Korean Researchers Challenge Study Linking Hair Loss Medication to Adverse Effects

On the 5th of this month, a rebuttal letter by Korean researchers on an article which is published last November about the correlation between suicidality/psychologic adverse effects and finasteride, a hair loss treatment medication, was published in the online edition of JAMA dermatology.

The original paper that triggered the debate was published based on the results of data analysis collected at VigiBase, which gathers drug side effects from 153 countries around the world. According to this study, 356 people had suicide-related side effects and 2,926 people had psychological problems from taking finasteride. As a result of this analysis, it was concluded that "young men taking 1 mg of finasteride for hair loss treatment are highly associated with suicide."

Prof. Choi Ji-Woong (Ajou University Hospital), Prof. Huh Chang-Hun (Seoul National University Bundang Hospital), and Prof. Choi Gwang-Seong (Inha University Hospital), who write this rebuttal letter, pointed out the limitations of the original research based on three main reasons, with suggesting that the tendency of suicide and psychological side effects are more likely to be affected by the hair loss disease itself than by drugs.

First, the authors pointed out that minoxidil, which was used as a comparative group, is mainly used for mild hair loss and is different from finasteride, which is used for severe hair loss, as the first limitation of the original paper. This is because, if it is a side effect of taking finasteride, the same report should be made for Dutasteride, a stronger 5 alpha-reductase inhibitor with the same mechanism, but it was not.

In addition, the original paper raised the influences of ‘post-finasteride syndrome (PFS)’ seen in young hair loss patients, but the definition of PFS and the connectivity between the two are not clear.

Finally, the letter touched on the limitation of racial differences because the original paper data were limited only to America and Europe. The authors emphasized that it is difficult to generalize the association between drugs and side effects without considering racial differences, as this study also did not include Asian patients and there have been few reports related to PFS from Asians so far.

Dr. Nguyen, the author of the original paper, also published a response letter agreeing with the limitation pointed by the Korean refutation letter, as the research at the time was based on pharmacovigilance analysis, only giving a signal that there may be a relationship between the drug and side effects thus it was not suitable for explaining biological causality. He also added that further detailed research is required because of the reporting bias, which was made by PFS stimulatingly stated by the media.

“After the article was published last year, there were a lot of inquiries from the hair loss patients who visited the hospital, and the media treat stimulatingly the relationship between drugs and the psychiatric adverse effects although there was no clear connection. As a specialist, I need to provide the correct information.”, said Prof. Choi Ji-Woong, explaining the background of participation in this letter.

“Some people think Dutasteride is safer than finasteride, but it is not true,” Prof. Huh Chang-Hun pointed out. “Dutasteride has not been approved as a remedy for hair loss in the United States or Europe, which was the subject of this research, so be careful when interpreting the result of the original research.”

In fact, Dutasteride was approved as a hair loss treatment in Korea, Japan, and Taiwan, but it was only approved as a medication for prostatic hyperplasia and not for men’s hair loss yet in the U.S.

Prof. Choi Gwang-Seong advised that “Finasteride has been safely used over 20 years for the treatment of male pattern baldness. Patients can receive the treatment without fear and should consult with a specialist if there are any unexpected adverse effects.”