Limited time: Use BLACKFRIDAY23 for 20% off sperm testing & freezing
Science-backed fertility tips, human stories, exclusive promos, and events.
Oxidative stress is a biological mechanism that plays a big role in male fertility. A 2019 review in the Journal of Human Reproductive Sciences found that oxidative stress is linked to reduced sperm motility, increased sperm DNA damage, and an increased risk of miscarriage and genetic disease. This article will explore oxidative stress, how it can affect male fertility, and what you can do to reduce oxidative stress.
Before we delve into what oxidative stress is and how oxidative stress can affect male fertility, there are a few terms that are helpful to understand: Free radicals, reactive oxygen species (ROS), and antioxidants.
Free radicals are unstable molecules with unpaired electrons. Free radicals are produced by a number of natural body processes, including metabolism, and can be increased by exposure to radiation or pollution, smoking, or illness.
Free radicals can cause damage by “stealing” electrons from other cells. This damage can contribute to many diseases.
ROS are a type of free radical that contains oxygen. Like other free radicals, they can cause cell injury.
Antioxidants are nutrients that prevent or slow cellular damage caused by free radicals. Antioxidants lend an electron to free radicals, thereby neutralizing and stabilizing them. Examples of antioxidant nutrients include vitamin C, vitamin E, and CoQ10.
Free radicals are inevitable, since they’re a natural byproduct of human life. Ideally, free radicals can be neutralized by antioxidants before they can cause real damage to your cells.
When there are too many free radicals in your body and not enough antioxidants, the free radicals can begin to damage your DNA, proteins, and lipids (fatty tissue). This is oxidative stress.
Scientists define oxidative stress as “an excess production of reactive oxygen species (ROS) relative to antioxidant defense.” Essentially, this means your body has an imbalance between free radicals and antioxidants. In other words, the ratio of free radicals is too high, and the antioxidants can’t keep up.
Reactive oxygen species aren’t all bad. Free radicals can actually help fight off pathogens that may lead to infection. However, the issue comes when there is long-term exposure to oxidative stress. This can lead to problems such as:
Oxidative stress also contributes to signs of aging.
One of the cells that oxidative stress can damage: Sperm cells.
Research tells us that oxidative stress significantly impacts male fertility and has harmful effects on sperm, including DNA damage.
Reactive oxygen species can negatively impact sperm cell membranes, which contain a high concentration of unsaturated fatty acids. ROS can cause a process called “peroxidation of lipids,” in which free radicals steal electrons from the lipids in cell membranes, leading to cell damage.
Common indicators of oxidative stress on a semen analysis include:
However, a number of other issues could also be contributing to these results. What are the specific signs of oxidative stress we can test in the semen?
Lower measures of TAC and higher levels of ROS and MDA in the semen have consistently been correlated with poorer semen parameters and fertility outcomes.
For example, one study of 42 semen samples found that, on average, samples with low sperm motility, count, and morphology had 40% lower measures of total antioxidant capacity, compared to healthy samples. The MDA levels in the unhealthy samples, on the other hand, were about 56% higher than the levels in healthy samples. Several other small studies have made similar observations.
Oxidative stress plays an independent role in the cause of male infertility, with 30% to 80% of infertile men showing elevated ROS levels in their semen. However, we’re not yet at the point where ROS, TAC, or MDA are common tests for male fertility. While many experts are pushing for these tests to become more mainstream, there is still work to be done to establish a reference range for normal measures.
For now, many doctors may use semen analysis and DNA fragmentation results along with lifestyle, exposure, and medical history to assess whether oxidative stress may be affecting male fertility. Reducing oxidative stress can be a useful treatment strategy for male infertility.
Oxidative stress is caused by the imbalance between the reactive oxygen species (ROS) and antioxidants in the semen. “Oxidative stress can result from either exogenous or endogenous factors that will eventually put pressure on the sperm quality and quantity,” explains Dr. Ramy Abou Ghayda, fellowship-trained urologist and chief medical officer at Legacy.
“Endogenous” means internal factors, like a medical condition, such as varicocele, or hormonal abnormality. “Exogenous” means external factors, such as lifestyle or environmental exposure like smoking or pollution.
According to Dr. Ghayda, both of these factors can cause an increase in oxidative stress. “This will eventually and subsequently lead to lower semen parameters and might be associated with an abnormal success rate for fertility, whether through natural or assisted reproductive techniques,” he discusses.
Exogenous causes are a little more within our control, and include:
Dr. Ghayda discusses there are three ways to help reduce oxidative stress:
Many general ways to help improve male fertility will also help reduce oxidative stress. Here are our top ten ways to boost fertility:
Learn more about improving sperm health.
Continue your fertility journey in your inbox.
Explore more collections
Parenthood starts with you — and your fertility. Our kits are the fastest way to test and freeze your sperm, without ever having to leave your home. Take our quiz to find out which Legacy services are right for you.