Everything You Need to Know About TMS Therapy Side Effects

Dr. Zaheer Aslam • February 18, 2026

Quick Summary / TL;DR

TMS side effects are usually mild — and serious risks are very rare.

Most people feel temporary discomfort (like headache or scalp sensitivity) and return to normal activities immediately after each session.

Most common (expected)

Headache, scalp discomfort, facial twitching, mild jaw/neck tension, or brief lightheadedness.

Rare (serious)

Seizure risk is extremely low (~0.31 per 10,000 sessions). Screening reduces risk further.

Not for everyone

Typically avoided with certain metal implants near the head, implanted electronics, or uncontrolled seizure disorders.

Tip: Comfort can often be improved by adjusting coil position or stimulation level.

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Transcranial Magnetic Stimulation (TMS) is a powerful intervention for people who haven’t found relief through medication or traditional therapy. But with any treatment that involves the brain, questions about safety are completely normal. What does TMS therapy actually do? And what TMS side effects should you expect?

TMS is an FDA-approved, noninvasive therapy commonly used to treat conditions like major depressive disorder, obsessive-compulsive disorder, migraines, and treatment-resistant depression, offering new hope when other treatments haven’t worked.

The good news is that most TMS side effects are mild and temporary. Still, understanding the full picture matters. In this guide, we’ll walk through how TMS works, common and rare side effects, who may not qualify for TMS therapy, and how to determine if it’s the right fit for your mental health needs.

What is TMS Therapy?

TMS therapy is a noninvasive mental health treatment that uses targeted magnetic pulses to stimulate specific areas of the brain involved in mood regulation. The treatment works by placing a magnetic coil near the scalp, which delivers controlled pulses that activate underactive brain regions linked to depression and other conditions. It does not require anesthesia, sedation, surgery, or recovery time.

TMS was first approved by the U.S. Food and Drug Administration in 2008 for major depressive disorder, particularly for individuals who haven’t responded to traditional antidepressant medications or therapy alone. Since then, its use has expanded to include conditions such as obsessive-compulsive disorder and migraines, with ongoing research exploring additional applications across varying mental health needs.

TMS is often compared to electroconvulsive therapy (ECT), but the two treatments are very different. Unlike ECT, TMS does not use electrical currents or induce seizures, making it a gentler and more targeted approach to brain stimulation.

Read More: Is TMS the Same as ECT?

How TMS Therapy Works in the Brain

TMS therapy works by directly stimulating specific areas of the brain that regulate mood, emotion, and cognitive function. As mentioned, a magnetic coil is placed on the scalp during treatment to deliver focused magnetic pulses to targeted brain regions. These pulses typically stimulate the prefrontal cortex, an area that is often underactive in individuals living with depression.

When these regions are activated, brain cells begin firing more efficiently. This process encourages the release of neurotransmitters like serotonin and dopamine, which play an essential role in mood balance and emotional well-being. Over time, repeated stimulation helps strengthen communication between brain cells.

Research shows that TMS therapy also promotes neuroplasticity. Neuroplasticity is the brain’s ability to reorganize and form new neural connections. By reinforcing healthier activity patterns, TMS helps “reset” dysfunctional circuits linked to depression and other mental health conditions.

Keep Reading: Different TMS Protocols for Mental Health Treatment

Common Side Effects of TMS Therapy

Like most medical treatments, TMS therapy can cause side effects. Thankfully, these side effects are typically mild, temporary, and manageable. Most people continue normal activities right after treatment, and initial side effect symptoms often improve as the body adjusts to therapy.

The most commonly reported side effects include:

Headaches: The most frequent side effect is headaches. They are usually mild and short-lived, often improving after the first few sessions.
Scalp or treatment site discomfort: Some people experience a tapping or pressure sensation where the magnetic coil touches the head. This also typically fades during or shortly after treatment.
Facial muscle twitching: Temporary stimulation of nearby facial nerves in the jaw or eyelids may cause brief muscle movement during sessions. This may feel uncomfortable or a little silly at first, but it is completely normal and often disappears over the course of treatment.
Jaw or neck pain: Mild muscle tension can occur in the jaw or neck but generally resolves quickly.
Lightheadedness: Some patients experience temporary dizziness immediately following treatment, but this tends to lessen over time.

Clinical studies confirm that the side effects of TMS therapy are usually mild to moderate and tend to decrease over time with repeated sessions. Most resolve within hours or days. Providers can also adjust stimulation levels or positioning to improve comfort, helping ensure a safe and tolerable treatment experience.

Side Effects Snapshot

Most effects are temporary and often improve as your body adjusts to treatment.

Common (expected)

Headache (often mild, early sessions)
Scalp or treatment-site discomfort
Facial muscle twitching during sessions

Many patients resume normal activities immediately after treatment.

Less common

Jaw or neck tension
Brief lightheadedness

Comfort can often be improved by adjusting coil position or stimulation level.

Rare (serious)

Seizure (extremely rare; ~0.31 per 10,000 sessions)
Hypomania/mania symptoms (more likely with bipolar disorder)
Hearing risk without protection (earplugs are standard)

Thorough screening helps minimize risk before starting treatment.

Uncommon or Rare Side Effects of TMS Therapy

Serious side effects from TMS therapy are highly uncommon. Still, understanding potential risks can help you make informed decisions and feel more confident about starting treatment.

One of the most serious, though extremely rare, risks is seizure. Research shows the likelihood is very low, with studies reporting about 0.31 seizures per 10,000 treatment sessions.

When seizures do occur, they are typically brief and manageable with appropriate medical care. Certain factors may increase your risk of seizure, including sleep deprivation, alcohol use, medication changes, or preexisting neurological conditions like a head injury or seizure conditions.

Other rare side effects may include:

Hypomania or mania symptoms, like agitation or irritability, are most often seen in individuals with bipolar disorder. Our team always observes any changes in behavior. If these symptoms arise, treatment is paused right away, and we’ll provide appropriate follow-up care.
Hearing loss, caused by the clicking sound of the device (similar to an MRI). We will always provide you with earplugs or other safety measures to make hearing loss an impossibility.
Psychological or expectation-related responses, sometimes called nocebo effects, occur when a person’s expectations or concerns about treatment influence how they perceive symptoms or side effects. These responses are not caused by the treatment itself but by psychological factors, and we will always provide clear communication and support to help reduce their impact.

At our TMS clinic in Fort Myers, Florida, our team will conduct a thorough evaluation to screen every patient’s medical history to minimize any potential risks. While the potential side effects of TMS may sound scary to some, we hope you can take comfort in knowing they’re extremely uncommon. And the common ones are very easy to manage. Our team is here to answer any questions you have and will support you every step of the way.

Who Is TMS Therapy Right For?

TMS therapy can be a life-changing option for individuals who haven’t found relief through traditional mental health treatments. It’s especially helpful for those living with treatment-resistant depression, where symptoms persist despite trying medications or psychotherapy.

TMS may also be a good fit for people who experience significant medication side effects or prefer a non-drug approach to improving their mental health. Individuals managing chronic mood disorders or ongoing depressive symptoms often benefit from the targeted, brain-based approach TMS therapy provides.

Who Should Avoid TMS Therapy?

While TMS therapy is safe for many people, it isn’t appropriate for everyone. A thorough medical evaluation helps guarantee treatment is both safe and effective before starting therapy.

TMS may not be recommended for:

Individuals with metal implants in or near the head, such as aneurysm clips or metallic fragments, should avoid TMS therapy because the magnetic pulses can interfere with these materials.
People with implanted electronic devices, including deep-brain stimulators or certain medical implants, may also face increased risks.
Individuals with uncontrolled seizure disorders or certain neurological conditions may require additional screening, since these factors can increase seizure risk during treatment.

A personalized medical assessment helps our team of TMS experts identify potential risks, guide treatment decisions, and ensure the safest possible care.

Often a good fit

Especially when depression symptoms persist despite standard treatments.

Treatment-resistant depression
Medication side effects are hard to tolerate
Preference for a non-drug option
Chronic mood symptoms needing a targeted approach

May not qualify (needs screening)

Magnetic stimulation can interact with certain implants or conditions.

Metal implants in/near the head (e.g., aneurysm clips, fragments)
Implanted electronic devices (e.g., deep-brain stimulators)
Uncontrolled seizure disorders or certain neurological conditions

The Bottom Line on TMS Side Effects

For many individuals, TMS therapy is a safe and well-tolerated treatment that offers meaningful relief from difficult mental health symptoms. Most side effects are mild, temporary, and manageable, and careful screening helps ensure the treatment is appropriate for each patient before therapy begins.

If you’re considering TMS, a personalized evaluation is the best place to start. Southwest Florida TMS & Ketamine Clinic provides expert guidance, tailored treatment plans, and compassionate care every step of the way.

Schedule a consultation today to learn whether TMS therapy is the right path for you.

Frequently Asked Questions

Quick answers about TMS side effects, safety, and what to expect.

Does TMS therapy cause seizures?

Seizures are the most serious potential side effect of TMS, but they are extremely rare. TMS is generally considered safe when proper screening protocols are followed.

Does TMS cause memory loss?

No. Unlike some other brain-based treatments, TMS has not been shown to cause memory loss. Cognitive side effects are uncommon, and some patients may even experience improved focus as symptoms improve.

Is TMS safe long-term?

Yes. TMS is widely regarded as safe and well-tolerated, with mostly mild and temporary side effects. Ongoing monitoring and standardized safety practices help support consistent outcomes.

How long do TMS side effects last?

Most side effects (like headaches or scalp discomfort) are mild and typically resolve within hours or days. Many symptoms also decrease as treatment continues.

Does TMS therapy hurt?

TMS is generally not painful. Some patients feel a tapping sensation or mild discomfort at the treatment site, but sessions are typically well-tolerated and require no anesthesia or recovery time.

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