Low sperm motility
Motility is the proportion of sperm moving, and particularly the proportion moving progressively — forwards rather than in place.
Interpreting a low result
The AUA/ASRM guideline notes that complete asthenozoospermia — no motile sperm at all — clearly causes infertility. Reduced but present motility is a different matter, and no single semen parameter is highly predictive of fertility on its own. Results carry most weight when several parameters are abnormal together.
Repeat before concluding. Semen parameters vary substantially between samples from the same man.
Collection issues that mimic low motility
Delay between production and analysis reduces motility. So does exposure to temperature extremes in transit, and contact with some lubricants or non-sterile containers. If your sample was produced at home and travelled, that alone may explain a low result.
Abstinence duration matters in both directions. Longer abstinence increases volume but reduces motility and increases DNA damage. Two to seven days is the usual recommendation.
Contributors worth addressing
Varicocele — where palpable and accompanied by abnormal semen parameters and infertility, repair should be considered. Repair is not recommended for non-palpable varicoceles found only on imaging; the guideline grades that a strong recommendation against.
Infection — where round cells exceed 1 million per mL, further evaluation is needed to distinguish white cells from immature sperm. Pyospermia should be evaluated for infection.
Medications and substances — testosterone and anabolic steroids are the most important, and gym supplements are a recognised hidden source.
Heat exposure, smoking, and heavy alcohol use.
Timescales
Sperm production takes roughly 72 to 90 days. Any change you make needs about three months before a repeat analysis reflects it. This is the single most useful thing to know, because most people expect faster results and give up early.
On supplements
A Cochrane review of 90 randomised trials in 10,303 subfertile men found a possible increase in live birth, but the signal disappeared when high-risk-of-bias studies were removed, and the authors rated the evidence very low certainty and inconclusive. There is also insufficient evidence supporting any one antioxidant or dose over another. The AUA/ASRM guideline reaches the same conclusion. Treat marketing claims accordingly.
Treatment
Where motility is low but sperm are present, IUI, IVF or ICSI may be options depending on the degree. See a urologist or andrologist for assessment rather than starting supplements and hoping.
Sources
- AUA/ASRM — Diagnosis and treatment of infertility in men (2021)
- Cochrane — Antioxidants for male subfertility (2022)
Frequently Asked Questions
Can sperm motility be improved?▾
Yes — in many cases significantly. Lifestyle interventions (quitting smoking, reducing heat exposure, losing weight) combined with a 3-month antioxidant protocol (especially L-carnitine and CoQ10) can improve progressive motility by 15–25%. Varicocele repair improves motility in 60–70% of men with this condition. Results take 3 months minimum. Retest with a new semen analysis 3–4 months after changes.
What is a good sperm motility percentage for fertility?▾
Per WHO 2021: ≥30% progressive motility is the lower reference limit. For natural conception, higher is better — above 50% progressive motility combined with adequate count gives the best chance. What matters most for IUI is Total Motile Sperm Count (TMSC) — the absolute number of moving sperm (target >5–10 million after preparation). IVF with ICSI bypasses motility requirements entirely.
Does L-carnitine improve sperm motility?▾
L-carnitine has the strongest specific evidence for improving sperm motility among individual supplements. It plays a direct role in fatty acid oxidation in the sperm midpiece — the energy-generating component that powers the tail. Multiple RCTs show significant motility improvement. Standard dose: 2g/day for a minimum of 3 months. Best used as part of a combined antioxidant protocol.