Chances are, you have been told by your dermatologist to “stay out of the sun and take a vitamin D supplement every day.” But sunlight and vitamin D are not the same thing.
I am a great fan of sunlight exposure, to both the skin and the eyes. We have been brainwashed into believing that the sun is toxic, whereas, in fact, it is life-giving. People who live in places with little sun have statistically higher risk of many chronic conditions, such as multiple sclerosis, diabetes, cardiovascular disease, autism, Alzheimer’s disease, and age-related macular degeneration. Sunlight exposure protects from many different types of cancer.
The facts behind sunlight and vitamin D
The story is not that simple, however.
In a paper published in 2016, Richard Weller wrote: “A substantial body of evidence shows that sunlight has health benefits and that these are independent of vitamin D and thus cannot be reproduced by oral supplementation.” 
Sunlight and Water
Those who are familiar with my research will know that I believe that humans are able to exploit the energy in sunlight by oxidizing hydrogen sulfide to make sulfate. 
Sulfate lining blood vessels promotes the growth of “exclusion zone” water–a gelled form of water that protects the wall of the blood vessel from exposure to damaging substances in the blood, and also creates a battery to capture the energy in the sunlight. The gel forms a slick surface to allow red blood cells to easily slide through the capillaries. Sunlight, but, most especially, infrared light, causes the exclusion zone water layer to expand dramatically, by as much as a factor of four.  The electricity held in the battery grows in direct correspondence.
Prof. Gerald Pollack from the University of Washington in Seattle has popularized much of this story in his book, Cells, Gels and the Engines of Life.
Sunscreen and Melanin
Most Americans heavily rely on sunscreen for sun protection if they are planning to be outside for an extended period. They strongly believe that they are protecting themselves from skin cancer through this practice, but, in fact, they may be increasing their risk to skin cancer.
In fact, sunscreen interferes with the body’s natural mechanisms of sun protection, which have been perfected over hundreds of millions of years of life’s evolution on earth.
Given how much advertising we get urging us to use sunscreen, people probably assume that there is plenty of evidence that sunscreen protects from skin cancer. If this is true, then it is hard to explain why
melanoma prevalence has been steadily rising in step with the rise in the use of higher and higher sun-protection-factor (SPF) sunscreens over the past two decades.
Sunscreen disrupts the body’s natural mechanism of sun protection: melanin synthesis. Sunscreen protection only lasts while the sunscreen is topically present. Melanin, produced in response to sunlight
exposure, on the other hand, builds up over time and eventually produces a healthy tan with protection that can last for weeks or even months.
The powerful antioxidant effects of melanin protect you from the UV rays, while you can still enjoy the many health benefits of visible light and infrared light.
Sunscreen also contains toxic ingredients that cause damage to the skin in ways that might result in sustained disruption of sulfate synthesis.
Particularly disturbing is the aluminum that is added to emulsify the zinc oxide and titanium dioxide additives (the active ingredients).
Sunlight is protective against at least four distinct diseases and conditions: cancer, heart disease, hypertension, and bone fractures. In each case, studies have shown that vitamin D supplements cannot replace these benefits of sunlight. Sunlight and vitamin D each play a role in our health.
 RB Weller. Sunlight Has Cardiovascular Benefits Independently of
Vitamin D. Blood Purification 2016; 41: 130-134.
 S. Seneff et al. Is Endothelial Nitric Oxide Synthase a Moonlighting
Protein Whose Day Job is Cholesterol Sulfate Synthesis? Implications for
Cholesterol Transport, Diabetes and Cardiovascular Disease. Entropy
2012; 14: 2492-2530.
 Binghua Chai et al. Effect of Radiant Energy on Near-Surface Water.
J Phys Chem B 2009; 113(42): 13953-13958.