Red light therapy for weight loss: does it work?

Red light therapy for weight loss is often marketed as an easy way to reduce body fat or contour your body’s shape. The idea behind this noninvasive treatment, also called low-level laser therapy (LLLT), is straightforward: specific wavelengths of red and near-infrared light are applied to targeted areas of the body with the goal of shrinking fat cells beneath the skin. 

But does red light therapy actually work for weight loss? It might have modest effects, but current evidence doesn’t support it as a first-line approach.

While a handful of small studies suggest potential benefits, red light therapy — like other trending weight loss approaches such as vibration plates or somatic exercises — has not been shown to produce  meaningful fat loss or weight loss on its own.

In practical terms, targeting fat cells with low-level laser light may lead to small reductions in certain measurements, such as waist or thigh circumference. But it’s no substitute for nutrition and physical activity. Plus, modest changes in measurements may not translate to meaningful weight loss.

Below, we break down what researchers think about how red light therapy for weight loss may work, what timelines studies suggest, and how red light therapy is used for fat loss.

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Red light therapy for weight loss is thought to work byusing low-level red or near-infrared light to create temporary pores in fat cell membranes, allowing stored fat to be released and  cells to shrink. 

Early research suggests that consistent red light therapy may reduce waist circumference, improve appearance of cellulite, and decrease inflammation. But it’s important to understand that most studies on red light therapy for weight loss so far have been small, short-term, and limited in scope.

“You should always use diet and exercise as a first line of treatment, but I don’t hate [red light therapy] as an adjunct for patients who understand the limitations,” says Supriya Rao, MD, a quadruple board-certified physician in internal medicine, gastroenterology, obesity medicine, and lifestyle medicine. 

Here are some ways red light therapy may contribute to weight loss.

It may increase fat loss

This is the most direct way red light therapy might work for weight loss. Exposing fatty tissue to LLLT  may “temporarily change how fat cells store and release energy,” Dr. Rao says.

Specifically, red light seems to stimulate fat cells to release stored triglycerides, allowing fat to be released from cells, which may then be metabolized depending on overall energy balance.

Studies back up the effects of red light therapy on numerous body measurements: 

• In one small study, participants experienced an average combined reduction of 3.5 inches across waist, hip, and thigh measurements after six red light therapy sessions over two weeks.

• In another small study, participants saw an average reduction of about  2 inches  in waist circumference after 12 red light therapy treatments over six weeks.

• A separate short-term study found an average reduction of about  1.5 inches in upper-arm circumference after two weeks of red light therapy. In this study, people received three treatments per week.  

These studies were small, short-term, and did not include long-term follow-up. So, it’s unclear whether these measurement changes were maintained over time.

It may reduce inflammation

Red light therapy may indirectly support weight management by reducing discomfort that can interfere with regular physical activity.

Red light therapy is commonly used to help manage pain, support muscle recovery, and reduce inflammation. And if joint pain or muscle soreness makes it harder to stay active, Dr. Rao notes that red light therapy may help some people exercise for weight loss more consistently. 

It may improve mitochondrial function

Red light therapy has been shown to stimulate mitochondria, the so-called “powerhouse of the cell.” Supporting mitochondrial function helps everything from muscle function to metabolism.

In animal research, obesity has been shown to cause mitochondrial dysregulation. Meaning, obesity interferes with the mitochondria’s efficiency at supplying the body with energy — including energy to burn fat. In theory, improving mitochondrial function could support your metabolism, though this has not been shown to result in meaningful weight loss in humans.

It may improve blood flow

Some research suggests that red light therapy may increase local blood flow. Healthy blood circulation does not directly cause weight loss. Research in mice has found that increased blood flow can influence fat metabolism. But it’s unclear whether this translates to meaningful fat loss in humans.

Bottom line: This potential benefit of red light therapy for weight loss is largely theoretical. More research is needed to know if red light therapy boosts circulation enough to increase fat-burning activity in humans. 

There’s no established timeline for how long red light therapy may take to affect body measurements or fat distribution. But some research suggests optimal results can be seen at six weeks. Unfortunately, the  handful of studies on this potential weight loss therapy did not include frequent check-ins or long-term follow-up. follow-up. 

Based on existing data, when you might expect to see measurement changes:

• Week 1: Odds are you won’t see anything just yet. Dr. Rao says that, in general, there is no evidence of noticeable measurement changes in the first week of red light therapy for weight loss.

• Week 2:Some people  may notice a slight reduction in waist, hip, thigh, or upper arm circumference after two weeks of consistent treatment. 

• Week 3–6: Body measurements usually continue to show a modest decrease if treatment is continued consistently. Some studies suggest maximum changes in body measurements may be observed at six weeks.

• Weeks 7+: There is not much data on how much weight loss or fat loss can be expected after six weeks of red light therapy. 

These timeframes are based on limited study data and may not reflect individual outcomes.

Several factors can influence your weight loss results with red light therapy. These include:

• Consistency. In most studies on red light therapy for weight loss, participants completed two or three sessions per week.

• Lifestyle. Dr. Rao emphasizes that lifestyle factors like diet and exercise have a much bigger impact on weight loss than red light therapy. Red light therapy should be considered an adjunct to lifestyle changes not as a substitute.

• Underlying conditions. Medical conditions, such as polycystic ovary syndrome (PCOS), hypothyroidism, and Cushing’s syndrome can make it harder to lose weight  or reduce your waist circumference even if you’re consistent with your diet and red light therapy. . 

Red light therapy is generally considered safe when used appropriately, according to the American Academy of Dermatology. However, long-term data for weight loss use are limited.

Risks

The main risks of red light therapy for weight loss are:

• Contraindications. Because LLLT stimulates cellular activity, some researchers advise caution for people with certain medical histories, including cancer or epilepsy. It may also be unsafe to use on the abdomen during pregnancy. Speak with your healthcare provider for individualized recommendations. 

• Risk of misuse. Red light therapy is typically considered gentle, but if used for too long or at a high setting, it can burn the skin or impact the eye’s retina.

• Potential long-term safety risk. Because this is an emerging therapy for weight loss, long-term side effects or risks are not known.

Downsides

• Cost. Red light therapy for weight loss can be expensive, especially for something with limited evidence of actually resulting in weight loss. At-home devices can cost hundreds. In-office treatment costs vary by clinic and geographic area, but since multiple sessions are required, the cost can add up to thousands.

• Time. The limited research on red light therapy for weight loss suggests that you’ll need twice-weekly treatments to see the best results. This can be an inconvenient commitment, and for many people, that time may be better spent on exercise or meal prep.

• May not work for everyone. Remember, research on red light therapy for weight loss is still minimal. Studies on the weight loss benefits have not compared how well it works for people of different sexes, ages, or with different health conditions. It’s too early to know if its fat-reducing effects work for everyone.

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If you’re considering red light therapy as part of a weight management plan,always follow the guidance on the device and from your healthcare provider. A red light panel for weight loss may be set up differently from a red light therapy belt for weight loss, so take a minute to read the instructions.

Some tips for safe and studied use of red light therapy for weight loss:

• Protect your eyes. Exposure to red light can harm your eyes. Wear the goggles provided with the device.

• Stay consistent. In a study on red light therapy for weight loss, participants achieved results after several weeks of twice-weekly sessions. Try not to skip sessions. Get personalized advice from your provider before using it more often than that.

• Don’t overdo it. You don’t need to wear a red light therapy belt all day. Session timing varies by device (again, read the instructions). In-office treatments are usually 20-30 minutes per session, which is consistent with research on red light therapy for weight loss.

• Pay attention to distance. Positioning varies by product, but most red light devices are not meant to come into direct contact with your skin. The general recommendation is to keep the light-emitting diodes about 8 inches from your skin, but you should always follow specific instructions from the manufacturer. 

How to choose a red light therapy device for weight loss 

There are a lot of red light therapy devices and services out there. 

“At home devices can be convenient and lower cost, while in clinic treatments may offer higher-powered equipment,” Dr. Rao says.

If you’re choosing a device for at-home use, follow these tips:

• Look for science-backed settings. Most research on red light therapy for weight loss used red or near-infrared light in the 630-880 nanometer range, Dr. Rao says.

• Confirm FDA clearance. Devices labeled as “FDA cleared” or “FDA 510k cleared” have been reviewed for safety by the US Food and Drug Administration (FDA), but not for effectiveness for weight loss.

• Get a professional’s opinion. Consult your healthcare provider before buying any device claiming to cause weight loss. They can advise you on an overall weight loss strategy — and may be able to recommend safe, high-quality red light therapy devices if you would like to include red light therapy as part of your routine.

On its own, red light therapy is unlikely to lead to significant or sustained weight loss.

There are several more time-tested strategies worth considering for weight loss, including:

• Regular exercise. Aerobic activities like running and swimming burn calories. Strength training helps build muscle, which also increases calorie burn while improving body composition. 

• Eat for a safe calorie deficit. Consuming fewer calories than you burn is still the gold standard for weight loss. Using a calorie calculator or speaking with a nutritionist can help you identify a safe deficit that supports progress without compromising overall health. Remember to prioritize whole, nutrient-dense foods to keep your body nourished while cutting calories.

• Get enough sleep. Quality rest is linked to healthy weight and fat loss. Inadequate sleep can lead to cravings for high-calorie foods and sabotage your diet. Aim for the standard 7–9 hours of quality shut-eye each night.

• Weight loss medication. In some cases, prescription weight loss medications such as Wegovy or Zepbound may be recommended alongside diet and exercise. Talk to a healthcare provider, such as through Ro, about whether medical weight loss medications may be right for you, especially when lifestyle changes don’t seem to be moving the needle enough. 

Using a combination of science-backed weight loss strategies can help you get much closer to your weight loss goals — and certainly reach them faster than relying on red light therapy alone. 

Does red light therapy work for weight loss? Early studies suggest the tactic may cause small, short-term changes in body measurements, such as waist circumference. But evidence does not support it as a primary weight-loss strategy. “Anything that promises effortless fat loss is usually overselling the benefits,” Dr. Rao says.

Let’s recap.

• Research suggests modest changes. A handful of studies suggest that red light therapy may support body contouring (and possibly weight loss) by shrinking fat cells, reducing inflammation, improving mitochondrial function, and stimulating blood flow.

• Red light therapy is not a shortcut. There is no evidence that red light therapy alone can cause meaningful weight loss or sustained, significant fat loss. It’s recommended as an adjunct (if at all) to lifestyle modifications. 

• It can be a low-risk add-on. Red light therapy is considered generally safe when used as directed.

• It can support, not replace, standard weight loss methods. Exercise, a balanced diet, and addressing underlying metabolic conditions should come first. Reliable, sustained weight loss comes from core healthy habits, Dr. Rao says.