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Doctor's Assessment Included

Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Hormones

SHBG (Sex Hormone Binding Globulin)

Sex hormone-binding globulin (SHBG) is a transport protein that regulates free hormone availability. For women, SHBG levels may fluctuate with hormonal changes and can influence symptoms related to estrogen and testosterone balance.

Reference Ranges

Female
nmol/l
Low 32.4 Normal 128 High

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

What It Measures

This test measures the level of SHBG in your blood, reported in nmol/l. SHBG binds to sex hormones and influences how much testosterone and estrogen is freely available for your body to use. Higher SHBG means less free hormone.

Why It Matters

For women, SHBG helps regulate the balance between free and bound sex hormones. Changes in SHBG may be associated with menstrual irregularities, skin changes, or metabolic shifts. Your healthcare provider can help contextualize your results.

When to Test

Testing may be recommended when experiencing symptoms of hormonal imbalance despite normal total hormone levels. Some healthcare providers may suggest SHBG testing alongside testosterone and estrogen tests for a more comprehensive hormonal assessment.

Symptoms

Low Levels

Some people with low SHBG levels may experience acne, oily skin, or hair thinning. In women, low SHBG could potentially be associated with symptoms of excess androgens. In men, it might contribute to hormonal imbalance symptoms.

High Levels

Some people with elevated SHBG levels may experience fatigue, reduced libido, or mood changes, as more hormones are bound and less are freely available. High SHBG could potentially mask adequate total hormone production.

Recommendations

Female

If Low

Low SHBG may indicate PCOS, insulin resistance, or metabolic syndrome. Consider weight management, low-glycemic diet, and PCOS evaluation.

If High

High SHBG may reduce free hormone availability. Consider thyroid evaluation and nutritional assessment.

Lifestyle Tips

Maintaining a healthy body weight, regular exercise, and balanced nutrition may support healthy SHBG levels. Excessive alcohol consumption and certain medications could influence SHBG. Discuss any concerns with your healthcare provider before making changes.

Frequently Asked Questions

What is the difference between SHBG and free testosterone?
SHBG is a transport protein that binds to testosterone, making it inactive. Free testosterone is the unbound portion that your body can actively use. When SHBG is high, less free testosterone is available, even if total testosterone levels appear normal.
Can weight affect SHBG levels?
Body weight may influence SHBG levels. Higher body weight, particularly excess abdominal fat, is often associated with lower SHBG levels. Maintaining a healthy weight through balanced nutrition and regular exercise could help support optimal SHBG levels.
Why are SHBG reference ranges different for men and women?
Women typically have higher SHBG levels than men due to the influence of estrogen, which stimulates SHBG production. Men generally have lower SHBG because testosterone tends to suppress its production. Your healthcare provider will use sex-specific ranges.