Testosterone Booster Side Effects: What’s Normal and What’s Not

A new supplement that promises more energy, better workouts, and a stronger sex drive can be tempting. Before you start, it helps to understand testosterone booster side effects so you can spot what is normal and what is a red flag.

Below, you will learn how testosterone boosters work, the side effects you might expect, and when you should stop and call your doctor instead.

How testosterone boosters work

Most over the counter testosterone boosters fall into two broad groups:

Products that try to nudge your body to make more of its own testosterone
Prescription testosterone replacement therapy (TRT), such as gels, injections, or capsules, used for men with clinically low levels

The two are not the same. TRT is regulated and prescribed only for men with diagnosable hypogonadism, usually when blood levels are below about 300 ng/dL and symptoms like low energy, erectile dysfunction, and reduced muscle mass are present (Harvard Health Publishing).

Non‑prescription boosters use herbs, vitamins, or minerals that claim to:

Support hormone production
Improve sleep or stress, which can affect testosterone
Raise libido or workout performance

Because many boosters are not carefully tested, you may not fully know what you are getting. That is why paying attention to testosterone booster side effects is so important.

Common “normal” side effects you might notice

Some side effects are relatively common when testosterone levels rise or your body responds to a booster. These may not be dangerous on their own, but they should still be monitored.

Skin changes and acne

Testosterone can increase oil production in your skin. You might notice:

Oily skin on your face, back, or chest
New or worsening acne breakouts

This is a well known effect of testosterone therapy, and it is listed as a possible immediate side effect of TRT in medical reviews (Harvard Health Publishing). If acne appears suddenly or becomes severe, it is a reason to check in with a healthcare provider, especially if you also have mood changes or hair loss.

Mild fluid retention

Some users report feeling a bit puffy or noticing slight ankle swelling when they first start testosterone treatment. Medical sources describe ankle swelling as a possible side effect of TRT (Harvard Health Publishing).

A small amount of temporary water retention can be expected, but you should not ignore:

Sudden, noticeable swelling in your legs or feet
Swelling combined with shortness of breath or chest pain

Those symptoms can point toward a more serious cardiovascular problem and require urgent care.

Changes in sex drive and erections

Because testosterone is involved in sexual function, shifts in libido are common. You may experience:

Higher sex drive
More frequent or stronger erections

For men with confirmed low testosterone, TRT can improve erectile dysfunction and sexual desire (Harvard Health Publishing). However, if you notice painful or very prolonged erections, or significant changes in sexual behavior that feel out of character, you should discuss this with your doctor.

Sleep changes and snoring

Testosterone boosters and TRT can affect sleep. Some men feel more energetic, but medical reviews also note that testosterone therapy can worsen sleep apnea in those who already have it (Harvard Health Publishing).

Pay attention if you or a partner notice:

Louder snoring than usual
Pauses in breathing while you sleep
Waking up gasping or unusually tired

These are not “just annoying” side effects. They suggest a possible sleep disorder that needs evaluation.

Side effects that are not normal and need quick attention

Not every testosterone booster side effect is harmless. Some can point to serious cardiovascular or metabolic problems.

Chest pain, stroke symptoms, or severe shortness of breath

Heart attacks and strokes have been reported as serious side effects of testosterone capsules used in TRT, and they require emergency care if they occur (Cleveland Clinic). Although many non‑prescription boosters have not been studied as closely, a similar risk profile is concerning.

Call emergency services right away if you notice:

Sudden chest pain or pressure
Pain that spreads to your arm, jaw, or back
Sudden weakness on one side of your body
Trouble speaking, confusion, or vision changes
Sudden shortness of breath, especially with chest pain

These are not side effects to “wait and see” about. Stop the product and seek immediate care.

Irregular heartbeat or palpitations

A large 2023 study following over 5,200 men with low testosterone found that TRT did not raise the overall risk of heart attack or stroke compared to placebo, which is reassuring (Cedars‑Sinai). However, it did show a slight increase in atrial fibrillation, a type of irregular heartbeat, in some men on therapy.

You should call your doctor promptly if you notice:

A racing or fluttering heartbeat that comes and goes
Feeling lightheaded, dizzy, or faint with palpitations
Shortness of breath during these episodes

Do not assume heart symptoms are “just from the gym” or “caffeine” if you recently started a booster or TRT.

Major mood or behavior changes

Testosterone affects your brain and mood. Imbalances in testosterone are linked to:

Mood swings, depression, anxiety, and difficulty concentrating
Aggressive or risky behaviors when levels are unusually high (Liondale Medical)

If you or people close to you notice you are:

Suddeny more irritable, angry, or impulsive
Taking risks that are out of character for you
Feeling very low, hopeless, or anxious

it is time to pause the supplement and talk with a healthcare professional.

Signs of blood clot risk

Testosterone therapy can increase red blood cell counts, which may raise the risk of blood clotting and is something doctors specifically monitor during TRT (Harvard Health Publishing).

Seek help immediately if you notice:

Sudden swelling, warmth, and pain in one leg
Sharp chest pain with breathing
Sudden shortness of breath

These can be signs of a clot in your leg or lungs and are emergencies.

Long‑term risks you should know about

Some testosterone booster side effects do not show up overnight. They develop quietly over months or years.

Cardiovascular risk and heart health

Research on TRT and heart health has been mixed over time. Earlier observational studies linked testosterone supplements to higher cardiovascular risk. For example:

One Veterans Affairs study found nearly a 30% increased risk of death, heart attack, or stroke in men on testosterone with low levels between 2005 and 2011 (Harvard Health Publishing)
A 2014 study reported a two‑fold increased risk of heart attack within 90 days of starting testosterone in men over 65, and a three‑fold increased risk in younger men with pre‑existing heart disease (Harvard Health Publishing)

More recent randomized trials are more reassuring and suggest that, for men with confirmed testosterone deficiency who are properly monitored, TRT does not appear to increase heart attack or stroke risk or new prostate cancer, at least over a few years of treatment (Harvard Health Publishing, Cedars‑Sinai).

The key takeaway for you is that:

Heart risks seem highest in men without proper testing or monitoring
Long‑term, lifelong use still needs more research (Cedars‑Sinai)

If you have any history of heart disease, high blood pressure, or high cholesterol, you should involve your doctor from the very beginning.

Fertility and testicular changes

Very high testosterone levels, especially from anabolic steroids, can interfere with your body’s own production of the hormone. This can lead to:

Shrinking testicles
Lower sperm production
Possible infertility (Liondale Medical)

Even medically supervised TRT can signal your body to make less of its own testosterone over time, which is why it is hard for some men to stop therapy without experiencing a sharp drop in hormone levels (Harvard Health Publishing).

If you plan to have children, talk with a specialist before starting TRT or aggressive testosterone boosting routines.

Breast changes and body composition

Hormonal shifts can also affect breast tissue and fat distribution. Men with low testosterone may develop:

Breast swelling, enlargement, or tenderness (gynecomastia) (Liondale Medical)

Testosterone therapy can sometimes improve body composition and reduce fat, but if you notice new breast tenderness, lumps, or rapid changes in chest shape while on any hormone‑related product, schedule a medical evaluation.

Why testing and medical guidance matter

It is easy to assume testosterone boosters are harmless because you can buy many of them over the counter. The research paints a more complex picture.

Here is what experts consistently recommend:

Do not use testosterone therapy for normal aging alone. The Mayo Clinic notes that the benefits for otherwise healthy older men are unclear and that it is not advised for simply “feeling younger” (Mayo Clinic).
Have your levels checked at least twice before starting TRT. This helps confirm real hypogonadism and avoids unnecessary treatment (Mayo Clinic).
Expect regular monitoring if you are on prescription testosterone. Doctors typically track cholesterol, prostate health, testosterone levels, and blood counts to detect side effects early (Cedars‑Sinai, Harvard Health Publishing).

If a supplement promises “steroid‑like” results with no need for medical supervision, treat that as a warning sign rather than a selling point.

Safer alternatives to try first

If your goal is more energy, better workouts, or improved libido, you may not need a testosterone booster at all.

The Mayo Clinic recommends natural approaches such as:

Losing excess weight if you are overweight
Strength training and resistance exercise
Improving sleep habits
Managing stress (Mayo Clinic)

These habits can support healthy testosterone levels without the same risk profile as hormone therapy or untested boosters, and they benefit your overall health at the same time.

When to stop and call your doctor

If you are already using a testosterone booster or TRT, you do not have to guess whether what you are feeling is normal. Use this simple guide:

Stop the product and seek urgent care if you have chest pain, stroke‑like symptoms, severe shortness of breath, or sudden leg swelling.
Contact your doctor promptly if you develop irregular heartbeat, major mood or behavior changes, sleep apnea symptoms, or new breast changes.
Schedule routine checkups and blood work if you are on ongoing TRT, even if you feel fine.

Being informed about testosterone booster side effects does not mean you should fear every supplement or prescription. It means you can make choices with clear eyes, watch for early warning signs, and work with a healthcare professional to find the safest path toward your health goals.