Safety of low-dose oral minoxidil for hair loss: A multicenter study of 1404 patients

J Am Acad Dermatol. 2021 Jun;84(6):1644-1651. doi: 10.1016/j.jaad.2021.02.054. Epub 2021 Feb 24.


Background: The major concern regarding the use of low-dose oral minoxidil (LDOM) for the treatment of hair loss is the potential risk of systemic adverse effects.

Objective: To describe the safety of LDOM for the treatment of hair loss in a large cohort of patients.

Methods: Retrospective multicenter study of patients treated with LDOM for at least 3 months for any type of alopecia.

Results: A total of 1404 patients (943 women [67.2%] and 461 men [32.8%]) with a mean age of 43 years (range 8-86) were included. The dose of LDOM was titrated in 1065 patients, allowing the analysis of 2469 different cases. The most frequent adverse effect was hypertrichosis (15.1%), which led to treatment withdrawal in 14 patients (0.5%). Systemic adverse effects included lightheadedness (1.7%), fluid retention (1.3%), tachycardia (0.9%), headache (0.4%), periorbital edema (0.3%), and insomnia (0.2%), leading to drug discontinuation in 29 patients (1.2%). No life-threatening adverse effects were observed.

Limitations: Retrospective design and lack of a control group.

Conclusion: LDOM has a good safety profile as a treatment for hair loss. Systemic adverse effects were infrequent and only 1.7% of patients discontinued treatment owing to adverse effects.

Keywords: alopecia; androgenetic alopecia; arterial hypotension; dizziness; edema; effluvium; fluid retention; frontal fibrosing alopecia; hair loss; hypertrichosis; lichen planopilaris; lightheadedness; new treatments; periorbital edema; safety; tachycardia.

Publication types

  • Multicenter Study

MeSH terms

  • Administration, Oral
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Alopecia / drug therapy*
  • Child
  • Dizziness / chemically induced
  • Dizziness / epidemiology
  • Edema / chemically induced
  • Edema / epidemiology
  • Female
  • Headache / chemically induced
  • Headache / epidemiology
  • Humans
  • Hypertrichosis / chemically induced
  • Hypertrichosis / epidemiology
  • Male
  • Middle Aged
  • Minoxidil / administration & dosage
  • Minoxidil / adverse effects*
  • Retrospective Studies
  • Sleep Initiation and Maintenance Disorders / chemically induced
  • Sleep Initiation and Maintenance Disorders / epidemiology
  • Tachycardia / chemically induced
  • Tachycardia / epidemiology
  • Young Adult


  • Minoxidil