Suan Zao Ren Tang (Sour Jujube Decoction) for Sleep: Evidence
Suan Zao Ren Tang (Sour Jujube Decoction) is a five-herb classical formula used for insomnia in China; here is the sleep trial evidence, its limits, and the safety points.
Content last updated . This page has not been medically reviewed.
What it is
Suan Zao Ren Tang, translated as Sour Jujube Decoction (also Suanzaoren decoction or SZRD), is a classical Chinese formula widely prescribed for insomnia. A review describes it as made of five herbs: suanzaoren (sour jujube seed), fuling (poria), chuanxiong, zhimu (anemarrhena) and gancao (licorice). [1] It was documented in the Jin Gui Yao Lue (Synopsis of Prescriptions of the Golden Chamber) by Zhang Zhongjing at the end of the Han dynasty. [1] One recent non-randomized study gave a modified version to people whose insomnia was labeled with the traditional pattern "yin-deficiency and fire-excess"; patterns like this are traditional labels, not diagnoses. [2] For the herbs, see Jujube (Da Zao) in Chinese Medicine and Food and Poria (Fu Ling) in Chinese Medicine.This page is information only. It gives no doses and does not advise using the formula for sleep problems.
What research shows
| Question | What the source found | Strength of evidence |
|---|---|---|
| Chronic insomnia, 2013 review | 12 trials (1,376 adults). Many were reported as better than benzodiazepines, but quality was poor: no placebo control, little blinding, small samples. The authors concluded there was insufficient evidence of efficacy. [3] | Insufficient evidence |
| Chronic insomnia, 2022 review | 12 trials (1,311 people) found a higher clinical effective rate and lower sleep-quality scores (PSQI) alone or with Western medicine. The authors said study quality varied and better trials are needed. [4] | Promising but limited |
| Sleep disturbance during methadone treatment | A double-blind placebo-controlled trial of 90 people reported better sleep quality (PSQI) and sleep efficiency after four weeks. Adverse events such as lethargy, diarrhea and dizziness were mild. [5] | Promising but limited (one trial, one narrow group) |
| The seed alone (suanzaoren) | A review of 9 trials (N = 785 with insomnia) found short-term subjective sleep-quality improvements versus placebo, mixed long-term effects, and no increase in major adverse events; the authors called for a larger trial. [6] | Promising but limited (single herb, not the formula) |
| Double-blind trial against zolpidem and placebo | A registered 150-person trial protocol exists; I did not find its results. [7] | Proper evidence not found |
Studies of this kind are often unblinded, and sleep is highly open to expectation effects. Reviews pooling Chinese trials have a known risk of publication bias. A 2025 network analysis of 186 trials ranked several herbal prescriptions, including this seed, among top options for PSQI scores, but it pooled many different formulas. [8] Laboratory and animal data on the seed's chemistry are preclinical and do not show a benefit in people.
How it compares with standard insomnia care
CBT for insomnia (CBT-I) is described by NCCIH as the most strongly recommended treatment for insomnia, and it says the evidence for most other complementary approaches is inconsistent or too limited to draw conclusions. [9] The NHS says a GP may offer cognitive behavioural therapy and advises checking with a doctor before taking anything for sleep problems. [10] See CBT for Insomnia, Insomnia and TCM for Insomnia and Sleep.Related pages
Chinese Herbs and Mental Health Medicines covers interactions with antidepressants and similar medicines.Frequently asked questions
What is Suan Zao Ren Tang?
A classical five-herb formula, led by sour jujube seed, documented in the Jin Gui Yao Lue and widely prescribed for insomnia in China. [1]
Does it help insomnia?
Possibly in the short term, but evidence is limited: a 2013 review found it insufficient, and a 2022 review was more positive while calling for better trials. [3][4]
Is it better than sleeping pills?
Some trials reported that, but they were poor quality and mostly unblinded, so this cannot be relied on. [3]
Does the seed alone help?
A review found short-term subjective sleep improvements versus placebo, with mixed long-term results. [6]
What should I do about long-term insomnia?
See a doctor. CBT for insomnia is the most strongly recommended treatment. [9][10]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
- Licorice is in the formula. It can cause irregular heartbeat in large amounts or with long use, and interacts with corticosteroids. [11]
- Drowsiness. Trial adverse events included lethargy and dizziness. [5] Be careful with driving and with other sedating medicines, and ask a clinician or pharmacist. See How Interactions Work.
- Safety data are thin. In the 2013 review only 3 of 12 trials reported adverse events. [3]
- Pregnancy, breastfeeding and children. Check with a clinician. See Pregnancy and Breastfeeding.
- Persistent insomnia needs assessment. The NHS advises seeing a GP if insomnia has lasted for months or affects daily life. [10] The NHS also notes a GP may refer you to a sleep clinic if you have symptoms of another sleep disorder such as sleep apnoea. [10]
- Quality. Some Chinese herbal products have been contaminated or adulterated. [12]
References
- BMC Complement Altern Med 2013. Efficacy and safety of Suanzaoren decoction for primary insomnia: systematic review of RCTs (PMC3554563). Read 2026-10-22.
- Prog Neuropsychopharmacol Biol Psychiatry 2026. Modified suanzaoren decoction versus estazolam in chronic insomnia disorder. Read 2026-10-22.
- BMC Complement Altern Med 2013. Efficacy and safety of Suanzaoren decoction for primary insomnia: systematic review of RCTs. Read 2026-10-22.
- Eur Rev Med Pharmacol Sci 2022. Suanzaoren Decoction for the treatment of chronic insomnia: systematic review and meta-analysis. Read 2026-10-22.
- Evid Based Complement Alternat Med 2015. Suan Zao Ren Tang for sleep disturbance during methadone maintenance: randomized, double-blind, placebo-controlled trial. Read 2026-10-22.
- Integr Cancer Ther 2023. The Herbal Medicine Suanzaoren (Ziziphi Spinosae Semen) for Sleep Quality Improvements: systematic review and meta-analysis. Read 2026-10-22.
- BMJ Open 2017. Suanzaoren decoction for chronic insomnia disorder in adults: study protocol. Read 2026-10-22.
- Medicine (Baltimore) 2025. Chinese herbal medicine for insomnia: systematic review and network meta-analysis. Read 2026-10-22.
- NCCIH. Sleep Disorders and Complementary Health Approaches: Usefulness and Safety. Read 2026-10-22.
- NHS. Insomnia. Read 2026-10-22.
- NCCIH. Licorice Root. Read 2026-10-22.
- NCCIH. Traditional Chinese Medicine: What You Need To Know. Read 2026-10-22.