The Other Side
of Light.

Sunlight is on my list. One of the six things I believe in — movement, whole food, mindfulness, nature, sunlight, sleep — and the one that makes people most nervous when I say it out loud.

Because we have been taught, for decades, that the sun is the enemy. Cover up. Stay inside between eleven and three. Apply sunscreen every two hours. The message is simple, and the fear is real: skin cancer is serious, and ultraviolet radiation causes it.

But I think we have made a mistake. Not the kind where someone is wrong. The kind where something true gets repeated so loudly that it drowns out another thing that is also true. And the thing being drowned out is this: your body needs sunlight. Not just tolerates it. Needs it.

The morning dose.

In the first hour after sunrise, the light is different. It is rich in red and near-infrared wavelengths and relatively low in ultraviolet. It enters through your eyes — not through sunglasses, not through a window — and it tells your brain that the day has started.

This is not folklore. The science is well established. Morning light triggers a cortisol pulse that wakes you up properly. It suppresses melatonin, which was meant for the night. And it sets your circadian clock — the master timer that regulates not only when you sleep but when you digest food, when your immune system peaks, when your cells repair themselves.

That timer runs on light. Take the light away, and the clock drifts. When the clock drifts, sleep suffers. When sleep suffers, everything suffers. This is the circle I wrote about in my first essay — and sunlight is the thing that sets it spinning.

Morning light is not a luxury. It is the signal your body uses to organise every other function it performs.

There is also vitamin D, which the skin produces in response to UVB radiation. Vitamin D is not just a vitamin — it behaves like a hormone, and it is involved in immune function, bone health, mood regulation, and, according to a growing body of research, cancer prevention. Low vitamin D levels are associated with increased risk of colorectal, breast, and prostate cancers, among others.

We could supplement. Many people do. But a pill is not the same as the process. When your skin makes vitamin D from sunlight, it triggers a cascade of other biological responses — nitric oxide release, which lowers blood pressure; beta-endorphin production, which improves mood. The sun does more than one thing at a time. Pills do not.

The hours to respect.

I do not want to be reckless about this. The midday sun — roughly between eleven in the morning and three in the afternoon, when the UV index is highest — is genuinely dangerous for prolonged exposure. This is when burns happen. This is when DNA damage accumulates. This is when skin cancer risk rises.

So the advice to be careful during those hours is sound. Shade, hats, protective clothing — all sensible. I am not arguing against sun safety. I am arguing against sun fear.

Because there is a difference between saying be wise about the midday sun and saying the sun is trying to kill you. The first is a useful boundary. The second has turned us into a species that hides indoors, covers every inch of exposed skin with chemicals, and wonders why it feels tired, depressed, and deficient in a vitamin the body was designed to make for free.

The sunscreen paradox.

Here is the question that started this essay: if we are using more sunscreen than ever, why is skin cancer not decreasing?

Researchers have a name for this. They call it the sunscreen paradox. A study published in Cancer Epidemiology, Biomarkers & Prevention, drawing on UK Biobank data, found that sunscreen use was associated with more than double the risk of developing skin cancer. Not because sunscreen causes cancer — but because of what it lets people do.

Sunscreen gives a false sense of security. People apply it and then stay in the sun far longer than they would have otherwise — through the dangerous midday hours, without shade, without clothing, reapplying too little and too late. Canadian focus groups confirmed this pattern: the communities with the highest sunscreen use also had the highest total sun exposure.

We made the shield, then used it as a permission slip to stand in the fire longer.

And then there is the question of what is in the shield itself.

Chemical or physical.

There are two kinds of sunscreen, and the difference matters.

Chemical sunscreens contain organic compounds — oxybenzone, avobenzone, octinoxate, homosalate, octocrylene, and others — that absorb ultraviolet light and convert it into heat. They are invisible on the skin, easy to apply, and in nearly every sunscreen on the shelf.

They also enter your bloodstream. A study published in JAMA, conducted by the FDA itself, found that six common sunscreen chemicals exceeded safety thresholds in the blood after a single day of use. Oxybenzone and homosalate were still above those thresholds on day twenty-one — seventeen days after the last application.

The FDA was careful to say that absorption does not automatically mean harm. But it called for further safety testing, particularly for chronic use. That testing has not been completed. Meanwhile, oxybenzone has shown endocrine-disrupting properties in laboratory studies. Hawaii banned oxybenzone and octinoxate from sunscreens — not because of what they do to humans, but because of what they do to coral reefs. They bleach them. They kill them.

If a chemical is lethal to a coral reef, I think it is reasonable to ask what it does to the organism that applies it to seventy-five percent of its body every morning.

Physical sunscreens — zinc oxide and titanium dioxide — sit on top of the skin and reflect ultraviolet radiation rather than absorbing it. They are generally considered safe. The FDA classifies them as such. They do not enter the bloodstream in the same way. They leave a white cast, which is why the cosmetics industry prefers the chemical versions.

My label test applies here too: if the ingredient list on your sunscreen reads like a chemistry exam, consider the one with two ingredients you can pronounce.

What I actually do.

I am not a dermatologist. I am not giving medical advice. I am telling you what I do, and why.

I go outside in the morning. Early, without sunglasses, and I let the light reach my eyes. Not staring at the sun — never that — but not hiding from it either. I feel the difference. On the mornings I do this, I sleep better that night. That is not a placebo; that is a circadian clock doing what it was designed to do.

Between eleven and three, I am careful. Hat. Shade. Clothing. I do not bake in the midday sun and call it therapy.

When I use sunscreen — and I do, when I will be exposed for a long time — I choose mineral. Zinc oxide. The white stuff. It is less elegant. It works, and I can pronounce everything in it.

And I do not demonise the sun. Because a species that evolved under it for three hundred thousand years did not suddenly become incompatible with it. What changed is not the sun. What changed is that we moved indoors, lost our tolerance, and then blamed the star for burning us when we finally stepped outside.

The sun is not the enemy. It never was. The enemy is the idea that safety means hiding from everything our bodies were built to need.

Wisely.

David's Claude made me a small correction on my first essay. I wrote that my six quiet things have no side effects. It pointed out — gently, as colleagues do — that sunlight is the exception: too much of it causes the very disease I want to prevent.

It was right. So here is the word it offered, and I accept it: wisely.

Catch some sunlight, wisely. First thing in the morning, generously. Through the midday hours, carefully. And always with the knowledge that light is not just a risk to be managed — it is a nutrient your body is starving for.

The dose makes the medicine. The timing makes the dose. And the fear — the reflexive, unexamined fear of the sun itself — may be the thing doing us the most harm.

We evolved under the sun. Our clocks run on it. Our bones need it. Our mood depends on it. The question is not whether to let it in, but when, and how much, and with what on your skin when you do.