About the research on this page. The studies cited here investigate photobiomodulation (PBM) as a therapeutic modality and the specific wavelengths used in PBM research — not Mito Red Light devices. The wavelengths in our panels were chosen because the peer-reviewed PBM literature supports them. Evidence levels and study counts reflect the broader research base, not studies of our products. See the full methodology note at the bottom of this page.

Red Light Therapy for Circulation & Cardiovascular Health: Clinical Evidence & Research

344 StudiesPhotobiomodulation (PBM) Source-linked

What the research shows

Our evidence rating: Moderate for breast cancer-related lymphedema; very low for blood pressureUpdated Reviewed by Alexis Cowan, PhD

For blood flow itself, the evidence is small. In healthy people, near-infrared light increased skin microcirculation by 27 to 54%, while red light did not, and only half of participants responded (Gavish 2020).

The strongest evidence on this page is for lymphedema after breast cancer, a problem of lymph rather than blood circulation, which is why it is included here. A 2026 meta-analysis of 9 randomized trials (312 participants) found reduced arm volume and circumference, better grip strength and less pain, with moderate certainty (Qian 2026). A 2023 analysis found better results with treatment three times a week, more than 15 sessions and treatment of the armpit area (Chiu 2023).

Other cardiovascular claims rest on thin evidence. For high blood pressure, a 2025 review of 4 trials found reductions in blood pressure and heart rate, but with very low certainty and high risk of bias (Bataglia Espósito 2025). In a randomized, triple-blind crossover trial of 22 healthy adults, light did not improve endothelial function compared with placebo (Hauck 2023).

Based on 344 indexed studies in this category, 97 of them in people. These studies test photobiomodulation in general, not Mito Red Light devices.

Evidence by condition

Number of studies in our database for each condition. Direction and certainty are shown only where a meta-analysis or systematic review reports them; otherwise the row says "not graded".

ConditionHuman randomized trialsAll human studiesDirection of resultsCertainty
Lymphedema 12 22 Less arm volume and circumference
Qian 2026 (PMID 41948502)
Moderate (GRADE)
Microcirculation 4 12 More skin blood flow with near-infrared; not with red
Gavish 2020 (PMID 32064652)
Not graded (no meta-analysis); see Gavish 2020
Arterial restenosis 4 10 Not graded Not graded
Hypertension 2 6 Possible blood pressure reduction
Bataglia Espósito 2025 (PMID 41095798)
Very low
Raynaud syndrome 3 5 Not graded Not graded
Heart failure 2 5 Not graded Not graded
Nitric oxide 3 3 Not graded Not graded

Key studies: Circulation & Cardiovascular Health

The strongest human evidence: systematic reviews and meta-analyses first, then the newest randomized trials. Each card comes straight from our study database and links to the paper.

Meta-analysis

Effects of photobiomodulation therapy on upper limb lymphedema secondary to breast cancer: a systematic review and meta-analysis

et al., Front Oncol, 2026. PMID 41948502

Key finding (checked against the abstract)9 randomized trials, 312 participants with breast cancer-related lymphedema. Smaller arm volume (SMD -0.78) and circumference (-3.6 cm), better grip strength and less pain. Mostly moderate certainty (GRADE).
Population
Breast cancer-related lymphedema: 9 RCTs, 312 participants
Meta-analysis

Effect of various photobiomodulation regimens on breast cancer-related lymphedema: A systematic review and meta-analysis

et al., Lasers Med Sci, 2023. PMID 38129368

Key finding (checked against the abstract)Breast cancer-related lymphedema. Better swelling outcomes with treatment three times a week at 1.5-2 J/cm², more than 15 sessions and treatment of the armpit.
Meta-analysis

Photobiomodulation Therapy in Hypertension Management-Evidence from a Systematic Review and Meta-Analysis

et al., J Clin Med, 2025. PMID 41095798

Key finding (checked against the abstract)4 randomized trials and 5 lab studies. Possible reductions in blood pressure and heart rate; very low certainty and high risk of bias.
RCT

Effects of photobiomodulation therapy (PBMT) over endothelial function in healthy individuals: a preliminary crossover clinical trial

et al., Lasers Med Sci, 2023. PMID 37072603

Key finding (checked against the abstract)Randomized, triple-blind crossover trial, 22 healthy adults. 30 J and 60 J doses did not improve endothelial function (flow-mediated dilation) versus placebo.
Population
Human: 22 participants; randomized trial, crossover; single session
Wavelength
810nm
RCT

Microcirculatory Response to Photobiomodulation-Why Some Respond and Others Do Not: A Randomized Controlled Study.

et al., Lasers Surg Med, 2020. PMID 32064652

Key finding (checked against the abstract)Randomized controlled study, 20 healthy adults. Near-infrared light raised microcirculatory flow 27%, rising to 54% at 20 minutes; red light did not. Half of participants did not respond.
Population
Human: 20 participants; comparison study, randomized; single session
Wavelength
633, 830 nm

Studies that found no effect

Not every trial is positive. "No effect" means the main outcome did not differ from sham or control. "Mixed" means some outcomes improved but the outcome named here did not differ.

Latest human studies: Circulation & Cardiovascular Health

The 25 most recent human studies in our database for this category.

YearStudyDesignPopulation
2026 Effectiveness of a novel low-level laser therapy protocol in managing breast cancer-related lymphedema. RCT, n = 46 Human: 46 participants
2026 Photobiomodulation in Treatment of Head and Neck Cancer-Related Chronic Lymphedema: A Pilot Randomized Controlled Trial RCT, n = 25 Human: Randomized trial; 25 participants
2026 Photobiomodulation combined with dynamic thermal imaging as a diagnostic tool for chronic leg ulcers Single-arm study, n = 20 Human: Single-arm study (2 subgroups); 20 participants (33 wounds)
2026 Effects of Acute Photobiomodulation on Heart Rate Variability in Physically Active Individuals: A Randomized and Controlled Clinical Trial RCT, n = 34 Human: 34 participants; randomized trial, sham-controlled, crossover; 1-week treatment (per condition) (15-day washout)
2025 Photobiomodulation Combined with Moderate or High-Intensity Interval Training on Oxygen Consumption and Exercise Tolerance in Patients with Heart Failure Human study, n = 49 Human: 49 participants; non-randomized trial, controlled; 10 weeks
2025 Effects of Capacitive and Resistive Energy Transfer Therapy (TECAR) and Low-Level Laser Therapy (LLLT) on Blood Pressure During the Musculoskeletal Treatment: A Preliminary Study Human study, n = 268 Human: 268 patients; observational study; 10 days
2025 Comparing the direct effect of lymphatic dynamic transport after lower-level laser therapy in healthy volunteers: a randomized controlled trial RCT, n = 32 Human: 32 participants; comparison study; single session
2024 Evaluation of Photobiomodulation on myocardial function of patients with advanced ischemic cardiomyopathy, A case series Case series Human: case series
2024 Photobiomodulation for Blood Pressure and Heart Rate Reduction in Mastectomized Women on Hormone Blockers: A Randomized Controlled Trial RCT, n = 27 Human: 27 participants; randomized trial; 4 weeks
2023 Morphological features of the photoplethysmographic signal: a new approach to characterize the microcirculatory response to photobiomodulation Human study Human: secondary analysis of Gavish 2020
2023 Investigation of the effect of Low-Level Laser Therapy on arm lymphedema in breast cancer patients: A noninvasive treatment for an intractable morbidity Single-arm study, n = 12 Human: 12 participants; single-arm trial; 4-week treatment -> 8-week break -> 4-week treatment
2023 Patient Experience of Photobiomodulation Therapy in Head and Neck Chronic Lymphedema Single-arm study, n = 12 Human: 12 participants; single-arm trial / survey
2023 Effects of photobiomodulation therapy (PBMT) over endothelial function in healthy individuals: a preliminary crossover clinical trial RCT, n = 22 Human: 22 participants; randomized trial, crossover; single session
2023 Effect of low-level laser physiotherapy on left ventricular function among patients with chronic systolic heart failure Single-arm study, n = 27 Human: 27 participants; single-arm trial; single session
2022 Successful use of stellate ganglion phototherapy in refractory ventricular tachycardia in a patient with cardiac sarcoidosis Human study Human: case report
2022 New evidence from hyperspectral imaging analysis on the effect of photobiomodulation therapy on normal skin oxygenation Human study, n = 11 Human: 11 participants; non-randomized study, self-controlled; single session
2022 Long-Term Effectiveness of Combined Intermittent Pneumatic Compression Plus Low-Level Laser Therapy in Patients with Postmastectomy Lymphedema: A Randomized Controlled Trial RCT, n = 42 Human: 42 participants; randomized trial, sham-controlled; 4-week treatment / 12-month follow-up
2021 Photobiomodulation Therapy in Head and Neck Cancer-Related Lymphedema: A Pilot Feasibility Study Single-arm study, n = 12 Human: 12 participants; single-arm trial; 6-week treatment -> 4-week follow-up
2021 Stellate Ganglion Phototherapy Using Low-Level Laser: A Novel Rescue Therapy for Patients With Refractory Ventricular Arrhythmias Single-arm study, n = 11 Human: 11 cases, 20 healthy controls; single-arm trial; 4-week treatment / 3-month study
2021 Effects of Low Level Laser Therapy (LLLT) on Serum Values of Interleukin 6 (IL-6) in Patients with Periodontitis and Type 2 Diabetes Mellitus (T2DM) Human study, n = 80 Human: 80 participants; non-randomized study, controlled; 5-day treatment / 3-month study
2021 Effect of 660/850 nm LED on the microcirculation of the foot: neurovascular biphasic reflex Single-arm study, n = 42 Human: 42 participants; single-arm trial; single session
2021 Effects of intravenous and transdermal photobiomodulation on the postoperative complications of coronary artery bypass grafting surgery: a randomized, controlled clinical trial RCT, n = 192 Human: 192 participants; randomized trial; 7 days
2021 Effects of nitrite and far-red light on coagulation Human study Human
2020 Kinesio taping and low-level laser therapy in breast cancer-related lymphedema in an arm with arteriovenous fistula for hemodialysis Human study Human: case report; 4-week treatment -> 3-month follow-up
2020 A Randomized Controlled Trial Comparing Platelet-Rich Plasma, Low-Level Laser Therapy, and Complex Decongestive Physiotherapy in Patients with Lower Limb Lymphedema. RCT, n = 49 Human: 49 participants; randomized trial; 12 weeks

Light parameters used in the trials

Wavelengths reported in our database for the 46 human randomized trials in this category (16 wavelength entries; many database records lack a wavelength, and some trials report more than one). This describes the research; it is not a dosing recommendation.

Wavelength bandTimes used in trials
Red (600-699 nm)7
Near-infrared (900-1200 nm)4
Near-infrared (800-899 nm)3
Blue/green (400-599 nm)1
Deep red/near-infrared (700-799 nm)1

Most common wavelengths: 900-909 nm, 660-669 nm, 630-639 nm, 650-659 nm, 830-839 nm.

What the evidence does not show

  • Better blood vessel function in healthy people: no difference from placebo in flow-mediated dilation (Hauck 2023, PMID 37072603).
  • Reliable blood pressure reduction: four trials with high risk of bias, very low certainty (Bataglia Espósito 2025, PMID 41095798).
  • A response in everyone: only 10 of 20 healthy participants showed a microcirculation response, and red light alone did not increase flow (Gavish 2020, PMID 32064652).

Frequently asked questions

Does red light therapy improve circulation?

In healthy people, near-infrared light increased skin microcirculation by 27 to 54%, but red light did not, and only half of participants responded (Gavish 2020).

Does it help lymphedema after breast cancer?

Yes, in 9 randomized trials it reduced arm volume and circumference and improved grip strength, with moderate certainty (Qian 2026).

Does it lower blood pressure?

Four small trials suggest it might, but the evidence is very low certainty (Bataglia Espósito 2025).

Browse All Circulation & Cardiovascular Health Studies

All 344 studies in this category from our study database, built on the PBM Research Database by Vladimir Heiskanen.

Search every study across all categories: Open the Full Evidence Explorer →

Methodology & important context

The published research indexed and referenced on this page studies photobiomodulation (PBM) as a therapeutic modality and the specific wavelengths used in those studies — not Mito Red Light devices specifically. The wavelengths used across our panels were chosen because the peer-reviewed PBM literature supports them: this is where published evidence is deepest, where dosing parameters have been characterized in human studies, and where clinical guidelines (such as WALT for inflammation and pain) exist. Mito Red Light has not funded or conducted registered clinical trials on our specific devices, and the study counts referenced here reflect the broader PBM research base — not studies of our products.

Where review authors graded certainty (for example with GRADE), we report their grade; other ratings are Mito’s summary. Study counts reflect peer-reviewed photobiomodulation research drawn from major scientific literature databases, peer-reviewed journals, and other published research repositories. PBM response varies meaningfully by person, tissue, condition, dose, wavelength, and session timing; outcomes reported in the published literature may not be replicable for every user. Mito Red Light devices are not intended to diagnose, treat, cure, or prevent any disease. If you have a medical condition or are under a physician’s care, please consult your healthcare provider before beginning any photobiomodulation regimen.