Testosterone Replacement Therapy: Benefits, Side Effects & More

Testosterone. Even the word alone sounds manly. 

For men, testosterone is important for sex drive, sperm production, energy and mood — to name just a few benefits.

When you have low testosterone, you might experience anything from low energy to erectile dysfunction (ED). 

Testosterone replacement therapy (or TRT) aims to fix some of these issues by topping up your natural supply of the hormone.

But TRT isn’t for everyone. It comes with serious risks, and it’s only FDA-approved for those with low testosterone caused by a medical condition — not aging. 

Read on to explore the benefits and side effects of TRT, as well as what you should know before starting the treatment.

What Is Testosterone Replacement Therapy?

So, what is testosterone replacement therapy, anyway? TRT is exactly what it sounds like: treatment for men with low testosterone.

There are various forms of testosterone, including:

• Transdermal patches

• Gels

• Pills

• Implants

• Intramuscular injections

• Nasal sprays

• Buccal testosterone

TRT can improve some of the symptoms of low testosterone by increasing the amount of the hormone in your system.

You may have low testosterone (also known as testosterone deficiency or male hypogonadism) due to:

• Damage to the testicles

• Medical conditions such as obesity and sleep apnea

• Aging

What Is Considered Low Testosterone?

The American Urological Association (AUA) defines low testosterone as a level less than 300 nanograms per deciliter (ng/dL). If your levels of testosterone are below 300 ng/dL and you have low T symptoms, your provider may recommend you start a testosterone treatment like TRT.

If you believe TRT could be right for you, the first step is to consult a relevant healthcare provider — namely, an endocrinologist or urologist —  about your symptoms. They can test you for low testosterone and prescribe hormone therapy if the treatment is appropriate for your needs.

Who Is a Good Candidate for TRT?

You may be a good candidate for TRT if you have low testosterone caused by a medical condition and are showing low T symptoms.

Notably, the FDA  has only approved testosterone products for men with no or low testosterone due to a medical condition like genetic issues and chemotherapy, both of which can stop the testicles from producing testosterone.

As noted, a healthcare provider can check your testosterone levels to confirm if they are indeed low. Additionally, they may want to discuss symptoms you’ve been having, like low libido (desire for sex) or erectile dysfunction (ED). They should also ask about your medical history, do a physical exam, and order any other related health tests.

Armed with all this info, a medical professional can diagnose you with low testosterone, figure out what could be causing it, and determine whether the benefits of TRT outweigh the risks based on your symptoms, health profile, and risk factors.

Who’s Not a Good Candidate for TRT?

You should avoid TRT if you have severe, untreated obstructive sleep apnea (testosterone use can worsen sleep apnea). TRT is also known to hinder sperm production, so you should steer clear of testosterone replacement therapy if you’re trying to conceive.

If you have erectile dysfunction but normal testosterone levels, there is conflicting evidence as to whether TRT is helpful in men with normal testosterone levels.

Also, if your testosterone levels aren’t low, TRT won’t likely be prescribed, unless a check of free testosterone reveals low levels and you’re having low-testosterone symptoms. More doesn’t equal better when it comes to testosterone, so boosting testosterone levels may not help symptoms that are caused by other underlying conditions.

If you do have low T and are an appropriate candidate for TRT, the treatments will get you back to baseline. Beyond that, there doesn’t seem to be any additional benefits in increasing your testosterone levels.

Symptoms of Low Testosterone

The symptoms of low testosterone include:

• Loss of libido

• Erectile dysfunction (trouble getting or keeping an erection)

• Depression

• Lack of energy

• Reduced cognitive function

• Loss of muscle mass and strength

• Osteoporosis (loss of bone density)

• Anemia

• Irritability

• Loss of body hair

• Reduce beard growth

• Increased body fat

• Obesity

It can be tricky to tell if you have low testosterone. After all, a lack of energy can be due to sleepless nights; loss of libido could boil down to relationship problems; and irritability might be because of, well… life.

Many men seek help after developing multiple symptoms of low testosterone.

If you think you may be suffering from low testosterone, reach out to a healthcare provider. They can run blood tests to measure your testosterone levels and check if they’re low.

Learn more in our guide to the signs of low testosterone in men.

Common Causes of Low T

Causes of low T include:

• Aging

• Obesity

• Metabolic syndrome

• Infection

• Medications like antidepressants

• Autoimmune disease

• Pituitary gland disease

• Damage to the testicles

• Removal of the testicles due to cancer

• Chemotherapy or radiation

• Klinefelter syndrome

• Noonan syndrome

Lots of guys have low testosterone, and it gets more common with age.

Studies use different metrics to define low levels, so numbers vary. But research shows low testosterone could affect 20 percent of men in their 60s, 30 percent in their 70s, and a whopping 50 percent of those over 80 years old.

Young guys don’t get away scot-free. Low testosterone can affect you at any age — it’s just rarer, potentially affecting around 1 percent of young men.

Also, low T is more common in men of all ages who are overweight or have diabetes.

How Testosterone Replacement Therapy Works

Testosterone replacement therapy works by increasing the amount of testosterone in your system. You’ll take synthetic testosterone to make up for low levels of the natural hormone in your body.

It may take six weeks to 12 months for symptoms to improve as testosterone builds up in your bloodstream and you figure out the best dose and regimen with your healthcare provider.

There are several different types of TRT formulations:

• Transdermal patches. Testosterone patches are applied to the skin, typically on the back, stomach, thigh or upper arm. Similar to a nicotine patch, a testosterone patch slowly releases testosterone into your skin, after which it absorbs into your bloodstream.

• Gels. Gels also deliver testosterone into the bloodstream via the skin. You can apply a testosterone gel to your skin once a day. Take care not to transfer testosterone gel onto other people through skin-to-skin contact.

• Pills. Oral testosterone can also come in pills or capsules. These often contain testosterone undecanoate, a long-acting form of the hormone.

• Implants. Now we’re on to the more scary-sounding TRT treatments. Implants (also known as pellets) are implanted under the skin and slowly release testosterone into your system. They usually last three to six months before a new implant is placed.

• Intramuscular injections. Testosterone can also be administered via an intramuscular injection. You might get this done by a healthcare professional in a clinical setting or be taught how to administer your own injections at home.

• Nasal sprays. Picture a nasal spray for allergies. Gel or liquid intranasal testosterone is pumped into your nostrils to reach your bloodstream nasally.

• Buccal testosterone. Buccal testosterone is an adhesive tablet that is applied to the upper gums. It releases the hormone slowly to mimic the body’s natural testosterone release pattern.

Your healthcare provider can help you assess which type of testosterone supplementation is right for you.

Be sure to let them know if there’s a type of TRT you’d rather avoid. Perhaps you’re not a fan of needles (who is?), so you’d rather not have a testosterone injection, for example.

The Benefits of TRT

There are many benefits of testosterone replacement therapy.

TRT benefits include:

• More energy

• Increased libido (sex drive)

• Better sexual function (including improved erectile dysfunction)

• More lean muscle mass and increased strength

• Increased bone mineral density (BMD)

• Improved depressive symptoms

• Weight loss

In terms of ED, a 2017 review found that TRT may help improve mild erectile dysfunction but not moderate or severe ED.

TRT and Erectile Dysfunction Medications

Phosphodiesterase 5 inhibitors (or PDE5 inhibitors) are a class of medication used to treat erectile dysfunction. Getting testosterone levels back to normal may help improve response to PDE5 inhibitors in men with low T who are unresponsive to the drugs.

You can learn more in our guide to low testosterone and ED.

TRT may also help treat hypoactive sexual desire disorder (loss of sexual desire) in postmenopausal women. It’s also sometimes used to create physical male sex characteristics in transgender people transitioning from female to male.

Risks and Side Effects of TRT

It’s not all sunshine and rainbows. TRT can bring real benefits to your health and well-being if you’re suffering from symptoms of low testosterone, but it can also come with some ugly side effects and serious risks.

The side effects of testosterone replacement therapy include:

• Acne

• Redness, itching, or a rash if you use gel or patches

• Swelling, bruising, pain, and clotted blood under the skin if you use testosterone implants or pellets

• Reaction at the injection site if you use short-acting testosterone injections

• Allergic reaction if you use long-acting injections

• Pain and soreness at the injection site

• Infections if you use injections

• Infertility

• Male pattern baldness*

*A quick note on male pattern baldness: Testosterone is converted into dihydrotestosterone (DHT), a hormone that can cause hair loss in men. If you’re genetically predisposed to androgenic alopecia (the clinical term for this type of hair loss), TRT could actually speed up hair loss.

The risks of TRT include:

• Polycythemia (increased red blood cell count), which raises the risk of blood clots

• Reduction in high-density lipoprotein (HDL) cholesterol (aka “good cholesterol”)

• Worsening of obstructive sleep apnea

Speak to a healthcare provider if you experience any distressing TRT side effects.

In the end, it’s best to get personalized medical advice to find out if this type of hormone therapy is right for you.

One final thing to keep in mind: If you use any kind of topical testosterone—like gels, creams, or liquids—another risk of testosterone therapy is that you can transfer the drug onto other people.

Be sure to cover the area and wash your hands after applying testosterone. You don’t want your partner, kids, or anyone else you touch to unwittingly join you in your TRT journey.

Things to Consider Before Starting TRT

TRT isn’t right for everyone. And, as with all medications, it comes with risks and side effects.

Before you start TRT, there are a few things to consider:

• Are you planning on having kids? If you plan on trying to conceive any time soon, let your healthcare provider know before starting TRT. Testosterone replacement therapy could disrupt normal sperm production, so your provider may recommend other treatment options or an additional treatment for sperm production.

• TRT isn’t a quick fix. Unfortunately, one pill or patch isn’t enough to fix all your low T symptoms. Also, it might take up to six months for testosterone to build up and start working its magic.

• You’ll need regular check-ups. You can’t just get a dose of testosterone and be on your way. And you may need regular follow-ups with a healthcare provider to see if TRT is working.

• You might be in it for the long haul. When taking synthetic testosterone, your body slows down or stops producing its own supply of the hormone. This means you may not be able to stop testosterone therapy once you start. If you suddenly stop TRT, symptoms of low testosterone could come back, and potentially be more severe.

How to Boost Testosterone Without TRT

If hormone replacement therapy isn’t for you, don’t fret. TRT isn’t the only way to boost testosterone — lifestyle changes can also make a difference.

Here’s how you can increase testosterone levels naturally:

• Exercise regularly. Aim for a mix of aerobic exercise (think running, cycling, or swimming) and strength training (like weight lifting or bodyweight exercises).

• Work to lose weight if you have overweight or obese. In men, obesity is associated with lower testosterone levels.

• Try testosterone boosters. Certain compounds have shown possible potential as natural testosterone boosters - include ashwagandha, zinc, certain types of ginseng, and fenugreek. (Psst — check out more foods that support testosterone here). These nutrients won’t serve as replacements for TRT, but they can support healthy endocrine function.

• Get enough sleep. You know the drill. Aim for at least seven hours of solid shut-eye a night.

Understanding Testosterone Replacement Therapy

If you’re experiencing symptoms of low testosterone, you might be eyeing up testosterone therapy as a treatment option.

Here’s a quick recap of what you need to know:

• TRT can help improve some symptoms of low testosterone. It may increase your energy levels and libido and improve mild ED.

• TRT isn’t for everyone. TRT is usually prescribed to men who have low testosterone due to a medical condition, not naturally low levels that come with age.

• Watch out for side effects and risks. TRT side effects range from acne to infertility to male pattern baldness. Not fun.

Talk to a healthcare provider if you’re considering hormone replacement therapy. They can assess if you have low testosterone levels, whether TRT is safe for you, and the right treatment for your symptoms. They may even recommend other treatments to try before TRT.

For example, if you have ED, erectile dysfunction medications may be a safer and more effective treatment. Find out if you’re a good candidate for them by getting advice from a healthcare professional today.