One of the best proofs of the power of vitamin C at high levels is using it in high internal doses, along with vitamin E, in lieu of sunscreen.
Here's how we protect ourselves from sunburn on the farm without the skin-cancer-causing sunscreen.
Drink ascorbic acid dissolved in water all day, staying just under bowel tolerance (make sure a bathroom is convenient in case you overdoo it).
Take 3 or 4 doses of vitamin E (we are using Solaray Dry E) every few hours through the day. Best to high dose E the day before sun exposure.
Here's the science that we extrapolated on when we tried this method for sunburn protection. It's easy to prove that it works.
Your BT for vitamin C will go way up when you are exposed to the sun, so make sure your intake is making your gut a little gassy or gurgly while you're in the sun (it can be "entertaining", but at least you're outdoors). This nutrient-based method of protecting your skin enhances your vitamin D production, whereas sunscreen inhibits vitamin D production. I also think that protecting the skin in this way helps thicken your skin. We need more thick-skinned humans in the Garden. #godsgardenscience
Note: If you do get sunburned, then the same method above will eliminate the pain of the sunburn, prevent blistering, and heal the burn much faster. It's best to use this to prevent the burn, but it also works dramatically on an existing sunburn if you get to it right away.