What is levocetirizine?

Levocetirizine is an antihistamine that also has anti-inflammatory properties. Levocetirizine is the purified and concentrated active version of cetirizine. Cetirizine is comprised of 50% levocetirizine. Levocetirizine blocks prostaglandin D2 and increases the release of prostaglandin E2. Prostaglandin E2 stimulates hair growth, while prostaglandin D2 inhibits hair growth.1 

Why is levocetirizine part of my treatment regimen?

Your genetic profile indicates you have normal activity of the prostaglandin D2 receptor, which promotes hair loss. Inhibiting this and increasing prostaglandin E2 will favor hair growth.

Is topical levocetirizine effective for alopecia?

1% topical cetirizine has been evaluated in clinical trials for alopecia. These trials found improved hair density, hair diameter with cetirizine, and self-reported symptom severity.1-3  

Are there adverse effects when using topical levocetirizine?

Topical cetirizine is well tolerated. One clinical study showed no adverse effects with topical treatment, however, topical therapy with any agent can result in skin reactions such as redness, rash, irritation, or hives.1 

Why do I need to keep taking cetirizine?

Continuous use for four months is recommended before evaluating treatment response. Hair shedding may occur at the initiation of treatment as hair follicles are being stimulated to reenter the growth phase, but this frequently subsides within two months. Hair growth usually occurs within four to eight months and stabilizes over 12 to 18 months. Hair loss will occur over several months if treatment is stopped because of the nature of the hair growth cycle. Cetirizine is not a cure for hair loss; it is a treatment.


  1. Hossein Mostafa D, Samadi A, Niknam S, Nasrollahi SA, Guishard A, Firooz A. Efficacy of Cetirizine 1% Versus Minoxidil 5% Topical Solution in the Treatment of Male Alopecia: A Randomized, Single-blind Controlled Study. J Pharm Pharm Sci. 2021;24:191-199. doi:10.18433/jpps31456
  2. Rossi A, Campo D, Fortuna MC, et al. A preliminary study on topical cetirizine in the therapeutic management of androgenetic alopecia. J Dermatolog Treat. 2018;29(2):149-151. doi:10.1080/09546634.2017.1341610
  3. Zaky MS, Abo Khodeir H, Ahmed HA, Elsaie ML. Therapeutic implications of topical cetirizine 1% in treatment of male androgenetic alopecia: A case-controlled study. J Cosmet Dermatol. 2021;20(4):1154-1159. doi:10.1111/jocd.13940