How Often Should You Use Red Light Therapy? The Truth About Cumulative Dose and Rest Periods

Red light therapy (RLT) is gaining popularity for everything from skin rejuvenation to brain health. But one question continues to puzzle both beginners and experienced users alike: how often should you use red light therapy?

Is once a day enough? Is twice too much? Do you need to take days off between sessions?

To answer these questions correctly, we need to dive deeper into some under-discussed but critical concepts in photobiomodulation (PBM) science:

• The cumulative dose effect
• The cellular response timeline
• The biphasic dose response
• Importance of rest periods between sessions
• Evidence-based clinical examples across different health goals

What Is the Cumulative Dose in Red Light Therapy?

Cumulative dose refers to the total biological effect of red light therapy over time, especially when treatments are spaced closely together.

One study puts it this way:

“The dose from one treatment lasts some time, and what remains is added to the next dose. Adequate time between doses allows the cells to respond and avoids entering the bio-inhibitory range.” [1]

Red light therapy doesn’t only work during your session. Studies show that:

• ATP levels peak around 6 hours after treatment and stay elevated for up to 48 hours [2][3]
• Cytochrome C Oxidase (CCO) activity remains elevated for 24 hours [4]
• Effects on nitric oxide (NO), HSP70, IL-2, and calcium can last up to 48 hours [5]

So if you treat too frequently without resting, you might “stack” these cellular effects too high and push your body into a bio-inhibitory state — the opposite of what you want.

The Biphasic Dose Response: Why More Isn't Always Better

The biphasic dose response (also called Arndt-Schulz Law) shows that:

• Too little dose = no effect
• Optimal dose = therapeutic benefit
• Too much dose = biological inhibition

Overuse of red light — especially multiple times daily — may reduce or even reverse the benefits.

This is particularly relevant for at-home red light therapy panels, where people may be tempted to “do more” in hopes of quicker results.

How Long Should You Wait Between Red Light Therapy Sessions?

Research suggests that:

• 24 to 48 hours is often the ideal recovery window

• Daily use may be fine if the dose and intensity are low

• For higher intensities, spacing out treatments is recommended

This is similar to exercise — your body needs time to adapt and recover between stimuli.

Real-World Clinical Examples

Let’s look at dosing frequencies in peer-reviewed research across different goals:

Hair Growth

• Frequency: Every other day
• Reason: Hair follicles are sensitive, and excessive dosing may inhibit growth
• Reference: [8]

Skin Rejuvenation

• Frequency: 2–3 times per week
• Study 1: Daily neck treatments improved wrinkles and were safe for the thyroid [9]
• Study 2: 72-hour rest between sessions optimized results [15]
• Study 3: 2x/week = same results as 3x/week in facial aesthetics [21]

Athletic Recovery

• Frequency: 2–3 times per week, typically post-workout
• Reason: Matches training schedule and prevents overuse
• Reference: [10]

Pain Relief

• Humans: 3x/week gave better results than 1x/week or 2x/week [20]
• Mice: Pain relief peaked 2–3 hours after therapy, wore off by 24 hours

Brain Health / Cognitive Function

• Study 1: 3x/week for 6 weeks with 48-hour rest intervals [14]
• Study 2: Daily Vielight use showed benefits, but age matters — young brains can experience suppression with excessive use [12]

Fat & Weight Loss

• Protocol:
  • 3x/week for 4 weeks
  • 2x/week for 6 weeks
  • 1x/week for 12 weeks
• Best Results: 2x/week group [19]

Full-Body Panels / Pods

• Protocol (planned): 3x/week for fibromyalgia [13]
• Note: Lower frequency may be for patient convenience — at-home use could support more flexibility

Practical Guidelines Based on Research

Key Takeaways

• Red light therapy effects continue for 24–48 hours post-treatment

• Overlapping treatments without rest may lead to cumulative inhibition

• Optimal frequency depends on goal, device intensity, and treatment area

• Less can be more — spacing out sessions leads to better long-term outcomes

• Use lower doses or lower intensity if planning daily sessions

The red light therapy industry often emphasizes more intensity, longer sessions, and daily use — but the science shows that smarter dosing delivers better outcomes. Whether you're targeting pain, skin, brain health, or performance, knowing how often to use your device is just as important as knowing how long or how far.

-Stick to a schedule

-Respect recovery time

-Stay within the stimulatory range

References

[1]Hawkins D, Abrahamse H. Effect of multiple exposures of low-level laser therapy on the cellular responses of wounded human skin fibroblasts. Photomed Laser Surg. 2006 Dec;24(6):705-14. doi: 10.1089/pho.2006.24.705. PMID: 17199470.

https://pubmed.ncbi.nlm.nih.gov/17199470/

[2]Ferraresi, Cleber et al. “Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.” American journal of physical medicine & rehabilitation vol. 95,10 (2016): 746-57. doi:10.1097/PHM.0000000000000490

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5026559/

[3]Ferraresi C, de Sousa MV, Huang YY, Bagnato VS, Parizotto NA, Hamblin MR. Time response of increases in ATP and muscle resistance to fatigue after low-level laser (light) therapy (LLLT) in mice. Lasers Med Sci. 2015 May;30(4):1259-67. doi: 10.1007/s10103-015-1723-8. Epub 2015 Feb 21. PMID: 25700769.

[4]Albuquerque-Pontes GM, Vieira RP, Tomazoni SS, Caires CO, Nemeth V, Vanin AA, Santos LA, Pinto HD, Marcos RL, Bjordal JM, de Carvalho Pde T, Leal-Junior EC. Effect of pre-irradiation with different doses, wavelengths, and application intervals of low-level laser therapy on cytochrome c oxidase activity in intact skeletal muscle of rats. Lasers Med Sci. 2015 Jan;30(1):59-66. doi: 10.1007/s10103-014-1616-2. Epub 2014 Jun 24. PMID: 24957189.

https://pubmed.ncbi.nlm.nih.gov/24957189/

[5]Novoselova EG, Glushkova OV, Cherenkov DA, Chudnovsky VM, Fesenko EE. Effects of low-power laser radiation on mice immunity. Photodermatol Photoimmunol Photomed. 2006 Feb;22(1):33-8. doi: 10.1111/j.1600-0781.2006.00191.x. PMID: 16436179.

https://pubmed.ncbi.nlm.nih.gov/16436179/

[6]A New Perspective on Delivery of Red-Near-Infrared Light Therapy for Disorders of the Brain

https://www.discoverymedicine.com/Nathan-S-Hart/2016/09/a-new-perspective-on-delivery-of-red-near-infrared-light-therapy-for-disorders-of-the-brain/

[7]Xuan, Weijun et al. “Repeated transcranial low-level laser therapy for traumatic brain injury in mice: biphasic dose response and long-term treatment outcome.” Journal of biophotonics vol. 9,11-12 (2016): 1263-1272. doi:10.1002/jbio.201500336

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025344/

[8]Lueangarun, Suparuj et al. “A Systematic Review and Meta-analysis of Randomized Controlled Trials of United States Food and Drug Administration-Approved, Home-use, Low-Level Light/Laser Therapy Devices for Pattern Hair Loss: Device Design and Technology.” The Journal of clinical and aesthetic dermatology vol. 14,11 (2021): E64-E75.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8675345/

[9]Lee, Young In et al. “The Use of a Light-Emitting Diode Device for Neck Rejuvenation and Its Safety on Thyroid Glands.” Journal of clinical medicine vol. 10,8 1774. 19 Apr. 2021, doi:10.3390/jcm10081774

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8073506/

[10]Ferraresi, Cleber et al. “Photobiomodulation in human muscle tissue: an advantage in sports performance?.” Journal of biophotonics vol. 9,11-12 (2016): 1273-1299. doi:10.1002/jbio.201600176

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5167494/

[11]Gavish L, Houreld NN. Therapeutic Efficacy of Home-Use Photobiomodulation Devices: A Systematic Literature Review. Photobiomodul Photomed Laser Surg. 2019 Jan;37(1):4-16. doi: 10.1089/photob.2018.4512. PMID: 31050938.

https://pubmed.ncbi.nlm.nih.gov/31050938/

[12]Cardoso, Fabrízio Dos Santos et al. “Photobiomodulation of Cytochrome c Oxidase by Chronic Transcranial Laser in Young and Aged Brains.” Frontiers in neuroscience vol. 16 818005. 18 Mar. 2022, doi:10.3389/fnins.2022.818005

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8971717/

[13]Navarro-Ledesma S, Gonzalez-Muñoz A, Carroll J, Burton P. Short- and long-term effects of whole-body photobiomodulation on pain, functionality, tissue quality, central sensitisation and psychological factors in a population suffering from fibromyalgia: protocol for a triple-blinded randomised clinical trial. Ther Adv Chronic Dis. 2022 Feb 21;13:20406223221078095. doi: 10.1177/20406223221078095. PMID: 35222905; PMCID: PMC8864274.

https://pubmed.ncbi.nlm.nih.gov/35222905/

[14]Zeng J, Wang C, Chai Y, Lei D, Wang Q. Can transcranial photobiomodulation improve cognitive function in TBI patients? A systematic review. Front Psychol. 2024 Jun 17;15:1378570. doi: 10.3389/fpsyg.2024.1378570. PMCID: PMC11215173.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11215173/

[15]Couturaud V, Le Fur M, Pelletier M, Granotier F. Reverse skin aging signs by red light photobiomodulation. Skin Res Technol. 2023 Jul;29(7):e13391. doi: 10.1111/srt.13391. PMID: 37522497; PMCID: PMC10311288.

[16]Oliveira FM, Borges MM, Malta CE, Moura JF, Forte CP, Barbosa JV, Silva PG, Dantas TS. Comparison of a daily and alternate-day photobiomodulation protocol in the prevention of oral mucositis in patients undergoing radiochemotherapy for oral cancer: a triple-blind, controlled clinical trial. Med Oral Patol Oral Cir Bucal. 2024 Apr 14;29(3):e430–40. doi: 10.4317/medoral.26436. Epub ahead of print. PMID: 38615257; PMCID: PMC11175575.

[17]de Sousa MVP, Kawakubo M, Ferraresi C, Kaippert B, Yoshimura EM, Hamblin MR. Pain management using photobiomodulation: Mechanisms, location, and repeatability quantified by pain threshold and neural biomarkers in mice. J Biophotonics. 2018 Jul;11(7):e201700370. doi: 10.1002/jbio.201700370. Epub 2018 May 18. PMID: 29484823; PMCID: PMC6037550.

[18]Maiello M, Losiewicz OM, Bui E, Spera V, Hamblin MR, Marques L, Cassano P. Transcranial Photobiomodulation with Near-Infrared Light for Generalized Anxiety Disorder: A Pilot Study. Photobiomodul Photomed Laser Surg. 2019 Oct;37(10):644-650. doi: 10.1089/photob.2019.4677. PMID: 31647775; PMCID: PMC6818480.

[19]Croghan IT, Hurt RT, Schroeder DR, Fokken SC, Jensen MD, Clark MM, Ebbert JO. Low-level laser therapy for weight reduction: a randomized pilot study. Lasers Med Sci. 2020 Apr;35(3):663-675. doi: 10.1007/s10103-019-02867-5. Epub 2019 Aug 31. PMID: 31473867.

[20]Mahmoud NR, Shehab WI, AlAraby AA, Habaka YF. Efficacy of different low-level laser therapy sessions in the management of masseter muscle trigger points. BMC Oral Health. 2024 Sep 26;24(1):1125. doi: 10.1186/s12903-024-04780-y. PMID: 39327563; PMCID: PMC11428541.

[21]Bragato EF, Paisano AF, Pavani C, Motta LJ, Varellis MLZ, Chiedde M, da Silva GA, Bussadori SK, Mesquita-Ferrari RA, Fernandes KPS. Role of photobiomodulation application frequency in facial rejuvenation: randomized, sham-controlled, double-blind, clinical trial. Lasers Med Sci. 2025 Apr 1;40(1):170. doi: 10.1007/s10103-025-04383-1. PMID: 40167796.