From the FDA Drug Label
The median circulating level of testosterone increased by approximately 10 to 20% but remained within the physiologic range In a separate study in healthy men treated with finasteride 1 mg per day (n=82) or placebo (n=69), mean circulating levels of testosterone and estradiol were increased by approximately 15% as compared to baseline, but these remained within the physiologic range In patients with BPH treated with finasteride (1 to 100 mg/day) for 7 to 10 days prior to prostatectomy, an approximate 80% lower DHT content was measured in prostatic tissue removed at surgery, compared to placebo; testosterone tissue concentration was increased up to 10 times over pretreatment levels, relative to placebo.
Yes, finasteride can cause elevated testosterone. The increase in testosterone levels is due to the inhibition of the conversion of testosterone to dihydrotestosterone (DHT) by finasteride. The increase in testosterone levels is approximately 10-20% and remains within the physiologic range 1.
From the Research
Finasteride can cause elevated testosterone levels in the body, as it inhibits the enzyme 5-alpha reductase, which normally converts testosterone to dihydrotestosterone (DHT), resulting in a modest increase in testosterone levels, typically around 10-15%. This medication works by blocking the conversion of testosterone to DHT, leading to a decrease in DHT levels and an increase in testosterone levels in the bloodstream. Finasteride is commonly prescribed at doses of 1mg daily for male pattern baldness or 5mg daily for benign prostatic hyperplasia (BPH) 2. The elevation in testosterone is generally not considered harmful for most patients, and regular monitoring of hormone levels is not routinely required for most patients on finasteride unless there are specific concerns 3.
Some key points to consider when evaluating the effect of finasteride on testosterone levels include:
- The increase in testosterone levels is typically modest, around 10-15% 4
- The reduction in DHT levels is significant, around 80% 5
- Finasteride is effective for conditions driven by DHT, but may also contribute to some potential side effects, such as impotence, decreased ejaculatory volume, and gynaecomastia 5
- The overall hormonal balance is still altered by the reduction in DHT, which may explain why most men don't experience symptoms of elevated testosterone while taking finasteride 6
It's worth noting that the most recent and highest quality study on this topic, published in 2025, found that finasteride was associated with a lower risk of prostate cancer compared to dutasteride, another 5-alpha-reductase inhibitor 6. However, this study did not specifically examine the effect of finasteride on testosterone levels. Overall, the available evidence suggests that finasteride can cause elevated testosterone levels, but the increase is generally modest and not considered harmful for most patients.