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Is My Semen Too Thick? Sperm Viscosity, Explained

If you’re trying to conceive, you’re probably thinking way more about your sperm and semen than you ever have, and viscosity is one thing to look into. If you’re starting to worry whether your semen is too thick – don’t panic. In most cases, thick semen isn’t a huge issue for male fertility.

However, if it’s consistently really thick and sticky, it could be a sign of high sperm viscosity – which can impact the way your sperm cells move and their chance of reaching the egg.

In this blog, we’ll break down everything you need to know about sperm viscosity and how you can improve it.


What is sperm viscosity?

The word ‘viscosity’ means a measure of a fluid’s resistance to deformation – or in non-scientific language, it’s a way of measuring how thick the liquid is. For example, maple syrup would have a high viscosity rating, custard would have a medium viscosity rating and water would have a low viscosity rating.

When it comes to a semen analysis there are generally two parameters used to assess the ‘thickness’ of semen.

First, the clinicians would look at liquefaction – or how long it takes for the semen to become more fluid after ejaculation. Under normal conditions, a healthy system will liquefy fairly rapidly thanks to enzymes breaking down the gel-like structure of the semen. This usually happens within 20 minutes (if you have done one of our at-home tests, you’ll have seen this for yourself!). Delayed liquefaction could indicate a problem with the prostate or the seminal vesicles.

They will then look at sperm viscosity. Viscosity is measured by drawing the sample into a pipette and allowing the semen to drop – pulled simply by gravity – and the thread it leaves is measured. A healthy semen sample will have a tiny thread. According to WHO specifications, semen that leaves a thread more than 2 cm long is classed as having ‘abnormal viscosity’.


How does tick semen impact fertility?

Semen with abnormally high viscosity makes it harder for your sperm cells to swim. If we think back to the earlier example, if you were trying to swim through treacle, you would find that much harder than swimming through water!

If your sperm find it harder to swim, it’s likely that you are struggling with low motility – a common reason behind male factor infertility. Low motility makes it harder for your sperm cells to reach the egg in time to fertilize it/before they die.

There are also studies linking semen with high viscosity (or hyper-viscous semen) to other issues surrounding male fertility. One study found that semen with high viscosity is more likely to have an elevated number of white blood cells, which can impact sperm health. Another study noted that hyperviscous semen could be a result of an inflammatory condition or infection of the genital tract, which would also make it more prone to other poor sperm health parameters including low motility and increased DNA fragmentation.


How can I improve sperm viscosity?

If you are looking to improve your sperm viscosity and make it healthier – there are a few things you can do. The good news is they are largely the same things we would advise for improving any factor of your sperm health!

  1. Stay hydrated – this is a huge one for sperm viscosity! If you don’t have enough fluids in your body then it’s tough for your body to produce nice, fluid semen! Try to drink at least 3 liters a day and avoid diuretics like alcohol (as they will make you dehydrated)
  2. Avoid inflammatory foods – If there is a connection between inflammation and sperm viscosity, then eating an anti-inflammatory diet could potentially help.
  3. Bad habits like smoking and alcohol can all have an impact on your sperm health – including its consistency – so try to avoid them.
  4. Avoid things that could cause heat damage in your testicles – including saunas, hot tubs, and using your laptop directly onto your lap.


Getting to know your semen – and your swimmers – is important for understanding your health and your fertility. With our at-home male fertility test, it’s never been easier.

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More to explore


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.