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Does Red Light Therapy for Weight Loss Work?

Written by Dr. Michael Ruscio, DC on July 21, 2025

Written by Dr. Michael Ruscio, DC on July 21, 2025 — Reviewed by Hannah Wright

• Red Light Therapy for Weight Loss|
• Hormones and RLT|
• Risks|
• Other Weight Loss Methods|

Can you use red light therapy for weight loss instead of dieting? Although some research shows that red light therapy can help a little with body sculpting and weight loss, it’s not a magic fix. 

Red light therapy probably isn’t enough on its own for weight loss, but it may help when combined with a healthy diet and regular exercise. It might also support hormones and metabolism in ways that promote a healthier body weight, along with other possible health benefits.

However, using red light therapy for weight loss can be costly and time-consuming, and it lacks standardized protocols. Even if you invest in a few sessions, it’s unclear whether the effects will be long-lasting or clinically meaningful. 

Red Light Therapy for Weight Loss: How Does It Work?

Red light therapy (RLT) can be done in clinics using large devices—this is common in body contouring treatments. Smaller devices are also available for home use and are often marketed for issues like joint pain or skin aging. 

Commercial red light therapy devices usually use both red light (600–700 nm) and near-infrared light (700–1100 nm), even though the term “red light therapy” technically only refers to the visible red part of the spectrum.

During a session, light is aimed at or placed directly on the skin. Treatments can last anywhere from five minutes to over an hour, depending on the size of the body area, the goal, and the device used. Some weight loss companies claim you can see results after one session, but others recommend repeated treatments over weeks or even a year.

RLT devices can emit visible red light and invisible near-infrared light. These don’t feel warm because they don’t generate heat—that’s why RLT may also be called cold laser therapy. Although the exact mechanism isn’t fully understood, research shows that these wavelengths can penetrate the skin and stimulate production of ATP, the body’s main energy molecule 1.

Some studies also suggest that RLT may enhance fat loss, which explains its popularity in fat-reduction treatments 2. It’s frequently used in body sculpting to reduce fat and tighten skin.

RLT may also improve blood flow, which supports metabolism and helps the body clear waste 1. Certain wavelengths can also reduce oxidative stress (linked to aging and hormone imbalances that promote weight gain) and increase collagen and elastin—key proteins for healthy skin 1. 

Clinical research is still ongoing, but some studies have reported measurable effects. For example, in an older randomized controlled trial (gold-standard type of study), participants treated with 635 nm red light therapy lost an average of 3.5 inches across their waist, hips, and thighs—mainly at the hips and waist 3. Results were significantly better than placebo, but some of the inch loss faded after stopping treatment.

Newer clinical studies (not randomized or controlled) have found that red light therapy is associated with meaningful fat reduction and inch loss—up to 26% fat reduction in targeted areas after a single treatment 4, and nearly 3 inches lost across the waist, hips, and thighs after six sessions 5.

That said, many claims made by body sculpting companies are overblown and not well supported by science. There’s some evidence that some wavelengths of RLT can modestly reduce body measurements in the short term, but results across studies are inconsistent. It’s still unclear how long the effects last, how meaningful they are, and whether they can be reliably repeated. And the evidence doesn’t support using RLT to reduce cellulite 6.

In short, red light therapy might help support weight loss, but it shouldn’t be seen as a standalone solution. Significant and lasting results require healthy habits, too.

How RLT May Aid Your Weight Loss Efforts 

Red light therapy may work better for fat loss when combined with exercise. For example, in women with obesity, adding RLT (infrared range) to a 20-week exercise program led to nearly twice the fat loss (24.8 lbs vs. 12.8 kg), a greater drop in insulin resistance (38% vs. 21%), and a muscle gain of 1.3 lbs (compared to a loss of 3 lbs) in the placebo group—showing clear added benefit over exercise alone 2.

Red light therapy can improve muscle endurance and recovery, and reduce soreness—especially in sedentary individuals and athletes 7 8 9. This can further support exercise as a weight loss goal. 

If pain is getting in the way of exercise, red light therapy may help with that, too. It’s been shown to reduce musculoskeletal pain 10, with meta-analyses (studies of studies) showing that it can benefit conditions like:

• Low back pain 11
• Tendon pain 12
• Knee osteoarthritis 13
• Plantar fasciitis 14
• Fibromyalgia pain 15
• Chronic neck pain 16

Mental health challenges—like depression or low motivation—can make it harder to stick to healthy habits like exercise and eating a nutritious diet. Another meta-analysis suggests that RLT can help reduce depression 17.

It’s important to note that most of the studies above used near-infrared light—not red light specifically. Light therapy should not replace standard therapies or prescribed treatments—it’s best used alongside other proven strategies.

If you’re thinking about trying it, red light therapy for weight loss is best used as a supportive tool—for targeting specific areas of fat and for managing pain or mood issues that might be holding you back from losing weight.

Weight and Hormones: Where RLT Fits In

Red light therapy may also support weight loss by affecting key hormones. Not getting enough sleep—whether short-term or long-term—can lower leptin (which helps you feel full) and raise ghrelin (which makes you feel hungry). Red light therapy may help restore these hormones to healthier levels, which could make it easier to manage your appetite and stay full longer 18.

When used alongside exercise, RLT can improve levels of insulin and adiponectin—two hormones that play major roles in controlling blood sugar, reducing inflammation, managing appetite, and regulating body weight 2. These hormonal changes not only support weight loss, but they also contribute to better overall health.

Risks of Red Light Therapy for Weight Loss

In the short term, red light therapy appears to be safe. Some studies even suggest it’s safe to use on sensitive areas like the head (for brain-related conditions) and neck (for thyroid issues) 19 20. However, we still need more long-term studies to fully understand its safety. 

Most known side effects are minor and affect the skin. These can include:

• Skin irritation
• Redness
• Stinging
• Skin peeling
• Hyperpigmentation (darkening of the skin)

Red light therapy may help reduce fat, but scientists still don’t fully understand how or how well it works. It’s not dangerous, but its benefits may not last—some people may stop seeing results over time, or the body could adapt to the treatment.

If you’re considering trying red light therapy, the most important thing is to choose a device that’s FDA-approved. Cheaper options are now widely available, but many don’t meet safety or effectiveness standards. You need to make sure the device emits the right wavelength and intensity, especially since both home and clinic treatments can be expensive. 

You can probably expect to pay $75–$250 per session or $500–$2,500 for a course of red light therapy for weight loss at a clinic. At-home devices are available for a one-time cost of $200–$1,000+. These costs are out-of-pocket, as insurance does not cover cosmetic red light therapy.

Even with a good device, there’s still a lot of uncertainty around the best treatment settings (like how strong the light should be or how long to use it). Sessions can take as long as a workout, and doing them daily can be time-consuming.

In the end, my biggest concern with using red light therapy for weight loss is the lack of solid research. It may help, but it’s expensive, time-intensive, and not guaranteed to deliver the results you’re hoping for.

Natural and Proven Weight-Loss Methods

Though red light therapy shows some promise for weight loss, the research is still early and not yet conclusive. In contrast, several other approaches have been well studied and offer more reliable support for healthy, long-term weight loss.

Meal replacements

Eating fewer calories is important for weight loss, but it can be difficult to sustain. Meal replacements—such as shakes fortified with essential vitamins, minerals, and nutrients—may be more effective than standard calorie restriction, particularly when they make up at least 60% of total calorie intake 21.

Mediterranean Diet

The Mediterranean diet emphasizes whole, minimally processed foods—like vegetables, whole grains, legumes, healthy fats, and lean proteins—while minimizing red meat, processed foods, and added sugar. Lots of evidence has found that eating a Mediterranean diet is a sustainable way to help you lose weight and keep it off 22.

Paleo Diet

A Paleo diet focuses on whole, unprocessed foods and avoids common inflammatory triggers. High-quality research shows it can also help lower body weight, BMI, and waist size 23.

Ketogenic Diet

The ketogenic (keto) diet—a high-fat, very low-carbohydrate approach—can result in notable weight loss, but many find it challenging to stick with over the long term 24.

Intermittent Fasting

Intermittent fasting involves eating only during certain time windows or cycling between eating and fasting days. A meta-analysis showed it can lead to greater weight loss and more fat loss than calorie restriction or regular diets 25.

Exercise

Doing an extra 30 minutes of aerobic exercise (cardio) each week may help you lose modest amounts of weight while supporting your overall health. You need at least 2.5 hours a week to see real changes in fat loss and waist size, but your results may plateau after 5 hours of cardio per week 26. 

If you’re more of a weightlifter, combining cardio with your resistance training can reduce fat mass and body weight more effectively than weightlifting alone 27.

A Final Note on Red Light Therapy For Weight Loss 

Red light therapy—also called cold laser therapy—has some research supporting its potential to aid weight loss. It may also help with joint pain, mood, and hormone balance, all of which can affect your weight.

That said, the science on RLT is still developing, and many companies overstate its benefits. It’s best to use red light therapy as a supplement to proven methods—not a replacement.

Keep in mind that the long-term effects aren’t well understood, and the treatment can be costly. In most cases, sticking with proven strategies like healthy eating and regular exercise is likely a better use of your time and money.

Beginning a weight loss journey? We can help. Read our related blog posts: Probiotics for Weight Loss and The Best Red Light Therapy Devices—A Clinical Take.

At the Ruscio Institute for Functional Medicine, we can help you along your journey to better health. Feel free to reach out and we can answer your healthcare questions and concerns.

The Ruscio Institute has developed a range of high-quality formulations to help our clients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you. The information on DrRuscio.com is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.