA Dermatol. 2024;160(2):156–163.
- Ramos PM, Sinclair RD, Kasprzak M, Miot HA. Minoxidil 1 mg oral versus minoxidil 5% topical solution for the treatment of female-pattern hair loss: a randomized clinical trial. J Am Acad Dermatol. 2020;82(1):252–253.