Sexual Wellness

Does Low Testosterone Cause Erectile Dysfunction?

Fact Checked

Is testosterone an effective ED treatment? The answer is complicated. Here’s what you need to know about low levels of testosterone and erectile dysfunction. 

Last Updated: 04/13/2023

Written by

Kimberly Wilkes

Medically Reviewed by

Dr. Paul Thompson, M.D.

Testosterone is a hormone involved in many aspects of sexual health in men including libido and sex drive. Therefore, it seems like a no-brainer that low T can cause erectile dysfunction (ED). However, the reality is far more complicated. There may be a link between low testosterone and erectile dysfunction but not directly and not in all men. 

Let’s take a look at the possible connection between testosterone and erectile dysfunction and answer the question, “Does low testosterone cause ED?”

How Testosterone Affects Sexual Function

There’s no doubt that healthy testosterone production is associated with optimal sexual function and sexual arousal. 

Normal levels promote:1

  • Daydreaming and sexual fantasies

  • Sexual desire and libido

  • Sexual arousal

  • Spontaneous erections

Testosterone also plays a key role in supporting erectile function. It stimulates the central nervous system to release brain chemicals called neurotransmitters that are involved in triggering erections. These brain chemicals include:

  • Dopamine, which controls sexual function and increases your motivation for sex.2

  • Nitric oxide, which increases blood flow to penile blood vessels.  

In addition, testosterone can promote changes in spinal nerves, which alters blood vessels in a way that leads to healthy erectile function.

Even so, testosterone’s effect on sexual intercourse may be more indirect in that it’s best known for increasing libido, sex drive, and sexual desire, making you more motivated to have sex. This is one of the reasons why a common symptom of low testosterone is sexual problems. 

Can Low Testosterone Cause ED?

While normal testosterone is tied to sexual function, it’s less clear whether low testosterone causes erectile dysfunction. 

If you’re suffering from erectile dysfunction, low testosterone is just one piece of the puzzle. Research found that only 20% to 40% of men with erectile dysfunction have low free testosterone.3  

Yet, some men with ED only respond to PDE5 inhibitors like Viagra if they are also given testosterone replacement therapy (TRT).4

Because low T causes low libido and reduced sex drive and sexual arousal, it may indirectly affect sexual activity rather than having a direct physical effect on erectile function.

It’s important to remember that many medical issues are risk factors for erectile dysfunction, such as heart disease and diabetes. These conditions also put you at higher risk for low testosterone. The low testosterone associated with these diseases may be to blame for ED, or the cause of ED may be another related factor such as reduced blood flow. 

More likely than not, erectile dysfunction is a combination of many factors, of which low T is only one. 

What Causes Low Testosterone Levels?

Several contributing factors can cause low testosterone levels. Here are some reasons why you might have low T. 

Metabolic Syndrome and Diabetes

Metabolic syndrome—a cluster of risk factors for heart disease including high blood sugar, fat around the belly, and high blood pressure—is tied to low T. An estimated 30% of men with this metabolic condition and up to half of men with diabetes have low T.1 

According to research, erectile dysfunction also occurs more often in men with metabolic syndrome compared to controls.5

In addition, if you have type 2 diabetes you have double the risk of having low testosterone compared to a man without diabetes.6 Diabetes is a common risk factor for both low testosterone and erectile dysfunction. It’s estimated that 35% to 75% of diabetics have erectile dysfunction.7

There are many ways in which these two conditions can lead to erectile dysfunction besides low testosterone. These two disorders can cause vascular problems that reduce blood flow, which can contribute to ED. The high blood sugar that occurs in diabetes can deplete levels of nitric oxide, which can reduce blood flow and damage blood vessels involved in erectile function.8

In addition, high blood sugar in diabetes causes nerve damage, including to nerves that stimulate erections.9  


Obesity often goes hand in hand with diabetes, as it is a risk factor for the disease. Obesity also is a risk factor for low testosterone. Peer reviewed studies suggest obese diabetic men have the lowest free T compared with non-diabetic men or men who are overweight.10 

Low testosterone may lead to obesity as low levels of this hormone promote weight gain around the middle and reduced lean mass.10 Losing weight can also boost testosterone.11 It may be a vicious cycle as obesity leads to low testosterone and low T causes men to pack on the pounds. 


Younger men have higher T levels. Peak testosterone levels occur during the teenage years, then total and free testosterone production falls gradually even in healthy aging men. At the same time, sex hormone-binding globulin (SHBG) increases.3 This is a double whammy, since not only does testosterone decline, but a higher percentage of the remaining testosterone is bound tightly to SHBG, further reducing the amount of bioavailable testosterone.3 

At age 75, free testosterone levels are half of what they were at age 25.11 But a lot of aged men have testosterone within the normal range, even if their levels are 50% less than when they were younger.3  

At the same time, ED increases and is found at a much higher rate in older men. 


Certain medications can cause a drop in testosterone and possibly affect a man’s sex life. These include:12

  • Antiandrogens

  • Beta-blockers

  • Anti-histamines

  • Drugs for arrhythmia

  • Opioids (especially long-acting opioids)

  • Antidepressants

  • Anti-anxiety medications 

  • Gonadotropin-releasing hormone agonists

  • Cimetidine (a heartburn medication)

If you are taking any of these medications, talk with your doctor about ordering a blood test to measure low testosterone levels. 

Alcoholism and Liver Disease

Alcoholism and alcohol-related liver damage cause testosterone to be converted into estrogen.13 This is why alcoholics often have low free testosterone levels and higher estrogen levels.3 


Emotional stress can cause low T, while stress-reduction techniques can cause a rebound in testosterone.14,15 Cognitive-behavioral stress management therapy can increase free testosterone levels in men. In a study of men with HIV,  raising free testosterone corresponded to the men feeling less stressed.15 

Common Symptoms of Low Testosterone Levels

If you don’t make enough testosterone, you’ll probably start to feel the effects on your sex life one way or another. Symptoms of low T may include:3,16

  • Low libido

  • Low sex drive

  • Erectile dysfunction

  • Decreased hair growth

  • A decline in muscle mass and strength

  • Insomnia

  • Depression

  • Increased body fat and weight gain

  • Low energy

  • Osteopenia (weak bones)

  • Cognitive problems

  • Irritability and mood changes

  • Excessive sweating

If you have any of these symptoms, your doctor can test your T levels and begin testosterone replacement therapy if your levels are low.

Diagnosing Low Testosterone

Your doctor will diagnose low T after reviewing the results of your testosterone measurement. 

The American Urological Association recommends men with ED have their T levels tested twice on separate occasions.17 This second measurement is required because many men with ED whose testosterone measured low when first testing have a normal level when testing a second time.3 

According to American Urological Association guidelines, a total testosterone level below 300 ng/dL is considered low.17 Your doctor may also want to test your free T levels. 

Testosterone Replacement Therapy for Low Testosterone and ED

Hypogonadal men are what scientists call men who have low T. These men will likely benefit from TRT. To treat low T, a doctor may prescribe topical gels, patches, injections, or capsules.

TRT may reduce some or all of the symptoms of low T and you may notice an improvement in your sex life. However, not all men with erectile dysfunction who also have low testosterone levels experience improvement in ED after testosterone treatment. 

Testosterone therapy may be more effective in men with mild ED than in men with moderate to severe ED.18

On the other hand, some men who are experiencing ED and have normal testosterone levels report improved erectile function after they are given TRT.3 

Even if your testosterone level is normal or borderline, your doctor may want to treat you with testosterone for a few months to see if it improves erection problems or other symptoms of low T.3 

Sometimes, ED won’t improve after treatment, but your doctor may keep you on testosterone anyway if your other symptoms of low testosterone get better.3

Your doctor will likely want to check for prostate problems before beginning treatment. 

There are some reasons why your healthcare provider may decide not to begin TRT. You should not use testosterone if you have:

  • Prostate cancer (past or present)

  • A type of blood cancer called polycythemia

  • Severe cardiac or coronary insufficiency

  • Lower urinary tract symptoms

  • Sleep apnea

According to the American Urological Association, there is no evidence to definitively support the concerns that testosterone treatment could increase cardiovascular risk.17 

You’ll want to make sure you’re not taking too much testosterone, which should not happen if your doctor is monitoring your levels and adjusting your dose accordingly. High levels can be turned into estrogen and cause symptoms. 

Common symptoms of too much testosterone in men include:19 

  • Breast growth

  • Aggressive behavior

  • Headaches

  • Acne

  • Irritability

  • Oily skin

  • Shrunken testicles

  • Body hair growth

  • An enlarged prostate

  • Heart or liver problems

  • High blood pressure

  • Insomnia

  • Unexplained weight gain

  • Swelling of the hands and feet

Other Ways to Raise Testosterone Levels

TRT will have the most dramatic effect, but there are other natural ways to raise levels. 


Exercise, especially weight lifting and resistance training, can boost testosterone levels in men. One study found that men who exercise regularly have higher testosterone levels than sedentary men.20 Research suggests that exercise is an even more powerful way to boost testosterone levels than losing weight.21 

Of course, if you exercise, you’re likely to lose weight, which can only work in your favor, both for raising testosterone and improving your sex life. 

Reduce Stress

Lowering stress leads to reduced levels of the stress hormone cortisol, which in turn raises testosterone. Stress-relief practices like transcendental meditation can support healthy levels.22         

Improve Sleep

Testosterone rises during sleep, so getting better shut-eye can boost levels. On the other hand, lack of sleep can cause low T. Sleep loss is tied to lower testosterone in the morning, afternoon, and over 24 hours.23 Not getting enough sleep can make you irritable and lead to mood changes, which isn’t good for your sex life.    

Dietary Supplements

In a recent blog post, we covered the best supplements to naturally boost testosterone and nitric oxide. If you’re looking to improve low libido and enhance your sex life, we encourage you to read that post here.

To summarize, nitric oxide (NO) increases blood flow to penile tissue, and supplements that raise levels of NO can work with supplements that raise testosterone levels to support sexual health. 

Nitric oxide boosters include:

  • L-citrulline

  • L-arginine

  • Beetroot juice

Natural testosterone boosters for low T include:

  • Zinc

  • Vitamin D3

  • B vitamins

  • Magnesium

  • DHEA

  • Saw Palmetto

  • Ashwagandha

  • Fenugreek

  • Tribulus terrestris

Frequently Asked Questions About Low Testosterone and ED

Does low T affect getting hard?

If you’re wondering “can low testosterone cause ED?” the answer for many men is probably yes. Low testosterone can play a role in erectile dysfunction and low libido. But low T levels are not always to blame for ED. Research found that only 20% to 40% of men with erectile dysfunction have low free testosterone. 

Erectile dysfunction is likely a combination of many factors, of which low T is only one. 

Many medical conditions that cause ED, such as diabetes and obesity, are associated with low T, so the line becomes blurred as to whether it’s the disease itself or the low testosterone that is causing the erectile dysfunction.

Does increasing testosterone improve ED?

In some men, testosterone replacement therapy may get rid of their erectile dysfunction. However, not all men with erectile dysfunction who also have a low testosterone level experience improvement in ED after treatment with testosterone. 

Testosterone therapy may be more effective in men with mild ED than in men with moderate to severe ED.

However, testosterone therapy improves erectile function even in some men who have ED and normal testosterone levels. 

Sometimes, even after treatment, ED won’t improve but your doctor may keep you on testosterone anyway if your other symptoms of low testosterone get better.

Will Viagra work if you have low T?

Studies have found that some men with ED only respond to PDE5 inhibitors like Viagra if they are also given testosterone replacement therapy. However, other studies have found that testosterone treatment did not affect the effectiveness of Viagra.24 

How long does it take for TRT to help erectile dysfunction?

Although increased sexual interest can begin after only three weeks of TRT, it can take up to six months for TRT to improve erectile function.25 

Improvements in mood can start after three to six weeks of treatment, peaking at 18-30 weeks.25 Reductions in high cholesterol can start in four weeks, with maximum improvements happening from six months to a year.25 Improvements in lean body mass, muscle strength, and fat mass happen at 12 to 16 weeks and stabilize at six to 12 months, with possible continued small improvements over the years.25