Total testosterone tells you one number. Your full panel tells the real story. Learn which markers actually matter and what research reference ranges look like.
Quick Summary Most testosterone panels only report total testosterone. Research shows that free testosterone, SHBG, LH, FSH, estradiol, and hematocrit are equally important for understanding hormonal health. This educational guide explains each marker and what published research shows about optimal ranges. This is not medical advice.
The standard testosterone test measures total testosterone -- the sum of all testosterone in the blood, most of which is bound to proteins and biologically unavailable. Research shows that up to 98% of testosterone is bound to SHBG or albumin at any given time. What your body actually uses is free testosterone.
Track your full hormone panel over time at [myprotocolstack.com/labs](https://myprotocolstack.com/labs).
Total Testosterone
Standard lab ranges: 264-916 ng/dL for adult males. Research published in the Journal of Clinical Endocrinology suggests symptoms are common below 400 ng/dL in many men. Research reference: 600-900 ng/dL commonly cited in optimization literature.
Free Testosterone
Research reference ranges suggest free testosterone of 15-25 pg/mL is associated with better outcomes in published studies.
SHBG (Sex Hormone Binding Globulin)
High SHBG reduces free testosterone even when total T is normal. Research reference: 20-50 nmol/L.
LH (Luteinizing Hormone)
Critical for understanding WHY testosterone is low. Low T + Low LH = secondary hypogonadism. Low T + High LH = primary hypogonadism. Research reference: 1.5-9.3 mIU/mL.
FSH (Follicle Stimulating Hormone)
Works alongside LH. Chronically elevated FSH may indicate impaired testicular function.
Estradiol (E2)
Research reference: 20-40 pg/mL commonly cited for adult males.
Hematocrit
Testosterone stimulates red blood cell production. Research reference: 38-50%. Values above 52-54% are flagged in most research protocols.
PSA (Prostate Specific Antigen)
A baseline PSA is important before starting any hormone protocol.
The relationship between LH and total testosterone reveals whether the issue originates in the brain or the testes. [StackAI](https://myprotocolstack.com/stackai) reads your full testosterone panel and identifies patterns across all markers.
CBC, Comprehensive Metabolic Panel, Lipid Panel with ApoB, and Thyroid Panel all provide important context for testosterone optimization.
Upload your Quest, LabCorp, or Function Health results at [myprotocolstack.com/labs](https://myprotocolstack.com/labs) to track all markers simultaneously across draws.
What is a good total testosterone level?
Published research shows symptom resolution at varying levels depending on individual sensitivity. Context from your full panel matters more than any single value.
Why is my free testosterone low if my total T is normal?
High SHBG is the most common reason. Research shows SHBG rises with age, low body weight, hyperthyroidism, and certain medications.
What does low LH with low testosterone mean?
This pattern -- secondary hypogonadism in research literature -- suggests insufficient pituitary signaling.
How often should I get a testosterone panel?
Research protocols for optimization programs typically measure quarterly.
What is the connection between testosterone and ApoB?
Some research shows testosterone therapy affects lipid metabolism. Tracking ApoB alongside testosterone provides additional cardiovascular context.
*This article is for educational purposes only. It does not constitute medical advice. Always consult a licensed healthcare provider before beginning any hormone-related protocol.*
*Written by the MyProtocolStack team. Last updated: January 2026.*
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