Low Sexual Arousal and Semen Volume
Low sexual arousal does not cause pathologically decreased semen volume, but the duration of preejaculatory arousal does influence semen parameters in individual ejaculates produced by masturbation. 1
Evidence on Arousal and Semen Volume
The relationship between arousal and semen volume is nuanced and context-dependent:
- Longer duration of preejaculatory sexual arousal significantly increases sperm concentration in masturbatory specimens, with a positive linear relationship demonstrated in controlled studies 1
- Sexual arousal during the abstinence period increases semen volume when men watch arousing content daily during the standard 3-day abstinence period before semen collection 2
- Total motile sperm count also increases with sexual arousal during abstinence 2
- However, other parameters including normal morphology, concentration, and progressive motility remain unchanged by arousal during abstinence 2
Clinical Context: When Low Volume Actually Matters
If a patient presents with genuinely low semen volume (<1.4 mL), the differential diagnosis has nothing to do with arousal levels:
- Ejaculatory duct obstruction presents with acidic semen (pH <7.0), volume <1.4 mL, azoospermia or severe oligospermia, normal testosterone, and palpable vas deferens 3
- Congenital bilateral absence of vas deferens requires checking for palpable vas deferens bilaterally and proceeding directly to sperm retrieval with ICSI for fertility 3
- Retrograde ejaculation should be ruled out with post-ejaculatory urinalysis when volume is <1 mL (except in bilateral vasal agenesis or hypogonadism) 3
- 5α-reductase inhibitors (finasteride 5 mg/day) are associated with decreased semen volume as a medication side effect 4, 3
Age-Related Changes vs. Arousal
- Natural declines in semen volume occur with aging and are not related to arousal levels 5
- Decreased force of ejaculation (77.9%) and decreased amount of semen (74.4%) are highly prevalent in men with lower urinary tract symptoms, strongly related to LUTS severity and age rather than arousal 6
Bottom Line for Clinical Practice
Do not attribute pathologically low semen volume to poor arousal. 3 If volume is consistently low, work through the structured diagnostic algorithm: check for palpable vas deferens, measure semen pH, assess testicular size, check serum testosterone and FSH, and perform post-ejaculatory urinalysis when indicated 3. The duration of arousal before ejaculation may cause minor fluctuations in individual specimens but does not cause clinically significant reductions in semen volume that would warrant medical evaluation 1.