Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

When optimizing your health and well-being as an individual have you explored how your genetic traits affect your reproductive and sexual health?

We explore bioavailable testosterone today because it serves as an essential biomarker affecting fertility, bone health and overall vitality. By gaining knowledge about bioavailable testosterone you can make educated choices for your health and lifestyle management. Bioavailable testosterone qualifies as a genetic characteristic within Reproductive & Sexual Health genetic testing and serves as a key contributor to multiple physiological processes. Testosterone, primarily produced by the testes in men and ovaries in women, exists in the blood in three main forms: Testosterone circulates in blood as SHBG-bound molecules, weakly attached to albumin and free molecules that remain unattached to proteins. The bioavailable testosterone fraction which the body can readily use consists of free testosterone which makes up 2-3% of total testosterone and a small portion that is weakly bound to albumin. The bioavailable fraction of free testosterone plays a critical role in health maintenance through its effects on bone strength, muscle mass and strength preservation, red blood cell production enhancement, libido and sexual function improvement, sperm production increase, and mood and brain function promotion. Genetic predispositions to elevated testosterone levels can lead to various health problems including depression and blood clotting complications as well as rheumatoid arthritis. Genetic factors account for roughly 45% of the variations seen in bioavailable testosterone levels. Both men and women experience a decline in free testosterone levels as they age after reaching their peak in the late 20s. Low testosterone levels have been observed to correlate with conditions such as obesity and medication use as well as chronic diseases like type 2 diabetes and obstructive sleep apnea. Total testosterone levels are the standard measurement for routine lab screenings because they are cheaper and easier to determine but measuring bioavailable and free testosterone levels becomes essential when patients show low testosterone symptoms while their total testosterone tests show normal results. Insights into your reproductive and sexual health emerge from understanding genetic predispositions related to bioavailable testosterone which can help direct personalized health interventions. People who aim to enhance their reproductive and sexual health need to examine these practical strategies.

Consult with a healthcare provider:

A qualified healthcare professional who can give individualized advice and recommendations should review your genetic test results concerning bioavailable testosterone levels.

Maintain a healthy lifestyle:

To maintain healthy testosterone levels you should practice regular physical activity while eating a balanced diet and managing stress effectively along with getting enough sleep.

Monitor your symptoms:

Pay attention to signs of low testosterone including fatigue and mood changes and get medical evaluation if necessary.

Consider genetic counseling:

Genetic counseling offers additional understanding and support for individuals worried about their inherited potential to produce bioavailable testosterone. Bioavailable testosterone functions as a vital genetic factor that affects multiple aspects of reproductive and sexual health. Understanding your genetic predispositions towards bioavailable testosterone allows you to actively work towards improved wellness. Utilize PlexusDx's Precision Health & Wellness tests to access critical data about your genetic profile which supports informed health decisions. Your genetic makeup is distinctive and learning about it enables you to live a healthier and more satisfying life.

Frequently Asked Questions

What is bioavailable testosterone and how does it differ from total testosterone?

Testosterone circulates bound tightly to SHBG, weakly attached to albumin, or free. Bioavailable testosterone is the portion the body can readily use: the free fraction, which the post puts at 2 to 3% of total testosterone, plus the small weakly albumin-bound portion. Total testosterone counts all three forms together, which is why the two measurements can tell different stories.

Why would someone measure free testosterone instead of the total?

Total testosterone is the standard routine screening measure because it is cheaper and easier to determine, the post says. But measuring bioavailable and free testosterone becomes important when a person shows symptoms of low testosterone while their total testosterone result looks normal. Which test to run, and how to read it, is a decision for a healthcare provider.

What body functions does bioavailable testosterone support?

The post credits the bioavailable fraction with maintaining bone strength, preserving muscle mass and strength, supporting red blood cell production, influencing libido and sexual function, contributing to sperm production, and supporting mood and brain function. That breadth is why the article treats it as a biomarker relevant to fertility, bone health and general vitality.

When do testosterone levels start declining, and what else lowers them?

Both men and women see free testosterone decline with age after it peaks in the late twenties, according to the post. It also associates low testosterone with obesity, medication use, and chronic conditions including type 2 diabetes and obstructive sleep apnea. Those associations are one reason it advises getting symptoms such as fatigue and mood changes evaluated.

What should I do with a genetic report about bioavailable testosterone?

Review it with a qualified healthcare professional, which is exactly what the post recommends. The post says genetic factors account for roughly 45% of the variation in bioavailable testosterone, a figure it does not source. A report describes variants associated with a pathway; it does not measure your hormone level or select a treatment, which blood testing and clinical evaluation do.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.