April 2019 in “The Journal of Urology” This study found that in 45-year-old German men, the use of metformin, insulin, and ACE inhibitors was associated with lower PSA levels, while low dose finasteride resulted in notable PSA decrease.
March 2019 in “European Urology Supplements” This study found that metformin, insulin, and ACE inhibitors were associated with lower PSA levels, but statins did not decrease PSA, whereas low dose finasteride (1 mg) reduced PSA levels similarly to the higher 5 mg dose.
3 citations
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September 2023 in “Prostate Cancer and Prostatic Diseases” 
9 citations
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January 2014 in “Medical Hypotheses” This article discusses the hypothesis that mechanisms driving androgenic alopecia may reduce the risk and proliferation of prostate cancer by increasing prostaglandin D2 levels but presents no new clinical findings.
4 citations
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May 2019 in “The World Journal of Men's Health” This study found no significant increase in depression risk associated with taking five-alpha reductase inhibitors for benign prostatic hyperplasia or alopecia, although further studies are needed to confirm these findings.