The ABC of Red Light Therapy: What You Need to Know

A couple of years ago, only hard-core followers of the longevity movement were aware of red light therapy (RLT), a method that uses low-level wavelengths of light to penetrate the skin, which aims to deliver certain health benefits.

Now, RLT has gone full mainstream. From being used by your favorite influencer to boost the skin glow to athletes all around the world adding it to their recovery routines, the popularity of this type of photobiomodulation has fully boomed.

As a doctor that works with patient information, I stumble upon health fads on a daily basis. Naturally, I was incredibly curious to see if red light therapy is one of them.

In this article, I review currently available evidence on red light therapy and tell you everything you need to know about RLT — if you’re keen to find out what science has to say about the effects and types of this innovative method, bear with me.

What is red light therapy?

Red light therapy (RLT) is a type of light therapy, a non-invasive treatment that uses certain light wavelengths to penetrate into your tissues, aiming to alter the process of how your cells work in order to potentially deliver benefits to your health. This includes potentially improving the appearance of the skin or helping relieve pain in certain conditions.

As red light therapy employs low-level light wavelengths, it may be called low-level laser therapy, or LLLT. Some sources also call it:

• Low-power laser therapy (LPLT)
• Soft laser therapy
• Cold laser therapy

High-intensity laser therapy (HILT) is a whole different method that delivers more focused and intense light energy, however, the rest of this article will focus on low-level laser therapy.

If you still don’t feel intrigued by the fact that NASA had something to do with RLT, your skepticism is completely understandable — it might seem hard to believe that something as simple as artificial light may have actual health effects.

In the following section, we’ll review the scientific basis of red light therapy and explain how it works.

How does red light therapy work?

Red light therapy, or RLT, exposes cells and tissues to low-level light — in particular, red and near-infrared light (NIR light). While you can see red light with the naked eye, humans cannot see NIR light.

As this light penetrates, it aims to stimulate certain biological processes in your body. Research suggests that red light therapy may:

• Increase the production of ATP, the ‘energy molecule,’ in the cell's mitochondria (remember ‘the powerhouse of the cell’ you’ve learned about in school? That’s the one)
• Stimulate production of the substances that play a role in tissue repair and renewal
• Have a potential effect on how the cells grow and divide
• Help lower the levels of oxidative stress, which may subsequently lower cell damage

These effects may potentially lead to changes that we observe as health effects.

Potential benefits of red light therapy

Due to these effects that red light therapy might have on the cells and tissues, it’s been suggested to potentially have numerous health benefits.

However, we must mention that most of these potential uses of red light therapy are suggested by limited evidence, therefore, currently, it shouldn’t be used as a sole method for managing any ailments. If you have any health problems, see your healthcare provider first.

As it’s a relatively new method, research is still ongoing — hopefully, we’ll get to know more about the effects of RLT in the near future.

Improved skin appearance

I think it’s safe to say that we currently know the most about the effects of red light therapy on skin health and appearance.

In fact, even though RLT is not (yet?) officially recommended by official health bodies for the treatment of any skin conditions and diseases, the potential results delivered by this method have been acknowledged by the American Academy of Dermatology Association (AAD).

Emerging evidence suggests that red light therapy may potentially help with managing:

• Signs of aging
• Dark spots and symptoms of melasma
• Acne lesions (when combined with blue light, another type of light therapy)
• Discoloration-like redness
• Skin roughness

Studies have concluded that red light therapy might have a positive impact on elastin, hyaluronic acid, and collagen production, all of which are crucial in improving skin elasticity and the process of skin rejuvenation.

Accelerated wound healing

Emerging evidence suggests that red light therapy could have a positive impact not only on the appearance of the skin, but its potential anti-inflammatory effects may also aid in accelerating the wound healing mechanism (that’s why those NASA scientists' hands seemed to heal faster!).

Knowing that some people with poorly controlled diabetes struggle with wound healing (which is partly caused by poor blood circulation or blood flow), researchers have looked into whether red light therapy could aid in managing diabetic wounds — surprisingly, their study, published in Cell Biochemistry & Function, has revealed promising results.

Hopefully, we'll get to know more about the effects of LED light therapy and its potential applications in clinical practice soon enough.

Boosted hair growth

Red light therapy shows promise in supporting the treatment of hereditary hair loss, or androgenetic alopecia, also known as male/female pattern hair loss. This is the most common cause of hair thinning.

Multiple studies have demonstrated that red light therapy may help improve hair density and count, potentially leading to some regrowth. Though it’s still unclear why, it’s been proposed to act by helping hair follicles re-enter the growth phase in the hair growth cycle.

However, remember that hair loss might have other reasons besides androgenetic alopecia, meaning if you experience hair thinning, you should see a healthcare provider who’ll make an adequate diagnosis and prescribe treatment first.

If they conclude that the cause behind hair thinning is male/female pattern hair loss, consult them if RLT could be used as an adjunct method.

Pain relief

Limited evidence shows that red light therapy might help manage musculoskeletal (muscle and joint) pain while potentially reducing inflammation and aiding in tissue healing.

It’s been demonstrated that RLT may potentially help manage chronic pain caused by rheumatoid arthritis and non-specific lower back pain. Past studies have shown that incorporating light therapy with a special exercise program may lead to the reduction of pain intensity in people with knee osteoarthritis.

An article published in Current Orthopaedic Practice has also suggested that red light therapy could be a potential adjunctive in managing ligament sprains, tendinitis, plantar fasciitis, and mild carpal tunnel syndrome.

Just like with other potential uses of RLT, it shouldn’t be used as the only line of treatment. If you experience any type of pain, seek diagnosis and adequate treatment recommendations from a healthcare professional first and consult whether red light therapy could be used as an additional method.

Other potential benefits

Growing evidence suggests that red light therapy may also aid in managing other concerns and have other uses, for example, potentially helping improve muscle recovery after exercise.

Researchers are also looking into whether red light therapy could have an use in:

• Helping manage depression
• Aiding in the treatment of cold sores caused by herpes simplex virus
• Addressing neurodegenerative disorders, such as Alzheimer’s disease

In conclusion, it’s important to note that new evidence on red light therapy is actively emerging, and the research is still very limited.

Though this type of therapy is a non-invasive treatment, it doesn’t mean it’s guaranteed to be safe. Potential benefits as well as risks of red light therapy are still not completely clear.

Types of red light therapy devices

There are various types of red light therapy products on the market which are designed for different uses:

• Large panels, saunas, pods, and beds are intended to deliver red light to extensive areas or the whole body
• Smaller panels are convenient if you need to target a certain area or prefer a portable option
• Handheld devices, such as wands, are small, portable units perfect for targeting specific smaller areas of the body
• Face masks and undereye patches are designed to target facial skin concerns
• Caps, hats, and combs are convenient to use for helping with hair growth
• Torso or knee belts can be comfortably worn wrapped around the area of concern

While larger devices have the benefit of covering a larger body area, they can be expensive. If you’re considering investing in a red light device, consider your individual needs first — whether you’re planning to use it for the face, full body, or a localized spot, such as your joints.

At-home vs. professional red light therapy

Professional red light therapy sessions are applied in clinics by dermatologists (skin doctors) for managing skin concerns, such as wrinkles or dark spots.

Typically, professionals use more powerful tools than those you can purchase for at-home use, and often, other lines of treatment are incorporated. Professional red light therapy may also be more customizable according to your individual needs.

At-home, over-the-counter red light therapy devices may be used alone or following a professional treatment, helping maintain consistency at the convenience of your own home.

However, a large number of devices designed for at-home use are not evaluated by authoritative bodies. Only a handful of them are FDA-cleared, meaning that the FDA has acknowledged that the device is substantially equivalent to another legally marketed device and, thus, is generally safe and effective.

Besides that, with hundreds of different red light therapy devices becoming available in the market, it remains unknown how their effectiveness compares to that of devices applied in clinical studies and used in clinics.

Is red light therapy safe?

Currently available scientific evidence shows that red light therapy is likely to be generally safe and is not associated with skin cancer. However, certain groups of people are recommended not to use red light therapy due to insufficient evidence about their safety or a high risk of side effects, including:

• Pregnant and lactating individuals
• People with cancer
• Those with health conditions that may cause photosensitivity or using drugs associated with increased photosensitivity

Photosensitivity is an increased sensitivity to light sources, including sunlight and red light. Certain skin conditions, such as rosacea, can make people more sensitive to light. Using some medications, such as antidepressants, hormonal contraceptives, or even ibuprofen, may also lead to a higher risk of adverse skin reactions.

As darker skin is more sensitive to light than light skin, the AAD also suggests being more cautious with red light for people with darker skin tones and emphasizes the importance of consulting a healthcare professional before trying out red light therapy at home.

The unknowns

As the evidence on the effects of red light is still limited, we only know about the safety of red light therapy in the short term. There’s no data on whether it’s safe to use in the long run. More research is needed.

Also, there's still no general consensus on whether red light can be harmful to the eyes or not. Therefore, it's important to make sure to avoid direct eye exposure and wear eye protection (protective goggles).

There have been some individual concerns about whether red light therapy is safe for those with low blood pressure (hypotension) and people with thyroid problems, which makes consulting your doctor before starting to use red light therapy applications crucial, even if you don't have any chronic health issues.

Red light therapy: the takeaway

It seems like red light therapy is here to stay. Though there are many unknowns (which includes its long-term safety), emerging evidence suggests that red light therapy shows promise in helping manage numerous ailments, such as hair thinning, wrinkles, or joint pain.

However, the fact that there’s still so much that scientists don’t know about the health effects of red light therapy makes it incredibly important to be extra cautious.

If you plan on giving red light therapy a go, remember to consult your healthcare provider first. They’ll help you decide if red light therapy is worth giving a shot for your individual needs and will evaluate whether it’s safe in your individual case.