Thread embedding (穴位埋线, xuewei maixian) pushes a short length of absorbable suture under the skin at an acupuncture point through a hollow needle, withdraws the needle and leaves the thread to dissolve. The thread stays in the tissue for days to weeks, so one session stands in for several needling sessions, and courses repeat it every one to four weeks. A 2026 review by Xu and colleagues dates the method to Chinese acupuncturists in the 1960s, who used it to extend stimulation and shorten courses. A 2012 bibliometric survey by Zhang and colleagues counted 1,075 Chinese papers over 40 years; the conditions treated most often were stomach pain (102 papers), low back and leg pain (79) and obesity (74). This page reports how the thread is placed, what it is made of, what reviews of the trials found, and the complications reported.
How it is done
The tool is a hollow needle with a stylet, a wire that fits inside it. Zhang’s survey found that the main tool was an adapted lumbar puncture needle. The method is described in detail in a 2022 multicentre trial by Chen and colleagues: 2 cm of chromic catgut was loaded into the tip of a 0.8 mm needle, the needle was inserted at the point, and the stylet pushed the thread into the tissue as the needle came out. The catgut and the firm lump around it took about two weeks to be absorbed, and the trial repeated the procedure every two weeks for 8 sessions.
Intervals vary. A 2026 safety review of 90 randomised trials by Hong and colleagues found an average of 11.7 days between sessions, most often 14 to 15 days and next most often weekly. A 2024 practical review by Kazemi and colleagues describes a schedule of about twenty threads of 1 to 2 cm, repeated every 3 to 4 weeks, and states that the method is not used in pregnant women or children. China’s national standard for the procedure is GB/T 21709.10-2008, part 10 of the standardised manipulations of acupuncture and moxibustion, in force since July 2008.
Catgut and synthetic threads
Catgut, the original material, is collagen from the small intestine of sheep. Kazemi’s review groups the threads into natural (catgut, chitosan), synthetic and bioactive kinds. The synthetic sutures are polyglycolic acid (PGA), polyglactin (PGLA) and polydioxanone (PDO). A 2025 review by Wang and colleagues gives PGA as losing half its strength within two weeks and being fully absorbed in four to six months.
The trials still mostly use catgut. Of the 75 trials in Hong’s review that named the thread, 62.7% used catgut, 17.3% PDO, 14.7% PGLA and 4% PGA. Catgut, PGLA and PGA appeared only in the Chinese trials; the Korean trials used PDO alone. Surgery in Europe had largely moved away from catgut by 2001, when the European Commission’s Scientific Steering Committee, reviewing animal-derived materials in medical devices during the BSE crisis, judged catgut from low-risk countries safe and noted that surgeons in Europe no longer widely used it because synthetic sutures were available.
What the reviews report
Obesity is the condition most studied; Obesity and overweight sets these reviews beside those of body and ear acupuncture. The reviews pool trials that compare embedding with sham embedding, with ordinary needling, with drugs or with nothing, and the size of the result depends on the comparison. Only a sham procedure separates the thread from everything else that comes with treatment; Sham acupuncture explains why no sham is inert.
| Review | Condition | Trials (participants) | What it found |
|---|---|---|---|
| Yue and colleagues, 2024 | Obesity, sham-controlled trials only | 6 (679), all in China | 1.68 kg more weight lost than with sham, and 2.42 cm more off the waist; adverse events no more frequent than with sham. |
| Guo and colleagues, 2015 | Obesity | 43 (3,520), all in China | 3.01 kg more weight lost than with sham (2 trials); against ordinary needling (30 trials), a better “improvement rate” but no significant difference in weight. The authors rated the trials’ methods poor. |
| Sheng and colleagues, 2019 | Abdominal obesity | 15 (1,584) | Embedding alone had effects similar to other kinds of acupuncture; added to electroacupuncture, 5.2 kg more weight lost than electroacupuncture alone. All trials were judged at high risk of bias. |
| Tang and colleagues, 2024 | Allergic rhinitis | 17 (1,231) | A higher “total effective rate”, a composite outcome common in Chinese trials, than controls including Western medicine; the authors ask for higher-quality trials. |
| Zhang and colleagues, 2020 | Functional dyspepsia (network meta-analysis) | 35 (3,301) | Embedding was one of five methods ahead of prokinetic drugs and sham acupuncture on symptoms; manual acupuncture ranked first overall. |
The sham-controlled obesity trials
Three trials give a sense of the size of the effect against sham. Chen’s 2022 trial in China randomised 216 middle-aged adults to 8 sessions of catgut embedding or sham over 16 weeks. Waist circumference fell by 8.80% against 4.09% with sham, and body weight by 4.17 kg against 1.85 kg; the difference in waist was still 4.94% after 24 weeks of follow-up. Women benefited significantly and men did not. In a 2018 double-blind trial in Taiwan, Chen and colleagues treated 90 women with abdominal obesity once a week for 6 weeks; they lost 1.65 kg against 0.38 kg with sham. In a 2014 trial in Mexico, Garcia-Vivas and colleagues divided 99 obese women among six groups, about 16 in each; catgut embedding combined with moxibustion was the only treatment that reduced body weight significantly against sham, by 3.1 kg. AcuiQ’s obesity and overweight pages list the protocols individual studies prescribed, each with its citation.
Adverse events
A 2021 systematic review by Huang and colleagues of 61 studies from China and South Korea found an adverse event rate of 11.1%: local reactions in 9.8% (480 of 4,882) and systemic reactions in 1.3%. The most common were induration, a firm lump around the thread, bleeding and bruising, redness and swelling, fever and pain. Five severe events were reported between 2013 and 2017, all with catgut. Hong’s 2026 review of 90 trials put the rate with embedding alone at 3%, with one serious event among 1,697 participants. Adverse events occurred in 7% of patients given catgut and 2% of those given synthetic thread, nodules or induration in 3.6% and 0.5%, and allergic reactions and infections only with catgut.
Case reports describe three kinds of complication:
- Nodules: Chuang and colleagues in Taiwan reported multiple tender lumps under the skin where catgut had been embedded for obesity, appearing a month after treatment.
- Foreign body granuloma, a chronic inflammatory reaction around material the body cannot clear: Xu’s 2026 review collected 11 published complications, 10 of them granulomas, 6 after catgut.
- Infection by mycobacteria other than those that cause tuberculosis: Zhang and colleagues reported a Mycobacterium avium infection after embedding, treated without recurrence over 22 months; Jiang and colleagues described an outbreak of Mycobacterium abscessus skin infection with draining nodules on the abdomen after catgut implants at a cosmetic clinic; and Xing and colleagues reported three cases after embedding for weight loss at one informal beauty institution.
Infection and clean needles covers sterile technique and the infections reported after acupuncture, and After a treatment lists the signs of a skin infection that call for a doctor.
How AcuiQ records it
Each protocol on AcuiQ records how the points were treated, from a fixed list of modalities, and an embedding study is recorded as “Thread embedding”. Its sessions and course length are recorded in the same entry, so a course of 8 embeddings over 16 weeks reads differently from 8 needling sessions over 2 weeks. Reading a protocol explains each field. The entry lists the points; the thread material and length are in the cited paper.
What the sources cannot settle
Wang’s 2025 review states that there are no standard rules for which points to use, how deep to embed or how often to repeat. The trials are almost all from China, most use catgut, and the reviews rate their methods poor, so the pooled weight differences against sham, between 1.7 and 3 kg, rest on a small number of trials. The reviews report results at the end of treatment or soon after; Chen’s trial, with 24 weeks of follow-up, is the longest above. Hong’s review compared catgut and synthetic thread for adverse events, not for effect. Where the trials come from discusses the share of positive results in trials by country.