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A space filling model of the molecule.
Clinical data
Trade names Rogaine
AHFS/Drugs.com Monograph
  • US: C (Risk not ruled out)
Routes of
Oral / topical
ATC code
Legal status
Legal status
  • UK: P (Pharmacy medicines) (for topical use, otherwise POM. Cannot be prescribed on the NHS)
Pharmacokinetic data
Metabolism Primarily hepatic
Biological half-life 4.2 h
Excretion renal
CAS Number
PubChem CID
PDB ligand
ECHA InfoCard 100.048.959
Chemical and physical data
Formula C9H15N5O
Molar mass 209.251 g/mol
3D model (Jmol)
Melting point 248 °C (478 °F)
Solubility in water <1 mg/mL (20 °C)
 NYesY (what is this?)  (verify)

Minoxidil is an antihypertensive vasodilator medication. It also slows hair loss and promotes hair regrowth in some people. It is available as a generic medication and over the counter for the treatment of androgenic alopecia, a form of hair loss, in men and women.[4]

Medical uses[edit]

Minoxidil, applied topically, is widely used for the treatment of hair loss. It is effective in helping promote hair growth in both men and women with androgenic alopecia.[5] About 40% of men experience hair regrowth after 3–6 months.[6] Minoxidil must be used indefinitely for continued support of existing hair follicles and the maintenance of any experienced hair regrowth.[4]

Its effect in people with alopecia areata is unclear.[7]

Side effects[edit]

Minoxidil is generally well tolerated, but common side effects include burning or irritation of the eye, itching, redness or irritation at the treated area, as well as unwanted hair growth elsewhere on the body. Exacerbation of hair loss/alopecia has been reported.[8][9] Severe allergic reactions may include rash, hives, itching, difficulty breathing, tightness in the chest, swelling of the mouth, face, lips, or tongue, chest pain, dizziness, fainting, tachycardia, headache, sudden and unexplained weight gain, or swelling of the hands and feet.[10] Temporary hair loss is a common side effect of minoxidil treatment.[11] Manufacturers note that minoxidil-induced hair loss is a common side effect and describe the process as "shedding".

Alcohol and propylene glycol present in some topical preparations may dry the scalp, resulting in dandruff and contact dermatitis.[12]

Side effects of oral minoxidil may include swelling of the face and extremities, rapid and irregular heartbeat, lightheadedness, cardiac lesions, and focal necrosis of the papillary muscle and subendocardial areas of the left ventricle.[9] There have been cases of allergic reactions to minoxidil or the non-active ingredient propylene glycol, which is found in some topical minoxidil formulations. Pseudoacromegaly is an extremely rare side effect reported with large doses of oral minoxidil.[13]

Mechanism of action[edit]

The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Hypothetically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood, and nutrients to the follicles. This may cause follicles in the telogen phase to shed, which are then replaced by thicker hairs in a new anagen phase. Minoxidil is a prodrug that is converted by sulfation via the sulfotransferase enzyme SULT1A1 to its active form, minoxidil sulfate. Several studies demonstrated that the activity of sulfotransferase in hair follicles predict minoxidil response in the treatment of hair loss.[14][15][16]

Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men who have experienced hair loss for less than 5 years. Minoxidil use is indicated for central (vertex) hair loss only.[17] Minoxidil is also a vasodilator.[18] Two clinical studies are being conducted in the US for a medical device that may allow patients to determine if they are likely to benefit from minoxidil therapy.[19]


Initial application[edit]

Minoxidil was developed in the late 1950s by the Upjohn Company (later became part of Pfizer) to treat ulcers. In trials using dogs, the compound did not cure ulcers, but proved to be a powerful vasodilator. Upjohn synthesized over 200 variations of the compound, including the one it developed in 1963 and named minoxidil.[20] These studies resulted in FDA approving minoxidil (with the trade name 'Loniten') in the form of oral tablets to treat high blood pressure in 1979.[21]

Hair growth[edit]

When Upjohn received permission from the FDA to test the new drug as medicine for hypertension they approached Charles A. Chidsey MD, Associate Professor of Medicine at the University of Colorado School of Medicine.,[20] who conducted two studies,[22][23] the second study showing unexpected hair growth. Puzzled by this side-effect, Chidsey consulted Guinter Kahn and discussed the possibility of using minoxidil for treating hair loss.

Kahn along with his colleague Paul J. Grant MD obtained a certain amount of the drug and conducted their own research, apparently without notifying Upjohn or Chidsey.[24] The two doctors had been experimenting with a 1% solution of minoxidil mixed with several alcohol-based liquids.[25] They tried to patent the drug for hair loss prevention, but found that Upjohn had already done this. A decade-long trial between Kahn and Upjohn ended with Kahn's name included in a consolidated patent (U.S. #4,596,812 Charles A Chidsey, III and Guinter Kahn) in 1986 and royalties from the company to both Kahn and Grant.[24]

Meantime the effect of minoxidil on hair loss prevention was so clear that in the 80's physicians were prescribing Loniten off-label to their balding patients.[21]

In August 18, 1988 the FDA finally approved the drug for treating baldness in men[21][25] under the trade name 'Rogaine' (FDA rejected Upjohn's first choice, Regain, as misleading[26]). The agency concluded that although "the product will not work for everyone", 39 percent of the men studied had "moderate to dense hair growth on the crown of the head".[26]

In 1991 Upjohn made the product available for women.[25]

On February 12, 1996 FDA approved both the over-the-counter sale of the drug and the production of generic formulations of minoxidil.[21] Upjohn replied to that by lowering prices to half the price of the prescription drug[25] and by releasing a prescription 5% formula of Rogaine in 1997.[21]

In 1998 a 5% formulation of minoxidil was approved for nonprescription sale by the FDA.[27]

As of 2014 it was the only topical product that is FDA-approved for androgenic hair loss.[5]

The drug is available over the counter in the United Kingdom.[4]

Trade names[edit]

Minoxidil is marketed under many trade names worldwide.[28]


Alternate formulations of minoxidil have been explored in order to reduce contact dermatitis from the alcohol and propylene glycol vehicle.[29][30]

See also[edit]


  1. ^ product, sigma. "M4145 Sigma ≥99% (TLC)". sigmaaldrich.com. sigma. Retrieved 29 September 2016. 
  2. ^ cayman chemical, company. "safety data sheet" (PDF). caymanchem.com. cayman chemical company. Retrieved 29 September 2016. 
  3. ^ archives, dailymed. "loniten- minoxidil tablet". dailymed.nlm.nih.gov. dailymed. Retrieved 29 September 2016. 
  4. ^ a b c "Minoxidil Regular Strength". UK Electronic Medicines Compendium. 18 August 2015. Retrieved 8 January 2017. 
  5. ^ a b Varothai, S; Bergfeld, WF (July 2014). "Androgenetic alopecia: an evidence-based treatment update.". American journal of clinical dermatology. 15 (3): 217–30. doi:10.1007/s40257-014-0077-5. PMID 24848508. 
  6. ^ "Clinical utility and validity of minoxidil response testing in androgenetic alopecia.". Dermatol Ther. 28 (1): 13–6. doi:10.1111/dth.12164. PMID 25112173. 
  7. ^ Hordinsky, M; Donati, A (July 2014). "Alopecia areata: an evidence-based treatment update.". American journal of clinical dermatology. 15 (3): 231–46. doi:10.1007/s40257-014-0086-4. PMID 25000998. 
  8. ^ http://www.drugs.com/sfx/rogaine-side-effects.html
  9. ^ a b "Minoxidil Official FDA information, side effects and uses". Drugs.com. 
  10. ^ Rogaine Side Effects | Drugs.com
  11. ^ FAQs | Rogaine
  12. ^ "Dandruff and Seborrheic Dermatitis". Medscape.com. Retrieved 2009-10-09. 
  13. ^ Nguyen, K.; Marks Jr, J. (2003). "Pseudoacromegaly induced by the long-term use of minoxidil". Journal of the American Academy of Dermatology. 48 (6): 962–965. doi:10.1067/mjd.2003.325. PMID 12789195. 
  14. ^ Goren, A.; Shapiro, J.; Roberts, J.; McCoy, J.; Desai, N.; Zarrab, Z.; Pietrzak, A.; Lotti, T. (2015). "Clinical utility and validity of minoxidil response testing in androgenetic alopecia". Dermatologic Therapy. 28: 13–6. doi:10.1111/dth.12164. PMID 25112173. 
  15. ^ Roberts, J.; Desai, N.; McCoy, J.; Goren, A. (2014). "Sulfotransferase activity in plucked hair follicles predicts response to topical minoxidil in the treatment of female androgenetic alopecia". Dermatologic Therapy. 27 (4): 252–254. doi:10.1111/dth.12130. 
  16. ^ Goren, A.; Castano, J. A.; McCoy, J.; Bermudez, F.; Lotti, T. (2014). "Novel enzymatic assay predicts minoxidil response in the treatment of androgenetic alopecia". Dermatologic Therapy. 27 (3): 171–173. doi:10.1111/dth.12111. 
  17. ^ Scow, DT; Nolte, RS; Shaughnessy, AF (April 1999). "Medical treatments for balding in men". Am Fam Physician. 59 (8): 2189–94. PMID 10221304. 
  18. ^ Vasodilators | MayoClinic.com
  19. ^ Minoxidil Response Testing in Males With Androgenetic Alopecia
  20. ^ a b Douglas Martin (2014-09-19). "Guinter Kahn, Inventor of Baldness Remedy, Dies at 80". https://www.nytimes.com/. The New York Times. Archived from the original on 2015-05-11. Retrieved 2015-05-11.  External link in |website= (help)
  21. ^ a b c d e Conrad, Peter (2008). "Extension". The Medicalization of Society: On the Transformation of Human Conditions into Treatable Disorders. JHU Press. p. 37. ISBN 0801892341. Retrieved 2015-05-11.  (Google Books)
  22. ^ Gilmore, Edward; Weil, John; Chidsey, Charles (March 5, 1970). "Treatment of Essential Hypertension with a New Vasodilator in Combination with Beta-Adrenergic Blockade". The New England Journal of Medicine, 10. Massachusetts Medical Society. 282: 521–527. doi:10.1056/NEJM197003052821001. Archived from the original on 2015-05-11. Retrieved 2015-05-11. 
  23. ^ Gottlieb, Thomas; Katz, Fred; Chidsey, Charles (March 1972). "Combined Therapy with Vasodilator Drugs and Beta Adrenergic Blockade". Circulation. Lippincott Williams & Wilkins. XLV: 571–582. doi:10.1161/01.CIR.45.3.571. Archived from the original (PDF) on 2015-05-11. Retrieved 2015-05-11. 
  24. ^ a b Norman M. Goldfarb. "When Patents Became Interesting in Clinical Research". The Journal of Clinical Research Best Practices, Vol. 2, No. 3, March 2006. Archived from the original (PDF) on 2015-05-11. Retrieved 2015-05-11. 
  25. ^ a b c d Will Lester (May 13, 1996). "Hair-rasing tale: no fame for men who discovered Rogaine". The Daily Gazette. Retrieved 2015-05-11. 
  26. ^ a b Kuntzman, Gersh (2001). Hair!: Mankind's Historic Quest to End Baldness. Random House Publishing Group. p. 172. ISBN 0679647090. Retrieved 2015-05-11.  (Google Books)
  27. ^ Pray, Stephen W. (2006). Nonprescription Product Therapeutics. Lippincott Williams & Wilkins. p. 663. ISBN 0781734983. Retrieved 2015-05-11.  (Google Books)
  28. ^ Drugs.com International brand names for minoxidil Page accessed April 8, 2016
  29. ^ Balakrishnan P, Shanmugam S, Lee WS, Lee WM, Kim JO, Oh DH, Kim DD, Kim JS, Yoo BK, Choi HG, Woo JS, Yong CS (1 February 2009). "Formulation and in vitro assessment of minoxidil Nanosomes for enhanced skin delivery". International Journal of Phermaceutics. 377 (1-2): 1–8. doi:10.1016/j.ijpharm.2009.04.020. PMID 19394413. 
  30. ^ Padois K, Cantiéni C, Bertholle V, Bardel C, Pirot F, Falson F (16 June 2011). "Solid lipid nanoparticles suspension versus commercial solutions for dermal delivery of minoxidil". International Journal of Pharmaceutics. 416 (1): 300–304. doi:10.1016/j.ijpharm.2011.06.014. PMID 21704140. 

External links[edit]