Hypospermia is defined against the WHO lower reference limit for semen volume, which is 1.4 mL in the 2021 figures, drawn from more than 3,500 men in twelve countries1. Earlier guidance used 1.5 mL2. When there is no ejaculate at all, the term is aspermia2.
It is easy to confuse with oligozoospermia (a low sperm concentration) and azoospermia (no sperm), but those describe the sperm, not the fluid. A man can have a normal volume with few sperm, or a low volume with plenty2.
Volume matters because the fluid is what carries sperm into the female reproductive tract, so doctors treat persistently low volume as a clue worth investigating when a couple is struggling to conceive3.
What causes hypospermia?
Causes fall into three broad groups: problems with collecting the sample, structural problems such as blockages, and functional problems with the nerves and muscles of ejaculation. Short gaps between ejaculations lower volume too.
The three groups doctors use3, with common examples:
- Collection and timing: part of the sample lost, or a short gap since your last ejaculation (see ejaculatory abstinence).
- Structural: physical problems in the glands or the ducts that carry semen, such as a blockage affecting the seminal vesicles or ejaculatory ducts3.
- Functional: retrograde ejaculation, where semen goes into the bladder. Recognised causes include alpha-blocker medicines, nerve damage from diabetes or spinal injury, and prostate or bladder-neck surgery2.
- Diabetes deserves a special mention: in one controlled study, 9 of 26 men with diabetes had retrograde ejaculation, compared with none of 16 men without it4.
How is hypospermia diagnosed?
It starts with a repeat semen analysis done under the lab's standard conditions. If volume is still low, a urine sample after orgasm checks for semen going into the bladder.
Low volume or no ejaculate should prompt a doctor to consider retrograde ejaculation, and finding sperm in a urine sample passed after orgasm helps confirm it2. The authors of the diabetes study recommend this urine test routinely for men with diabetes and low ejaculate volume4.
Beyond that, doctors follow a step-by-step approach to narrow down the cause3. Depending on the results, that may include checking seminal fructose, a scan of the prostate and seminal vesicles, or hormone tests.
Does hypospermia matter if you are not trying for a baby?
Not always. If the cause is harmless, such as frequent ejaculation, nothing needs doing. A new, lasting change is still worth checking, because the cause can matter more than the volume.
Low ejaculate volume can be the first visible sign of something else, such as nerve changes linked to diabetes or a side effect of medication. In the diabetes study, men with retrograde ejaculation were also more likely to have erectile dysfunction4. Mentioning a change early gives your doctor the chance to look for these links.
Can hypospermia be treated?
Often, but the treatment depends entirely on the cause. Some cases need nothing more than a longer gap before testing.
If a medicine is responsible, your prescriber may be able to suggest an alternative; do not stop a prescribed medicine on your own. Retrograde ejaculation and blockages each have specific options, and where conception is the goal, sperm can sometimes be recovered, for example from urine after orgasm, for assisted reproduction2.
See your GP if your volume is persistently very low, you have a dry orgasm or cloudy urine after sex, you notice pain or blood when you ejaculate, or you have been trying for a baby for a year without success.
Common questions
Is low semen volume a sign of infertility?
Not necessarily. Many men with low volume have normal sperm, and fertility depends more on sperm count, movement and shape. Persistently low volume is still worth investigating if you are trying to conceive.
Can low semen volume be temporary?
Yes. Frequent ejaculation, a short gap before a test or a partly lost sample can all produce a low reading. That is why doctors repeat the test before diagnosing hypospermia.
What is the difference between hypospermia and aspermia?
Hypospermia means less semen than the reference range; aspermia means none at all. Both can be caused by retrograde ejaculation, which a urine test after orgasm can check for.
Read more on this
How to increase semen volume: what actually works
Is it normal for semen volume to change day to day?
Lifestyle factors that affect male fertility: a practical guide
Sources
- Campbell MJ, Lotti F, Baldi E, et al. Distribution of semen examination results 2020 - A follow up of data collated for the WHO semen analysis manual 2010. Andrology. 2021;9(3):817-822. PubMed
- Parnham A, Serefoglu EC. Retrograde ejaculation, painful ejaculation and hematospermia. Transl Androl Urol. 2016;5(4):592-601. PubMed
- Roberts M, Jarvi K. Steps in the investigation and management of low semen volume in the infertile man. Can Urol Assoc J. 2009;3(6):479-485. PubMed
- Fedder J, Kaspersen MD, Brandslund I, Højgaard A. Retrograde ejaculation and sexual dysfunction in men with diabetes mellitus: a prospective, controlled study. Andrology. 2013;1(4):602-606. PubMed
Not medical advice. Written by Eric Stephens from the research cited above; not reviewed by a doctor. If something worries you, see a GP.