Male infertility and oxidative stress: how sperm DNA gets damaged

What causes oxidative stress in men?

Our ability to produce antioxidants is controlled by our genetic makeup and can be influenced by lifestyle - such as a diet rich in antioxidants like fruit and vegetables. The production of free radicals is increased by many environmental and lifestyle factors, including:

• Smoking

• Alcohol consumption

• High BMI

• Poor-quality diet high in saturated fats

• Exposure to heat (like hot tubs or saunas)

• Illness, infections, or pollution

• Ageing and excess weight

Ideally, our body’s natural antioxidant production should be enough to balance the free radicals we generate. But for many individuals, there’s an excess - leading to cell damage, including to sperm, and potential long-term effects on fertility.

How do we test for oxidative stress?

At Care Fertility, we use the Sperm Oxidative Stress (SOS) test to assess whether oxidative stress is affecting sperm function. This test helps us identify whether excess free radicals may be contributing to fertility issues, particularly when semen analysis results appear normal or borderline.

Though a standard semen analysis may pick up signs of oxidative stress, such as low sperm count, poor motility, or abnormal morphology, it doesn’t explain why those results have occurred. The SOS test helps us dig deeper, measuring the balance of free radicals and antioxidants in a semen sample to give us a clearer picture of what’s going on.

One of the key advantages of the SOS test is that it can be done at the same time as a routine semen analysis or during any stage of fertility treatment. There’s no need to freeze or transport sperm to a separate lab, unlike more complex testing methods. And because oxidative stress can cause DNA damage in sperm, this quick and accessible test can act as an early indicator for whether further investigations might be needed.

If you’ve had fertility treatment without success, or if your semen analysis results are unexplained or borderline, the SOS test may be a helpful next step. 

Learn more about male fertility testing

What can help reduce oxidative stress?

Dr Campbell notes that while oxidative stress can’t always be avoided, there are things that may help reduce its impact:

• Stopping smoking

• Cutting down alcohol

• Improving diet (especially antioxidants)

• Managing weight and reducing heat exposure

• Getting enough sleep and managing stress

Lifestyle is an important part of managing oxidative stress. Making positive changes - like improving your diet, reducing alcohol, or managing weight - can help support sperm health over time.

You can learn more about nutrition and fertility in this blog

When to consider further testing or IVF

If you’ve been trying for over 12 months (or 6 months if your partner is over 35), it’s a good idea to explore male fertility tests. Dr Campbell stresses that early testing can make all the difference.

You might also consider testing if you fall into one of the following groups:

• Partners of women with a history of two or more pregnancy losses

• Males over the age of 40

• Males with suboptimal semen analysis results (particularly low morphology or motility)

• Males with poor lifestyle, BMI over 30, smoking habits, high alcohol intake or poor diet

In some cases, test results may lead us to recommend ICSI or IVF as the most effective route to pregnancy.

Your next step

Our Patient Enquiry Team will help book your initial fertility tests for men. Once those results are in, your doctor will talk you through them in your consultation and help you decide on the right path forward.