Severity of Transient Shedding with Minoxidil for Alopecia Linked to Treatment Efficacy

New findings suggest that topical minoxidil use temporarily increases hair shedding among individuals with angrogenetic alopecia, with a longer duration for 2% minoxidil than 5%, and the severity of shedding is linked to treatment efficacy.1

These findings were the result of a study authored by Lingbo Bi, from the Department of Dermatology at Jiangsu Province Hospital and the First Affiliated Hospital of Nanjing Medical University in China. Bi and colleagues noted the limited research on shifts during the ‘shedding phase’ associated with minoxidil.

Given the notable length of androgenetic alopecia treatment periods, the investigators highlighted the importance of both patient confidence and treatment adherence during minoxidil use.2 To expand upon these topics, this analysis was conducted.

“In this study, by regularly counting the amount of shedding hairs before and after treatment, we validated the authenticity of increased shedding after minoxidil use,” Bi and colleagues wrote. “We also explored the extent and duration of temporary hair shedding, helping patients overcome shedding phase anxiety and improving treatment adherence.”1

The investigative team involved a variety of participants in their analysis, looking at those diagnosed with androgenetic alopecia at the First Affiliated Hospital of Nanjing Medical University in the timeframe between January 2023 - June 2023. The subjects were included after providing the team with written informed consent to take part.

Two cohorts were created by the investigators with the aim of categorizing participants based on their use of minoxidil. These 2 arms of the study were the 2% minoxidil arm, or the 2% group, and the 5% minoxidil group, or the 5% group.

The analysis required that all subjects met the criteria for involvement, with a confirmed angrogenetic alopecia diagnosis and signed written consent acknowledging the study's purpose and procedures being examples of such criteria.

The investigative team selected 49 individuals who were undergoing topical treatment with either 2% or 5% minoxidil for a course of 24 weeks. They evaluated density of participants' hair at a standardized location—17 cm above the glabella located along the midline of subjects' heads and faces. The team tracked hair shedding continuously for a single week, calculating both the total loss of participants' hair and the average amount of daily hair shedding.

On an every-4-week basis, the team looked into hair shedding data throughout the study's timeframe, conducting their assessment both prior to and after medication use. Additionally, they would document BASP classification and trichoscopy findings both pre- and post-minoxidil treatment.

The analysis evaluated the relative amount of hair shedding (RAHS) following a normalization of recorded hair loss. The correlations identified between sulfotransferase activity, the maximum RAHS (MRAHS), and treatment efficacy were all also noted among those in the research team.

In their findings, the team reported that a transient rise in shedding of hair among the 49 trial subjects was seen within the initial 12 weeks of treatment using minoxidil. They highlighted the length of this shedding phase, with persistence lasting longer in the 2% minoxidil cohort as opposed to those in the 5% cohort.

In one notable finding, the investigators expressed that a correlation had been identified between the severity of this hair shedding and trichoscopy improvements seen among those involved in the 5% minoxidil group. However, this was not observed within the 2% group.

Despite such conclusions, the study led to the conclusion that both treatment arms showed a significant association between MRAHS and BASP classification improvements.

“In summary, our study clarifies the temporary hair loss after topical minoxidil treatment in [androgenetic alopecia] patients by systemically evaluating the duration, extent of increase, and related factors of temporary hair loss post-treatment,” they wrote. “It provides valuable clinical evidence for the treatment of [androgenetic alopecia], helping to guide patients in understanding the temporary nature of increased hair loss with minoxidil use and improving patient compliance, thus achieving better therapeutic outcomes.”1

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References

1. Bi L, Kan H, Wang J, Ding Y, Huang Y, Wang C, Du Y, Lu C, Zhao M, Sun W, Su T, Fan W. Whether the transient hair shedding phase exist after minoxidil treatment and does it predict treatment efficacy? A retrospective study in androgenetic alopecia patients. J Dermatolog Treat. 2025 Dec;36(1):2480739. doi: 10.1080/09546634.2025.2480739. Epub 2025 Mar 23. PMID: 40122142.

2. Blumeyer A, Tosti A, Messenger A, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men. J Dtsch Dermatol Ges. 2011;9(6):S1–S57.