Questions about TMS side effects are reasonable, especially when depression treatment has already required difficult tradeoffs. Repetitive transcranial magnetic stimulation, or rTMS, is noninvasive and does not require surgery or anesthesia. Most reported effects are mild and short-lived, but every patient still needs a careful safety screening and a clear plan for reporting changes.
The most common concerns are scalp discomfort, headache, facial muscle tingling or twitching, brief lightheadedness, and dizziness. Serious problems such as seizure or hearing injury are rare. Your personal risk depends on your health history, medications, implanted devices, and the treatment protocol, so an eligibility visit matters more than a generic list online.
Quick guide
Are TMS side effects usually serious?
For most appropriately screened patients, TMS side effects are mild to moderate and improve soon after a session. The National Institute of Mental Health describes rTMS as generally safe and well tolerated. Because treatment uses magnetic pulses aimed at a specific brain area, it does not require an incision, implanted electrode, sedation, or general anesthesia.[1]
That safety profile does not make screening optional. The U.S. Food and Drug Administration classifies rTMS systems as Class II medical devices with special controls. FDA guidance identifies risks that device labeling and clinical procedures must address, including seizure, hearing effects, scalp discomfort, worsening depression or suicidality, and interaction with metal or implanted devices.[2]
At Kalamazoo TMS & Behavioral Health, an eligibility review is a chance to discuss those risks in the context of your diagnosis and medical history. It is also the right time to ask what device and protocol may be used, because side-effect information can vary by system and treatment parameters.
Common TMS side effects and what they may feel like
The coil rests against the scalp and delivers repeated magnetic pulses. People often describe a tapping sensation during the session. Common effects involve the scalp and nearby muscles rather than the whole body.
Scalp discomfort or tenderness
The treatment area may feel tender, pressured, or uncomfortable while the pulses are active. In clinical data discussed by the National Institute of Mental Health, stimulation-site discomfort occurred in 18% of participants receiving active treatment and 10% receiving sham treatment.[3] Individual device trials and protocols may report different rates.
Discomfort often becomes easier to tolerate after the first several sessions. If it feels sharp or keeps increasing, tell the treatment technician during the session. Coil position or stimulation settings may need clinical review.
Headache
A mild headache can occur during or after treatment. It may feel like pressure near the forehead, temple, or scalp. Headaches often ease after the session and may become less frequent as treatment continues.
Do not automatically take a new medication for a headache without checking with your clinician. Your care team can consider your medical history, current prescriptions, and the pattern of symptoms before recommending an approach.
Tingling, twitching, or facial muscle movement
Some people notice tingling or brief contractions in the scalp, jaw, or facial muscles while the coil is pulsing. These sensations should be reported when they are painful, affect your vision, or continue after treatment. A technician should know what you are experiencing in real time rather than waiting until the next appointment.
Brief lightheadedness or dizziness
Lightheadedness and dizziness are listed among possible rTMS effects by the National Institute of Mental Health.[1] Sit for a moment before standing if you feel unsteady. Tell the treatment team immediately if the feeling is severe, returns repeatedly, or comes with fainting, chest pain, weakness, confusion, or a new neurological symptom.
Rare but serious TMS risks
Serious adverse events are uncommon, but informed consent should cover them plainly. Your clinician can explain how the risk information applies to the specific device, indication, and protocol being considered.
Seizure
TMS can cause a seizure, although the risk is low when patients are screened and current safety guidance is followed. Risk may be affected by a seizure history, neurological illness, sleep deprivation, alcohol or substance withdrawal, medications that alter seizure threshold, and treatment parameters.[1][2]
Give the clinician a complete medication and supplement list. Report recent changes, missed doses, heavy alcohol use, withdrawal, or a night of unusually poor sleep before a session. These details may change the safest plan for that day.
Hearing changes
The device produces repeated clicking sounds. FDA guidance addresses the risk of acoustic trauma, and properly fitted hearing protection is a standard safety measure.[2] Tell the team about existing hearing loss, tinnitus, ear pain, or a hearing device before treatment. Report new ringing, muffled hearing, or ear discomfort promptly.
Mood activation or worsening symptoms
Rare mood changes, including mania in a person with bipolar disorder, require clinical attention. FDA guidance also calls for monitoring for worsening depression, suicidal thoughts, and unusual behavior during treatment.[2] Family members may sometimes notice changes in sleep, speech, energy, impulsivity, or behavior before the patient does.
If you develop thoughts of suicide or feel unable to stay safe, call or text 988 in the United States or go to the nearest emergency department. Call 911 for immediate danger. Do not wait for the next scheduled TMS visit.
Interaction with metal or implanted devices
The magnetic field can interact with certain metal objects and electronic implants in or near the head. FDA guidance specifically warns about implanted stimulators, cochlear implants, and device leads.[2] Eligibility depends on the object, its location, the device instructions, and clinical judgment.
Tell the clinician about aneurysm clips or coils, stents, bullets or fragments, implanted pumps, pacemakers, deep brain stimulators, cochlear implants, dental hardware, and any other metal or electronic device. Dental fillings and braces are not automatically disqualifying, but they still belong on the screening form.
Who should receive extra screening before TMS?
Every patient needs screening. A longer discussion is especially important when the history includes:
- a previous seizure, epilepsy, significant head injury, stroke, or brain surgery;
- a metal object or electronic implant in or near the head;
- a pacemaker, medication pump, implanted stimulator, or hearing implant;
- bipolar disorder, past mania, psychosis, or rapidly changing mood;
- pregnancy or a possibility of pregnancy;
- frequent migraines, severe headaches, tinnitus, or hearing loss;
- heavy alcohol use, recent withdrawal, or other substance use;
- medications or supplements that may affect seizure threshold; or
- a recent major change in sleep, health, or prescriptions.
This list is not a pass-or-fail test. It tells the clinician what must be reviewed before deciding whether, when, and how treatment can proceed.
How a treatment team reduces TMS risks
Safety begins before the first pulse. A responsible process should include a diagnosis review, medical and medication history, implant and metal screening, discussion of prior seizures or head injuries, informed consent, and baseline symptom assessment.
During care, the team may:
- determine an individualized motor threshold and treatment intensity;
- confirm coil placement and treatment parameters;
- provide properly fitted hearing protection at every session;
- ask about sleep, medication changes, alcohol use, and new symptoms;
- monitor pain, movement, mood, and neurological changes;
- adjust positioning or settings when clinically appropriate; and
- document side effects so patterns can be reviewed over time.
Motor threshold is the minimum stimulation intensity that produces a small, observable motor response under controlled conditions. It helps the clinician tailor dosing rather than using the same intensity for everyone.
What should you do if TMS side effects occur?
Tell the technician as soon as discomfort begins. You do not need to endure a painful session to be a “good patient.” Precise details help: where the symptom occurs, when it starts, how strong it feels on a 0-to-10 scale, how long it lasts, and whether it changes after treatment.
Contact the clinic promptly for a new or worsening headache, persistent dizziness, hearing changes, unusual confusion, significant sleep reduction, agitation, impulsive behavior, or worsening depression. Seek emergency care for a seizure, loss of consciousness, a sudden severe headache, new weakness, trouble speaking, or immediate safety concerns.
Keep a short daily record during treatment. Note sleep, headache or scalp discomfort, dizziness, mood changes, medications, and anything unusual. A consistent record is more useful than trying to reconstruct several weeks at the end of the course.
Questions to ask at a TMS eligibility review
Bring a current medication list and details about any implanted device or past neurological event. Then ask:
- Which TMS device and protocol are you considering for me?
- What side effects are most common with that protocol?
- Does anything in my medical history increase seizure risk?
- Are any of my medications or supplements relevant to safety?
- What should I do if I sleep poorly or miss a medication before a session?
- How will you protect my hearing?
- Who should I contact after hours if symptoms change?
- What findings would cause you to pause or stop treatment?
Clear answers should leave you informed, not pressured. You can ask for written device information and take time to discuss the decision with people you trust.
Frequently asked questions
Do TMS side effects get worse over time?
Common effects such as scalp discomfort and headache often become less noticeable after the early sessions, but experiences vary. A symptom that becomes stronger, lasts longer, or appears for the first time later in treatment deserves review. Report the pattern so the clinician can decide whether anything should change.
Can I drive after TMS?
TMS does not usually require anesthesia or sedation, so many patients return to regular activities after a session. However, do not drive if you feel dizzy, lightheaded, confused, or otherwise unsafe. Ask your clinician for advice based on your response and any other medication or condition that affects driving.
Does TMS cause memory loss?
Memory loss is not considered a common TMS side effect. TMS differs from electroconvulsive therapy in how stimulation is delivered and does not require anesthesia. Still, report any new cognitive change so your clinician can assess medication effects, depression symptoms, sleep, medical factors, and treatment timing.
Is a headache after TMS normal?
A mild, short-lived headache can occur. Tell the treatment team even when it seems manageable, especially during the first week, so they can track it. Seek urgent care for a sudden severe headache or one accompanied by weakness, speech difficulty, fainting, confusion, or another new neurological symptom.
Can TMS make anxiety worse?
Some people notice temporary tension or anxiety around a new procedure, while mood activation or worsening psychiatric symptoms requires prompt assessment. Tell your clinician about increased restlessness, panic, reduced sleep, racing thoughts, or impulsive behavior rather than assuming it will pass on its own.
Discuss TMS side effects in a personal safety review
A general article can explain common TMS side effects, but it cannot determine your eligibility. Kalamazoo TMS & Behavioral Health serves patients in Kalamazoo and nearby communities, including Portage, Battle Creek, Paw Paw, Comstock, Oshtemo, Texas Corners, Mattawan, Vicksburg, and Grand Rapids.
If depression has not improved enough with prior care, schedule a TMS eligibility review. Bring your medication list, treatment history, and implant information so the conversation can focus on your actual risks, questions, and goals.
References
- National Institute of Mental Health. Brain Stimulation Therapies. Accessed August 11, 2026.
- U.S. Food and Drug Administration. Repetitive Transcranial Magnetic Stimulation Systems: Class II Special Controls Guidance. Accessed August 11, 2026.
- National Institute of Mental Health. Transcranial Magnetic Stimulation Safety and Risk. Accessed August 11, 2026.
- Mayo Clinic. Transcranial Magnetic Stimulation: Risks. Accessed August 11, 2026.
