Two LED face masks side by side on a vanity, one glowing red and one glowing blue

Red light vs blue light therapy: which one does what

What is the difference between red light and blue light therapy?

They are studied for different things. Red light, often paired with near-infrared, has controlled trials for wrinkles, elasticity and collagen. Blue light is studied for acne, where a systematic review of randomized trials found significant improvements but asked for better studies. Red light has also been tested for acne, with no significant difference from conventional treatments.

Part of the Glow Protocol guide. Start here: The Glow Protocol

Five things worth knowing

Red is the wrinkle wavelength in the research. The skin-aging trials here used red and near-infrared light.
Blue is the acne wavelength in the research. The evidence is promising and not yet settled.
Red light has acne trials too. Pooled, they showed no significant difference from conventional treatments.
The biggest review of light for acne was cautious. It found few clear effects and asked for better-designed trials.
Acne is a medical condition. A light device is not a substitute for seeing a dermatologist.

Red vs blue, side by side

	Red light	Blue light
Wavelength in home masks	About 630–633 nm, often with near-infrared at 830–850 nm	415 nm in the CurrentBody Series 3, for example
Mainly studied for	Wrinkles, elasticity, roughness, collagen density	Acne
Evidence in this article	Controlled trials of 76 and 136 people	A systematic review of 8 randomized trials; a Cochrane review of light therapies for acne
How confident the research is	Trials found significant improvements against sham or control	Improvements reported; reviewers call for more detailed trials
Also tested for	Acne: no significant difference from conventional treatments across 13 trials	—

Illustration of a block of skin with a pore: a blue beam stays at the surface while a red beam passes down into the deeper layers — *Blue light acts near the surface; red light reaches deeper. Illustration, not to scale.*

Does blue light therapy work for acne?

Possibly, and the evidence is not settled. A 2021 systematic review included 8 randomized trials comparing blue light with another intervention and reported significant improvements in acne overall. Its authors still concluded that more detailed trials are needed. A Cochrane review of light therapies for acne found few clear effects and rated its evidence cautiously.

The 2021 systematic review (Diogo and colleagues). The reviewers screened 81 articles, read 50 in full and kept 8 randomized clinical trials. Those studies showed significant improvements in the overall picture of acne. The conclusion was measured: blue light has great potential, and more detailed trials on inflammatory acne are needed.

The Cochrane review (Barbaric and colleagues, abridged version 2018). This is the largest review here: 71 randomized trials and 4,211 participants, with a median trial size of 31. It used GRADE, a standard system for rating how certain evidence is. What its abstract reports:

A single study of 266 people found little or no difference between a photodynamic therapy activated by blue light and a dummy cream plus blue light. The evidence was rated low quality.
Pooled data from three studies, 360 people, found that a photodynamic therapy activated by red light had a similar effect on lesion counts to a placebo cream with red light. That evidence was rated moderate quality.
Several other comparisons, including infrared light against no treatment, showed no clinically significant effects.
Side effects were reported inadequately. Evidence on them was rated very low quality.

The reviewers' conclusion: carefully planned studies are needed, using standard outcome measures and common acne treatments as comparators.

Two things to keep in mind. The comparisons the abstract grades are mostly of photodynamic therapy, an in-clinic treatment in which light activates a medicated cream. And the abstract gives no standalone verdict on plain blue light of the kind a home mask emits.

Does red light therapy help acne?

A 2021 meta-analysis pooled 13 randomized trials with 422 participants who had moderate-to-severe acne. It found no statistically significant difference between red light therapy and traditional therapies, for inflammatory or non-inflammatory lesions. Side effects in the red light groups were generally mild or absent.

Read that carefully. "No significant difference" means red light was not shown to be better, and not shown to be worse. The authors asked for caution because the trials varied and were small.

What red light is studied for: wrinkles and collagen

This is where red light has its clearest trials.

Lee 2007. 76 people with facial wrinkles had LED light at 633 nm, 830 nm, both, or a sham light on one side of the face, twice a week for four weeks. Wrinkles fell by up to 36% and elasticity rose by up to 19% against baseline in the three treatment groups.
Wunsch 2014. 136 volunteers, 113 treated and 23 controls, had sessions twice a week for 30 sessions with 611–650 nm or 570–850 nm light. Treated skin had better complexion, roughness and ultrasound-measured collagen density than controls.

None of the studies in this article tested blue light for wrinkles.

More: Red light masks and Red light vs near-infrared light.

Masks that combine red and blue

Some home masks include both. The CurrentBody LED Red Light Therapy Face Mask: Series 3 lists 633 nm red, 830 nm near-infrared, 1072 nm deep near-infrared and 415 nm blue, according to the brand's product page.

A combined mask is one way to get both wavelengths. Whether combining them works better than either alone is not something the studies in this article tested.

Which should you choose, red or blue?

Choose by your goal. If it is fine lines, firmness or skin texture, red and near-infrared light have the controlled trials. If it is breakouts, blue light is the wavelength studied for acne, but the evidence is less certain, so talk to a dermatologist first. If you want both, some masks include both wavelengths.

A little more detail:

Lines and texture, no acne. A red and near-infrared mask matches the research.
Occasional breakouts. A mask with blue light is a reasonable thing to ask a dermatologist about. Keep expectations modest.
Moderate or severe acne. See a dermatologist. Light was not shown to beat conventional treatments.
Both concerns. A combined mask covers both wavelengths.

Is light therapy safe?

In the Cochrane review, most studies reported side effects, but inadequately. Scarring was reported as absent. Blistering was reported only in studies of intense pulsed light, infrared light and photodynamic therapy, with very low quality evidence. In the red light meta-analysis, adverse events were generally mild or absent. In the Lee wrinkle trial, LED light was well tolerated with no adverse effects.

Follow the maker's instructions on eye protection and session length. Check with your doctor first if you are pregnant, take medication, or have a skin or eye condition.

What light therapy does not do

It does not replace acne care. If acne is painful, scarring or not improving, see a dermatologist.
Blue light is not a wrinkle treatment in this evidence.
Red light was not shown to beat conventional acne treatments.
Neither works overnight. The wrinkle trials ran for weeks.
Neither is made stronger by hydration. Hydration does not make light go deeper.

Make it a Glow Protocol

Before. Start with clean, dry skin, unless your device's instructions say otherwise.
During. Follow the maker's session length and weekly schedule.
After. Go back to your usual routine: moisturizer, and sunscreen in the daytime.
Daily. Hydration is the layer underneath, every day. That is Step 0. It supports the skin's own water content. It does not make the light work better.

H2Glow is Step 0: the hydration layer underneath the routine. It does not make any device work better. See the full Glow Protocol.

Where H2Glow fits

Light works from the outside. H2Glow is Step 0: what is inside your skin before anything goes on it. One stick has 17 actives, including 250 mg of sodium hyaluronate, 40 mg of rice phytoceramides, electrolytes and 1,500 mg of glycine, proline and lysine, collagen's amino acids.

When we say hydrated skin performs better, we mean the skin's own water content, barrier and elasticity. We do not mean a light device works better on it. H2Glow is not an acne product, and no study has tested H2Glow, alone or with light therapy.

Frequently asked questions

Is red or blue light better for acne?

Blue light is the wavelength most studied for acne, and a review of 8 randomized trials found significant improvements. A meta-analysis of red light found no significant difference from conventional treatments. See a dermatologist for acne.

Is red or blue light better for wrinkles?

Red. The controlled trials for wrinkles, elasticity and collagen used red and near-infrared light. None of the studies in this article tested blue light for wrinkles.

Can you use red and blue light together?

Some masks include both. The CurrentBody Series 3, for example, lists 415 nm blue alongside red and near-infrared. The studies here did not test whether the combination works better.

Does blue light therapy really work?

A 2021 systematic review reported significant improvements in acne and called for more detailed trials. A Cochrane review of light therapies for acne found few clear effects and asked for better-designed studies.

How certain is the evidence for light therapy and acne?

Mixed. The Cochrane review rated its main comparisons as low or moderate quality, and its evidence on side effects as very low quality.

Does red light therapy make acne worse?

In a meta-analysis of 13 trials, adverse events in the red light groups were generally mild or absent. If your skin reacts, stop and see a dermatologist.

How long does light therapy take to work?

The wrinkle trials ran sessions twice a week for four weeks or for 30 sessions. See Red light therapy before and after for the timelines.