What SHBG tells you
Hormones are chemical messengers involved in energy, mood, body composition, and reproductive health. This group covers the key hormones a clinician may review when looking at these areas.
Which Honed panels include SHBG
SHBG is measured in the Hormone Panel. Every sample is collected at a pathology collection centre and processed at a NATA-accredited laboratory against RCPA reference ranges, with personalised plain-English commentary in your secure online report.
Why SHBG matters
Sex hormone-binding globulin (SHBG) is a glycoprotein produced by the liver that binds testosterone, oestradiol, and other sex hormones, regulating their availability to tissues. SHBG levels directly influence the fraction of testosterone that remains free and biologically active. In athletes, SHBG is often lower than in sedentary populations due to training-induced changes in liver metabolism. SHBG also varies with metabolic state, body composition, and insulin levels.
The range explained
Low levels
Low SHBG (below 20 nmol/L in men) increases the free fraction of testosterone, potentially improving muscle protein synthesis. However, very low SHBG may indicate insulin resistance or metabolic dysfunction. A clinician interprets this alongside insulin and glucose markers.
Normal range
Reference ranges: typically 20–60 nmol/L in adult men and 30–100 nmol/L in women. Higher SHBG in women reflects sex hormonal differences in liver metabolism.
High levels
Elevated SHBG (above 60 nmol/L in men) reduces free testosterone availability despite adequate total testosterone. This can occur with conditions that impair insulin signalling or with high oestrogen exposure.
What affects SHBG
- Training: Intense resistance training lowers SHBG, increasing free testosterone availability. This is one mechanism by which training supports hormonal adaptation.
- Nutrition: High carbohydrate and sugar intake can reduce SHBG by promoting insulin sensitivity changes. Fibre and whole foods support metabolic health.
- Sleep: Sleep deprivation increases SHBG. Consistent sleep quality supports optimal SHBG levels.
- Stress: Chronic stress impairs insulin signalling, which can elevate SHBG. Stress reduction supports hormonal balance.
When to retest
Every 12 weeks when optimizing hormones; every 12 months for general health. Always interpret alongside total and free testosterone.
Why athletes care
Athletes monitor SHBG because lower levels increase free testosterone, supporting muscle synthesis and performance. SHBG is a useful marker to understand how much testosterone is actually available to tissues.
Related hormones markers
FAQ
What does the SHBG blood test measure?
Sex Hormone Binding Globulin, a protein that binds sex hormones in the blood. SHBG is considered when interpreting testosterone results.
Which Honed Health panels include SHBG?
SHBG is included in the Hormone panel.
What unit is SHBG measured in?
SHBG is reported in nmol/L, measured at NATA-accredited laboratories against RCPA reference ranges, with personalised plain-English commentary in your secure report.