Normal Testosterone Levels by Age in Australia: How to Read Your Results
Key Takeaways
What is a normal testosterone level for an Australian man? Reference ranges by age, total vs free testosterone, PBS threshold, nmol/L vs ng/dL — everything you need to interpret your blood test results.
Units: Australia Uses nmol/L, Not ng/dL
Australian laboratories report testosterone in nanomoles per litre (nmol/L). US sources use nanograms per decilitre (ng/dL).
To convert: divide ng/dL by 28.8 to get nmol/L. The commonly cited US lower limit of 300 ng/dL = approximately 10.4 nmol/L.
Reference Ranges by Age
| Age Group | Approximate Reference Range (nmol/L) |
|---|---|
| 20–29 | 14–25 nmol/L |
| 30–39 | 12–22 nmol/L |
| 40–49 | 10–20 nmol/L |
| 50–59 | 8–18 nmol/L |
| 60–69 | 7–15 nmol/L |
| 70+ | 6–14 nmol/L |
Reference ranges vary between laboratories. Always interpret results alongside the specific lab's stated range.
These ranges derive from the distribution of testosterone levels in apparently healthy men. The European Male Ageing Study (NEJM, 2010) found that the syndrome requires three specific sexual symptoms combined with total testosterone below 11 nmol/L.
The PBS Threshold vs the Clinical Threshold
PBS subsidy threshold: Total testosterone ≤ 5 nmol/L on two separate morning samples. Below this, PBS-subsidised TRT is available at the standard co-payment.
Clinical treatment threshold: Approximately 8–12 nmol/L in a symptomatic man, with free testosterone and symptom burden also considered.
Men with levels between 5–12 nmol/L may be clinically appropriate for TRT — but won't qualify for PBS subsidy. This gap is explicitly addressed in the Endocrine Society of Australia's position statement in the Medical Journal of Australia.
Total vs Free Testosterone
Only ~1–3% of circulating testosterone is "free" (biologically active). The remainder is bound to SHBG or albumin.
A man with high SHBG may have a total testosterone in the normal range with significantly low free testosterone. The Vermeulen formula (J Clin Endocrinol Metab, 1999) is the validated standard for calculating free testosterone.
A free testosterone below approximately 225 pmol/L is generally considered deficient in a symptomatic man.
A Practical Interpretation Guide
| Total T (nmol/L) | Interpretation | Action |
|---|---|---|
| < 5 | Definite deficiency | PBS-eligible TRT; investigate cause |
| 5–8 | Probable deficiency | Assess free T and symptoms; private TRT if appropriate |
| 8–12 | Borderline | Free T and symptom assessment critical |
| 12–20 | Low-normal | Investigate other causes of symptoms |
| > 20 | Normal | Low T unlikely the cause |
Why "Normal" Doesn't Always Mean Adequate
Reference ranges are population statistics — not individual prescriptions. A man who had testosterone of 22 nmol/L at 30 and now has 10 nmol/L at 45 is technically "in range" but has lost more than half his testosterone. His symptoms may be significant.
This is why the Endocrine Society explicitly states that diagnosis requires both biochemical evidence and consistent symptoms.
References
- Wu FCW, et al. Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men. N Engl J Med. 2010.
- Bhasin S, et al. Testosterone Therapy in Men with Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018.
- Vermeulen A, et al. A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab. 1999.
- Endocrine Society of Australia — MJA position statement.
- Healthdirect Australia — Testosterone.
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