THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
Angina is chest pain or tightness that appears when the heart muscle is not getting enough blood, most often during exertion and eases with rest.
Every one of the 5 human studies reviewed for angina, covering 369 participants between them, found red light therapy to be effective. The CURE Index scored angina 71 out of 100, indicating strong confidence.
Chest pain attacks tended to become less frequent after red light therapy, with patients also using less angina medication and managing more exercise before symptoms set in.
No randomized controlled trials appear in this set, which is made up of 2 clinical trials and 3 observational studies. All 5 reported effective outcomes.
Across the set, wavelengths ran from 633 to 1400 nm, with 632 nm recorded as the most cited. Sessions were given 2 to 618 times per week across 10 days.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTH
The wavelength appearing most often in studies that showed benefit for angina.
632 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across angina studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 633-1400 nm |
| Session Frequency | 2-618 per week |
| Therapy Duration | 10 days |
Note: We have excluded meta-analyses and reviews from scoring, but the list of human studies below contains them for your reference.
6 Human Studies on Red Light Therapy for Angina
Angina Relief Lasted 6 Months After a Single Laser Course
When researchers followed angina patients for 6 months after a single 10-day course of infrared laser treatment, a 1999 clinical trial tracked how long the benefit held. The light fell in the near-infrared band between 780 and 1400 nm and was aimed at the heart. 80% to 82% of patients appeared to gain relief from angina, though the effect only showed itself 1 month after treatment ended. By 6 months the benefit still held in 62.5% of them, and it was strongest in those whose blood supply to the heart was most reduced.
- Study Type
- Clinical Trial
- Treated Area
- Heart
- Wavelength(s)
- 780-1400 nm
- Therapy Duration
- 10 days
Study Title: [The clinical efficacy of a one-time course of infrared laser irradiation in stenocardia patients based on 6-month follow-up data].
87% of Angina Patients Improved With Infrared Laser Therapy
Published in 1992, this observational study tested infrared laser therapy in people with effort angina. 54 patients aged 30 to 75 received near-infrared light between 780 and 830 nm from a gallium arsenide laser directed over the heart. 47 of the 54 appeared to gain a clear benefit, needing fewer nitroglycerin tablets than before. Researchers reported that results from a supervised exercise test on a stationary bike, an ultrasound scan of the heart, and a heart tracing all moved in the same direction.
- Study Type
- Observational Study
- Participants
- 54
- Treated Area
- Heart
- Wavelength(s)
- 780-830 nm
- Study Scope
- Angina Pectoris, Effort Angina
Study Title: [Effects of laser therapy in patients with functional class II-IV effort angina (using instrumental techniques of the study)].
Angina Patients Reported Fewer Attacks After Laser Acupuncture
200 patients with angina received red light at 632.8 nm from a helium-neon (HeNe) laser applied to acupuncture points in a 1990 observational study. Researchers reported that attacks became less frequent and nitroglycerin use fell, while the amount of exercise patients could manage rose. An ultrasound scan of the heart, measures of blood flow and scores on an anxiety questionnaire all moved in a favourable direction.
- Study Type
- Observational Study
- Participants
- 200
- Treated Area
- Body
- Wavelength(s)
- 632.8 nm
Study Title: [Laser acupuncture in the complex treatment of stenocardia].
Blood Clotting Reduced With Laser Therapy in Unstable Angina
Whether adding helium-neon (HeNe) laser therapy to standard treatment could lower the risk of a heart attack in unstable angina was examined in a 1990 observational study. Red light at 632.8 nm was delivered both into a vein and onto specific zones of the skin, at 2 to 3 sessions a week for some patients and 4 to 5 internal plus 6 to 8 skin sessions for others, depending on their starting clotting-protein levels. According to the report, several markers of how readily the blood clots shifted towards normal, with a clot-forming protein falling and a natural blood-thinning protein returning to typical levels. A further clotting protein showed no meaningful change, which the researchers read as a sign that the effect did not run through the usual enzyme pathway.
- Study Type
- Observational Study
- Treated Area
- Head And Blood
- Wavelength(s)
- 632.8 nm
- Session Frequency
- 2-3, 4-5, 6-8 per week
Study Title: [Helium-neon laser therapy in the combined treatment of unstable stenocardia].
Unstable Angina Eased With Laser Light Delivered Into a Vein
Comparing 90 patients with unstable angina against a randomly selected reference group of 25, a 1989 clinical trial tested helium-neon (HeNe) laser light delivered into a vein. 618 treatment sessions were carried out in total, using red light at 632.8 nm, with attacks and daily nitroglycerin tablets counted and exercise capacity measured on a stationary bike. Set against the reference group, the treated patients showed a genuine reduction in angina, and the trial found their exercise capacity rose both in total work done and in how long they lasted. The heart's main pumping chambers also activated noticeably faster on a heart tracing.
- Study Type
- Clinical Trial
- Participants
- 115
- Treated Area
- Blood
- Wavelength(s)
- 632.8 nm
- Session Frequency
- 618 per week
- Study Scope
- Unstable Angina
Study Title: [Intravenous use of low-energy helium-neon laser irradiation in unstable angina].
Review Called Near-Infrared Light Promising but Untested for Stable Angina
In 2019, a review explored whether photobiomodulation (PBM) using far-red to near-infrared light between 600 and 1000 nm might help people with long-standing stable angina. The wavelengths discussed ranged from 630 to 830 nm at 10 to 100 mW/cm², applied to the chest wall over the heart in sessions of 2 to 10 minutes. The authors concluded that near-infrared light might protect the heart after a heart attack or where blood flow cannot be restored surgically, but framed this as an opportunity still to be tested rather than an established result. They described the approach as non-invasive, inexpensive and painless, with a low rate of side effects and serious events.
- Study Type
- Review
- Treated Area
- Chest/Heart
- Wavelength(s)
- 600-1000, 630-830, 665, 670 nm
- Session Duration
- 2-10 minutes
- Study Scope
- Chronic Stable Angina
Study Title: Cardio-light: nitric oxide uncaged.
The CURE Index (Clinical Understanding of Red-light Evidence) by Helio Cure is a 0-100 evidence score based on published human clinical trials. Higher scores mean stronger evidence. Read full methodology →
Data is powered by AI and reviewed by the Helio Cure team.
This page is for educational purposes only. Not medical advice. Consult a healthcare provider before starting red light therapy. Helio Cure does not diagnose, treat, or cure any medical condition.
Last updated: Aug 26, 2026