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3 Min Read
Last Updated: 12.06.23

Using Light (Sunlight, Blue Light & Red Light) to Optimize Health

Huberman explores how different light wavelengths affect the body, from sleep and hormone regulation to mood enhancement. He shares actionable tools for using light therapies to improve mental and physical health. Additionally, he discusses the benefits of ultraviolet and infrared phototherapies for pain relief, hormone balance, skin health, wound healing, vision, and neuroprotection.

Key Takeaways

High level takeaways from the episode.

Light is electromagnetic energy

  • Wavelengths of light are measured in nanometers (nm)
  • Different wavelengths (colors) of light have different effects on the body

Red light therapy can improve skin health and appearance.

Red light can stimulate collagen production, reduce inflammation, and promote wound healing.

Blue light can kill acne-​​causing bacteria and improve skin clarity.

Exposure to natural sunlight during the day can help regulate sleep and hormone balance.

Red light therapy has been shown to improve age-​​related vision loss by increasing ATP production in eye cells.

Brief exposures to red light early in the day can offset vision loss in people 40 years or older

  • Visible spectrum: red, orange, green, blue, purple
  • Invisible spectrum: infrared, ultraviolet 
    • Infrared: sensed by pit vipers, emitted as heat from our bodies
    • Ultraviolet: can burn our skin, but also has positive effects (e.g., reducing pain)
  • Longer wavelengths (red, near-​​infrared) can penetrate deeper into tissues

Light can be used to stimulate the function of particular organelles within cells and organs

  • No other form of energy (sound, chemical, touch) can target specific locations in cells, organs, and the body as precisely as light can

Protective effects of melatonin

  • Activates the immune system
  • Acts as a potent antioxidant
  • Has anticancer properties

Melatonin supplementation

  • Can have various effects on the body
  • Should be used cautiously and with a doctor’s guidance

Light inhibits melatonin production

  • Bright light exposure at night can disrupt melatonin levels

Melatonin supplementation can change the total amount and normal rhythms of melatonin release.

Melatonin suppresses the gonadal axis, inhibiting testosterone and estrogen output from testes and ovaries.

Study on UVB: 20–30 minutes of midday sun exposure, 2–3x/week for 10–12 treatments

  • Increased testosterone and estrogen levels with sunlight exposure
  • Both males and females reported increased romantic passion

Study: Skin exposure to Ultraviolet B rapidly activates systemic neuroendocrine and immunosuppressive responses

  • One exposure to UVB light changed hormone and neurochemical output
  • Increased levels of corticotropin hormone and beta endorphins (endogenous opioids)
  • Suggests sunlight exposure may have a natural pain-​​relieving effect

Exposure to UVB light increases the release of beta-endorphins

  • Beta-​​endorphins are endogenous painkillers that counter physical and emotional pain

Recent study in the journal Neuron shows that light landing on the eyes triggers anti-​​pain pathways.

Tanning salons provide UVB exposure to the skin, but not the eyes

  • UVB exposure beneficial for mood, hormone pathways, and pain reduction
  • But, high UVB intensities may pose risks to skin health

Caution for those with retinitis pigmentosa, macular degeneration, glaucoma, or prone to skin cancers — consult with ophthalmologists and dermatologists before increasing UVB exposure.

UVB light can enhance immune function by activating spleen and immune cells

  • Fewer colds and flus in summer months due to better immune response

Wound healing is faster with sufficient UVB exposure.

Hair, skin, and nails grow faster and look better with sufficient UVB exposure to eyes and skin.

Localized light therapies can help with skin issues, but systemic activation across large areas of skin and eyes is more effective.

Getting as much UVB light in eyes and on skin in the early day and throughout the day as safely possible is beneficial for mood.

Light exposure during sleep disrupts autonomic nervous system function and metabolism. One night of sleeping in a moderately lit environment (100 lux) caused:

  • Increases in nighttime heart rate
  • Decreases in heart rate variability
  • Increases in next morning insulin resistance

Infrared light LLLT shown to be effective for treating acne and skin lesions

  • Reduces scars and acne cysts

Red light or near-​​infrared light can stimulate skin repair, can help with wound healing, scar reduction, and pigmentation issues.

Red light does not inhibit melatonin production or increase cortisol at night.

Red light can penetrate cells and access mitochondria

  • Increases ATP and reduces ROS
  • Can help preserve or reverse neuronal function

Study: eye exposure to red light of 670nm for 2–3 minutes per day, about a foot away, at a low intensity that did not damage the eyes

  • Visual acuity improved 22% in 40–72 age group


Optimal Sunlight Exposure Protocol


Avoid UVB Exposure after 8PM for Depression


Red Light Therapy Protocol for Visual Function


Gamma Light Entrainment for Brain Health



We recommend using this distillation as a supplemental resource to the source material.

  • Using Light (Sunlight, Blue Light & Red Light) to Optimize Health

    Huberman Lab #68

    Huberman explores the impact of light on the body and shares actionable strategies to enhance overall mental and physical health.

Full Notes

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