Why Is My Total Testosterone Normal but I Still Feel Low? What Is Free Testosterone?
When the Numbers Don't Match How You Feel
Many men get their testosterone checked because they feel tired, unmotivated, or have low libido—only to be told their levels are "normal." If that sounds familiar, the answer may lie in a number that isn't always checked: free testosterone.
Total vs. Free Testosterone
Testosterone travels through your blood in three forms:
- Bound tightly to SHBG (sex hormone-binding globulin): Not available for your body to use
- Bound loosely to albumin: Partly available
- Free testosterone: Only about 2–3% of the total, but it's the portion that's fully active in your tissues
Total testosterone measures all three together. Free testosterone measures only the active part.
Why SHBG Matters
If your SHBG is high, more of your testosterone is locked up and less is free—even if your total looks fine. SHBG tends to rise with:
- Aging
- Hyperthyroidism
- Liver conditions
- Certain medications
- Very low body fat or heavy endurance training
On the other hand, obesity and insulin resistance tend to lower SHBG, which can make total testosterone look low even when free testosterone is okay.
Other Reasons You Might Still Feel Low
Low energy and libido aren't always about testosterone. Other common causes include:
- Poor sleep or sleep apnea
- Thyroid problems
- Low iron, vitamin D, or B12
- Depression, anxiety, or chronic stress
- Blood sugar issues
- Medication side effects
What to Test
A thorough evaluation may include total and free testosterone, SHBG, LH, estradiol, a thyroid panel, a complete blood count, vitamin D, B12, ferritin, and metabolic markers like A1c.
Learn more about comprehensive lab testing here: Heva Lab Testing
The Bottom Line
Total testosterone doesn't tell the whole story. Checking free testosterone and SHBG—along with other common causes of fatigue—can explain why you still feel low and point to the right next step.