“Red light therapy helps you lose fat.”
Red light has not been shown to reduce body fat; short trials found smaller waists, but body fat percentage did not change where it was measured.
Red light sessions will not meaningfully lower your body fat. Any change seen in studies was in tape-measure inches, mostly when light was added to diet and exercise, so changes in eating and activity are still where real fat loss comes from.
Put the money you would spend on body-contouring light sessions toward an eating and activity plan you can keep up.
Safety note: Strong light, especially from lasers and other bright light devices, can injure the eyes. Eye damage has been reported with clinic light devices used without eye protection, so never look into the light and wear the eye protection that comes with the device.
Talk to a healthcare professional if: you want help losing weight or body fat, or you notice eye pain, blurred vision or other vision changes after using a light device.
Trials show drops in waist size and weight, mostly when light was added to diet or exercise, but body fat percentage did not change in the two trials that measured it. Confidence is limited because the trials are few, small and short, the key trial behind the FDA clearance was sponsored by the device maker, and the evidence is rated very low to moderate quality.
Red light has not been shown to reduce body fat; short trials found smaller waists, but body fat percentage did not change where it was measured. A 2025 review of 3 randomized trials with 160 people found waists shrank about 1 inch with laser treatment versus about a quarter inch in control groups. In a 2009 sham-controlled trial of 67 adults treated 6 times over 2 weeks, waists shrank about 1 inch, and 2 weeks after treatment ended, people had regained about a third of an inch across the treated areas. A 2025 review of 11 small trials found no difference in body fat percentage in the 2 trials, with 126 people, that measured it.
Waist size measured with a tape is not the same as fat loss. The same 2025 review of 11 trials found that adding light to diet or exercise programs took off a few extra pounds and about 3 more inches at the waist than diet or exercise alone in most trials; it rated the weight result low quality, with results that varied a lot between studies, and the waist result moderate quality. One green-light laser device is cleared by the FDA as a cosmetic treatment to reduce the measured size of the hips, waist and upper abdomen, based on a 4-week trial sponsored by its maker; that clearance is about tape-measure inches, not weight or fat loss.
- Mustafa GA, Alawi YF, Kasem MS, et al. Low-level laser therapy for reducing body circumferences: a systematic review. Lasers in Medical Science. 2025;40(1):534. DOI: 10.1007/s10103-025-04755-7. PMID: 41423522
- Sun W, Zhuang Z, Yang L, Zhou J, Zhang L, Yuan J. Effectiveness of photobiomodulation therapy in improving health indicators in obese patients: a systematic review and meta-analysis of RCTs. BMC Complementary Medicine and Therapies. 2025;25(1):133. DOI: 10.1186/s12906-025-04874-2. PMID: 40217252. PMCID: PMC11992763
- Jackson RF, Dedo DD, Roche GC, Turok DI, Maloney RJ. Low-level laser therapy as a non-invasive approach for body contouring: a randomized, controlled study. Lasers in Surgery and Medicine. 2009;41(10):799-809. DOI: 10.1002/lsm.20855. PMID: 20014253
- Roche GC, Shanks S, Jackson RF, Holsey LJ. Low-level laser therapy for reducing the hip, waist, and upper abdomen circumference of individuals with obesity. Photomedicine and Laser Surgery. 2017;35(3):142-149. DOI: 10.1089/pho.2016.4172. PMID: 27935737
- Al Muqarrab FJ, Alsuwaidan S, Al Muqarrab Z, Alajlan A. Is it possible for light-based hair removal home devices to induce ocular damage? Systematic review. Clinical, Cosmetic and Investigational Dermatology. 2023;16:3731-3742. DOI: 10.2147/CCID.S442963. PMID: 38152153. PMCID: PMC10752016