MRI scans can and sometimes do make people feel sick, though the effects are almost always temporary and mild. The most common complaint is dizziness or vertigo caused by the scanner’s magnetic field acting on your inner ear, and it tends to resolve within minutes of leaving the machine. Other issues range from nausea and headaches to temporary hearing shifts from the scanner’s noise, and, when contrast dye is involved, occasional allergic-type reactions. Understanding what causes each of these effects makes it easier to prepare and reduces the chance that any of them catch you off guard.
Why the Magnet Itself Makes You Dizzy
The most distinctive way an MRI can make you feel unwell has nothing to do with radiation or chemicals. It comes from the static magnetic field. Your inner ear contains fluid-filled canals that detect rotation and balance. When your head enters a strong magnetic field, a physical force (called a Lorentz force) pushes on the electrically charged fluid inside those canals, tricking your brain into thinking you are moving when you are not.1PubMed. Neurophysiology: vertigo in MRI machines The result is genuine vertigo, sometimes with nausea, that can start as you slide into the bore and usually fades once your head is stationary inside.
The strength of this effect scales with the power of the magnet. Modeling work comparing different field strengths found that the inner-ear response increases in a roughly linear fashion as the field goes up, meaning a 3-Tesla scanner provokes more vestibular stimulation than a 1.5-Tesla unit, and research-grade 7-Tesla machines provoke considerably more still.2PubMed Central. Longer duration entry mitigates nystagmus and vertigo in 7-Tesla MRI A study of over 1,000 outpatients found that new-onset vertigo or dizziness occurred in about 5.6% of people scanned at 3 Tesla, compared with much lower rates at weaker field strengths, and that women were disproportionately affected.3PubMed. Biologic effects of 3 Tesla (T) MR imaging comparing traditional 1.5 T and 0.6 T in 1023 consecutive outpatients
For most clinical scans at 1.5 or 3 Tesla, any dizziness is mild and passes quickly. At ultra-high field strengths used in research settings, though, the effect can be strong enough to cause vomiting. One case report described a patient who vomited so forcefully during a 7-Tesla scan that the retching caused a cerebrospinal fluid leak from the nose. That is an extreme and unusual outcome, but it illustrates how real the vestibular disturbance can be at very high field strengths.
The Noise Problem
MRI machines are loud. The banging and buzzing you hear come from the gradient coils vibrating inside the main magnet as they rapidly switch on and off to build images. Sound levels during a scan routinely reach the range of a rock concert or a power tool, and some sequences at 3 Tesla push well above 100 decibels. One neonatal study measured equivalent sound pressure levels of roughly 104 to 114 dBA during brain scans.4PubMed. Auditory Effects of Acoustic Noise From 3-T Brain MRI in Neonates With Hearing Protection
Can this noise actually damage your hearing? The short answer is that proper hearing protection makes the risk very small for a single scan, but temporary shifts can occur. A study measuring hearing thresholds in adults before and after a 1.5-Tesla head and neck scan found that certain high-frequency thresholds shifted immediately after the scan, but those shifts had fully reversed when tested again 24 hours later.5PubMed Central. Hearing Thresholds Changes after MRI 1.5T of Head and Neck In the neonatal study mentioned above, babies who wore proper ear protection showed no significant changes in auditory function after a 40-minute 3-Tesla scan.4PubMed. Auditory Effects of Acoustic Noise From 3-T Brain MRI in Neonates With Hearing Protection
The concern becomes more relevant for people who undergo many scans. Research participants in long-running neuroscience studies, for example, may sit through dozens of sessions over months or years. The cumulative effect of repeated MRI noise exposure on hearing is still being studied, and researchers have flagged it as an area where more data is needed.6PubMed Central. MRI noise and auditory health: Can one hundred scans be linked to hearing loss? The case of the Courtois NeuroMod project For the vast majority of patients getting an occasional clinical scan, the takeaway is straightforward: wear the earplugs or headphones the technologist gives you, and you should be fine.
Contrast Dye Reactions
Not every MRI involves contrast dye, but many do, particularly scans of the brain, spine, joints, or blood vessels. The dye used is a gadolinium-based contrast agent, or GBCA, injected into a vein to make certain tissues show up more clearly on the images. GBCAs have a generally strong safety profile, but they can cause side effects.
Acute reactions are the most noticeable. In a study of nearly 2,400 pediatric patients who received gadolinium, about 1.7% experienced an acute side effect, and the large majority of those were nausea and vomiting.7PubMed Central. Acute side effects of three commonly used gadolinium contrast agents in the paediatric population Reactions can also include hives, skin flushing, or mild respiratory symptoms. True life-threatening reactions resembling severe allergy, with breathing difficulty and swelling, are rare but have been documented.8PubMed. Adverse reactions to gadolinium contrast media: a review of 36 cases If you have had a previous reaction to gadolinium, let your ordering physician and the MRI team know well ahead of time so they can premedicate you or choose an alternative approach.
A more serious concern that emerged over the past two decades is nephrogenic systemic fibrosis, or NSF, a rare condition that causes progressive thickening and scarring of the skin and internal organs. NSF has been reported exclusively in people with advanced kidney disease, and it is linked to certain types of GBCAs, particularly the less chemically stable “linear” formulations. The number of new cases has dropped sharply since guidelines were tightened to screen kidney function before administering contrast and to avoid high-risk agents in vulnerable patients.9PubMed. Gadolinium Deposition and Nephrogenic Systemic Fibrosis: A Radiologist’s Primer Most facilities now use macrocyclic agents, which hold onto the gadolinium more tightly and carry a much lower risk.10PubMed. Gadolinium-based contrast agents: What we learned from acute adverse events, nephrogenic systemic fibrosis and brain retention
Gadolinium Deposition and What It Means
Even in people with healthy kidneys, small amounts of gadolinium can linger in the body after a contrast-enhanced scan. Deposits have been found in the brain, bones, and skin across all types of GBCAs.11PubMed Central. Gadolinium toxicity: mechanisms, clinical manifestations, and nanoparticle role This discovery, first widely reported around 2014, alarmed both patients and clinicians and prompted regulatory reviews worldwide.
The reassuring part, at least so far, is that no proven health effects have been linked to gadolinium retention other than NSF in kidney-impaired patients.9PubMed. Gadolinium Deposition and Nephrogenic Systemic Fibrosis: A Radiologist’s Primer That said, the evidence is not entirely settled. Some patients report symptoms like headaches, bone pain, and brain fog after receiving gadolinium, and while these reports have not been confirmed in controlled studies, the topic remains an active area of investigation. In people with kidney impairment, conditions such as low clearance of the gadolinium-carrier complex and competition from other metals in the blood can increase the amount of free gadolinium circulating in the body, raising the theoretical risk for toxicity.
The practical advice here is measured. If your doctor orders a contrast-enhanced MRI, the diagnostic benefit almost always outweighs the known risks. But it is reasonable to ask whether contrast is strictly necessary for your particular scan, especially if you have had many contrast-enhanced studies in the past or have compromised kidney function.
Heating, Tingling, and Burns
The radiofrequency energy that MRI machines use to excite hydrogen atoms in your body does deposit a small amount of heat. In a typical scan, this warming is trivial and you will not feel it. However, the energy can concentrate in certain situations, particularly around conductive materials, and that is where problems arise.
RF-induced burns, while uncommon, do occur. They tend to happen when something metallic or conductive creates a pathway for current to concentrate: a wire loop from an ECG lead, a tattoo with metallic ink, or skin-to-skin contact that forms a closed electrical loop. A review of the topic noted that RF exposure during MRI occasionally causes burn injuries to patients.12PubMed Central. Progress in Understanding Radiofrequency Heating and Burn Injuries for Safer MR Imaging This is one reason the technologist asks you to remove jewelry, separate your limbs so skin does not touch skin, and wear a hospital gown without metal snaps.
Separately from RF heating, the rapidly switching gradient coils can stimulate peripheral nerves, producing a tingling or twitching sensation, most often in your arms or legs. As MRI technology pushes toward faster imaging sequences, the likelihood of peripheral nerve stimulation increases because the gradients switch more aggressively.13PubMed Central. Prediction of peripheral nerve stimulation thresholds of MRI gradient coils using coupled electromagnetic and neurodynamic simulations The sensation is startling but not harmful, and the scanner has built-in limits to prevent the stimulation from reaching painful levels. If you feel unexpected tingling or warmth during a scan, use the squeeze-ball alert to notify the technologist immediately.
The Metallic Taste and Other Odd Sensations
Some people report a metallic or electric taste in their mouth during an MRI, especially when moving their head near the edge of the magnet where the field changes rapidly. This is not imagination. Research at a 7-Tesla scanner found that relatively normal head movements in the stray field could produce field changes fast enough to trigger a metallic taste in a majority of subjects, with a threshold that varied considerably from person to person.14Journal of Magnetic Resonance Imaging. Threshold for perceiving metallic taste at high magnetic field Some people perceived the taste at rates of field change barely above 1 Tesla per second, while others needed higher levels.
Another unusual phenomenon is magnetophosphenes: brief light flashes or flickering that you see with your eyes closed. These happen when the changing magnetic field stimulates the retina or the visual cortex directly. In the outpatient study cited earlier, magnetophosphenes were reported primarily at 1.5 Tesla and not at 3 Tesla, which is a bit counterintuitive.3PubMed. Biologic effects of 3 Tesla (T) MR imaging comparing traditional 1.5 T and 0.6 T in 1023 consecutive outpatients The reasons likely relate to differences in gradient sequences and head positioning rather than to the static field alone. None of these sensory oddities are dangerous, but they can be unsettling if you do not know they are coming.
Implants and Metal in the Body
If you have metallic hardware in your body, the MRI’s magnetic field and radiofrequency energy introduce additional risks that go beyond the symptoms most patients worry about. The RF field from the scanner’s transmit coil, along with the switching gradient fields, induces electrical currents in any conductive object inside the bore. Those currents can heat the surrounding tissue to dangerous levels.15PubMed. MRI-Related Heating of Implants and Devices: A Review Simulations of an artificial hip joint at 1.5 Tesla, for example, measured temperatures rising by over 4 degrees Celsius at the tip of the implant, exceeding international safety thresholds.16PubMed Central. Measurement and evaluation of specific absorption rate and temperature elevation caused by an artificial hip joint during MRI scanning
Beyond heating, ferromagnetic objects can experience a strong pull toward the magnet or torque that tries to rotate them. This is why the screening questionnaire before any MRI asks extensively about implants, surgical hardware, shrapnel, and even occupational metal exposure. Most modern orthopedic implants and many cardiac devices are now labeled “MR conditional,” meaning they can be safely scanned under specific conditions (certain field strengths, certain body positions, limited scan durations). But “MR conditional” is not the same as “MR safe,” and the conditions matter. If you have any implanted device, the MRI team will check compatibility before proceeding. Never assume a scan is safe just because you have had one before with the same implant; protocols and field strengths vary between facilities.
Claustrophobia and Anxiety-Related Symptoms
A substantial number of people who feel sick during or after an MRI are experiencing the physical effects of anxiety rather than a direct biological reaction to the scanner. The bore of a standard MRI machine is narrow and noisy, the scan can take 30 minutes or more, and you have to lie still the entire time. For people who are claustrophobic, or simply anxious about medical procedures, this combination can trigger a genuine stress response: racing heart, shallow breathing, sweating, nausea, and lightheadedness.
These symptoms are real and physiologically measurable, not “all in your head” in the dismissive sense. But they respond to different interventions than the magnetic-field-related symptoms discussed above. Strategies that help include visiting the MRI suite beforehand to see the machine, asking about open or wide-bore scanners (which feel less confining), using an eye mask so you do not see the tight space, listening to music through the headphones, and, when appropriate, taking a mild sedative prescribed by your doctor. Communicating with the technologist through the intercom and knowing you can stop the scan at any time also reduces the sense of being trapped.
How to Prepare and Reduce Your Risk
Most of the unpleasant effects of an MRI are manageable or avoidable with preparation. Here are the practical steps, organized by the type of issue they address:
- For dizziness: Move slowly when entering and exiting the bore. Quick head movements in the changing magnetic field are what provoke the strongest vestibular response. Research on 7-Tesla scanners found that entering the bore more slowly substantially reduced both the involuntary eye movements and the sensation of vertigo.2PubMed Central. Longer duration entry mitigates nystagmus and vertigo in 7-Tesla MRI Even at clinical field strengths, asking the technologist to move the table slowly can help. If you are prone to motion sickness, an over-the-counter antihistamine like diphenhydramine (Benadryl) taken before the scan has been shown to reduce vertigo at ultra-high field strengths.17PubMed. Efficacy of diphenhydramine in the prevention of vertigo and nausea at 7 T MRI Check with your doctor first, since diphenhydramine causes drowsiness.
- For noise: Always wear the hearing protection provided. If you find standard foam earplugs uncomfortable, ask whether the facility has MRI-safe over-ear options or combination plugs-plus-headphones. Do not bring your own earplugs with metal components.
- For contrast reactions: Tell the ordering physician and the MRI technologist if you have had any previous reaction to gadolinium or iodine-based contrast, if you have kidney disease, or if you are pregnant. If your kidney function is reduced, the team will evaluate whether contrast is necessary and may choose a more stable agent or avoid it altogether.
- For heating and burns: Remove all jewelry, body piercings, and clothing with metal closures before the scan. Do not cross your arms or legs, and keep your skin from touching itself (the technologist may place pads between your limbs). If you have tattoos with metallic ink, mention them so the team can monitor those areas.
- For anxiety: Arrive early so you are not rushed. Ask questions about what the scan will feel like, how long it will take, and what each noise means. Knowing what to expect removes a lot of the fear. Practice slow breathing beforehand if you are worried about claustrophobia.
When MRI Workers Get Sick
Patients spend minutes to an hour in the scanner, but MRI technologists, nurses, and researchers work around strong magnets every day. Occupational studies have found that MRI workers report vertigo during shifts at rates that track with their cumulative exposure to the magnetic field. In one study, the probability of experiencing vertigo during a work shift exceeded 5% once peak exposure reached around 400 milliTesla or when time-weighted average exposure to the changing field topped about 0.6 milliTesla per second.18PubMed. Exposure to MRI-related magnetic fields and vertigo in MRI workers These are not the levels inside the bore itself but the stray fields that workers pass through while positioning patients, adjusting equipment, or moving around the MRI suite.
For workers, the practical concern is chronic, low-grade vestibular irritation from daily exposure rather than the acute episode a patient might experience during a single scan. Some technologists describe getting used to the feeling over time, while others report persistent issues with balance and concentration by the end of long shifts. Workplace guidelines generally recommend moving slowly near the magnet, avoiding sudden head turns, and designing MRI suites so that the stray field in the operator area is as low as possible. The growing use of higher-field clinical magnets, including the spread of 3-Tesla scanners for routine imaging, makes this a topic with increasing practical relevance for the thousands of MRI professionals working daily shifts.
Tattoos, Piercings, and Cosmetics
Tattoo ink sometimes contains metallic pigments, particularly iron oxide in darker inks. During an MRI, the RF energy can cause localized heating at the tattoo site, and some patients have reported stinging, burning, or raised skin over tattooed areas. The risk depends on the ink composition, the size and density of the tattoo, and the specific MRI sequence used. Most people with tattoos go through MRI without any problems, but large tattoos in the direct path of the RF field (like a full-sleeve arm tattoo during a shoulder scan) carry a slightly higher chance of irritation.
Permanent cosmetics, including tattooed eyeliner and lip liner, raise similar questions because they use pigments that may contain metal particles. Eye-area cosmetics are particularly noted because of the sensitivity of the surrounding tissue. If you have permanent makeup or large tattoos, mention them during the screening process. The MRI team can place cold compresses near the area, choose lower-energy scan settings, or monitor for warmth during the procedure. Piercings that cannot be removed for any reason are handled case by case; non-ferromagnetic materials like titanium and surgical steel are generally tolerated, but the team needs to know about them to make that determination.