Pulmonary oil microembolism — POME — is real, and it is rare. A 2023 literature review of intramuscular testosterone undecanoate injections concluded exactly that: across 29 studies covering 7,978 patients, eight studies reported a combined total of 88 incidences of POME or cough, and when POME did occur, almost all cases resolved spontaneously within 60 minutes without intervention.[1]
One post-market review cited in the same paper reported 223 cases per 3,107,652 injections.[1]
What POME is
Testosterone undecanoate for injection is an oil-based depot.[1] The drug is dissolved in oil and deposited into muscle, from which it releases slowly. POME occurs when some of that oil reaches the pulmonary circulation, producing an acute reaction — characteristically a sudden cough, sometimes with chest tightness or breathlessness, beginning during or shortly after the injection.
It is frightening to experience and it looks alarming. The clinical course, per the reviewed evidence, is usually short.
What the numbers actually support
The review is careful about its own limits, and those caveats matter more than the headline.
The true rate is not known. The authors state plainly that the rate of POME during routine intramuscular TU injection is unknown.[1] What they could assemble was published reports, not a denominator-controlled incidence study.
The 88 figure is deliberately generous. It includes episodes of cough that were not originally declared as POME.[1] The reviewers counted possible cases rather than only confirmed ones — which pushes the number up, not down.
Overall conclusion: rare.[1]
Why it belongs to a formulation, not to testosterone
This is the key distinction. POME is a consequence of injecting oil into muscle. It is not a property of the hormone.
That makes it one of the "formulation-specific adverse effects" the Endocrine Society guideline explicitly asks clinicians to weigh when choosing a preparation, alongside pharmacokinetics, patient preference, treatment burden and cost.[2] A man weighing an oil depot injection against a daily topical is weighing different risk profiles, not different amounts of the same risk.
What it does not mean
It does not mean injections are unsafe. The reviewed evidence describes a rare event that mostly resolves without intervention inside an hour.[1]
It also does not mean the reaction should be ignored. An acute cough or breathlessness during or just after an injection is something to report to the clinician administering it — which is part of why long-acting injectable testosterone is typically given in a clinical setting with a period of observation afterwards.
Frequently asked questions
How likely is POME? The true rate is unknown.[1] The post-market figure cited in the review is 223 cases per 3,107,652 injections, and the review's overall assessment is that POME is rare.
How long does it last? Almost all reported cases resolved spontaneously within 60 minutes without intervention.[1]
Does this happen with gels or sprays? No. POME is specific to injecting an oil-based depot into muscle.[1] Topical formulations have their own distinct issue — transfer to other people, covered in gel transfer risk.
Should this change my choice of treatment? It is one input among several the guideline names.[2] Worth discussing, not worth deciding on alone.
Next in this series
POME belongs to the long-acting depot. The older esters had a different problem entirely — one of frequency.
Continue with propionate, the every-three-days nightmare.
References
2 sources
- Adam JA, Pastuszak AW, Christensen MB, et al. Occurrence of pulmonary oil microembolism (POME) with intramuscular testosterone undecanoate injection: literature review. Int J Impot Res. 2023;35(5):439–446. doi:10.1038/s41443-022-00585-1 · PMID 35610506
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. doi:10.1210/jc.2018-00229 · PMID 29562364
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