Side effects & safety
Acupuncture side effects: what to expect afterwards
What acupuncture can feel like afterwards — stated plainly.
Most people who ask about side effects are not looking for reassurance so much as a straight answer. This page gives one: what is common, what is rare, what it means, and when to pick up the phone.
The short answer
Serious events are very rare. Minor ones are not.
These are two different claims and they are often blurred together, usually in the direction of overselling. Kept apart, both are defensible.
Two large British prospective surveys published in 2001 followed roughly 66,000 treatments between them and recorded no serious adverse events. That is the reassuring half, and it is genuinely reassuring — provided the person treating you has the training behind it. A practitioner needs a working knowledge of anatomy and biomedicine before a needle goes anywhere near you, which is what registration with a professional body is for.
The other half: the largest study of the question, covering 229,230 patients, found that roughly one person in nine reported some reaction — most commonly tiredness, or soreness where the needles had been. Short-lived, not dangerous, and worth knowing about in advance rather than discovering afterwards and wondering.
A useful comparison: the first few seconds of a hot bath are not comfortable, and nobody concludes the bath is dangerous. Your body responds to treatment, and the response is not always neutral.
The effects nobody complains about
Changes you did not come in for.
Very few people seek out needles for entertainment. Almost everyone arrives because something has not settled — and then reports something else improving alongside it.
Sleeping more deeply, digesting more comfortably, feeling less wound up, steadier energy through the afternoon: these come up constantly, and they are not the treatment missing its target. Because Chinese medicine works from the whole picture rather than a single symptom, effects are rarely confined to the complaint you booked for. None of this is a promise. It is simply common enough that you should not be surprised by it.
What can happen
Six reactions, and what each one means.
In order of how often they are asked about. Each is short-lived, and each tells the practitioner something useful about how to treat you next time.
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Feeling faint
The one that worries people most, and the one most easily prevented.
Fainting during acupuncture is a vasovagal response — a brief drop in heart rate and blood pressure that reduces blood flow to the brain. You may notice lightheadedness, sweating, pale skin, blurred vision or nausea before it happens. It is not dangerous, but it does mean treatment stops for that day.
Almost every case follows the same pattern: arriving over-hungry or exhausted. In Chinese medicine terms, acupuncture works by moving Qi, and there needs to be enough of it to move. In physiological terms, the body misreads the situation and triggers a reflex that would be useful if you were losing blood — slowing the heart to limit bleeding — but is simply unhelpful here.
What to do Lie flat with your legs raised slightly and have something to eat. It passes quickly. The prevention is simpler still: eat something beforehand, and say so if you have skipped a meal or slept badly. Bring a snack if you are coming straight from work.
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Tiredness afterwards
Common, usually informative, and occasionally a sign the treatment was too strong.
Feeling washed out after a session is one of the most frequently reported reactions in the safety literature. Most often it is not a problem with the treatment but a message about the state you arrived in — a demanding city routine keeps people running on reserves they have not noticed spending.
The less common explanation is that the treatment was simply too intense for you, which happens more often with long-standing conditions where the body has less capacity to respond.
What to do Tell me about it at the next appointment. It is not something to push through quietly: the treatment plan can be made gentler, or spaced differently, and that adjustment is part of the work rather than a sign it is failing.
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A short flare before it settles
Common with long-standing pain, and often mistaken for the treatment failing.
Some people find the problem they came in with feels briefly worse — usually that evening or the next morning — before easing. It is reported most often with persistent musculoskeletal pain, and least often when the complaint is recent.
The honest position is that this is well recognised in practice but not well explained. It is sometimes presented as proof that the treatment is working; that claim goes beyond what anyone can demonstrate, and a flare predicts neither a good nor a poor outcome. What it does reliably indicate is the strength of the treatment relative to you on that day.
What to do Give it forty-eight hours. If it has settled and left you no worse, the next session is pitched slightly lighter and it usually does not recur. If it has not settled, or the flare was severe rather than merely noticeable, tell me before the next appointment rather than after it.
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Bruising and soreness
Minor, self-limiting, and more likely on certain medication.
The needles are extremely fine, but a needle can still catch a small blood vessel and leave a purple patch. Bruises of this kind fade over a few days and carry no significance beyond the mark itself. A traditional remedy is a poultice of grated raw potato, which some people find soothing.
If you take anticoagulant or antiplatelet medication, bruising is more likely — please say so before your first treatment so needle choice and technique can be adapted. Some points are naturally more sensitive than others, and a small number of people notice soreness at a specific site.
What to do Soreness almost always settles within twenty-four hours. If a bruise is unusually large, spreading, or painful rather than merely visible, contact me.
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Emotional release
Unexpected the first time it happens, and not a problem.
Some people find tears arrive during or shortly after a treatment, sometimes attached to a memory they were not thinking about. It is most common in people who have been holding something down for a long time.
Rather than a sign that something has gone wrong, this is usually a sign that the treatment has reached the level it was aimed at. Sustained pressure is held physically as well as mentally, and releasing one tends to release the other.
What to do There is no need to apologise or hold it back — the room is private and there is no hurry. If it is part of something larger that would be better served by talking therapy, I will say so.
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Feeling wired, or sleeping badly
Uncommon, and specific enough to be worth naming.
Occasionally a treatment leaves people feeling energised rather than settled, and that can spill into a poor night. It is reported most often after moxibustion — the warming technique using mugwort — rather than after needling alone.
It generally means the treatment was pitched slightly too warming or too stimulating for you on that day.
What to do Mention it, and the plan is adjusted: less moxa, different points, or a gentler technique. It is straightforward to correct once it is known about.
Before your appointment
The sentence that prevents most of this.
A surprising proportion of the reactions above are avoidable, and the prevention is conversation rather than technique.
- Eat something firstArriving hungry is the single most common cause of feeling faint on the couch. If you are coming straight from work, bring a snack.
- Say if you have slept badlyOr are unwell, or have had a genuinely punishing week. The treatment is pitched differently, and that is a better outcome than pushing on and feeling flattened afterwards.
- Bring your medication listAnticoagulants and antiplatelet medication make bruising more likely. Nothing is ruled out because of them, but needle choice and technique change.
- Mention implants and devicesA pacemaker or other implanted electrical device rules out electroacupuncture at certain sites. There are alternatives; they just need to be planned.
- Tell me if you have fainted beforeDuring blood tests, dental work, or anything similar. You will be treated lying down, and the first session kept deliberately light.
- Say if you are pregnant, or think you might beAcupuncture is used throughout pregnancy, but certain points are avoided and the approach is adapted from the first appointment onwards.
When to get in touch
What warrants a message, and what warrants a doctor.
Nearly everything on this page settles by itself within a day or two. A short list does not.
Message me if tiredness lasts more than a couple of days, if soreness has not gone within twenty-four hours, if a bruise is unusually large or spreading, or if sleep was disturbed after a session. None of these are emergencies. All of them change how you are treated next time, which is the point of knowing about them.
Seek medical attention rather than contacting me for breathlessness or chest pain after treatment, a fever, or redness, heat and swelling spreading from a needle site. These are not things I have seen, and the prospective surveys suggest they are very rare indeed — but they are the situations where a doctor, not an acupuncturist, is the right person, and no time should be lost being polite about it.
This page is general information about treatment reactions and does not replace individual clinical advice. If you are unwell and unsure how urgent it is, contact your GP, or NHS 111 if you cannot get an appointment. In an emergency, call 999.
Frequently asked questions
The questions people actually send before booking.
Answered as they would be in the room, including where the honest answer is less tidy than the reassuring one.
Is acupuncture safe?
In the hands of a properly trained practitioner, the safety record is strong. Two large British prospective surveys published in 2001 recorded no serious adverse events across roughly 66,000 treatments between them. The training matters more than anything else here: a practitioner needs a working knowledge of anatomy and biomedicine before putting a needle anywhere near you. Check that yours is registered with a professional body — in the UK that generally means the British Acupuncture Council.
How common are side effects of acupuncture?
It depends what is being counted. Serious events are very rare. Minor, short-lived reactions are not: the largest study of the question, covering 229,230 patients, found that about one person in nine reported something — most often tiredness or soreness at the needle site. Almost all of it settles within a day or two. Anyone telling you side effects never happen at all is overselling.
Why do I feel tired after acupuncture?
Tiredness is the single most commonly reported reaction. Usually it reflects the state you arrived in rather than the treatment itself — the session removes the stimulus that was keeping you going, and the accumulated fatigue underneath becomes noticeable. Less often it means the treatment was too strong for you, particularly with a long-standing condition. Either way it is worth mentioning, because the plan can be adjusted.
Can acupuncture make your pain worse?
It can feel briefly worse before it settles, most often that evening or the next morning, and most often with long-standing musculoskeletal pain. It usually resolves within forty-eight hours and the following session is pitched more lightly. You will sometimes see this described as proof the treatment is working — that goes further than the evidence supports, and a flare predicts neither a good nor a poor result. What it does tell us is that the treatment was a little strong for you that day. If it does not settle, or it was severe rather than just noticeable, say so before the next appointment.
Is bruising after acupuncture normal?
It is common and harmless. A fine needle can catch a small vessel; the mark fades over a few days. Tell me before treatment if you take anticoagulant or antiplatelet medication, as bruising is more likely and technique is adapted accordingly. A bruise that is unusually large, spreading, or genuinely painful rather than just visible should be reported.
Can acupuncture make you emotional?
Yes, and it is not a sign that anything has gone wrong. Some people find tears arrive during or after a session, occasionally alongside a memory they were not expecting. It is most common in people who have been carrying something for a long time without putting it down. If what surfaces would be better held by a psychological therapist, I will say so rather than treat around it.
Are there good side effects of acupuncture?
Frequently. Because treatment is directed at the whole person rather than one symptom, people often notice changes they did not come for — sleeping better, digesting more comfortably, feeling less wound up, or having steadier energy through the day. These are not guarantees, but they are common enough to be worth expecting.
What should I tell my practitioner before treatment?
Anticoagulant or antiplatelet medication, a pacemaker or other implanted device, pregnancy, a bleeding disorder, a compromised immune system, and any history of fainting during medical procedures. Also say if you have not eaten, have slept badly, or feel unwell that day — that single sentence prevents most of the reactions on this page.
About the practitioner
Written and reviewed by Phoebus Tian.
Phoebus Ye Tian, BMed, MBAcC — acupuncturist, Chinese medicine practitioner and former clinical lecturer.
Phoebus completed a five-year medical degree at Heilongjiang University of Chinese Medicine, qualified as a licensed doctor of Chinese medicine in China, worked in a hospital orthopaedics unit and later taught at London South Bank University. In 2024 he authored the “Moxibustion” chapter in Springer’s Acupuncture Techniques: A Practical Manual.
He is a member of the British Acupuncture Council, whose members are required to meet standards of training in anatomy, physiology and safe practice, and to carry professional indemnity insurance.
References
Where the numbers on this page come from.
Prospective surveys — practitioners recording events as they happen — rather than retrospective case reports, which tend to over-represent the unusual.
Large prospective safety surveys
- White A, Hayhoe S, Hart A, Ernst E (2001). Adverse events following acupuncture: prospective survey of 32,000 consultations with doctors and physiotherapists. BMJ, 323(7311), 485–486. View
- MacPherson H, Thomas K, Walters S, Fitter M (2001). A prospective survey of adverse events and treatment reactions following 34,000 consultations with professional acupuncturists. Acupuncture in Medicine, 19(2), 93–102. View
How often minor reactions occur
- Witt CM, Pach D, Brinkhaus B, Wruck K, Tag B, Mank S, Willich SN (2009). Safety of acupuncture: results of a prospective observational study with 229,230 patients and introduction of a medical information and consent form. Forschende Komplementärmedizin, 16(2), 91–97. View