Are There Mental Side Effects of Testosterone Injections?

While testosterone replacement therapy (TRT) can be life-changing for guys living with low T, it's not all sunshine and six-packs. Taking testosterone shots stands to improve life for many guys, but the injections may also affect mood in undesirable ways. 

Yep, what’s meant to boost your mood, energy, and maybe even your sex life, could turn you into an irritable and restless insomniac if you and your healthcare provider are not paying attention to your T levels. 

Here, we’re uncovering what you should know about testosterone injections before signing up—particularly the possible implications for your mental health.

Testosterone is a key male sex hormone that is involved in building muscle mass, regulating sex drive and libido, and impacting a host of other markers of health. It also plays a central role in emotional regulation and overall brain function. 

Testosterone levels are regulated by a feedback loop involving the pituitary gland and the hypothalamus, which communicate with the testes to regulate the production of the hormone based on the body’s needs. This is also known as the hypothalamic-pituitary-gonadal axis. Disruptions to this delicate system can lead to a testosterone deficiency. There are a number of causes of low T, though, which are often associated with mood disorders like depression, fatigue, and irritability.

Medically supervised hormone replacement therapy is one way to help bring your testosterone levels back to a normal range. As a result, this can also help restore your mood-related side effects. 

However, as is true with many things in life, there is likely such a thing as too much testosterone. The goal is to balance levels of the hormone, not to send your body into overdrive, which can bring undesirable effects. 

That said, much of the data surrounding the mental health side effects of testosterone injections comes from animal studies. And not all of those conclusions translate directly to humans. However, there are some human studies that demonstrate minor mood changes in men as a result of testosterone injections. 

More robust research conclusions are needed to say with scientific confidence what the effects of testosterone injections could be on mood. But in the meantime, it’s helpful to understand what factors are at play and symptoms to look for if you’re using testosterone replacement therapy. 

For men with low testosterone levels, getting things back to normal can feel like somebody turned the lights back on, even if you never realized you were wandering in the dark.

Many guys who experience restored testosterone levels notice improvements in overall energy, mood, and motivation to do things again—especially if their testosterone levels were previously low enough to nurture the opposite. 

One review looked at whether testosterone treatment can help reduce depression symptoms in men. Researchers reviewed several clinical trials where men received either testosterone or a placebo and found that men who received testosterone generally felt less depressed than those who didn’t. 

Men with hypogonadism or testosterone deficiency—especially cases caused by aging or pituitary dysfunction—may see significant improvements in mood, energy levels, and sexual function after TRT treatment begins.

When administered appropriately and under medical supervision, testosterone injections have the potential to help you feel more like yourself again. But there are also potential psychological drawbacks to know, as well.

While testosterone therapy can bring positive emotional balance to some guys, it’s possible to experience some less desirable psychological side effects. Here are some science-backed side effects to be aware of.

1. Mood Swings

Testosterone affects how your brain regulates emotions, so when levels spike or fluctuate excessively, you might notice sudden shifts in mood. 

While feeling a bit off one day may just be a result of getting up on the wrong side of the bed, ongoing concerns could be due to inconsistent testosterone levels.

2. Increased Irritability and Aggression

Feeling a bit short-tempered? Some men report heightened irritability or even out-of-character bursts of aggression while receiving testosterone therapy.

The stereotype of having “roid rage” is exaggerated, as cortisol and serotonin work against these effects of testosterone. Still, increased aggression has been associated with the presence of higher levels of testosterone.

Keep in mind that medically supervised TRT aims to maintain testosterone within the normal physiological range, and the risk of such extreme behavioral changes is low.

3. Depression or Emotional Numbness

While testosterone therapy may help to treat depression in some cases, in others, it can actually contribute to the root issue.

Feeling detached or “flat” emotionally can happen when testosterone is out of whack, and guys who have a history of mood disorders may feel especially disoriented. 

4. Sleep Disruptions & Mental Clarity

No one functions at their best when sleep-deprived. Unfortunately, testosterone therapy may exacerbate symptoms of sleep apnea, according to research.

Not every guy on testosterone injections will experience negative mental side effects. Why do they affect men differently, anyway? 

Several factors can influence how your brain reacts to TRT:

• Dosage and frequency. Too much testosterone at once or inconsistent injection schedules could impact mood. 

• Method of administration. Testosterone can be delivered via injection, topical gel, or pellet—and the absorption rate and hormone levels may vary by method. This can also influence side effects.

• Age and baseline hormone levels. Older men and those with significantly low T levels may respond differently than younger guys with borderline deficiencies.

• Genetics and brain chemistry. Everyone’s response to hormone therapy is different based on how their body metabolizes testosterone and how it interacts with brain chemicals.

• Lifestyle factors. Poor sleep, high stress, alcohol or drug use, and lack of exercise can make you feel worse overall, which doesn’t help.

How to Minimize Negative Mental Side Effects of Testosterone Injections

If you’re noticing changes in your mood, focus, or other mental health symptoms following TRT treatment, don’t panic. There are practical steps you can take to level things out. 

First, be sure that you’re working with a knowledgeable healthcare provider who can tailor your dosage, monitor blood levels regularly and also offer medical advice. It’s important that your provider is aware of any medical conditions you have, like heart disease, diabetes, cancer, kidney disease, or if you and a partner are trying to conceive.

Also, make sure to have a consistent injection schedule and avoid overcorrection with high doses, which can trigger significant fluctuations in your hormones. Avoid self-medicating or adjusting without guidance.

Especially when you’re starting TRT, it’s a good idea to track any symptoms, including mood changes, energy levels, and sleep patterns. Having this documented can help your provider make informed adjustments should you need them. 

You can support the success of TRT by engaging in healthy lifestyle habits. Keep mental and physical health a priority by exercising regularly, optimizing your diet, managing your stress levels, and aiming to clock seven to nine hours of quality sleep per night.

Finally, know that testosterone therapy isn’t a one-size-fits-all solution that’ll work for every guy. Fine-tuning your approach can make a big difference in how you feel, mentally and physically.

In addition to mental and emotional changes, testosterone injections can bring certain physical side effects. These may include things like acne and injection-site pain. More significant issues may occur, like increased red blood cell count (called erythrocytosis), which may raise blood pressure and the risk of heart attack if not monitored.

Long-term use of testosterone can lead to testicle shrinkage and infertility due to the body reducing its own testosterone production. For more, read our guide about fertility risks for guys taking testosterone. 

On the positive side, some men experience reduced cholesterol levels or changes in their body fat distribution, particularly a decrease in fat mass and an increase in lean muscle when testosterone increases. 

Regarding libido,some guys notice improved sex drive, erections, and overall sexual function as a result of TRT. But, it’s also possible to experience the opposite, such as erectile dysfunction, if testosterone levels aren’t properly balanced. But again, this is not a universal experience for all guys taking testosterone injections. 

Men undergoing testosterone therapy should be screened for conditions like prostate cancer before starting treatment, as increasing testosterone levels could potentially exacerbate undiagnosed prostate issues (though more research is needed here). 

Testosterone therapy is meant to improve your well-being and quality of life, not make you feel like a stranger in your own head. If you start experiencing serious or ongoing mental side effects, speak up. 

Don’t brush off mood swings, persistent irritability, or emotional numbness as just part of the treatment.

Some signs that it’s time to talk to your healthcare provider may include:

• You feel more anxious, depressed, or emotionally unstable than before starting injections.

• You're experiencing thoughts of self-harm or hopelessness.

• Aggression or irritability is affecting your relationships or ability to get through the day.

• Your sleep is consistently disrupted, and it’s taking a toll on your mood or mental clarity.

• You’re dealing with overwhelming restlessness or agitation and can’t seem to relax.

It’s also important to watch for any signs of worsening symptoms, whether mental or physical. Regular blood tests are essential for monitoring testosterone levels, red blood cell count, and markers that could indicate other risks.

Getting help doesn’t mean testosterone therapy isn’t for you. It might just mean the dose, frequency, or delivery method needs tweaking. 

Ultimately, mental health is just as important as physical health, and there’s no shame in asking for support. A good provider will listen, adjust, and work with you to make sure TRT is the best option for normalizing your levels of testosterone—without making things worse.

Testosterone injections can be an effective tool for balancing levels of the sex hormone levels. But like anything else, this intervention is not free of possible side effects. 

Keep these potential issue in mind if you’re using or considering TRT:

• Testosterone can boost mood and motivation when hormone levels are restored to a healthy range. However, too much testosterone can cause emotional turbulence that doesn’t feel great.

• It’s possible to experience mental side effects from testosterone injections, like mood swings, irritability, restlessness, and anxiety. 

• Working with a provider to customize your plan and help monitor your progress is the best way to reap the benefits of TRT and to minimize the baggage.

Have more questions? Check out our men’s sexual health resources, including our guide on how to increase testosterone levels naturally. 

You can even be connected with a licensed healthcare provider by taking our free online assessment.

If you are experiencing a mental health crisis, please call or text 988 to be connected with help, or go to your nearest hospital emergency department