Sun and Sperm: How Does Vitamin D Affect Male Fertility?

vitamin d and male fertility

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In the area of male fertility, the significance of Vitamin D, often dubbed the “sunshine vitamin,” has gained increasing attention. Amid growing concerns of Vitamin D deficiency in recent times, the question arises – should Vitamin D supplementation be considered when aiming to conceive? This exploration delves into the current evidence that sheds light on the pivotal role Vitamin D might play in male fertility.

Emerging research illuminates the profound influence of Vitamin D on health, particularly its association with sperm count, sperm quality, and testosterone levels – key factors intertwined with male fertility. Through sun exposure, select dietary choices, and supplementation, achieving optimal Vitamin D levels becomes a strategic move to maximize fertility potential.


Understanding Vitamin D

Vitamin D, often referred to as calciferol, operates as a steroid hormone produced when the skin basks in sunlight. It is a fat-soluble vitamin and exists in minimal natural food sources. Additionally, it’s commonly fortified in certain foods and is available in supplement form.

Vitamin D facilitates calcium absorption in the gut, fostering bone mineralization and robust bone development. Furthermore, it supports various bodily functions, including inflammation reduction, cellular growth, sugar metabolism, and remarkably, fertility.


Importance of Vitamin D Supplementation

Vitamin D supplementation finds its place among those at higher risk of deficiency, encompassing office workers, shift employees, and residents in cooler climates with limited sunlight exposure. Deficiency symptoms span from fatigue and discomfort to severe bone or muscle pain and heightened risk of stress fractures.

For specific groups, Vitamin D supplementation proves pivotal. Children can avoid rickets, and adults can prevent osteomalacia. Notably, around 41.6% of the US population lacks sufficient Vitamin D, and deficiency is even more prominent among individuals with darker skin tones who necessitate increased sunlight exposure.

Moreover, individuals grappling with nutrient absorption challenges, such as those with inflammatory bowel disease (IBD), confront Vitamin D deficiency due to hindered fat processing and absorption.


Vitamin D’s Link to Male Fertility

Research underscores Vitamin D’s integral role in reproductive health, with ties to sexual function, testosterone levels, and overall fertility. The intricate connection between Vitamin D and male fertility becomes evident upon reviewing the scientific studies that explore this association.

Vitamin D and Sperm Quality

A pivotal 2022 study probed the correlation between blood Vitamin D levels and various sperm parameters among men with unexplained fertility issues. The results indicated a significant connection between low Vitamin D levels and heightened sperm DNA fragmentation, suggesting potential damage to sperm’s genetic material.

Further findings from this study established links between Vitamin D levels and sperm count, motility, and morphology. Lower Vitamin D levels were observed in infertile men compared to their fertile counterparts, emphasizing the influence of Vitamin D on male reproductive health.

Another study in 2011 emphasized the significance of Vitamin D in sperm motility, further highlighting its role in sperm function.

Can You Improve Sperm Quality Through Vitamin D Supplementation?

Studies explore the potential benefits of Vitamin D supplementation on sperm quality. A Danish study employed a triple-blind randomized controlled trial (RCT) to investigate the effects of Vitamin D supplementation on semen quality and hormonal balances in infertile men. Although high-dose Vitamin D supplementation did not significantly enhance semen quality, it showcased higher pregnancy rates in the test group.

A more recent 2021 study echoed potential improvements in sperm motility following Vitamin D supplementation among men with poor sperm motility.

Vitamin D’s Link to Testosterone

The relationship between Vitamin D and testosterone remains nuanced and inconclusive. Various studies have associated lower Vitamin D levels with reduced testosterone production. However, research outcomes vary, indicating a need for further exploration.


Elevating Vitamin D Intake

To bolster Vitamin D levels, focus on sources beyond food, particularly sunlight and supplementation. Aim for moderate sun exposure of 10–30 minutes several times a week, particularly during midday. Individuals with darker skin may require slightly longer exposure.

For supplementation, consider these guidelines:

  • Ages 1–70: Minimum of 600 IU (15mcg) of Vitamin D daily
  • Infants up to age 1: 400 IU (10mcg) of Vitamin D daily
  • Individuals over 70: 800 IU (20mcg) of Vitamin D daily

Prefer Vitamin D3 supplements over D2, as D3 is better absorbed by the body. While a multitude of nutrients influence male fertility, an all-in-one multivitamin can streamline nutrient intake. Legacy’s male fertility supplement, for instance, encompasses these key active ingredients.


Embrace the Sun-Kissed Path

In the journey toward optimized fertility, Vitamin D assumes an essential role. As a pivotal factor affecting sperm health, quality, and testosterone levels, Vitamin D’s significance cannot be overlooked. With a balanced approach to sun exposure, thoughtful dietary choices, and informed supplementation, individuals seeking to enhance their fertility prospects can leverage the sunshine vitamin’s potential to the fullest.

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Wearing tight pants and underwear

Studies show that men who wear looser underwear have higher sperm concentration and total sperm count compared to men who wear tighter underwear. So, lose the tight clothes and wear something loose to give your testicles some air.

CONCLUSION: learn more about how heat can affect sperm quality here.


Besides higher mortality rate and various diseases, stress is associated with low sperm quality. Stress is known to be associated with lower testosterone levels and oxidative stress with both playing an essential role in producing and maintaining healthy sperm cells.

CONCLUSION: If you feel stressed, we recommend you get some help so you can have a balanced mental health. For a stress management guide, download the ExSeed app for free and start your personalized action plan today.

Physical activity

Scientific studies show that men who are physically active have better semen parameters than men who are inactive. Fertility specialists also state that regular physical activity has beneficial impact on sperm fertility parameters and such a lifestyle can enhance the fertility status of men.

Prioritizing exercise can help improve your overall health and result in healthy, fast swimming sperm cells that have good chances of fertilizing an egg.

CONCLUSION: Try incorporating exercise in your weekly schedule to you ensure exercising at least twice weekly. We recommend a combination of cardio training and strength exercise. Read more about exercise and male fertility on our blog.


Fast Food
Processed foods damage the health of sperm-producing cells and cause oxidative stress, which lead to poorer sperm quality. Heavy consumption of junk food (every week) can increase the likelihood of infertility since men who consume vast amounts of unhealthy food are at risk of having poor sperm quality. Besides harming your fertility, junk food enlarges your waistline, harms your cardiovascular system, kidneys, and more.

Eating more fruit and vegetables can increase your sperm concentration and motility. It’s important that you consume a healthy diet filled with antioxidants and that you eat vegetables every day. Foods such as apricots and red bell peppers are high in vitamin A, which improves male fertility by nurturing healthier sperm. Men who are deficient in this vitamin tend to have slow and sluggish sperm.

Sugary snacks/beverages: several times a week Excessive consumption of high sugar items can lead to oxidative stress, which negatively impacts testosterone levels and sperm motility. Sugary snacks and beverages are also highly associated with obesity and low fertility.
CONCLUSION: To boost sperm quality, stay away from fast food, processed food, and sugary snacks or beverages. You need to implement a healthy prudent diet filled with necessary superfoods needed for good sperm production. Check out our guide to Male Fertility Superfoods. For personalized guidance and support on how you can start improving your sperm health, check out the Bootcamp.


Direct heat can inhibit optimal sperm production and cause Sperm DNA damage. Sperm cells like environments that are a couple of degrees lower than body temperature. Avoid overheating from warm blankets, seat warmers, heat from your laptop, hot showers, and saunas.

Cigarette smoking

The exposure to tobacco smoke has significant negative effects on semen quality. The damage of cigarettes and nicotine of course depends on how many cigarettes you smoke per day and for how long, but even low usage (up to 10 cigarettes / day) can inhibit healthy sperm production.  

CONCLUSION: Stay as far away from cigarette smoking as possible if you care about your general health and your fertility. Read more here.

Cell phone

When you have your cell phone in your front pocket, your testicles are exposed to electromagnetic radiation, which studies have shown to damage the sperm cells. Put your phone in the back pocket of your pants or in your jacket pocket.


There is a clear association between obesity and reduced sperm quality. At least part of the reason for this is that obese men may have abnormal reproductive hormonal profiles, which can impair sperm production and lead to infertility. 

A BMI higher than 30 can lead to several processes in the body (overheating, increase in oxidative stress in the testes, sperm DNA damage, erectile dysfunction) that can have a negative impact on male fertility. This can result in problems when trying to conceive.  

CONCLUSION: BMI is one of the risk factors that influence semen quality and, for example, sperm motility.  


A beer or glass of wine now and then do not really harm sperm quality. But excess alcohol drinking (more than 20 units per week) can reduce the production of normally formed sperm needed for a successful pregnancy.

CONCLUSION: If you want to stay safe, stay under 14 units of alcohol per week. For more information on how alcohol can affect male fertility, take a look at our blog: “Alcohol and Sperm Quality”.


Studies show that women younger than 35 and men younger than 40 have a better chance of getting pregnant. Men can produce sperm cells almost through their entire life, but the sperm cell DNA is more fragile and prone to damage after the age of 40.

As men age, their testes tend to get smaller and softer resulting in a decline in sperm quality and production. These changes are partly because of an age-related decrease in testosterone level, which plays a very important role in sperm

production. Higher male age (>40 years) is not only associated with a decline in sperm production but also with increased sperm DNA fragmentation and worsened morphology (shape) and motility (movement). These negative effects make the sperm cells less qualified for egg fertilization.

CONCLUSION: with an age under 40, you shouldn’t have to worry much about age as a factor in itself. However, studies have shown a slow decline after the age of 30-35 years

and if you are above 40 years of age, your sperm quality can be affected due to increased sperm DNA damage resulting in a decrease of sperm motility and concentration. Remember that you cannot evaluate the quality of a sperm sample by just looking at it – this requires a sperm analysis.