Medically reviewed content. Last updated: April 2026.
Medically reviewed content. Last updated: April 2026.
Fertility is not just about the person carrying the pregnancy. Around 30 to 40% of fertility difficulties involve male factors, and in about 20% of cases, the cause is found in the male partner alone. The good news is that many of the factors affecting sperm health are within your control. This guide explains how sperm quality works, what can affect it, and what your partner can do to give you the best chance of conceiving.
When a semen analysis is carried out (the standard first test for male fertility), three main things are assessed.
This is the total number of sperm in the sample. The WHO defines a normal count as at least 15 million sperm per millilitre, or at least 39 million in the total sample. A lower count does not make conception impossible, but it can make it less likely.
This measures how well the sperm move. At least 40% of sperm should be moving, and at least 32% should have progressive motility (moving forward in a straight line or large circles rather than in small circles or not moving at all). Sperm need to swim through the cervix, uterus, and fallopian tube to reach the egg, so good motility is important.
This describes the shape of the sperm. At least 4% of sperm should have a normal shape (oval head, intact midpiece, and single tail). Abnormally shaped sperm may have difficulty reaching or fertilising the egg.
Other factors assessed include semen volume, pH, and the presence of white blood cells (which can indicate infection).
Sperm take approximately 74 days to develop fully, from initial stem cell to mature sperm ready for ejaculation. This means that any lifestyle changes your partner makes today will take roughly two to three months to show their full effect on sperm quality.
This is why starting healthy habits well before you begin trying to conceive is ideal, though it is never too late to make improvements.
The testicles sit outside the body for a reason: sperm production requires a temperature about 2 to 3°C below core body temperature. Anything that raises scrotal temperature can temporarily reduce sperm production and quality.
Common heat sources to be aware of:
Switching to loose-fitting boxers, taking breaks from sitting, and keeping laptops on a desk rather than a lap are simple, evidence-based changes.
Smoking directly damages sperm DNA and reduces count, motility, and morphology. A meta-analysis published in Human Reproduction Update found that smoking was associated with a 13% reduction in sperm concentration and a 10% reduction in motility. Stopping smoking improves sperm quality within three months.
The NHS offers free stop-smoking support through local services, the NHS Smokefree helpline (0300 123 1044), and the NHS Quit Smoking app.
Heavy drinking lowers testosterone levels and reduces sperm production. The NHS recommends no more than 14 units of alcohol per week, spread over three or more days. When actively trying to conceive, reducing intake further is sensible.
Both being overweight and underweight can affect sperm quality. Excess body fat can disrupt hormone levels, lowering testosterone and raising oestrogen, which impairs sperm production. Underweight men may have lower sperm counts. A BMI between 20 and 25 is associated with the best sperm parameters.
Regular moderate exercise supports healthy testosterone levels and improves sperm quality. Aim for at least 150 minutes of moderate-intensity activity per week, as recommended by the NHS. However, excessive endurance exercise (very long-distance running, extremely intense cycling) may temporarily reduce sperm quality. Balance is key.
Cycling specifically has been studied, and prolonged cycling (more than five hours per week) may affect sperm quality due to heat, pressure, and vibration. Occasional cycling is unlikely to cause problems, but if you are concerned, consider reducing long sessions while trying to conceive.
Cannabis, cocaine, and anabolic steroids all negatively affect sperm production. Anabolic steroids are particularly harmful, as they suppress the body's own testosterone production, which can cause sperm counts to drop to zero. Recovery after stopping steroids can take months or even longer, and in some cases the damage is not fully reversible.
Some prescription medications can affect sperm quality. These include:
If your partner takes any regular medication, it is worth checking with a GP whether it could affect fertility. Medication should never be stopped without medical advice.
Chronic stress can affect hormone levels and reduce sexual function. While the direct link between stress and sperm quality is still being studied, managing stress through regular exercise, adequate sleep, and support from family or professionals is beneficial for overall health and wellbeing.
Male fertility does decline with age, though more gradually than female fertility. After 40, sperm quality tends to decrease, with lower motility, increased DNA fragmentation, and a longer time to conception. The risk of certain genetic conditions in offspring also increases with paternal age. This does not mean conception is not possible, but it may take longer.
A balanced diet rich in fruits, vegetables, whole grains, lean protein, and healthy fats is associated with better sperm quality. Key nutrients include:
A Mediterranean-style diet pattern, emphasising these foods, has been associated with better sperm parameters in several studies.
While a healthy diet is the foundation, some supplements may help, particularly if dietary intake is low:
There is no need to take expensive "male fertility" branded supplements. A standard multivitamin plus a balanced diet covers most needs. Discuss with a GP before starting any new supplements.
NICE guidelines recommend having sex every two to three days without specifically timing it. Regular ejaculation helps maintain sperm quality, as sperm that remain in the reproductive tract for too long accumulate DNA damage. There is no need for abstinence periods when trying to conceive naturally.
Your partner should see a GP if:
The first test is a semen analysis, which can be arranged through the GP. Two samples taken at least three months apart are usually required for a reliable result. If results are abnormal, a referral to a urologist or fertility specialist may follow.
When a semen analysis is carried out (the standard first test for male fertility), three main things are assessed.
Sperm take approximately 74 days to develop fully, from initial stem cell to mature sperm ready for ejaculation. This means that any lifestyle changes your partner makes today will take roughly two to three months to show their full effect on sperm quality.
Your partner should see a GP if:
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