Free vs Total Testosterone: Which Test Do You Need?

Free testosterone testing measures the amount of unbound testosterone available for your body to use, while total testosterone includes both bound and unbound forms. Understanding the difference helps you choose the right test for your symptoms and health goals.

Understanding Free Testosterone

Your body produces testosterone in two forms: bound and free. About 98% of testosterone travels through your bloodstream attached to proteins like SHBG (sex hormone-binding globulin) and albumin. The remaining 2% circulates freely, ready for immediate use by your cells.

This free testosterone is what actually drives the effects you associate with healthy T levels. It’s the portion that builds muscle, maintains bone density, and supports your energy and mood. Low free testosterone can cause symptoms even when total testosterone appears normal.

Many men discover this distinction after getting a total testosterone test that comes back “normal” despite experiencing clear symptoms. Their total T might be 500 ng/dL, but high SHBG levels mean very little is actually available for use.

Free testosterone levels naturally decline with age, typically dropping 1-2% per year after age 30. However, factors like obesity, stress, and certain medications can accelerate this decline or increase protein binding, making the problem worse.

Symptoms to Watch For

• Low energy and fatigue despite adequate sleep
• Decreased sex drive or erectile dysfunction
• Difficulty building or maintaining muscle mass
• Mood changes, irritability, or depression
• Increased body fat, especially around the midsection
• Poor concentration or mental fog
• Reduced motivation and drive
• Sleep disturbances or poor recovery

Recommended Tests

A comprehensive testosterone panel should include both total and free testosterone measurements. Total testosterone gives you the big picture, while free testosterone shows what’s actually available for use. Many doctors also order bioavailable testosterone, which includes both free testosterone and testosterone loosely bound to albumin.

The free testosterone test uses either direct measurement or calculation based on total testosterone, SHBG, and albumin levels. Calculated free testosterone is often more reliable than direct measurement methods, according to research comparing different testing approaches.

Best Testing Services

These testing services offer reliable free testosterone testing with fast results and transparent pricing. All provide detailed reports with reference ranges to help you understand your results.

Understanding Your Results

Free testosterone reference ranges vary by age and testing method, but generally fall between 9-30 pg/mL for healthy adult men. Levels below 9 pg/mL often indicate low free testosterone that could benefit from treatment.

However, symptoms matter more than numbers alone. Some men feel great with free testosterone at 8 pg/mL, while others experience symptoms at 12 pg/mL. The American Urological Association emphasizes that diagnosis should combine laboratory results with clinical symptoms.

Your results will typically include both your values and age-appropriate reference ranges. Pay attention to where you fall within the range — being at the bottom of “normal” might explain ongoing symptoms.

Frequently Asked Questions

What’s the difference between free and total testosterone?

Total testosterone measures all testosterone in your blood, including the 98% bound to proteins. Free testosterone measures only the 2% that’s unbound and immediately available for use. Free testosterone better reflects what your body can actually use for muscle building, energy, and other functions.

Can I have normal total testosterone but low free testosterone?

Yes, this is common. High levels of SHBG or other binding proteins can make most of your testosterone unavailable, even if your total levels look normal. This explains why some men have typical low-T symptoms despite “normal” blood tests.

Do I need to fast for a free testosterone test?

No, fasting isn’t required for testosterone testing. However, timing matters — testosterone levels are highest in the morning, so most doctors recommend testing between 8-10 AM for the most accurate results.

How accurate are at-home free testosterone tests?

At-home tests use the same lab equipment and methods as doctor-ordered tests. The key difference is convenience — you collect the sample at home and mail it to a certified lab. Results are typically just as accurate as tests ordered through your doctor’s office.

This content is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.