Blue Light Therapy Before and After: What Changes by Week 12
Blue light therapy before and after results in acne trials show a gradual, partial change: inflamed spots fell by roughly a quarter to three quarters over 12 weeks, depending on the device and the schedule. Below: the trial timeline, which spots respond, flares, fair photos, clinic photodynamic therapy and a home test with the Kivorla mask. Every number here comes from published research.
Key takeaways
- A 2025 meta-analysis of 6 home LED trials with 216 people found inflamed acne spots fell 45.3% more than with control. Ershadi, 2025
- In a small home study without a control group, 6 minutes a day of 414 nm blue light cut papules by 21.8% at day 7 and 41% at day 28. Gold, 2009
- In a 107-person trial, 12 weeks of daily blue light reduced inflamed spots by about 63%, and blue plus red light by 76%. Papageorgiou, 2000
- The American Academy of Dermatology says visible light is "not effective against blackheads, whiteheads, acne cysts, or nodules". AAD
- A fair before-and-after test starts with baseline photos before the first session and compares week 0 with weeks 4, 8 and 12.
What do blue light therapy before and after results look like in trials?
They look like steady progress rather than overnight clearing: in home LED trials, improvement was typically seen at 4 to 12 weeks. The largest falls in inflamed spots were measured at week 12.
The 2025 meta-analysis pooled 6 randomised trials of home LED devices in 216 people with mild to moderate acne. Ershadi, 2025 Inflamed spots fell 45.3% more than with control. Non-inflamed spots fell 47.7% more. The authors concluded that home devices, "particularly those that combine red and blue light, are efficacious for acne".
| Timepoint | What was measured | Study |
|---|---|---|
| Day 7 | Papules down 21.8%, comedones down 22.8%, with 414 nm blue light for 6 minutes a day | Gold, 2009 (21 people, no control group) |
| Day 28 | Papules down 41%, open comedones down 50%, closed comedones down 30.4% | Gold, 2009 |
| Week 4 | Blue plus red ahead of blue alone; in a mask trial, the fall in inflamed spots was significant from this point | Papageorgiou, 2000; Nestor, 2016 |
| Week 8 | Papules 35.6% below the starting count | Gold, 2009 |
| Week 12 | Inflamed spots down about 63% with blue alone and 76% with blue plus red | Papageorgiou, 2000 (107 people) |
| Week 12 | Inflamed spots down 24.4% with a 445 and 630 nm LED mask, 15 minutes a day | Nestor, 2016 (105 people) |
| 8 weeks after the last session | A 59 to 67% fall in inflamed spots still held after 8 clinic sessions | Elman, 2003 |
The spread reflects different devices, schedules and people. In these trials, red spots were already fewer by week 4, with a clearer picture by week 12. Blue light therapy for acne results also depend on the type of spot.
Which spots change first: red pimples, blackheads or cysts?
Red, inflamed pimples change first and most, because blue light targets acne bacteria near the surface of the skin. Blackheads and whiteheads respond less, and cysts and nodules do not respond to visible light.
Acne bacteria make porphyrins, natural compounds that absorb light most strongly at about 415 nm. DermNet Because the bacteria make their own light-sensitive compound, blue light for acne needs no cream on the skin. Cleveland Clinic
- Red pimples: the main target in every trial above, and the first count to move.
- Blackheads and whiteheads: smaller, less consistent changes. In the small home study, open comedones fell 50% by day 28, and the total edged back up slightly by day 56.
- Cysts and nodules: these belong with a dermatologist.
So count red spots separately from blackheads and whiteheads in your photos.
Can blue light make acne worse in the first weeks?
A flare can happen, but in the four-arm trial it was uncommon and not significantly more frequent than with white light. No trial describes a separate "purging" phase, so judge progress at week 4 or later.
In the 2000 trial, acne flared in 11.1% of the blue group, 6.6% of the blue plus red group and 8% of the white light group, differences that were not significant. Papageorgiou, 2000
Across the home LED trials, there were no severe reactions. Ershadi, 2025 Minor effects such as a flare, dryness, itch or mild redness affected about 3% to 11% of participants in the trials that reported any. If new spots are deep, painful or leave marks, stop and see a doctor.
Does adding red light change the 4-week and 12-week results?
Mainly the speed: blue plus red led blue alone at weeks 4 and 8, and the two were level by week 12. The 2025 meta-analysis also found that combined red and blue appeared more effective, based on one comparison.
The 2000 trial was randomised and observer-blinded, with four groups over 12 weeks; the light groups had 15-minute daily sessions. Papageorgiou, 2000
- Blue plus red (415 and 660 nm): inflamed spots down about 76%.
- Blue alone (415 nm): about 63%.
- 5% benzoyl peroxide: about 58%.
- Cool white light: about 26%.
A double-blind home trial in 35 people compared a 420 and 660 nm device, used twice a day for 4 weeks, with a sham device. Kwon, 2013 Eight weeks after the last session, 14 of 18 people in the active group were clear or almost clear, against 2 of 17 with sham.
Our mask's blue mode pairs 460 nm blue with 850 nm near-infrared, not with red. People who want both colours alternate the blue mode and the red mode on different days, as the alternating trials did. See blue vs red light therapy and our red and blue light therapy mask guide.
What schedules did the blue light acne trials use?
Most home trials used short daily sessions for 8 to 12 weeks, with blue light at 414 to 445 nm. Clinic trials used fewer sessions, about twice a week for 4 weeks.
| Trial | Light | Minutes | Sessions per week | Weeks | Setting |
|---|---|---|---|---|---|
| Papageorgiou, 2000 | 415 nm blue, alone or with 660 nm red | 15 | 7 | 12 | Portable lamp, face |
| Gold, 2009 | 414 nm blue | 6 | 7 | 8 | Home device, goggles worn |
| Nestor, 2016 | 445 nm blue + 630 nm red | 15 | 7 | 12 | LED mask |
| Elman, 2003 | 405 to 420 nm blue | 8 to 15 | About 2 | About 4 | Clinic light |
| Ershadi, 2025 (6 trials) | Blue 414 to 445 nm, red 630 to 670 nm | Varied | Varied | 2 days to 12 weeks | Home devices |
The mask trial gave its light once a day and saw a steady fall from week 4 to week 12. Nestor, 2016 These figures describe what trials used, not settings for any particular device; our mask follows its own manual limits, set out below.
How do you take fair before-and-after photos of acne at home?
Use the same window light, time of day, phone, distance and pose every time, on clean, bare skin and never straight after a session. Take a baseline set before the first session, and judge by comparing week 0 with weeks 4, 8 and 12.
The AAD's advice on photographing skin fits the method in our red light therapy before and after guide. AAD
- Light: bright window light on your face, no direct sun, no flash. Each photo should be "free of shadows, glare, and harsh lighting".
- Skin: makeup off. Skin can look flushed just after a session, so take photos before it.
- Camera: the same phone and rear camera, filters and beauty mode off, no zoom, propped at the same height and distance.
- Shots: front, left and right views on a plain background, plus a close-up with a coin or ruler for scale.
- Count: note red spots and blackheads or whiteheads separately.
- Routine: change nothing else in your skincare, and do not edit the photos.
Take a set every two weeks if you like, but judge by comparing week 0 with weeks 4, 8 and 12. Any gallery that gives no number of people, timeline or routine cannot be compared with your own photos.
Do blue light acne results last after you stop?
In a clinic study, the fall in inflamed spots held for 8 weeks after the last of 8 sessions. Clinics usually plan maintenance sessions, from monthly to every few months.
That clinic work used 405 to 420 nm light. Elman, 2003 Inflamed spots fell 59 to 67% after 8 treatments, and the reduction held at 2, 4 and 8 weeks of follow-up.
Cleveland Clinic describes maintenance for in-office LED treatment as monthly or every few months. Cleveland Clinic For a home routine that helped, keep going within the device's weekly limits and keep taking photos.
Is blue light suitable for darker skin, melasma or acne medicines?
Blue light can darken skin that pigments easily, so anyone prone to melasma or dark marks should use the mask's red mode instead. Many acne medicines also make skin more sensitive to light, which needs checking first.
A 2020 review describes a clear dose effect on pigmentation with 415 nm light, while 630 nm red light did not cause darkening. Photochem Photobiol Sci, 2020 It also says visible light "may play a role in the pathogenesis of melasma".
- Melasma or easy dark marks: choose the red mode, wear sunscreen daily and see a dermatologist. See our melasma guide.
- Darker skin without melasma: if you use the blue mode, keep to 50% brightness, the 5-minute timer and earlier in the day, and stop if any patch darkens.
- Panel: not for Fitzpatrick skin types V or VI.
Doxycycline, a common acne antibiotic, can make skin more sensitive to the sun. NHS Cleveland Clinic lists isotretinoin and lithium among medicines that rule out LED treatment. Cleveland Clinic Our precautions rule out use with photosensitising medication, so anyone taking a medicine should check with their pharmacist or doctor before using the device.
Our precautions also rule out use during pregnancy, with epilepsy, with a thyroid condition or thyroid medication, and on broken skin. Skip open or picked spots until they have closed.
How is clinic photodynamic therapy different, and what is the aftercare?
Photodynamic therapy (PDT) puts a light-sensitising solution on the skin before the light, so it is a different, clinic-only treatment with stricter aftercare. Blue light for acne on its own uses no cream.
For acne, the solution stays on for about 15 minutes to 3 hours before the light, and most people need a series of treatments. AAD In one study the AAD describes, spots fell 72% twelve weeks after the last treatment.
- Days 1 and 2: redness, peaking around day 2. Cleveland Clinic
- Days 3 to 7: blisters, itching or peeling can appear.
- 1 to 2 weeks: skin usually back to normal.
- Light avoidance: the AAD advises avoiding sunlight for 48 hours after acne PDT.
Aminolevulinic acid, an approved prescription treatment for actinic keratoses, is applied 14 to 18 hours before blue light, and its guidance gives at least 40 hours of protection from light. Mayo Clinic Follow your clinic's aftercare and never use a device on raw, peeling or broken skin. Our blue light therapy guide covers PDT further.
How do you run a before-and-after test with the Kivorla mask's blue mode?
Take baseline photos, then use the blue mode for 10 minutes at 50% brightness on two mornings a week, with the red mode on two evenings if you want both colours. Judge it at week 12, comparing week 0 with weeks 4, 8 and 12.
The 4-Wavelength Red Light Therapy Mask has a blue mode of 460 nm blue plus 850 nm near-infrared. 460 nm sits at the long end of the blue band used in trials, about 410 to 445 nm. Its red mode combines 665 nm red with 850 and 1064 nm near-infrared.
- Before: clean, dry skin with nothing on it; adjust the strap for a comfortable fit.
- Controls: the handheld controller with its colour screen, or voice. Brightness 50, 70 or 90%; timer 5, 10 or 15 minutes, after which the mask switches off by itself.
- Weekly limits: 10-minute sessions up to 4 times a week at high brightness, or 15-minute sessions up to 3 times a week after building up with three 10-minute sessions the week before. Never more than 20 minutes a day, counting blue and red sessions together.
- Eyes: keep them closed and do not stare into the light. The eye opening has no diodes over it.
- Power: about 3.5 hours to charge, around 40 minutes of use per charge; it cannot be used while charging.
Trials used daily sessions; follow the manual's weekly limits instead. Start at 50% brightness and move up only if your skin stays calm.
The mask is a full-face shell with an eye opening; it does not cover the jawline, under the chin or the neck. For those areas, and for the back or chest, the 9-Spectrum Red Light Therapy Panel reaches them. Its 480 nm channel is one of its nine wavelengths, each dimmable from 1 to 100%, not a dedicated acne setting. For the back or chest, set it about 12 inches away for 10 to 15 minutes per area, goggles on and eyes closed; for the jaw, place it side-on, never aimed at the face. See our back acne guide.
When should acne go to a dermatologist instead of a home test?
See a dermatologist first for severe, cystic, nodular, painful or scarring acne. If your blue light therapy for acne results show no clear change by about week 12, book an appointment rather than adding sessions.
For acne treatment in general, the AAD says "you should notice some improvement in 4 to 6 weeks", and clearing can take two to three months or longer. AAD Light sits alongside any treatment a dermatologist prescribes, never instead of it.
Read the precautions before ordering. Standard shipping to the US, UK and Germany is free. Under our return and refund policy, returns are accepted within 30 days: an unopened device with its seals intact is refunded less a 10% restocking fee, and an opened device that is undamaged and complete is refunded less 20%.
Kivorla devices are general wellness devices, not medical devices, and are not intended to treat acne. See a dermatologist for cystic, painful or scarring acne.