Studying Human Photobiology


Human beings and our ancestors have evolved under the sun for approximately 6 million years (6,000,000). Our surfaces have been designed over the course of millennia to be the perfect antenna to receive, process, and utilize photonic energy. The dominant wisdom in modern dermatology and ophthalmology has been that the sun (and UV rays in particular) are evil, cause cancer, and accelerate aging. For a moment, suspend your belief in these modern assumptions and consider the validity of these claims from an evolutionary perspective. Would it make sense for humans to evolve for hundreds of thousands of years under a poison sun with no notion of sunscreen or sunglasses? It turns out that science is uncovering some of the mechanisms by which our surfaces are optimally engineered solar panels and how our bodies decipher the rhythm of these frequencies to create life. I’d like to consider some of the research today.

How Does Light Interface With Our Tissues?

Solar radiation reacts with any surface that is exposed to the outer environment. In humans this is chiefly the eyes and skin.

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Structures in human tissues are able to absorb photons for a biologic effect, and these structures contain chromophores. Chromophores are molecules which are tuned to certain wavelength ranges, as discussed in Circadian Biology I. Aromatic amino acids such as tyrosine and histidine make up the scaffolding of chromophore proteins that compose our tissues that interact with sunlight. These chemicals include melanin (a UV fluorophore protein)(R) and porphyrins in red blood cells among others. (R)

Radiant energy is converted into an electric current in humans, at our surfaces. In Dr. Robert O. Becker’s book The Body Electric he discusses the semiconducting DC electric current that exists in mammals for the regeneration of injured tissue. Humans cannot grow and heal without a strong DC (Direct Current) electric current. This DC electricity is converted from sunlight via DHA (Docosahexaenoic acid) in cellular membranes. DHA is an essential fatty acid that has a 600 million year history on earth and is a semiconductor, meaning it has the ability to absorb energy directly from light waves.(R)(R)

Light also has major interactions with another atom in our tissues: nitrogen. Light and nitrogen control carbon flows in organisms and this process is called ubiquitination.(R) The interaction of light and nitrogen are foundational to all kingdoms of life and photosynthesis is the basis of the food web. This is evident in the molecular sctructure of both chlorophyll and hemoglobin:


Chlorophyll has a magnesium ion surrounded by four nitrogens, while hemoglobin has an iron surrounded by four nitrogens. In other words, the pigment that is known to capture light in plant photosynthesis has a parallel molecular structure to human red blood cells. Every place you find life in any kingdom, you find pigment that had four nitrogens around a metal. This proves how foundational light is to life.(R)

Aside from interacting with the tissue structures, light acts significantly on the water within the human body. According to the work of professor Gerald Pollack at the University of Washington, light has massive effects on the biochemical utility of water. His experiments have shown that light (most profoundly in the 600-1400nm range) charge separates water and forms a kind of battery within the molecular structure of H2O.(R) This electrical gradient in water is called the exclusion zone, referring to the exclusion of protons and the density of electrons in the area. An Italian theoretical physicist Emilio Giudice found that 13% of the exclusion zone in water forms something called the Coherent Domain: a phenomenon in which one million free delocalized electrons are released from the water.(R) This means the coherent domain is capable of powering all the 100,000 biochemical reactions in a cell per second. Water that is subject to EZ formation by incident light makes up 92% of blood plasma, 99.8% of cerebral spinal fluid, and 70% of the cytosol is water (mitochondria make the cytosolic water as a byproduct of oxidative phosphorylation). That means all of these areas are perfect red light chromophores and most likely powered by the battery function of water in sunlight.


Every protein in our body has a hydration shell and acts as a UV antenna. When the electro magnetic light wave hits the hydration shell it turns into an electro mechanical sound wave that is collected in water. Water is a magnetic dipole, referring to t)he positive hydrogen and the negative oxygen. Magnetism controls electromechanical sound waves.(R) These acoustic phonons in the blood plasma can send signaling cascades throughout the body via molecular resonance transfer.(R)

Light & The Eye

The eye is the primary surface humans use to interface with light. Our eyes give us the reality we receive in life by both visual and non-visual effects. The eye is both a camera and a clock.

The spectrum of the sun is 250-3000nm. Humans can only see 380-780nm. It turns out that frequencies excluded here, in the UV and IR ranges, are key signaling frequencies for biochemistry. This is by design and in accordance with the Zeno effect of quantum physics, which essentially states that what you can observe changes your reality. If these frequencies were available to the eye camera they wouldn’t be of use to the eye clock.(R)

Despite the fact that ophthalmologists regard UV light as toxic, it appears that 1% of UVB and 3% of UVA get through to the back of the eye for signaling purposes. The vitreous collagen and retinal pigment epithelium are UV fluorophore proteins that are designed to receive these frequencies. These and other structural tissues of the eye are loaded with aromatic amino acids specifically to trap photons. UV is the only frequency in the visible spectrum that works in a non linear fashion, meaning that a small stimulus can lead to massive amplification. Therefore that 1-3% that gets through can have big implications.(R)

The significance of UV exposure through the eye on neurological signaling was detailed by the experiments of a German ophthalmologist named Fritz Hollwich. His data showed that after he removed the cataracts of patients and allowed UV to enter the eye, their biomarkers of growth and metabolism improved. He was able to show hormonal metabolites in the urine that hadn’t been present before the cataracts surgery.(R)

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Opsins are a group of light sensitive proteins found in the eye. They are involved in vision, mediating the conversion of a photon of light into an electrochemical signal. Some opsins, such as melanopsin and neuropsin are vital to circadian signaling. Neuropsin, a UVA light detector, is on the cornea of the eye and the skin. Melanopsin works with the retinal ganglion cells to control the central retinal pathway. We even have opsins in our central nervous system to detect light and tell time.

The fovea is where the rest of the light spectrum falls. This is where acute vision and the “eye camera” happen.

The central circadian anatomy that controls photoendocrinology and chronobiology in the body is a combination of the eye, the central retinal pathway, and the brain. This connects the suprachiasmatic nucleus in the hypothalamus and the pituitary gland to the photo stimulus of the eye.

Light & The Skin

The skin is actually quite complex. It contains nerve fibers, capillary layers, melanocytes, keratinocytes, and the stratum corneum as the outermost layer that makes the skin robust to the outer environment. There are several similarities between the retinal structures and our skin tissue, making both the optimal receptacles for sunlight. Light acts on the skin in various ways including specific cell activation, water activation, and increased ATP production.

The various frequency ranges have different optical windows in dermal tissue and have different applications. While UV radiation barely penetrates the epidermis, red and infrared have the ability to penetrate several centimeters.

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Although UV doesn’t penetrate tissue very deeply, the nitric oxide system in humans makes blood irradiation possible. UV light via nitric oxide causes 40-60% dermal pooling. This is why we get pink when we’re outside in strong UV light. This is to expose as much of our RBC pigmentation and porphyrins to the solar radiation. UV also simulates specialized cells like melanocytes to produce hormones and antioxidants like MSH. (R)

The Red/IR ranges are primarily responsible for activating regeneration pathways, stimulating water by producing the exclusion zone and coherent domain, and increasing ATP production. Infrared acts like a beacon for fibroblasts in the skin, the cells that repair and synthesize collagen.(R) Pollack’s work has shown the effects of infrared on water.(R)This is why it’s important for the skin to be hydrated. Lastly, IR stimulates cytochrome c oxidase in the mitochondria to produce more ATP(R) increasing the energy status of the cell.


Photoendocrinology is the study of how sunlight’s interaction with human tissue effects the hormonal systems. A hormone is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior.

Molecular photoendocrinology is the study of biomolecules like aromatic amino acids in tissue structures that upon activation by sunlight can synthesis biochemicals. The basic law of photochemistry is the law of Grotthuss Draper which states that in photochemical activation, only absorbed photons have an effect. Therefore we have to examine biology and look for structures that are capable of absorbing photons. Aromatic amino acids happen to be the precursors for my hormones and neurohormones. Some hormones that are made up of aromatic amino acids include many that have to do with photo-adaptation, but also many that are vital for cognition, growth & metabolism, sexual reproduction, and tissue repair. These include Amines, Peptide/Proteins, and steroids.

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The aromatic amino acids (with the benzine ring photon trap that make proteins into chromophores) form many different substances that are important for photoadaptation:

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Steroid Hormones and POMC are also tied to light:

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These hormones are synthesized by specific bandwidths of sunlight like UVA and IRA and are manufactured according to the rhythm of the day/night and seasonal cycles.(R)

Clearly getting natural light on your surfaces is more effective and economical that taking hormones exogenously.


Chronobiology is the study of how the circadian rhythm affects biochemistry.

The circadian rhythm is tied to the regular changes of sunlight, for this reason it can be considered that changes over time are more important than the characteristics of the light itself. These changes include irradiance, day and night cycles, seasonal variations, and spectral distribution.

The principal change is the 24 hour cycle of light and dark that is integral to human life. It tunes our solar panels.(R)

In humans, the suprachiasmatic nucleus in the hypothalamus of the brain regulates all of the internal clocks of the body, it is the main circadian oscillator. It works with the central retinal pathway and is highly sensitive to ocular signaling to decipher time. This is known as the “non-visual” or “vegetative” pathway that runs the circadian clock.(R)


Professor Nicolas Bazan at LSU has described how the central retinal pathway that connects the eye and suprachiasmatic nucleus energetically has more DHA than any other part of the body. This is because the DC electric current has to be stronger here than anywhere else in the body. The clock in the SCN has to be faster than all the peripheral clocks of the body in order to synchronize the circadian rhythm.(R)

Morning bright light (in the perfect natural balance) stimulates a hormonal cascade of wakefulness and an assimilation of neurotransmitters and neurohormones.(R)

Hormonal tides controlled by light:

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Melatonin (the most famous marker of circadian rhythm) is made in the morning when its precursor, tryptophan, encounters UVA and IRA light. However, melatonin is released by the pituitary gland at night. Four hours of complete darkness is required for optimal melatonin release:

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Optimal circadian rhythms and the consequential hormonal cascade of ocular stimulus has been a hallmark of evolution for millennia. The destruction of this rhythm is a major underlying factor for modern diseases.


Each consecutive step in the evolution of humans has occurred under the light of the sun. This relationship to the sun is evident in all aspects of our biology: our tissues have evolved to be the ultimate solar panels. The two major light pathways in us, the skin and eye, control all of photoendocrinology and chronobiology. The closer the field of biology moves towards biophysics, the more science uncovers about how light sculpts life. Our connection to the sun will only expand as our pool of scientific knowledge deepens.


-Many of these slides are from Dr. Alexander Wunsch, a German photobiologist. You can watch his presentations on Vimeo.

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