Walnuts may support some aspects of sperm health, but they have not been shown to reliably increase sperm count. Small randomized trials found improvements in sperm movement and shape after men added nuts to their diets, while a systematic review found no overall effect on sperm concentration. Walnuts can be part of a balanced diet, but they are not a proven treatment for infertility or a substitute for medical evaluation.
Research on walnuts and male fertility focuses on several features of semen, including the number of sperm, how well they move, and whether they have a typical shape. These measurements provide different information, so an improvement in one does not necessarily mean that all aspects of fertility have improved.
What does research say about walnuts and sperm count?
Research suggests that eating walnuts may improve certain measures of sperm quality, particularly motility (movement), vitality (the proportion of living sperm), and morphology (shape). However, the evidence for increasing sperm count itself is less convincing.
The U.S. National Library of Medicine's PubMed record of a randomized controlled trial describes a study involving 117 healthy men aged 21 to 35 who regularly ate a Western-style diet. For 12 weeks, one group added 75 grams of walnuts daily, while the comparison group avoided tree nuts. The researchers found improvements in sperm vitality, movement, and normal shape in the walnut group. These findings support a possible benefit for sperm quality, but they do not establish walnuts as a reliable way to increase sperm count.
A broader review helps clarify this distinction. Researchers writing in the American Society for Nutrition's journal Advances in Nutrition published a systematic review and meta-analysis in 2024. It included four studies involving 875 participants, of whom 646 were men. The analysis of two randomized trials involving healthy men found improvements in sperm movement, vitality, and shape with higher nut intake, but no overall improvement in sperm concentration. Because these results cover different types of nuts, they should not be interpreted as proof that walnuts alone increase sperm count.
Can walnuts increase sperm count in men experiencing infertility?
Some research has examined walnuts in men already receiving care for fertility problems. A 2019 randomized clinical-trial report archived by the U.S. National Library of Medicine described 75 men who received usual infertility care and were assigned either to add 42 grams of walnuts daily or to take a nutritional supplement intended for male reproductive health.
After three months, the walnut group showed an improvement in sperm movement. Sperm concentration also increased, but the finding did not reach conventional statistical significance. Preliminary pregnancy results were not statistically significant either. This report offers a reason for further research, but it does not establish that walnuts increase sperm count or improve the chance of pregnancy in every man experiencing infertility.
Why might walnuts support sperm health?
Walnuts contain plant-based omega-3 fatty acids, including alpha-linolenic acid, as well as other nutrients and naturally occurring plant compounds. These nutritional features have led researchers to investigate whether regular nut consumption can support reproductive health.
However, the studies do not establish which nutrients are responsible for the observed changes in sperm quality. They also do not prove that eating more walnuts will correct a particular fertility problem. A food's nutritional value and its ability to produce a specific medical outcome are two different things.
How many walnuts should you eat for sperm health?
There is currently no established walnut dose proven to increase sperm count. Research has tested different quantities, including 42 grams and 75 grams daily, but these were study interventions rather than universally recommended fertility doses.
If you enjoy walnuts and do not have a walnut allergy, you can include them as part of a varied, balanced diet. There is no need to force yourself to eat large amounts or assume that a greater quantity will produce better results. The overall quality of your diet matters more than relying on one food as a treatment.
Before taking supplements marketed for male fertility, discuss them with a healthcare professional, particularly if you use prescription medicines or have an underlying health condition. The American Society for Reproductive Medicine's guidance on male infertility states that the clinical benefits of fertility supplements, including vitamins and antioxidants, remain uncertain and that the available evidence is insufficient to recommend specific products routinely. This guidance concerns supplements and should not be confused with a recommendation to avoid nutritious foods such as walnuts.
How long might dietary changes take to affect sperm?
Changes in diet are unlikely to produce an immediate change in semen results. According to Mayo Clinic's guidance on low sperm count, sperm take approximately 42 to 76 days to mature, and the effects of lifestyle changes may take several months to become apparent. This does not mean that eating walnuts for a particular period will necessarily increase sperm count.
Semen measurements can also vary between samples. A change in a single result may not reflect a lasting change in sperm production, so a healthcare professional may recommend repeat testing when appropriate.
What should you do if your sperm count is lower than expected?
A semen analysis is the main test used to assess sperm number and other features of semen. If a result is lower than expected, a healthcare professional can consider it alongside reproductive history, relevant health conditions, medicines, and other test findings.
The American Society for Reproductive Medicine's guidance developed with the American Urological Association recommends that an initial male fertility evaluation include a reproductive history and one or more semen analyses. When an initial result is abnormal, repeat testing may help account for natural variation between samples. Both partners may need assessment when pregnancy has been difficult to achieve.
Walnuts can be a reasonable part of a healthy eating pattern, but they should not delay an evaluation when fertility is a concern. Low sperm count can have different underlying causes, and the appropriate next step depends on the findings rather than diet alone.