What is Free Testosterone? Free testosterone refers to the amount of testosterone in the blood that is not bound to other molecules, such as sex hormone-binding globulin (SHBG) or albumin. Testosterone is a steroid hormone that plays a vital role in the development of male characteristics and is important for overall health and well-being.
It is produced primarily by the testicles in men and in smaller amounts by the ovaries in women. However, not all of the testosterone in the blood is available to the body to perform its functions. Only a small portion of it, called free testosterone, is not bound to other molecules and is considered biologically active.
The level of free testosterone is affected by various factors such as age, sex, diet, exercise, and certain medical conditions. Low levels of free testosterone can lead to symptoms such as fatigue, decreased libido, and muscle weakness. While total testosterone can give a general idea about the testosterone levels in the body, free testosterone is considered a more accurate indicator of the hormone’s active levels.
Free testosterone can be measured through a blood test. The normal range for free testosterone levels in men is around 2.5-8.2 pg/mL, and for women, it’s about 0.3-1.8 pg/mL. However, it’s important to note that these values can vary depending on the lab and the measurement method used.
In the supplement industry, there are numerous products many of which feature ingredients that purportedly increase testosterone levels in healthy males. Whereas many of the claims are far-reaching attempts to sell a product, there exist certain ingredients clinically substantiated to have a safe and desired effect on testosterone levels.
One such ingredient is Fenugreek seed standardized to its content of a specific compound, called saponins. Saponins are a group of compounds commonly found in plants and known for their medicinal properties.
If you’re on the market for an all-natural “test” booster, look for a supplement containing Fenugreek seed standardized to contain at least 50% Fenuside, which is a specific saponin found in fenugreek seed. Standardization ensures a consistent amount of the active ingredient in each dose. This is important to understand because it lets consumers know exactly what they get in each dose.
- Morgentaler, A. (2018). Testosterone therapy in men and women. New England Journal of Medicine, 379(7), 611-619.
- Wittert, G. A., Chapman, I. M., Haren, M. T., Mackenzie-Proctor, R., Coates, P., & Morley, J. E. (2003). Measurement of bioavailable testosterone: comparison of 2 methods. Clinical Chemistry, 49(1), 70-76.
- “The effects of a commercially available botanical supplement on strength-training males”, by D.K. Willoughby et al. (2007)
- “The effects of fenugreek supplementation on strength and body composition” by J.A. Kerksick et al. (2018)