When you’re planning for a baby, medication might not be the first thing that comes to mind. But what you take can sometimes matter to male fertility. That doesn’t mean medication is generally bad for sperm, or that you should stop taking something because you’re trying to conceive. In many cases, continuing effective treatment is important for your health, and the condition being treated can itself affect fertility. We recommend booking a preconception health check with your doctor, where you can discuss any medications or supplements you’re taking and if they might impact fertility. In the meantime, here’s what you need to know about the most common medications affecting male fertility.
How can medication affect male fertility?
Medicines can potentially affect reproduction in several different ways. Depending on the drug, effects may involve:
These aren’t all the same as infertility.
For example, researchers often look at sperm count, movement and shape when studying whether a medicine affects male reproduction. Changes in these measures can be important, but they don’t automatically tell us whether a man will or won’t be able to conceive.
There’s another question too: whether a medicine taken by a man around the time of conception can affect the pregnancy or health of the child.
We know considerably less about this. Research into medication safety around pregnancy has historically focused much more on medicines taken by women. A 2024 systematic review of paternal medication exposure found just 17 eligible database studies published over the period it examined.
So, for many medicines, the fact that “we don’t have evidence of harm” is not the same as “we know there is no risk”.
Which medications can affect male fertility?
The evidence varies considerably between medications. Some have reasonably well-established effects on sperm production. For others, studies have produced mixed findings, or there simply isn’t enough good-quality research to be certain.
Here are some of the medicines worth knowing about.
Testosterone
Testosterone treatment should be avoided if you want to have children.
Taking testosterone turns off the hormonal signals that normally tell the testes to produce sperm. As a result, sperm production can fall to a level that makes it
If you use prescribed testosterone and want to have children, talk to the clinician managing your treatment. Don’t stop treatment or change your dose without medical advice.
Anabolic steroids
Anabolic-androgenic steroids used for muscle growth or performance have the same effects as testosterone, so they can also suppress sperm production.
Tell your doctor if you use or have recently used anabolic steroids when discussing fertility. It matters even if they weren’t prescribed.
Stopping anabolic steroids does not mean that sperm production immediately returns to normal. Recovery varies between people, so individual advice is needed.
Sulfasalazine
Sulfasalazine is used to treat conditions including inflammatory bowel disease and some forms of arthritis.
Unlike many medicines where the fertility evidence is uncertain, there is reasonably consistent evidence that sulfasalazine can adversely affect sperm in some men. Effects include lower sperm counts, poorer movement and abnormal shape. These effects can improve after the medication is stopped or changed.
Not every man who takes sulfasalazine will be infertile. Pregnancies have occurred while fathers were taking it, and evidence about pregnancy outcomes following paternal exposure has generally been reassuring.
If you take sulfasalazine and are having difficulty conceiving, discuss it with your doctor rather than stopping it yourself. The reason you need the medicine — and what could happen if your condition becomes poorly controlled — matters too.
Cyclophosphamide
Cyclophosphamide is used to treat some serious autoimmune diseases and cancers.
It can damage the cells involved in sperm production and can cause very low sperm counts or no sperm in the ejaculate. The effect can sometimes improve after treatment, but recovery is not guaranteed.
This makes fertility planning particularly important when cyclophosphamide treatment is being considered. Depending on the situation, discussing fertility preservation before treatment may be appropriate.
The evidence about the effect of paternal cyclophosphamide exposure on a pregnancy, however, is much more limited than the evidence about its effect on sperm production.
Methotrexate and other medicines that suppress the immune system
The picture becomes less straightforward with many other medicines used for inflammatory and autoimmune conditions.
Systematic reviews have found largely reassuring evidence for paternal exposure to several treatments, including methotrexate and some biologic and immunosuppressive medicines. But the amount and quality of evidence varies considerably between individual drugs.
Methotrexate is a good example of why paternal medication advice needs to be specific rather than based on assumptions about how a drug affects pregnancy when taken by women.
Research looking at men has not established the same pattern of reproductive risk that might be assumed from maternal exposure. One systematic review found the evidence for an effect on male fertility was uncertain, while another found no increased risk of adverse pregnancy outcomes or congenital malformations across most studies of paternal exposure.
There are also immunosuppressive medicines for which there is very little or no useful evidence about male fertility or paternal exposure.
So if you take one of these medicines, check your individual treatment rather than assuming the advice for another drug in the same broad category applies to yours.
What about antidepressants, epilepsy medicines and diabetes medicines?
Studies have investigated whether antidepressants, anti-epileptic medicines and diabetes medicines taken by fathers around conception are associated with pregnancy or child outcomes. Some individual studies have reported associations with adverse outcomes, while others have not.
An association in an observational study does not necessarily show that the medicine caused the outcome. The underlying health condition, other medicines and other characteristics of the parents can influence the results. If you take medication for diabetes, epilepsy, depression or another ongoing condition, discuss pregnancy plans with the clinician managing your treatment. The aim is to understand the evidence for your particular medicine while keeping the condition itself appropriately treated.
What about cancer treatment?
Some cancer treatments can have substantial effects on sperm production, and those effects may be temporary or permanent depending on the treatment.
If you’re about to have chemotherapy, radiotherapy or another cancer treatment that could affect fertility, fertility preservation may need to be discussed before treatment starts. Sperm freezing is one option that may be appropriate for some men. This is a different situation from simply wondering whether a commonly used medicine might alter sperm quality. If future biological children matter to you, raise the issue with your treating team as early as possible.
Do over-the-counter medicines and supplements count?
Yes. A medication review shouldn’t stop at your prescriptions.
Tell your doctor about over-the-counter medicines, vitamins and supplements, complementary medicines, testosterone or hormone products, and performance-enhancing drugs.
Something being available without a prescription — or being marketed as “natural” — doesn’t establish that it improves fertility or is harmless to it. Roughly 9–15% of commercial dietary supplements contain undeclared or unapproved substances, with stimulants and anabolic agents the most common.
It’s also worth being wary of supplements promoted specifically as “male fertility boosters”. A plausible effect on a hormone, antioxidant marker or semen measurement is not the same as good evidence that a product improves the chance of having a baby.
Does medication taken by the father cause birth defects?
Research on paternal medication exposure is much less developed than research on maternal exposure. Studies have looked at outcomes including miscarriage, premature birth, birth weight, congenital conditions and childhood development, but only a relatively small number of medicines have been studied well.
For many of the anti-rheumatic and immunosuppressive medicines that have been studied, pregnancy and offspring findings have been broadly reassuring, although important evidence gaps remain.
If you’re worried about a particular medicine, ask about that medicine specifically rather than relying on a general list online.
Should you stop medication before trying for a baby?
Not without speaking to your doctor.
Stopping or changing treatment can have consequences of its own. Poorly controlled illness can affect your health and, in some circumstances, reproductive health as well. Research in men with inflammatory diseases illustrates this problem particularly well: separating an effect of medication from an effect of the disease itself can be difficult.
Depending on what you take and why, your doctor might advise continuing treatment, changing it, adjusting your treatment plan, investigating fertility or taking other steps. The right answer depends on the medicine and your circumstances.
What should you do before trying for a baby?
A medication check is a simple addition to preconception planning.
Make a list of everything you use, not just prescription medicines. Include medicines you only take occasionally, over-the-counter products, vitamins and supplements, complementary medicines, testosterone and other hormones, and performance-enhancing or recreational drugs. Take the list to your GP or relevant specialist.
If a medicine could affect fertility, the next question isn’t automatically “how do I stop it?” It’s “what is the safest plan for me?”. The goal is not to be medication-free before conception. It’s to make sure the treatment you need and your plans for having children have been considered together.
