Optimal Ranges
What is the optimal range for SHBG?
Clinical (NHS) Range
18.3-54.1 nmol/L (male)
nmol/L
Performance-Optimised Range
25-45 nmol/L
nmol/L
| Range | Value | Unit |
|---|---|---|
| Clinical (NHS) reference range | 18.3-54.1 nmol/L (male) | nmol/L |
| Performance-optimised range | 25-45 nmol/L | nmol/L |
The clinical range defines what is considered medically “normal” — broad enough to cover 95% of the population. The performance range reflects where research and clinical experience suggest most people feel and function at their best. A result in either range suggests typical status and is not a diagnosis; any individual reading should be interpreted by a qualified clinician.
Why It Matters
Why SHBG matters for performance
A man can have a normal total testosterone level but still experience symptoms of low T if his SHBG is too high — because most of his testosterone is bound and unavailable. Conversely, very low SHBG can lead to excess free testosterone converting to oestrogen via aromatase, causing its own set of problems. SHBG is a critical piece of the hormonal puzzle that is often missed in standard blood tests. Elevated SHBG is associated with hypothyroidism, liver disease, and caloric restriction; low SHBG is linked to insulin resistance, obesity, and type 2 diabetes risk.
Symptoms
What are the symptoms of low or high SHBG?
Low / Deficiency
- Symptoms of excess free testosterone (acne, hair loss, aggression)
- Increased oestrogen conversion
- May indicate insulin resistance or metabolic syndrome
High / Excess
- Fatigue despite normal total testosterone
- Low libido and erectile dysfunction
- Muscle wasting and difficulty building mass
- Depression and brain fog
Dietary Sources
Which foods support SHBG levels?
Supplementation
How do you improve SHBG levels?
SHBG itself cannot be supplemented — the goal is to address the underlying cause of abnormal levels. For high SHBG: check thyroid function (hypothyroidism raises SHBG), ensure adequate caloric intake (undereating raises SHBG), and consider boron supplementation (6-10mg daily has been shown to reduce SHBG by ~10% in some studies). For low SHBG: improve insulin sensitivity through exercise and weight management, reduce refined carbohydrates, and address any fatty liver disease. Nettle root extract (Urtica dioica) is marketed as an SHBG modulator but clinical evidence is limited to in-vitro studies.
Testing
How is SHBG tested in the UK?
SHBG is measured from a blood sample. With Helvy, that means a finger-prick kit taken at home and posted to a UKAS-accredited UK laboratory, with results in around 5 days, reviewed by a qualified clinician. Your result is reported against both the clinical range (18.3-54.1 nmol/L (male)) and the performance-optimal range (25-45 nmol/L), so you can see not just whether you are “normal” but whether you are optimal. If you make a change, retest after 8-12 weeks to confirm it worked.
Research
Key study
Sex hormone-binding globulin and risk of type 2 diabetes in women and men
Ding EL, Song Y, Manson JE, et al.
New England Journal of Medicine (2009)
DOI: 10.1056/NEJMoa0804381Related Biomarkers
Related Guides
Explore SHBG in depth
Test your SHBG levels
SHBG is included in the Helvy 50+ biomarker panel. Get your results in 5 days with a personalised protocol.
Order Your TestThis content is for educational purposes only and does not constitute medical advice. Your data suggests areas for optimisation, but any concerns should be discussed with a qualified healthcare professional. If your results flag values outside safe ranges, we recommend consulting your GP.