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 receiving finasteride tablets 5 mg/day, increases of about 10% were observed in luteinizing hormone (LH) and follicle-stimulating hormone (FSH), but levels remained within the normal range
Finasteride does not cause low testosterone (hypogonadism). In fact, the median circulating level of testosterone increased by approximately 10 to 20% and remained within the physiologic range 1. Additionally, finasteride treatment resulted in increased levels of testosterone, which remained within the normal range. Key points:
- Increased testosterone levels by 10-20%
- Testosterone levels remained within the physiologic range
- LH and FSH levels increased by about 10%, but remained within the normal range 1
From the Research
Finasteride does not typically cause hypogonadism or low testosterone levels, as it works by inhibiting the conversion of testosterone to dihydrotestosterone, which can actually increase circulating testosterone levels. According to the most recent and highest quality study, finasteride 1 mg/day significantly increased total hair count compared to placebo after 24 weeks and 48 weeks, with no significant decrease in testosterone levels 2. However, some men taking finasteride report symptoms that overlap with those of hypogonadism, such as decreased libido, erectile dysfunction, and fatigue, which may be related to the reduction in DHT or other hormonal changes.
Key Points to Consider
- Finasteride's mechanism of action tends to increase circulating testosterone levels rather than decrease them
- Some men taking finasteride may experience symptoms that overlap with hypogonadism, but these are not typically due to low testosterone
- The most recent study found no significant decrease in testosterone levels with finasteride treatment 2
- In rare cases, finasteride might affect the hypothalamic-pituitary-gonadal axis, potentially influencing testosterone production indirectly
Important Considerations
- If you're experiencing symptoms of hypogonadism while taking finasteride, it's essential to consult with your healthcare provider to determine the cause of your symptoms
- Your healthcare provider can measure your hormone levels to determine if your symptoms are related to the medication or have another cause
- It's crucial to discuss the potential side effects of finasteride with your healthcare provider before starting treatment, especially regarding sexual function and testosterone levels 3, 4, 5