Ho'oponopono Research: What the Studies Actually Show

Ho'oponopono research is small and early: one uncontrolled blood-pressure study, one 2008 forgiveness dissertation and a 2026 trial with no results yet. The blood-pressure study had 23 participants, the dissertation had 79, and the trial is registered but unpublished. The early findings are encouraging but preliminary. None of them proves that Ho'oponopono changes outer circumstances, and none of them is large or independent enough to settle the question.

If you are skeptical, that is a reasonable place to start. This page lays out what has actually been studied, what each study can and cannot tell you, and how to test the practice for yourself without taking anyone's word for it.

The short answer

• Studied, with small preliminary results: reductions in blood pressure after a Self-Identity Through Ho'oponopono (SITH) class, and reductions in self-reported unforgiveness after a Ho'oponopono process.
• Completed, no results posted yet: a randomized trial in Türkiye on adjustment and quality of life in people living with an ostomy.
• Not studied at all: money, manifestation, "attracting" outcomes, healing other people at a distance, or the famous Hawaii State Hospital story.
• Bottom line: Ho'oponopono is a reflective forgiveness practice with a small, early research base. It is not a medical treatment and should never replace care from a doctor or mental health professional.

Study 1: SITH and blood pressure (Kretzer and colleagues)

The most frequently cited study is "Self Identity through Ho'oponopono as Adjunctive Therapy for Hypertension Management," by Kikikipa Kretzer and colleagues, published in the journal Ethnicity & Disease (volume 17).

What they did. Twenty-three Asian, Native Hawaiian and other Pacific Islander adults from a community in Hawaii took a half-day class in Self-Identity Through Ho'oponopono. The class taught participants to look at stress through their own self-identity and introduced processes of repentance, forgiveness and transmutation. The researchers measured blood pressure before and after.

What they found. Average systolic blood pressure dropped by about 11.9 mmHg and diastolic by about 5.4 mmHg, and participants' spirituality scores rose. The authors described the result as statistically and clinically significant and suggested SITH may be useful as an adjunctive (add-on) therapy.

What it cannot tell you. There was no control group. Without one, you cannot separate the effect of the practice from other explanations: people who sign up for a class may already be motivated to change their habits, blood pressure readings naturally drift toward the average over time, and simply expecting to feel better can lower readings. The authors themselves called the results preliminary and said further research was needed.

This line of work began with Kretzer's 2005 doctoral dissertation at the University of Hawai'i at Mānoa, and a later report in Holistic Nursing Practice (2013) reviewed lessons from this research on stress and blood pressure in women. Even taken together, it is a small and early body of evidence.

If you want to understand the method these participants learned, see Self-Identity Through Ho'oponopono (SITH) explained and how traditional Ho'oponopono differs from SITH.

Study 2: Ho'oponopono and unforgiveness (James, 2008)

The second study is a Ph.D. dissertation in psychology completed by Matthew B. James at Walden University in 2008, titled "Ho'oponopono: Assessing the effects of a traditional Hawaiian forgiveness technique on unforgiveness."

What they did. Seventy-nine participants were split into a group that went through a Ho'oponopono process and a control group that did not. Unforgiveness was measured with an established questionnaire, the Transgression-Related Interpersonal Motivations Inventory (TRIM), which asks how much a person still wants to avoid or get back at someone who hurt them.

What they found. The Ho'oponopono group showed a statistically significant drop in unforgiveness. The control group showed no significant change.

What it cannot tell you. This design is stronger than the blood-pressure study because it has a control group. But it is still one study, it is a dissertation rather than a paper in a peer-reviewed journal, and the outcome is self-reported. It also cannot tell you whether the four-phrase wording matters, or whether any structured forgiveness exercise of the same length would do as well. Forgiveness research in general suggests that deliberately working through a grievance can help people let go of it, so this result fits a broader pattern. It does not show that Ho'oponopono is uniquely powerful.

For the practical side of using it this way, see Ho'oponopono for forgiveness.

Study 3: A 2026 trial on ostomy adjustment (results pending)

A randomized study registered on ClinicalTrials.gov (NCT07521774) tested "The Effect of Ho'Oponopono Technique on Ostomy Adjustment, Body Image, and Quality of Life" in people with a colostomy. It is sponsored by the University of Health Sciences in Türkiye and run at a hospital in Istanbul, with 64 participants enrolled. The registry lists it as completed, but no results had been posted when this page was written.

This is worth watching because it has a randomized design. Until results are published, though, it tells you only that researchers think the question is worth asking, not what the answer is.

What has never been studied

Much of what you read about Ho'oponopono online goes far beyond this research. As far as we could find, no study has tested:

• Whether Ho'oponopono brings money, abundance or specific outcomes.
• Whether you can "clean" someone else's problem or heal another person at a distance.
• Claims about "rewiring the brain," "quantum" effects, or changing your DNA.
• The story of Dr. Ihaleakala Hew Len and the Hawaii State Hospital ward. That account comes from Hew Len and from people who repeated it. We looked at what can and cannot be verified in the Dr. Hew Len Hawaii State Hospital story.

If a page tells you science has proven any of these, ask which study. In most cases there isn't one.

So is it worth trying?

That depends on what you want from it. The honest summary of the evidence is: a short, repeatable forgiveness-and-responsibility practice that some small studies associate with less resentment and lower stress markers, and that costs nothing but a few minutes a day.

That is a modest claim, and modest claims are easy to test on yourself. For a fuller look at the skeptic's case, read does Ho'oponopono work? An honest answer, and for a simple daily routine, see how to practice Ho'oponopono daily.

A simple two-week self-test

You do not need a lab to run a fair personal experiment.

1. Pick one specific issue. A recurring irritation, a person you resent, or a worry that keeps replaying. Keep it specific. 2. Rate it before you start. On a scale of 0 to 10, how strong is the emotional charge when you think about it? Write the number down with the date. 3. Practice daily for 14 days. Five minutes a day, repeating the four phrases ("I'm sorry, please forgive me, thank you, I love you") while holding the issue in mind. 4. Rate it again every few days. Same question, same scale. Note anything you did differently. 5. Look at the trend, not one day. If the number falls and stays lower, the practice is doing something useful for you, whatever the mechanism. If nothing changes, you have learned that too.

This will not tell you why something changed, and it is not a scientific study. It is simply more reliable than guessing, and it keeps you in charge of your own conclusions.

Important note

Ho'oponopono is a reflective and spiritual practice, not a medical or psychological treatment. If you have high blood pressure, a mental health condition, or any other health concern, keep working with your doctor or a qualified professional. Use Ho'oponopono, if at all, alongside that care, never instead of it.

Frequently asked questions

Is there scientific proof that Ho'oponopono works? No. There is a small amount of preliminary research, mainly one uncontrolled study on blood pressure (23 participants) and one controlled dissertation study on forgiveness (79 participants). That is enough to call it promising for stress and resentment, not enough to call it proven.

What is the best-known Ho'oponopono study? The Kretzer and colleagues study in Ethnicity & Disease, which reported lower blood pressure after a half-day Self-Identity Through Ho'oponopono class. It had no control group, so the authors called the findings preliminary.

Has the Hawaii State Hospital story been verified by research? No. It has never been studied or independently documented. It is a story told by Dr. Hew Len and retold by others.

Can Ho'oponopono replace therapy or medication? No. None of the research supports that, and no responsible teacher should suggest it.

Are there new Ho'oponopono studies coming? Yes, at least one. A randomized trial in Türkiye on people with an ostomy (ClinicalTrials.gov NCT07521774) is listed as completed, with results not yet posted.

Try it the practical way

If you would rather test the practice than read about it, our free Ho'oponopono guide is a simple place to start your own two-week experiment.