TMS Therapy Side Effects: What to Expect and How Common They Are

Short answer: The most common side effects of TMS are scalp discomfort at the treatment site and headache. Both are usually mild to moderate, tend to ease after the first week of treatment, and rarely cause people to stop. TMS does not require anesthesia or sedation. It does not cause the weight gain, sexual side effects, or daytime sedation that many patients associate with antidepressant medication. Seizure is the most serious potential risk, and it is rare.

The two most common side effects

Scalp discomfort at the treatment site

TMS delivers magnetic pulses through a coil positioned against the scalp. Most people describe the sensation as tapping, knocking, or tightness at the stimulation site. Some report a pulling feeling in the muscles of the forehead or jaw.

This is the side effect patients notice most in the first several sessions. It typically decreases as treatment continues, partly because the scalp accommodates to the sensation and partly because stimulation intensity is often titrated upward gradually rather than started at full dose.

Headache

Headache after a session is common and usually mild. It generally responds to over the counter analgesics and tends to become less frequent after the first week or two of treatment.

How common are side effects overall

A safety analysis pooled data from three clinical protocols involving 325 patients across 23 sites in the United States, Australia, and Canada. TMS was administered in more than 10,000 cumulative treatment sessions. There were no deaths and no seizures. Most adverse events were mild to moderate in intensity, with transient headache and scalp discomfort the most commonly reported. Auditory threshold testing and cognitive function testing showed no change. The discontinuation rate due to adverse events during acute treatment was 4.5 percent (Janicak et al., Journal of Clinical Psychiatry, 2008).

That last figure is worth noting. More than 95 percent of patients in that dataset completed the acute course without stopping because of side effects.

Less common side effects

• Facial muscle twitching during stimulation. Contraction of muscles near the coil can occur while pulses are being delivered. It stops when the pulse train stops.
• Lightheadedness after a session, usually brief.
• Discomfort from the clicking sound. The coil produces a loud click with each pulse. Earplugs are used during every session to protect hearing.
• Tearing or eye twitching when stimulation is close to the muscles around the eye.

Seizure risk

Seizure is the most serious potential risk associated with TMS. It is rare.

The 2020 expert guidelines from the International Federation of Clinical Neurophysiology reviewed accumulated safety data and concluded that seizure risk is low, including among patients taking medications that act on the central nervous system, when conventional stimulation parameters and focal coils are used (Rossi et al., Clinical Neurophysiology, 2021).

Risk is reduced further by screening. Before starting treatment, a clinician should review your seizure history, any history of head injury or neurological condition, current medications that lower seizure threshold, alcohol use, and sleep deprivation.

Side effects TMS does not produce

Patients frequently ask about TMS because they are trying to avoid something else. These distinctions matter.

• No anesthesia and no sedation. You remain awake and alert throughout the session. You can drive yourself home and return to work the same day.
• No memory loss. TMS is not electroconvulsive therapy. It does not induce a seizure as part of treatment and it is not associated with the autobiographical memory effects seen with ECT. In the safety dataset above, cognitive testing did not change over the treatment course.
• No systemic medication side effects. Because TMS is not a drug and does not circulate through the body, it does not cause weight gain, sexual dysfunction, gastrointestinal upset, or dry mouth.

Who should not have TMS

The primary contraindication is non-removable ferromagnetic metal in or near the head, such as aneurysm clips, coils, stents, or certain implants. Dental fillings and most dental hardware are not a problem.

Caution and individualized assessment apply if you have a seizure disorder, a history of significant head injury, an implanted neurostimulator or cochlear implant, or an unstable medical condition. TMS during pregnancy requires a case by case discussion.

This is not a complete list, and screening is done individually. A clinician reviews your full history before treatment is recommended.

What reduces side effects in practice

• Gradual titration. Starting below target intensity and increasing over the first sessions improves tolerability.
• Coil positioning adjustments. Small changes in placement can reduce facial muscle activation and discomfort.
• Hearing protection every session.
• Reporting discomfort early. Discomfort is adjustable. Most of it is addressed by changing intensity or position rather than by stopping treatment.

Frequently asked questions

Do TMS side effects get worse over the course of treatment?

Generally the opposite. Scalp discomfort and headache are most noticeable early and tend to decrease over the first one to two weeks.

Can I drive after a TMS session?

Yes. TMS does not involve sedation or anesthesia, and there is no recovery period required before driving.

Does TMS cause brain damage?

There is no evidence that TMS delivered within standard clinical parameters causes structural brain injury. Cognitive testing in clinical safety studies has not shown decline.

Will TMS make my depression worse?

Worsening of depressive symptoms during TMS is uncommon, but any change in symptoms should be reported to your treating clinician promptly so the plan can be reassessed.

How long do side effects last after treatment ends?

Scalp discomfort and headache are tied to the sessions themselves and typically resolve within hours. They do not persist after a course is completed.

Next steps

Side effects are only one part of the decision. Whether TMS is appropriate also depends on your diagnosis, your treatment history, and your insurance plan’s criteria. You can read more about TMS therapy at Exxceed Wellness, review what TMS costs in California, or see how it is applied in OCD and anxious depression.

If you want to know whether you are a candidate, request a consultation and we will review your history and verify your benefits.

This article is for educational purposes and is not medical advice. It does not establish a clinician and patient relationship and it is not a substitute for individual evaluation. TMS is not appropriate for everyone, outcomes vary, and no treatment result is guaranteed. Discuss risks, benefits, and alternatives with a qualified clinician who knows your history. If you are in crisis or thinking about harming yourself, call or text 988 in the United States.