The ingredient is used in a glaucoma treatment manufactured by Allergan and was found during original drug trials to have the secondary side effect of increasing eyelash length.
A bimatoprost-containing product manufactured by Allergan and marketed for eyelash growth (Latisse) was approved last year as a prescription drug by the FDA and the company has pinned significant hopes on the product, estimating sales of over $500m a year.
Despite giving Latisse approval, the regulatory body did criticize the company’s marketing, claiming that Latisse’s potential negative side effects were not made sufficiently clear on the product's website.
Some negative side effects
According to a recent study published in the Journal of Cosmetic Dermatology, a bimatoprost-containing gel can be effective at lengthening lashes but the number of participants to experience negative side effects during use was significant.
Fifty-two patients were enrolled in the study with 16 applying a placebo gel to the eyelid margin and 36 the bimatoprost-containing gel, once a day.
After 6 months the average difference in lash length between the test and the control group was 0.89mm.
In addition a patient questionnaire revealed that more subjects in the bimatoprost group evaluated their lashes as being longer at the end of the study than at the beginning, compared to the control group.
However, 25 percent of the participants using the test gel experienced adverse effects, compared to 12.5 percent in the control group. In the test group side effects included darkening of eyelid color, reddening due to increased blood flow to the inner and outer eyelids and excessive tear production.
Four out of the 36 subjects withdrew from the study completely due to these adverse effects.
The researchers conclude that the study illustrated a significant lengthening effect of a bimatoprost-containing gel but that it is not without risk or complication.
They recommend that all patients using such products have their eyes checked regularly by an appropriate physician.
Source: Journal of Cosmetic Dermatology
2010, volume 9, pages 96-102
Bimatoprost 0.03 percent gel for cosmetic eyelash growht and enhancement
Julie A Woodward, Chris J Haggerty, Sandra S Stinnett, DrPH & Zinaria Y Williams