The Decline in Sperm Quality: What Men Can Do to Support Reproductive Health

Research has reported a long-term decline in average sperm counts in many parts of the world. This can feel worrying, but it should not be framed as a reason for panic or blame. Sperm health is influenced by many factors, including environment, lifestyle, age, medical history and overall health.

Understanding these factors can help men and couples make more informed decisions about testing, preconception preparation and when to seek professional support. This page explains what the research says, what may be contributing to the trend, and practical steps men can review as part of a wider fertility plan.

What does the research say about sperm count decline?

Large-scale analyses have reported a decline in average sperm concentration over recent decades. One widely cited meta-analysis reported that average sperm concentration fell from around 104 million per millilitre in 1973 to around 49 million per millilitre in 2018, with the rate of decline appearing to accelerate after 2000.¹

These findings describe population-level trends. They do not mean every individual man has poor sperm quality, and they do not replace individual testing such as semen analysis.

What factors may affect sperm quality?

The reasons behind the population-level decline are likely to be complex and are still being researched. A number of environmental, lifestyle, age-related and medical factors are commonly discussed in relation to sperm quality.

Environmental exposures

Phthalates, bisphenol A (BPA) and other chemicals found in some plastics, cosmetics and household products are often described as endocrine-disrupting chemicals. These substances are commonly discussed in relation to hormonal pathways and reproductive health, although individual exposure and risk varies, and research in this area continues to develop.²

Air and noise pollution

Some studies have reported associations between higher air pollution exposure and lower sperm concentration, total sperm number and motility, although findings vary between studies and this should not be described as proven or definitive.³ Chronic exposure to noise pollution has also been discussed as a possible factor in reproductive health, though the evidence here is less developed.

Lifestyle factors

Sedentary routines, ultra-processed diets, low nutrient intake, obesity, poor sleep, long-term stress, smoking and alcohol are among the lifestyle factors commonly discussed in relation to sperm quality. Age is also relevant, with some research suggesting sperm quality may change as men get older, particularly after 40.

Heat exposure

Saunas, hot baths, laptops used on the lap, tight clothing and occupational heat exposure are commonly discussed in relation to sperm production, since the testes are sensitive to raised temperature.⁴

Age and medical factors

Sperm DNA fragmentation, varicocele, infections, hormonal issues, certain medications and chronic health conditions may also play a role for some men. Where any of these are a concern, male fertility tests such as semen analysis can help build a clearer picture alongside a GP or fertility clinic.

Why the 72 to 90 day sperm cycle matters

Sperm development takes place over roughly 72 to 90 days when production, maturation and transport are considered.⁵ This is why many preconception plans focus on the three months before trying to conceive or starting fertility treatment. It gives time to review diet, alcohol, smoking, sleep, stress, heat exposure, medical factors and, where appropriate, supplementation.

For a deeper explanation of sperm count, motility, morphology, DNA fragmentation and the sperm development window, watch our Sperm Health Masterclass.

What can men review to support sperm health?

Although wider environmental and population-level factors require broader action, individual men can still review practical areas that may support reproductive health.

Eat a varied, nutrient-rich diet

A diet that includes colourful fruit and vegetables, quality protein, whole grains, healthy fats, omega-3 sources and zinc and selenium-rich foods is commonly discussed in relation to reproductive wellbeing.

Review smoking and alcohol

Smoking and alcohol are commonly discussed in relation to sperm count, motility and reproductive health. If you smoke, seeking support to stop may be one of the most useful health steps to consider.

Move regularly

Regular movement may support overall metabolic health, weight management and wellbeing.

Review heat exposure

Where practical, some men choose to review habits such as frequent saunas or hot baths, laptops used directly on the lap, tight clothing and occupational heat exposure.

Support sleep and stress

Sleep and stress may influence hormone balance, energy and wider wellbeing.

Reduce unnecessary chemical exposure where practical

Where practical, men may choose to reduce exposure to plastics, BPA, pesticides and heavily fragranced products, while recognising that not all exposures are fully within individual control.

Consider semen analysis or medical advice

If you have concerns, semen analysis can provide useful information about sperm count, motility and morphology. A GP, fertility clinic or healthcare professional can help interpret results and advise on next steps. Read more about male fertility tests.

Where supplements may fit

Supplements may be considered as part of a wider preconception plan, particularly where diet, lifestyle, semen analysis results, age, nutritional intake or professional guidance suggest they may be relevant.

They should not replace semen analysis, medical advice, lifestyle foundations or investigation of possible underlying factors. If you are unsure what is appropriate, speak to a GP, fertility clinic or healthcare professional.

Some men choose to review the following nutrients and products as part of their wider fertility plan:

• Vitamen – a daily male fertility multivitamin with nutrients including zinc and selenium, which contribute to normal fertility and reproduction.
• Vitamen Boost – an additional nutrient formula that may be considered where extra antioxidant-focused support is appropriate.
• Vitaseed Pro – a more advanced male fertility formula that may be considered where broader micronutrient and antioxidant support is being discussed.
• Menceive – a friendly bacteria supplement that may be considered as part of a wider gut and reproductive wellbeing plan.
• Vital DHA – an omega-3 supplement that may be relevant where oily fish intake is low or additional DHA is being considered.⁸
• Kaneka Ubiquinol CoQ10 – a CoQ10 supplement that may be considered where cellular energy or motility support is being discussed.⁷ Read more in our guide to CoQ10 and male fertility.

For a practical guide to choosing and combining products, read our male fertility supplement guide.

Male fertility should not be overlooked

Fertility is often discussed mainly in relation to women, but male factors can contribute to fertility challenges. Talking openly about male fertility can help couples seek testing earlier, understand their options and feel better supported.

This is not about blame. It is about making sure both partners have access to the right information and support. For a broader introduction to male fertility and sperm health, see Male Fertility Matters.

Frequently asked questions

Why are sperm counts declining?

The reasons are likely to be complex and are still being researched. Possible contributing factors include environmental exposures, lifestyle patterns, age and some medical factors, alongside the population-level trends reported in large-scale analyses.

Does declining sperm quality mean every man has a fertility problem?

No. Population-level trends do not diagnose individual men. Semen analysis is needed for an individual assessment of sperm count, motility and morphology.

What affects sperm quality?

Lifestyle factors such as smoking, alcohol, sleep, stress and heat exposure are commonly discussed in relation to sperm quality, alongside age, medical factors and environmental exposures such as endocrine-disrupting chemicals and air pollution.

Can lifestyle changes support sperm health?

Diet, movement, sleep, stress management, smoking cessation, alcohol reduction and reviewing heat exposure are commonly discussed in relation to sperm health, although individual responses vary.

How long does it take for sperm health to change?

Sperm development takes place over roughly 72 to 90 days, so many men allow around three months to review diet, lifestyle and other factors before expecting any change to be reflected in a semen analysis. Individual responses vary.

When should men consider semen analysis?

Semen analysis is often considered after 12 months of trying to conceive, or after 6 months if the female partner is over 35. It may be worth considering sooner if there are known concerns, planned IVF or ICSI, previous fertility issues or relevant medical history.⁶

Are supplements useful for sperm health?

Supplements may support nutritional status as part of a wider plan, but they should not replace semen analysis, testing or medical advice. Individual circumstances vary.

Is sperm quality affected by age?

Age may be associated with changes in sperm DNA fragmentation and other aspects of reproductive health, particularly after 40, although individual circumstances vary.

Where to go next

If you want to understand male fertility and sperm health in more detail, these resources are a helpful next step.

• For a broader overview of causes, semen analysis, sperm health and practical next steps, read our main male fertility issues guide.
• Learn more about male fertility and sperm health in Male Fertility Matters.
• Watch the Sperm Health Masterclass for a deeper explanation of sperm count, motility, morphology, DNA fragmentation and the 72 to 90 day sperm cycle.
• Understand male fertility tests, including semen analysis and when further investigations may be useful.
• Read our male fertility supplement guide for how products may fit into a wider plan.
• Explore the male fertility supplements collection if you are reviewing products as part of a wider preconception plan.

References

1. Levine H, Jørgensen N, Martino-Andrade A, et al. Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries. Human Reproduction Update. 2023;29(2):157-176.
2. Skakkebaek NE, Rajpert-De Meyts E, Buck Louis GM, et al. Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility. Physiological Reviews. 2016;96(1):55-97.
3. Xu R, Zhong Y, Li R, et al. Association between exposure to ambient air pollution and semen quality: A systematic review and meta-analysis. Science of the Total Environment. 2023.
4. Jung A, Schuppe HC. Influence of genital heat stress on semen quality in humans. Andrologia. 2007;39(6):203-215.
5. Amann RP. The cycle of the seminiferous epithelium in humans: a need to revisit? Journal of Andrology. 2008;29(5):469-487.
6. NHS. Infertility. View source.
7. Alahmar AT, et al. Coenzyme Q10 and Male Infertility: A Systematic Review. Antioxidants. View source.
8. Safarinejad MR. Effect of omega-3 polyunsaturated fatty acid supplementation on semen profile. Andrologia. 2011;43(1):38-47.