Minoxidil for Hair Loss

Minoxidil for Hair Loss

Minoxidil was initially developed in the late 1950s by the Upjohn Company to treat ulcers. In 1967, Charles A. Chidsey, associate professor at the University of Colorado School of Medicine, started carrying studies on minoxidil in hypertensive patients. During his work, he noticed something unexpected: massive hair growth on the faces and shoulders of some of his women subjects, as well as hair growth on the bald part of male patients[1]. 

In the 1980s, the effects of minoxidil on human hair growth became widely recognized, as in august 1988, the FDA finally approved minoxidil for treating baldness in men under the name “Rogaine.” As per their report, the minoxidil was effective in 39% of the men involved in studies[2]. Later, in 1991, Upjohn made the product available for women too. Five years later, in February 1996, the FDA approved the over-the-counter sale of minoxidil.

To date, topical minoxidil represents the pillar treatment for androgenetic alopecia and other hair loss conditions. It’s known to promote hair growth in people with androgenic alopecia and other hair loss forms in men and women[3]. It’s also found topically in two concentrations of 2% and 5%.

How does minoxidil work?

Just as Propecia has a mechanism of blocking testosterone’s conversion to DHT, it is believed that minoxidil also has a mechanism to stop hair loss. However, even today, the mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a potassium channel opener causing hyperpolarization of cell membranes, required for early-stage cell proliferation[4]. This suggests that minoxidil increases the anagen interval in humans, which may be relevant to hair growth. Also, by widening blood vessels and opening potassium channels, minoxidil allows more oxygen, blood, and nutrients to reach hair follicles[5]. 

Does minoxidil work?

Clinical trials in androgenic alopecia patients treated with minoxidil showed a remarkable increase in hair growth, and better results were evident with the 5% formulation. For treating male androgenic alopecia, 5% minoxidil demonstrated a significant increase in the mean difference in hair density compared to the 2% minoxidil, which is more tolerable by women[6]. A study of 352 men treated with 5% minoxidil for 16-weeks showed an improved hair loss condition in all patients. They concluded that minoxidil is a safe and effective treatment for androgenic alopecia[7].

Another research demonstrated the efficacy of minoxidil in treating female androgenic alopecia[8]. 381 women between 18-49 suffering from hair loss applied topical minoxidil in 2% and 5% concentrations. Primarily hair count improvements have been noticed at 48 weeks. Results show that 5% topical minoxidil was superior to 2% minoxidil, but it causes more irritations. Minoxidil in 2% is believed to be more tolerable and appropriate for treating hair loss in women. 

Usage & side effects

Minoxidil needs to be applied regularly, once or twice daily, for visible hair growth. Also, side effects are common. Minoxidil contains inactive ingredients, including water, as well as ethanol and propylene glycol (PG)[9]. PG facilitates drug delivery into the hair follicles; however, it frequently causes irritation. Also, facial hair growth induced by minoxidil may be a concern for women. A study found that 27% of the females enrolled had facial hair growth reported at baseline[10].


Sources:

  1. https://www.magiworld.org/Journal/2006/0603_Patents.pdf
  2. https://books.google.ro/books?id=omYBD2Ncn4YC&pg=PT172&redir_esc=y#v=onepage&q&f=false
  3. Varothai S, Bergfeld WF. Androgenetic alopecia: an evidence-based treatment update. Am J Clin Dermatol. 2014 Jul;15(3):217-30. doi: 10.1007/s40257-014-0077-5. PMID: 24848508.
  4. Xu D, Wang L, Dai W, Lu L. A requirement for K+-channel activity in growth factor-mediated extracellular signal-regulated kinase activation in human myeloblastic leukemia ML-1 cells. Blood. 1999 Jul 1;94(1):139-45. PMID: 10381506.
  5. Rossi A, Cantisani C, Melis L, Iorio A, Scali E, Calvieri S. Minoxidil use in dermatology, side effects and recent patents. Recent Pat Inflamm Allergy Drug Discov. 2012 May;6(2):130-6. doi: 10.2174/187221312800166859. PMID: 22409453.
  6. Olsen EA, Dunlap FE, Funicella T, Koperski JA, Swinehart JM, Tschen EH, Trancik RJ. A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2002 Sep;47(3):377-85. doi: 10.1067/mjd.2002.124088. PMID: 12196747.
  7. Olsen EA, Whiting D, Bergfeld W, Miller J, Hordinsky M, Wanser R, Zhang P, Kohut B. A multicenter, randomized, placebo-controlled, double-blind clinical trial of a novel formulation of 5% minoxidil topical foam versus placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2007 Nov;57(5):767-74. doi: 10.1016/j.jaad.2007.04.012. Epub 2007 Aug 29. PMID: 17761356.
  8. Lucky AW, Piacquadio DJ, Ditre CM, Dunlap F, Kantor I, Pandya AG, Savin RC, Tharp MD. A randomized, placebo-controlled trial of 5% and 2% topical minoxidil solutions in the treatment of female pattern hair loss. J Am Acad Dermatol. 2004 Apr;50(4):541-53. doi: 10.1016/j.jaad.2003.06.014. PMID: 15034503.
  9. https://jpharmsci.org/article/S0022-3549(15)49613-3/pdf
  10. Dawber RP, Rundegren J. Hypertrichosis in females applying minoxidil topical solution and in normal controls. J Eur Acad Dermatol Venereol. 2003 May;17(3):271-5. doi: 10.1046/j.1468-3083.2003.00621.x. PMID: 12702063.

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