Testosterone Injections in Australia: Reandron & Enanthate

For many Australian men diagnosed with testosterone deficiency, injections are the most common way to deliver testosterone replacement therapy (TRT). They are effective, generally well tolerated and, for eligible men, subsidised through the Pharmaceutical Benefits Scheme (PBS). But "testosterone injections" is not a single product — in Australia there are two main types, given on very different schedules. Testosterone is a Schedule 4 (prescription-only) medicine, prescribed only where blood tests confirm genuine deficiency, so this article is about understanding the options rather than obtaining them without proper assessment.

The two main testosterone injections used in Australia

Injectable testosterone comes as an oil-based solution given by intramuscular (IM) injection. The hormone is attached to an "ester" that controls how quickly it is released — the longer the ester, the less often you inject. The two options your GP is most likely to discuss are long-acting testosterone undecanoate (Reandron) and shorter-acting testosterone enanthate (Primoteston Depot).

Reandron (testosterone undecanoate)

Reandron is a long-acting injection. A typical schedule is an initial dose, a second "loading" dose about six weeks later, then maintenance injections roughly every 10 to 14 weeks. Because it is a large-volume, deep intramuscular injection (usually into the buttock), it is almost always given by a doctor or nurse rather than self-administered, and you are generally observed for a short period afterwards — there is a rare risk of an oil-related reaction (pulmonary oil microembolism) or, uncommonly, an allergic reaction. Its main appeal is convenience and steadier hormone levels: only a handful of injections a year, with fewer of the peaks and troughs seen with shorter-acting options.

Testosterone enanthate (Primoteston Depot)

Testosterone enanthate is a shorter-acting ester, typically given every two to three weeks. It can be administered at a clinic or, once you are trained and your GP agrees, self-injected at home. Because each dose clears more quickly, levels rise after the injection and fall away before the next one, so some men notice fluctuations in energy or mood across the cycle; smaller, more frequent doses can help smooth this out. Enanthate is inexpensive and long established, which is part of why it remains widely used. Mixed-ester products such as Sustanon are also available in Australia and behave in a broadly similar way.

Pros and cons at a glance

• Reandron: fewer injections (about every 10–14 weeks) and steadier levels, but it usually needs a clinic visit, involves a large-volume injection, and is slower to adjust or clear if a problem arises.
• Enanthate / Primoteston: cheaper, can be self-administered, and its shorter action means levels can be corrected quickly if needed — but it requires far more frequent injections and can cause more noticeable peaks and troughs.

There is no single "best" injection. The right choice depends on your preferences, how your body responds, cost, and whether you would rather inject at home or attend a clinic. Some men also weigh injections against topical options — we compare these in our guides to TRT injections vs gels and testosterone gels (Testogel and AndroForte).

Getting testosterone injections on the PBS

Testosterone therapy is only appropriate when there is genuine androgen deficiency confirmed on blood tests — not simply because of ageing, tiredness or a single borderline result. Australian and international guidelines recommend making the diagnosis from consistent symptoms plus low testosterone measured on at least two separate morning blood samples, after reversible causes have been excluded and treated (Endocrine Society of Australia, 2016; Endocrine Society guideline, 2018).

For men who meet the criteria, testosterone is subsidised on the PBS. In practice this generally means documented low morning testosterone on repeat testing; for older men without a clear pituitary or testicular cause, the PBS usually requires the diagnosis to be confirmed by, or in consultation with, a specialist such as an endocrinologist or urologist (Endocrine Society of Australia treatment statement, 2016). Your GP can explain whether you are likely to qualify and what any out-of-pocket cost would be — see our guide to TRT cost and the PBS in Australia.

Monitoring while you're on injections

Testosterone is a long-term treatment, and using it safely depends on regular review — usually at baseline, within the first several months, and then periodically once you are stable (Endocrine Society guideline, 2018). Key checks include:

• Testosterone levels. For injections these are often measured as a "trough" — a sample taken just before your next dose — to confirm the lowest point in the cycle still sits within a healthy range.
• Haematocrit (full blood count). Testosterone raises red-cell production and can thicken the blood; if the haematocrit climbs too high (the Endocrine Society guideline suggests above roughly 54%), treatment may be paused or the dose reduced.
• Prostate health (PSA). Older men are usually monitored with PSA and a prostate assessment, particularly during the first year of treatment.
• Oestradiol. Some testosterone converts to oestrogen, and oestradiol is sometimes checked when relevant symptoms are present, though routinely treating it to a target is not well supported by the evidence.

Heart health is a common concern. The large TRAVERSE trial, in middle-aged and older men with hypogonadism and elevated cardiovascular risk, found that testosterone therapy did not increase major adverse cardiac events compared with placebo — reassuring context, although the trial used a gel rather than an injection and still noted some other effects, so individual risk assessment and ongoing monitoring remain important (Lincoff et al., 2023). You can read more in our overview of TRT side effects in Australia.

The bottom line

Injectable testosterone is a well-established, effective form of TRT for Australian men with confirmed testosterone deficiency. Long-acting Reandron offers convenience and stable levels from only a few clinic-based injections a year, while shorter-acting enanthate is cheaper and can be self-administered but needs more frequent dosing. Both require a proper diagnosis, meeting the PBS criteria for subsidy, and ongoing monitoring of testosterone, blood count and prostate health. The best option is the one that fits your body, your lifestyle and your GP's advice — decided together, not bought online.

References

1. Lincoff AM, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. N Engl J Med. 2023;389(2):107–117. https://www.nejm.org/doi/full/10.1056/NEJMoa2215025
2. Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. https://pubmed.ncbi.nlm.nih.gov/29562364/
3. Yeap BB, et al. Endocrine Society of Australia position statement on male hypogonadism (part 1): assessment and indications for testosterone therapy. Med J Aust. 2016;205(4):173–178. https://www.mja.com.au/journal/2016/205/4/endocrine-society-australia-position-statement-male-hypogonadism-part-1
4. Yeap BB, et al. Endocrine Society of Australia position statement on male hypogonadism (part 2): treatment and therapeutic considerations. Med J Aust. 2016;205(5):228–231. https://pubmed.ncbi.nlm.nih.gov/27581270/

This article is general information only and is not a substitute for personalised medical advice. Testosterone is a prescription-only (S4) medicine in Australia and is prescribed only where clinically appropriate. Speak with an AHPRA-registered GP about your individual situation.