Does low testosterone cause erectile dysfunction?

If you have erectile dysfunction (ED), you might be wondering: Does low testosterone cause ED? Low testosterone (aka low T) can play a role, but it's rarely the main cause.

Conditions that affect blood flow, such as diabetes and high blood pressure, are more common drivers of ED. When low T does impact erections, it usually shows up through reduced libido. However, testosterone also helps keep the blood vessels and smooth muscle in the penis healthy. 

Read on for a closer look at the connection between low testosterone and ED, including how low testosterone can affect erections, treatment options, and more. 

Low testosterone can contribute to ED, but it’s unlikely to be the only cause. They are separate conditions that can overlap, but having one doesn't mean you'll have the other.

Here's why: An erection depends on healthy blood flow, working nerves, and relaxed muscles in the penis. Testosterone supports several parts of that process, from the desire that gets things started to the blood vessel health that keeps things working. When levels are low, one or more of those steps can be affected.

Estimates of how many people with ED also have low testosterone vary widely, depending on the population studied and the threshold used to define low T. 

But that doesn't mean low testosterone is the reason for their ED. Many people with low T still get and keep erections just fine, and plenty of people with ED have testosterone levels in the normal range.

The rate of low T among people with ED has been estimated at 20%–40%, though results vary. The number depends on where the cutoff for “low” is set, whether testosterone is tested more than once (which is the standard approach), and whether symptoms are also required for diagnosis.

Stricter definitions tend to produce lower estimates.

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Low testosterone, or hypogonadism, is commonly defined as occurring when testosterone levels fall below 300 nanograms per deciliter (ng/dL) on two morning blood tests, and symptoms are present. The exact cutoff can vary by age, and some providers use slightly different numbers. But what matters most is low levels paired with symptoms.

Levels generally start to decline as early as a person's 20s, falling roughly 1%–2% per year. The rate varies from person to person and is influenced by overall health, weight, and other factors, not just age. That slow decline is normal; low T is only diagnosed when levels are consistently low and causing symptoms.

Low T doesn't always look the same from person to person. Some individuals notice one or two changes; others experience several. Common low testosterone symptoms include:

• ED

• Low sex drive

• Fatigue and low energy

• Loss of facial and body hair

• Decreased muscle mass

• Depressed mood or irritability

• Weight gain (often increased body fat, especially around the midsection)

• Difficulty concentrating

• Poor sleep

• Decreased sperm production

• Anemia (low red blood cell count)

• Decreased bone density

Many of these symptoms can also be caused by other conditions, including diabetes, obesity, and hypothyroidism. That's one reason blood testing is important — symptoms alone aren't enough to confirm low T.

Low testosterone can affect erections through several paths, from reduced desire to changes in blood vessel health.

The most direct path, though, is through libido. When testosterone is low, the desire for sex often drops. Without that desire, the arousal needed to trigger an erection may not happen. It's not that the body can't produce an erection; it's that the signal to start one never gets sent.

If you're dealing with low desire, you might be tempted to try over-the-counter libido pills. But these supplements are not regulated by the US Food and Drug Administration (FDA) and lack scientific evidence supporting their efficacy or safety. You’re better off talking to your healthcare provider to see if there is an underlying cause that can be addressed. 

Low T can also contribute to structural changes in penile tissue that affect erectile function over time. Testosterone also supports nitric oxide production. Nitric oxide is a chemical that relaxes blood vessels in the penis, allowing blood to flow in. When testosterone drops, the body may produce less of it, making the process less efficient. 

Low T can also lead to tiredness, low mood, and less drive to be active — all of which can make having sex unappealing. 

Over time, less physical activity may lead to weight gain. And weight gain can raise the risk of conditions that directly cause ED, like diabetes, high blood pressure, and heart disease.

Excess body fat can also make low T worse. Fat tissue converts testosterone into estrogen, which can lower the amount of testosterone in the bloodstream. This can create a cycle in which low T leads to weight gain, and weight gain leads to worsened low T.

Most cases of ED come down to blood flow rather than hormones.

An erection happens when blood flows into the penis and stays there. Anything that gets in the way of that process can lead to ED. The most common causes of the condition include:

• High blood pressure: Hypertension harms blood vessel walls and limits blood flow over time.

• Atherosclerosis: Plaque buildup in the arteries narrows blood vessels and cuts off flow.

• Diabetes: High blood sugar can damage both nerves and blood vessels needed for erections.

• Obesity: Extra weight raises inflammation and can harm blood vessels in the penis, while also lowering testosterone.

• Mental health factors: Stress, anxiety, and depression can block arousal and make it harder to get or keep an erection.

• Medications: Some drugs, including certain blood pressure meds and antidepressants, can affect erections as a side effect.

Often, more than one of these factors is at play simultaneously to cause ED.

Whether testosterone replacement therapy (TRT) can help with ED depends on what's behind the erectile problems in the first place.

If low testosterone is the main reason, meaning low desire is the core issue, and there's no major blood vessel or nerve damage, then bringing testosterone back to normal levels may help with both libido and erections.

But here's the key: Raising testosterone above the normal range doesn't help erections and carries risks. These include higher red blood cell counts (which may increase the risk of blood clots) and acne.

TRT can also suppress sperm production, in some cases significantly, which is an important consideration if you're planning to have children. Testicular shrinkage and sleep apnea are other possible side effects.

There's also limited proof that treating low testosterone alone can fully resolve ED when other causes, such as blood vessel damage from diabetes or high blood pressure, are involved. In those cases, TRT may help with desire and potentially some aspects of wellbeing, such as mood and energy.

At the end of the day, whether testosterone replacement therapy may be a fit for you and potentially help your ED is a conversation that you should have with a healthcare provider. 

When both low testosterone and ED are present, they're usually treated as overlapping but independent conditions.

Treating low testosterone

If blood tests confirm low T, a healthcare provider may suggest TRT. Options include skin patches, gels, shots, or pellets placed under the skin.

For people with low T who want to keep their fertility, a medication called clomiphene (Clomid) may be an option worth discussing with a healthcare provider.

Taking clomiphene for low T is an off-label use of the drug, which was originally approved for female infertility. Unlike TRT, the medication works by pushing the body to make more of its own testosterone while preserving or even improving sperm counts.

Treating ED

No matter your testosterone levels, PDE5 inhibitors are typically the go-to treatment for ED. These prescription drugs work by helping the muscles and blood vessels in the penis relax so blood can flow in. Options include:

• Sildenafil (Viagra)

• Tadalafil (Cialis)

• Vardenafil (generic; formerly sold as Levitra)

• Avanafil (Stendra) 

Certain PDE5 inhibitors can also be found in other non-pill formulations. Ro, for example, offers the following (if prescribed):

• Ro Sparks*, a fast-acting, dissolvable lozenge that contains both sildenafil and tadalafil (the active ingredients in Viagra and Cialis, respectively). It can start to work in 15 minutes (after dissolving) and last up to 36 hours.

• Daily Rise Gummies*, fruit-flavored gummies made with a daily dose of tadalafil. Designed to be taken every day, the treatment can work continuously — no planning of sexual activity required. 

Some research suggests that pairing TRT with PDE5 inhibitors may help in cases where PDE5 inhibitors alone haven’t been effective, though overall evidence for the combination is mixed. This is worth discussing with a healthcare provider.

Other options include vacuum devices (aka penis pumps) and, in more severe cases, penile injections. Some people also look into procedures like the Priapus shot, though the best available evidence has not shown it to be more effective than placebo. 

*Though these particular formulations are not FDA-approved, their active ingredients have been individually approved for the treatment of ED. 

Lifestyle changes

Healthy habits can support both T levels and erectile function:

• Exercise regularly: Physical activity improves cardiovascular health and may help boost testosterone.

• Maintain a healthy weight: Excess body fat can lower testosterone and increase ED risk. Weight loss may improve both.

• Sleep 7–9 hours each night: Poor sleep reduces testosterone production.

• Eat a balanced diet: Foods rich in healthy fats, zinc, and leafy greens may support hormone production. A testosterone support supplement may also offer some benefits.

• Manage stress: Chronic stress raises cortisol levels, which can suppress testosterone.

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If you think low T might be playing a role in your ED, the first step is a blood test.

Testosterone levels change throughout the day and are highest in the morning. That's why testing is usually done in the morning on two separate days when you’re fasting. One low reading isn't enough for a diagnosis. It needs to be confirmed with a second test.

Normal testosterone levels for adults generally fall between approximately 300 and 1,000 ng/dL, though what counts as "normal" can depend on your age and the lab running the test.

A healthcare provider may also check other hormones, like luteinizing hormone (LH) and prolactin. These can help identify the root cause of low testosterone — whether the problem is in the testicles, the pituitary gland, or somewhere else.

So, does low testosterone cause ED? It can be part of the picture, but it's rarely the whole story. Here’s what to keep in mind:

• Low T can affect libido and tissue health. Low testosterone tends to lower your desire for sex, which can make erection problems worse. It can also directly affect blood flow and tissue health in the penis.

• Vascular damage can drive ED. Blood vessel damage from conditions like diabetes and high blood pressure is behind many cases of ED, even when low T is also present.

• Treatment may need two tracks. If blood tests confirm low T, treating it may help restore sex drive and energy, but you could still benefit from a separate medication like sildenafil or tadalafil for erections.

• Healthy lifestyle practices can support both conditions. Habits, such as regular exercise, consistent sleep, and maintaining a healthy weight, can help you maintain adequate testosterone levels and reduce or prevent ED at the same time. 

A healthcare provider can run a simple blood test to check your testosterone levels and help you figure out what's going on. The sooner you get answers, the sooner you can start feeling better.