Written by Helen Seers, Edzard Ernst and the CAM-Cancer Consortium.
Updated June 10, 2017


Does it work?

Systematic reviews

No systematic review specifically looking at Reiki and cancer exists. The included reviews look at Reiki across all diseases, or a more general term for Reiki known as “energy healing”.

Lee et al. (2008)  published a systematic review of 9 RCTs of Reiki as a treatment for any condition including cancer for which trial data were available (results were not separated by condition) 8.  Overall results suggested that there was insufficient evidence that Reiki is effective for depression, pain, anxiety, stress and helplessness. Most of these studies had serious methodological limitations.

Another systematic review (2011) of various types of energy healing specifically for cancer included 6 quantitative and two qualitative studies and arrived at very similar conclusions: “The existing research does not allow conclusions regarding the efficacy or effectiveness of energy healing” 9.

A recent, (2014) non-systematic review which calculated the overall effect of Reiki for pain and anxiety for all health conditions, including cancer, found four randomised controlled trials where Reiki may be beneficial in reducing pain and anxiety 10.  However, this review concluded that more high quality research with larger sample sizes, standardised treatment protocols and consistent randomisation are needed.  This review was also not specific to cancer and included non-cancer trials in its overall conclusion.

Clinical trials

Since the publication of these reviews a further four controlled trials in cancer patients have become available.

An RCT randomised 189 cancer patients receiving chemotherapy in three groups: standard care, placebo-Reiki or Reiki 11.  The main outcome measures were self-reported comfort and wellbeing. The analyses showed that both Reiki and placebo-Reiki were superior to standard care. This seems to suggest that Reiki is associated with sizable placebo effects but has no specific effects.

Alarcao and Fonseca (2016) presented a RCT of the effects of Reiki on quality of life for patients with blood cancer 12. Fifty-eight people were randomly assigned to Reiki and 58 to sham Reiki (control), the interventions were two one-hour sessions per week for 4 weeks.  The methodology of the trial is stated as double-blind, however, no specific details on how the blinding occurred for those giving the Reiki, or receiving it, are given; also the success of blinding is not reported.  Results showed a significant benefit of the Reiki group for general, physical, environmental and social aspects of the WHOQoL Brief measure.  It must be noted that a large number of the control group (n=16) died before the trial was completed, however this attrition occurred after randomisation, and those that died had the worst prognosis – those with the worse prognosis were equally represented in the experimental arm.  Larger sample size testing would be needed to improve the reliability of this trial.

Orsak et al. (2015) conducted a pilot RCT (n=36) on breast cancer patients who received either Reiki, a companion, or usual care during chemotherapy 13. Measures of quality of life (FACT B – Functional Assessment of Cancer Therapy: Breast Cancer version) and mood (Profile of Mood States) were found to be better than usual care in the Reiki and companion groups.  This study would have benefitted from an additional sham Reiki condition, also, an increased sample size and blinding participants to their intervention groups would have been desirable.

Demir et al. (2015) reported a pilot CCT (n=18) of the effects of distant Reiki on pain, anxiety and fatigue in patients with cancer compared to a control group of usual care 14. Significant reductions in measures of pain, anxiety and fatigue (generated by a VAS numerical rating) were found for the Reiki group, however, the two groups were not comprised of similar sexes of participants and the number of participants was very small.


Helen Seers, Edzard Ernst, CAM-Cancer Consortium. Reiki [online document]. http://cam-cancer.org/The-Summaries/Mind-body-interventions/Reiki. June 10, 2017.

Document history

Summary fully updated and revised in June 2017 by Helen Seers
Summary fully updated and revised in March 2015 by Helen Seers.
Summary fully updated and revised in March 2013 by Edzard Ernst.
Summary first published in July 2011, authored by Edzard Ernst.


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