Testosterone injections are a common form of testosterone replacement therapy (TRT) that helps restore low hormone levels and improve symptoms like low sex drive, fatigue, and decreased muscle mass in men with clinically low testosterone.
Key Takeaways:
Testosterone injections are a common form of testosterone replacement therapy (TRT) that helps restore low hormone levels and improve symptoms like low sex drive, fatigue, and decreased muscle mass in men with clinically low testosterone.
Different TRT formulations — including testosterone enanthate, cypionate, and undecanoate — vary in how long they last, which affects how often you’ll need injections.
Learning how to inject testosterone safely at home becomes easier with practice, and a clear step-by-step routine can help reduce stress and prevent mistakes.
In men with clinically low testosterone, Injectable TRT can offer benefits like improved energy, sexual function, mood, and lean muscle mass, but it also comes with potential side effects.
Testosterone injections are one of the most commonly prescribed forms of testosterone replacement therapy (TRT). But if you’ve never injected yourself, the idea could be daunting. Where do you inject? How do you angle the needle? What if your hands can’t stop shaking?
Don’t worry, it’s not as hard as you think.
Ahead, we’ll share how testosterone injections work, the benefits of TRT, and a step-by-step guide to self-injection. Once you get the hang of it, you might just be shocked by how routine it becomes after the first go.
Like other forms of TRT, testosterone injections work by replacing testosterone in men whose bodies are not producing adequate amounts.
As the primary male sex hormone, or androgen, testosterone regulates various aspects of male health, so it’s crucial to maintain levels within a healthy range. Testosterone plays a key role in male sexual development during puberty and helps maintain muscle mass, bone density, and body fat distribution throughout adulthood. It also drives reproductive functions like sperm production, sex drive, and aspects of erectile function.
Testosterone injections use testosterone esters, or testosterone chemically linked to a fatty acid. These esters allow testosterone to sit in the muscle and slowly disperse (rather than hitting your system all at once). After injection, the body’s enzymes slowly break down the medication, releasing testosterone into the bloodstream over several days or weeks, depending on the type used.
Several injectable testosterone formulations are available, and each one differs in how long it lasts in the body. These differences come down to the length of the ester attached to testosterone, which controls how slowly the hormone is released from the injection site.
Common FDA-approved testosterone injection formulations include:
Testosterone enanthate (TE). Testosterone enanthate is a medium-acting ester that is commonly injected weekly or every one to two weeks and is one of the most widely used TRT formulations. It is known for early peaks followed by a gradual decline toward the end of the dosing interval.
Testosterone cypionate (TC). Similar to enanthate in both duration and dosing frequency, testosterone cypionate is typically dosed every one to two weeks and commonly prescribed, but it may cause noticeable peak-to-trough fluctuations.
Testosterone undecanoate (TU). Testosterone undecanoate is a long-acting ester that allows for slow, steady release over roughly 10 to 12 weeks after initial loading doses. It requires fewer injections and is usually given in larger volumes.
TRT injections are an effective treatment for hypogonadism, or clinically low testosterone levels, accompanied by symptoms that interfere with your daily life.
Common symptoms of low testosterone include:
Low libido
Erectile dysfunction (ED)
Decreased muscle mass
Increased body fat
Reduced bone density
Less body hair
Low red blood cell count (in some men)
Low energy levels
“Brain fog” and trouble concentrating
Mood changes
Sleep disturbances
If you suspect your hormone levels are low, an at-home testosterone test may serve as an initial screening, but results should be confirmed with a healthcare provider, as the symptoms above can also stem from other health conditions.
The American Urological Association (AUA) defines low testosterone as a level below 300 nanograms per deciliter (ng/dL), typically confirmed with at least two morning measurements.
Studies show that testosterone injections for men with low T effectively improve several hallmark symptoms of low testosterone, leading to:
Increased muscle mass
Improved sexual function
More energy
Enhanced mood
While TRT won’t magically transform you into a bulky bodybuilder without any effort, men with clinically low testosterone may see improvements in lean body mass and strength.
According to one 2018 review, intramuscular TRT was more effective than transdermal formulations (like creams or patches) at increasing lean body mass and improving muscle strength in middle‐aged and older men.
Low sex drive and erectile dysfunction are some of the most common complaints of men with low testosterone levels, though erectile dysfunction often has multiple contributing causes. Like other forms of TRT, testosterone injections have been shown to improve sexual function, particularly libido, and may improve erectile function in some men with low testosterone.
Research shows that testosterone therapy can meaningfully boost sexual desire and help with mild ED, particularly in men who haven’t responded well to PDE5 inhibitors, the most commonly prescribed medications for ED.
A large meta-analysis of randomized trials also found that testosterone therapy — including injectable forms — significantly improves libido, orgasmic function, intercourse satisfaction, and mild ED in men with low testosterone.
And one of the most extensive studies on injectable testosterone found that long-acting testosterone undecanoate significantly improved sexual desire and erectile function. In that treated cohort, the percentage of men with low libido dropped from 64 to 10 percent, and moderate-to-severe ED fell from 67 to 19 percent after several injections.
Studies also link testosterone therapy, including injections, to improved energy and reduced fatigue in men with low testosterone, though the effect is usually modest and varies by individual.
For instance, one observational study found that men who had been on testosterone therapy for more than a year reported significantly less fatigue than men just starting treatment — nearly a 15-point reduction on a validated fatigue scale.
Another placebo-controlled study using biweekly testosterone injections found that 59 percent of men reported improved energy after six weeks of treatment, compared to just 25 percent in the placebo group.
Testosterone injections may also improve mood in men with low testosterone, with the strongest evidence in those with mild depressive symptoms.
A large meta-analysis found that testosterone therapy, including intramuscular injections, significantly improved depressive symptoms compared with placebo, with larger effects seen at higher therapeutic doses.
A smaller trial using testosterone cypionate injections every 10 days found that men with chronic mild depression experienced greater mood improvements than placebo, though testosterone therapy is not considered a first-line treatment for depression.
So you’ve been prescribed testosterone, and you’re ready to inject. You’ve got this. Follow these steps to help perform injections safely and correctly.
If you don’t feel comfortable injecting yourself the first time, ask your healthcare provider for guidance. They can share specific tutorials, tips, or even supervise your first self-injection to build your confidence.
If you’re scared, you’re not alone. Trypanophobia, the fear of needles in a medical setting, is a real condition, and there are ways to deal with it proactively.
You’re about to perform a medical procedure, so make sure your hands are clean. To reduce the risk of infection or contamination, wash your hands and thoroughly dry them before giving yourself the shot.
Always start with a fresh, sterile needle — never reuse one. Testosterone is thick and oily, and a larger-gauge needle (such as a 20G or 21G) is often used to draw the medication, based on your provider’s instructions. Attach this needle to your syringe, making sure it’s secure.
Using a vial stored according to the manufacturer’s instructions, here’s how to draw up your dose:
First, pull air into the syringe equal to your prescribed dose.
Clean the vial’s rubber top with an alcohol swab and let it dry.
Insert the needle into the vial and push the air inside to pressurize the vial.
Flip the vial upside down and slowly draw the medication into the syringe without drawing in air bubbles.
Double-check that you’ve taken the correct amount.
Before injecting, hold the syringe upright and look for air bubbles. Gently tap the barrel so they rise to the top. Press the plunger slowly until a tiny droplet appears at the needle tip to confirm the syringe is air-free.
Where you inject depends on the type of testosterone shot you’re giving — intramuscular or subcutaneous — and choosing the right spot makes the process smoother and safer.
Intramuscular injection sites. Intramuscular injections go deep into the muscle, and the most common sites are the butt cheek, outer thigh, and shoulder.
Subcutaneous injection sites. Subcutaneous injections go just under the skin. The easiest and most reliable sites include the abdomen (at least an inch away from your belly button) and the outer thigh.
Whether you’re doing intramuscular or subcutaneous injections, try not to use the same spot each time. Repeated poking of one area can lead to swelling, soreness, or scar tissue. Try alternating from your right thigh to your left or different points around the abdomen.
Once you’ve chosen your injection site, wipe the area with an alcohol swab and let it dry completely. Injecting through wet alcohol can sting, and you want the surface thoroughly disinfected before you insert the needle.
For intramuscular injections, you’ll want to hold the needle at 90 degrees and stretch the skin slightly to stabilize the muscle. Needle depth depends on the injection site, needle length, and your body composition, and should follow your provider’s instructions.
For subcutaneous injections, you’ll pinch 1 to 2 inches of skin between your thumb and forefinger and insert the needle at 90 degrees.
Inject the medication slowly and steadily, following the technique recommended by your healthcare provider, as routine aspiration is no longer required for many injection sites.
When the medication is dispersed, withdraw the needle at the same angle you inserted it.
After withdrawing the needle, use gauze or cotton to apply gentle pressure and apply a bandage if you need it. Then, dispose of the needle in a sharps container (don’t store for later use!).
Testosterone replacement therapy isn’t for everyone. All formulations carry a risk of side effects, but there are some specific to injectables, too.
Potential testosterone injection side effects include:
Skin reactions, like swelling, itching, and redness
Pain at the injection site
Gynecomastia (breast growth)
Acne
Allergic reactions
Infections
Low sperm count and infertility
Acceleration of male-pattern hair loss in genetically predisposed men
Increase in red blood cells, hematocrit, or hemoglobin (which can cause blood clots)
Worsening of sleep apnea and benign prostatic hyperplasia (enlarged prostate)
Although evidence is mixed, some research suggests that testosterone therapy may increase cardiovascular risks in certain men, particularly those with existing conditions such as heart disease, heart failure, a history of heart attack, or uncontrolled high blood pressure.
It’s essential to review your medical history and current medications with your healthcare provider before starting TRT, and never use testosterone that hasn’t been prescribed and monitored by a clinician.
The price of testosterone injections may vary depending on the dose, where you buy it, and whether or not your insurance plan covers it.
However, compared to topical testosterone, pills, patches, and pellets, injectable testosterone is often among the more affordable TRT options.
Without insurance, you can expect to pay $20 to $100 per month for injectable testosterone, depending on dose, pharmacy pricing, and available discounts.
In addition to the medication itself, you may also need to factor in costs for initial and follow-up blood tests, provider visits, and dose adjustments, which can add up to several hundred dollars per year depending on what your clinic charges and how often your provider requires monitoring.
Opting for a brand-name medication like Aveed® or Depo-Testosterone® can also increase costs, so consider choosing the generic drug if available.
If you’re considering testosterone injections, the first step is talking with a licensed healthcare provider. Injections are prescription-only and must be obtained through a clinician who can evaluate your symptoms, confirm low testosterone, and monitor your treatment safely.
Prefer to skip the needles? Enclomiphene citrate is an oral therapy that can stimulate the body’s own testosterone production and may preserve fertility compared with TRT. Enclomiphene citrate is not approved by the Food and Drug Administration (FDA). Decisions about treatment should be made in consultation with a licensed healthcare provider.
Plans start at $99 per month and include easy at-home lab testing to confirm eligibility.
Learn more about alternative testosterone treatments through Hims.
Testosterone injections can be an effective way to treat clinically low testosterone, especially when symptoms like low sex drive, fatigue, and difficulty concentrating start affecting your everyday life. They work by delivering testosterone via intramuscular or subcutaneous injection to raise blood testosterone into a therapeutic range, which may improve symptoms in men with a confirmed deficiency.
While injections can seem intimidating at first, most men find that the process becomes surprisingly simple after the first couple of tries. With proper technique, site rotation, and supervision if you need it, injectable TRT can be a safe, reliable way to boost energy, support sexual health, increase muscle mass, and improve mood.
Just remember: Testosterone therapy isn’t for everyone. It requires a diagnosis, regular monitoring, and a treatment plan that meets your exact health history and goals. If injections aren’t your thing, there are plenty of other needle-free options to consider.
It depends on the formulation.
Testosterone enanthate and cypionate typically last one to two weeks, with levels peaking early and dipping toward the end.
Testosterone undecanoate is long-acting and can last 10 to 12 weeks after initial doses.
Your provider will determine your schedule, but standard regimens include:
TE or TC: Once weekly or every two weeks
TU: Every 10 weeks after the first two doses
More frequent, smaller doses may keep levels more stable for some men.
For intramuscular injections: the upper outer glute, outer thigh, or shoulder. For subcutaneous injections: the abdomen or outer thigh. Always rotate sites to reduce irritation.
Yes, many men self-inject safely once they learn the proper technique. Your provider can walk you through the steps or supervise your first injection.
Some men feel a brief pinch or soreness, especially with intramuscular injections, as they run deeper. Icing the area beforehand, relaxing the muscle, and injecting slowly can make the process more comfortable.
Yes. TRT can suppress sperm production. If fertility matters to you, ask your provider about alternatives that may preserve sperm production, such as off-label options like enclomiphene citrate.
Contact your provider for guidance; in general, you should not double up, and timing depends on how close you are to the next scheduled dose.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.
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