From the Guidelines
Increased free testosterone levels can lead to improved sexual functioning and quality of life, particularly in men with low testosterone levels, as evidenced by a 2020 study published in the Annals of Internal Medicine 1. The effects of increased free testosterone levels are multifaceted, influencing various physiological processes in the body.
- In men, elevated free testosterone can promote masculine characteristics, such as facial hair growth and a deeper voice.
- It can also lead to enhanced muscle growth and strength, improved bone density, and increased red blood cell production.
- Additionally, heightened libido and potentially greater energy levels and improved mood are common effects of increased free testosterone. However, artificially increasing testosterone without medical need can lead to side effects, including acne, sleep apnea, testicular shrinkage, reduced sperm production, increased risk of blood clots, and liver problems.
- These effects occur because testosterone influences numerous bodily systems by binding to androgen receptors in various tissues, triggering genetic expression changes that affect metabolism, tissue growth, and other physiological processes. A 2024 study published in Diabetes Care 1 highlights the importance of assessing free testosterone levels in men with obesity and hypogonadism, as testosterone replacement therapy may have benefits, including improved sexual function, well-being, muscle mass and strength, and bone density. The most recent and highest quality study, published in 2024, suggests that testosterone replacement therapy may be beneficial for men with hypogonadism, but emphasizes the need for careful evaluation and monitoring to minimize potential risks 1. It is essential to note that the safety of testosterone therapy has been a topic of debate, with some studies suggesting a possible increased risk of heart attack and stroke, particularly with the use of testosterone injections 1. Overall, the effects of increased free testosterone levels are complex and depend on various factors, including the individual's health status, medical history, and the presence of any underlying conditions.
- As such, any decisions regarding testosterone replacement therapy should be made under the guidance of a healthcare professional, taking into account the latest evidence and the individual's specific needs and circumstances.
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
The effects of increased free testosterone (FT) levels are not directly stated in the drug label. However, it is mentioned that the median circulating level of testosterone increased by approximately 10 to 20% and remained within the physiologic range.
- Key points:
- Increased testosterone levels remained within the physiologic range
- No specific effects of increased free testosterone levels are mentioned 2
From the Research
Effects of Increased Free Testosterone (FT) Levels
- Increased free testosterone (FT) levels have been associated with various physiological effects, including:
- Testosterone, including FT, plays a crucial role in regulating metabolism, including:
- Increased FT levels have been linked to improved insulin sensitivity, reduced body fat mass, and decreased cardiovascular risk factors, such as triglycerides and cholesterol 5
- Exercise and magnesium supplementation have been shown to increase FT levels, with greater increases observed in individuals who exercise regularly 4
- Testosterone replacement therapy, which increases FT levels, has been found to improve metabolic parameters, such as insulin resistance and glycaemic control, in hypogonadal men 3, 5