Free testosterone

Explore the importance of free testosterone—the unbound, bioavailable form that directly impacts muscle growth, energy, and overall male health. Learn how to test, interpret, and optimize your free testosterone levels for peak performance.

Start here

The essentials for free testosterone — then explore the latest posts below.

Function Health testosterone results: What “out of range” really means and what to do next

Function Health testosterone results: What “out of range” really means and what to do next

Dr. Susan Carter, MD avatar
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Feb 09, 2026 · 13 min read

An “out of range” testosterone result means your value fell outside that lab’s reference interval, not that you have hypogonadism. The next step is to repeat a morning total testosterone and add confirmatory labs (free testosterone with SHBG, plus LH/FSH) interpreted alongside symptoms before deciding on treatment. “When a lab report says ‘normal’, it mostly ...

How to measure testosterone accurately: The blood tests that actually matter

How to measure testosterone accurately: The blood tests that actually matter

Dr. Alexander Grant, MD, PhD avatar
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Dec 10, 2025 · 14 min read

You measure testosterone most accurately with a morning blood test that reports total testosterone and free testosterone, ideally processed by a CLIA certified laboratory. The details matter, because timing, test type, and follow up labs can be the difference between useful data and a false alarm. “If you want to know how to measure testosterone ...

What is sex hormone binding globulin? How SHBG levels shape testosterone in men

What is sex hormone binding globulin? How SHBG levels shape testosterone in men

Dr. Alexander Grant, MD, PhD avatar
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Dec 09, 2025 · 14 min read

Sex hormone binding globulin is a liver made protein that binds testosterone and other sex hormones, and SHBG levels help predict how much testosterone is actually available to your tissues. If you have low testosterone symptoms but “normal” total testosterone, SHBG is often the missing piece that explains why you still feel off. “Most guys ...

Enclomiphene: Double testosterone without injections

Enclomiphene: Double testosterone without injections

Dr. Alexander Grant, MD, PhD avatar
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Oct 12, 2025 · 13 min read

In randomized trials of men with functional hypogonadism, daily enclomiphene (a SERM) blocks estrogen feedback in the hypothalamus and pituitary to raise LH and FSH. This can increase morning testosterone into or near the normal range, and in some men with very low baseline levels it may roughly double testosterone on labs while sperm counts ...

Finding testosterone your local guide to wellness: A practical plan for testing and treatment near you

Finding testosterone your local guide to wellness: A practical plan for testing and treatment near you

Dr. Bruno Rodriguez, DPT, CSCS avatar
Dr. Bruno Rodriguez, DPT, CSCS: Strength, Recovery, and Physical Therapy Expert
Aug 07, 2025 · 18 min read

You can find clinically appropriate testosterone testing and treatment locally by starting with a primary care doctor, urologist, or endocrinologist and confirming low testosterone on two early morning blood tests before you consider any therapy. This guide turns “finding testosterone your local guide to wellness” into a simple, evidence based checklist you can use to ...

Special OfferLab panels included: $300/year free for all members