We’re back with another Special Report, and with just over 50 days left of summer, we’re focusing on none other than Mr. Sun 🌞. The sun is basically like that barista at your local coffee shop in that you see them all the time, buuut you don’t know much about them. Oh—also when they’re not there one day, you’re sad ☹️. Should I keep this metaphor going?
Anyway, let’s get to know the giant fireball our world literally revolves around—and that has a massive impact on everything from our skin to our metabolism. After a zillion hours of research, my takeaway is the sun is one of the most underutilized health tools we have—free, powerful, and profoundly misunderstood. (Reading pairs well with one of my fave songs of all time from The Beatles.)
Let There Be Light
#1 Getting to know Mr. Sun (Oh, Mr. Golden Sun)
If the sun had a dating profile 😎, it’d look something like this:
Name: Sun, but my close friends call me Sol or Helios
Age: 4.6 billion years young
Location: Center of our solar system
Height: 865,000 miles (technically my diameter, but who's measuring?)
Occupation: Powering all life on Earth, NBD.
Star sign: Astronomically speaking, a Yellow Dwarf. Cosmically speaking? A Leo, probably.
Where did the sun come from? Science tells us that over four billion years ago, a giant, spinning cloud of gas and dust collapsed under its own gravity 💥. (Just your average rags-to-nuclear-fusion tale.) Since then, the sun’s been doing the most—powering our food systems, driving the weather and syncing our sleep. No wonder it’s been mythologized for millennia.
How does he do it? Basically here’s how I see it:
The sun gives off electromagnetic energy in waves—some we can see (like visible light), and some we can’t (like ultraviolet or infrared).
These wavelengths carry energy that affects our bodies in different ways.
Shorter wavelengths (like UV and blue light) hit the surface.
Longer ones (like red and near-infrared…ever heard of them?) can penetrate deeper (like, real deep)—impacting tissues, cells, and even internal systems.
Some of the sun rays are blocked by the ozone layer (which is apparently healing?!), but not all. What gets through can cause damage to our skin, eyes, and even crops. That’s where the UV Index comes in: A scale from 0 to 11+ exists to help you gauge how strong the rays are.
But it’s not all doom and sunburns. The right amount of sunlight also helps our bodies produce vitamin D (more on that in a sec), and supports your mood, immune system, and metabolism. Like most things in health, it’s about balance. (And—hey—there’s no GTL without tanning.)
Before we get into all that, here are five sun-believable (sorry, not sorry) facts about the sun ☀️:
1️⃣ The sun is technically teal. While it looks yellow from Earth, most of its energy peaks in the teal range of the visible spectrum. 🤯
2️⃣ Earth is actually farthest from the sun in summer. In the Northern Hemisphere, we’re more distant from the sun in July than in January.
3️⃣ Sunlight takes 8 minutes and 20 seconds to reach us. Every sunrise is 8 minutes old.
4️⃣ In some places, the sun never sets. Countries like Finland, Iceland, and Norway experience what’s called a "Midnight Sun,” basically continuous daylight, during summer. Sounds more fun than it really is.
5️⃣The sun makes up 99.866% of the solar system’s mass. Everything else—planets, moons, asteroids, comets—makes up the remaining 0.134%. You could say that’s really a-mass-ing (okay, this time I’m a little sorry).
#2 Destined to follow the sun
We’re not the only planet that follows the sun’s lead. Our solar system includes eight planets, all of which orbit the sun. In order from the sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
And in all this research, I realized the sun doesn’t just power our planet and solar system—it programs us. We are, quite literally, disciples of the sun god: Amun-Ra! 🌞 Days, seasons, and calendars all follow the sun’s lead. Our bodies do, too. While everyone’s internal clock (circadian rhythm) ticks a bit differently, it naturally syncs to the sun.
Sounds a little culty, but stick with me. When you’re in rhythm, everything functions better, from your sleep to your gut. That’s why daytime sun exposure can boost sleep quality later on—and why stepping outside, even for a few minutes, can be one of the simplest ways to reset your system. In some ways, light really is a natural medicine worth soaking up.
Buuut we’re also up against a bunch of modern disruptors that mess with those natural rhythms. Think: Long nights, artificial light, late scrolling, and not getting enough daylight. Let’s break down three common body-clock bullies.
🕒 Work
Growing research shows our “typical” work schedules clash with our natural body clocks. According to Paul Kelley at the University of Oxford’s Sleep and Circadian Neuroscience Institute, more than 70% of people get up earlier than they should—if the goal is optimal performance and to be well rested. The impact is worse for night shift workers, who are 33% more likely to have depression than those working regular daytime schedules. Yikes. And it’s not just adults, either. There’s been a growing push to have schools adjust start times. (I’m for this in theory, but against it every morning when my kids wake up early.)
Also, yes, I’m one of those people who wakes up early (5am early) when it’s very much dark outside. One thing that’s helped me jumpstart my system is using a sun lamp for 20 minutes at my desk when I start working. Technology!
✈️Travel
Yup, you guessed it—we’re talking jet lag, which is basically your body struggling to keep up when you jump time zones. Jet lag hits differently depending on how far you travel (the more time zones you cross, the harder it is for your internal clock to adjust) and which direction you go. Westward travel stretches your day and delays your clock, often easier on the body. Eastward travel shortens the day, forcing your clock to speed up. Most people find it easier to travel west, because you're working with your body clock versus fighting against it.
📱Digital
It’s not news that screentime affects our circadian rhythm and sleep. Screens emit blue light, tricking our brains into thinking it’s daytime even when it's not. So nighttime scrolling, binge-watching, and late-night laptop sessions? They all delay melatonin production.
#3 Big vitamin D energy
Vitamin D has long been called “the sunshine vitamin”—for good reason. Sunlight ☀️ is arguably the most efficient way to get your dose of vitamin D, which is linked to better bone health, reduced inflammation, improved immunity, and even weight loss. Here’s how it works:
The key principle is absorption: Different pigments or cellular components absorb different wavelengths, triggering biological effects.
Most commonly, the recommended daily dose of vitamin D is 20 mcg (800 IU), and the “optimal” amount of sun exposure is between 5-30 minutes/day. Yet, over a third of U.S. adults and half of the world’s population have a vitamin D deficiency. Most people never test their vitamin D levels—but should. Studies suggest optimal levels for longevity and immune function are likely higher than the current “normal” range. Definitely recommend a blood test. I do Function twice a year, as y’all know.
Not getting enough time in the sun isn’t the only reason someone might have a vitamin D deficiency. A handful of factors can impact how much vitamin D your body actually absorbs—even if you’re basking in the sun.
What’s throwing shade on your vitamin D levels:
Latitude. You don’t need to live on an island in the sun, buuut farther from the equator, the less UVB light reaches the ground.
Skin tone. People with darker skin have more melanin, which provides some natural protection against UV rays, but also means it takes longer for their skin to produce vitamin D from sunlight.
Windows. UVB rays don’t penetrate glass, so, sorry to say, working by a sunny window doesn’t count.
Sunscreen. Most sunscreens block UVB rays to protect skin, buuut they also reduce vitamin D production.
Body temp. People with warmer skin tend to produce vitamin D more efficiently.
Air pollution. Smog and air pollutants can block UVB rays, also blocking vitamin D production.
For those who are deficient, you can boost your vitamin D levels with vitamin D-rich foods like egg yolks, fatty fish, and mushrooms. And you can supplement. (I take 50mcg Momentous Vitamin D3 2000 IU daily along with Vitamin K2 for better absorption.)
Pro tip: Studies show the body is most efficient at making vitamin D at noon. (This is also when the sun is usually at its highest point, and its UVB rays are most intense.)
When The Light Hits
#4 The sun and our mental health
It’s a summer Friday. Slack notifications are off. The sun’s on your face. You’re sipping your favorite iced bev. Life is good.
There’s a scientific reason why people seem to be so much happier when the sun is out. Sunlight exposure activates a part of the brain called the pineal gland, which helps regulate serotonin—aka the feel-good hormone 🧬 (and the inspiration behind 5HT 😎). More sunlight = more serotonin = better mood. Simple math.
But it’s not just mood, either. Sun exposure is linked to higher energy, improved cognitive function, and overall life satisfaction. According to Dr. Mark Hyman, getting sunlight within the first hour of waking up is key to improving your mood, balancing stress hormones, and boosting serotonin and melatonin for better sleep and emotional well-being. Andrew Huberman, Kayla Barnes Lentz, and Gary Brecka all recommend getting sunlight in the morning, too.
Then there’s the social layer. Sunlight often comes bundled with connection—beach days, park picnics, outdoor workouts with friends. Combine movement, laughter, and shared experiences, and you’re not just soaking up rays—you’re getting a chemical cocktail of dopamine, oxytocin, and serotonin 🍹.
But as great as that sounds, it also means a lack of sunshine can have the opposite effect. When sun exposure drops, so does serotonin—and this shift has been linked to higher risks of depression, anxiety, and seasonal affective disorder (or SAD) 😞. Yes, the actual acronym is SAD, and there isn’t a more perfect acronym.
Most SAD cases show up in winter—when days get shorter and we spend more time indoors—but about 10% follow a summer pattern. (Cue summertime sadness 🎶.)
Zoom out, and it’s no coincidence the more time we spend indoors and online, the lonelier and more anxious we get. Experts are even calling attention to how kids are spending less time outdoors, and how spending more time outdoors can decrease their odds of exhibiting anxiety symptoms later on.
It’s sad in many ways that we evolved to chase the light… and now we live in boxes lit by screens. So don’t be a mole person and get some sunshine on your shoulders and fresh air, okay?
#5 The sun and our eyes
Here’s a fun fact I didn’t know before writing this special edition: Your eyes can get a sunburn. Who knew 👀? Without proper eye protection, sun exposure can also lead to cataracts, eye cancers like ocular melanoma, and growths around the eyes.
But sunlight isn’t all bad news for your eyes 👁. A recent study found natural bright light improves contrast sensitivity, which is basically your ability to distinguish objects from their background. Based on the study, the simple act of reading a book outside 📖 could actually improve your vision.
Sunlight also supports retinal dopamine production, helping regulate healthy eye growth in kids. At the same time, natural blue light from the sun protects the retina and may lower the risk of kids developing myopia (or nearsightedness). In fact, kids who spend more time outdoors are less likely to need glasses for nearsightedness. Experts recommend kiddos get at least 90 minutes of outdoor time daily—ideally in the early morning or late afternoon, when the sun is less intense.
Of course, the key to sun exposure is smart exposure 👍. Here are a few ways to protect your eyes—and your kids’ eyes—while still getting the sun’s benefits:
😎 Wear UV-blocking sunglasses. Most sunglasses today have UV protection, buuut if you want to be sure, look for these on the label: 100% protection against both UVA and UVB or 100% protection against UV 400. Fun fact: I constantly lose my sunglasses. A few years ago, I stopped buying fancy ones and just got tons of these Goodr glasses—and haven’t looked back.
🧢 Pair your sunglasses with a hat or visor. I’m no style expert, but my wife tells me summer hats are very in this year.
👓 Don’t confuse UV protection with polarization. According to the American Academy of Ophthalmology (AAO), polarized lenses don’t block UV rays. But they do reduce light glare and eyestrain, which is still helpful when outside.
🔵 Try blue-light filtering glasses indoors. These aren’t directly related to sun exposure, but they could help you stay on track with your internal clock, especially if you’re spending more time in front of screens than in the sun. I just got a pair of Subtle Optics (mentioned in this edition) which blocks the blue AND optimizes eyesight. Will report back soon. 🤓
Annnnd whoever needs to hear this: Never look directly at the sun.
#6 The sun and longevity
You didn’t think I’d do a whole special edition about a topic and not talk about longevity, did you?! Well, here it is. Because apparently moderate sun exposure is linked to a longer lifespan.
One study followed nearly 30,000 women in Sweden (cue ABBA, right?) for 20 years and found those who spent more time in the sun lived longer—an extra 7 months to 2 years—than those with less sun exposure. They also had lower rates of heart disease and fewer non-cancer deaths, including from type 2 diabetes, autoimmune disease, and chronic lung conditions.
Another study in the UK tracked 300,000+ participants and found that, after 13 years, participants with more active sun-seeking behaviour were at a lower risk of all-cause mortality and cancer mortality compared to those who avoided the sun.
So, could sun avoidance be as risky as smoking? IDKID. It’s worth noting these studies found associations—not proof that sun exposure causes a longer life. Still, when you zoom out and look at the broader picture, it’s hard not to connect the dots.
After all, sunlight helps:
Reduce inflammation (which I’m mildly obsessed over lately)
And yet…Despite all this data, there’s a bit of fearmongering out there about sun exposure. There’s even some biohackers who consider it a no-go. Bryan Johnson, for one, avoids the sun entirely (unless the UV is below 3). As usual, I appreciate his provocative stance.
But most longevity experts largely agree early morning sun is the sweet spot.
There’s something fascinating (and a little uncomfortable?) about the idea that sunlight is both pro-aging (skin) and pro-longevity (overall lifespan). My takeaway here is not to avoid the sun, but dose it wisely.
Annnd do it before the sun explodes and kills us all. 😅
Our Skin In The Game
#7 The sun and our skin
Here’s another fun fact for you: The sun has sunspots. Not the kind we can get on our skin, but dark areas on its surface where magnetic fields get twisted and tangled. Our sunspots, on the other hand, are flat brown patches that show up after too much sun exposure—and they’re just one of several ways the sun’s UV rays can affect our skin.
To understand the sun’s impact on our skin, we need to break down the two types of UV rays that reach us:
🔆UVA makes up about 95% of UV rays. These penetrate deep, breaking down collagen and elastin, and are responsible for most visible signs of aging. They also play a major role in the development of skin cancers. Think of these as a “slow burn.”
🔆UVB makes up the other 5%. These hit the surface layers, are the main culprit behind sunburns and blistering, and can lead to skin cancer. That said, they’re also the same rays that trigger vitamin D production—so, like many things, it’s about moderation.
Beyond tan lines or pigment changes, UV exposure affects our skin in more subtle (but significant) ways. Both UVB and UVA weaken the skin barrier, making our skin more prone to dehydration, inflammation, and irritation.
They also break down collagen, the protein that gives our skin structure, firmness, and youthful bounce. We naturally lose collagen as we age (starting as early as our 20s ☹️), but sun exposure accelerates the process. An estimated 80% (!) of visible skin aging in Caucasian women is caused by the sun.
It’s also worth noting that certain medications and skincare ingredients—like antibiotics (e.g., doxycycline), acne treatments (e.g., isotretinoin), or retinoids and AHAs—can increase your skin’s sensitivity to sunlight, raising the risk of burning or irritation even with brief exposure.
To be clear: Not all UV exposure is harmful. After all, our skin is what enables vitamin D synthesis. Plus, in some clinical settings, UV rays are used in phototherapy to treat conditions like psoriasis, eczema, and vitiligo. The real risk comes from cumulative, unprotected exposure—especially sunburns, which inflame and damage skin cells.
#8 The link between sunburns and skin cancer
My Mom was a dermatologist, and she’d regularly flag melanomas, a form of skin cancer, sometimes just by glancing at someone’s elbow 👀. Pretty wild. And, unfortunately, wildly common. At least 1 in 5 Americans will develop skin cancer by the age of 70. In fact, more people are diagnosed with skin cancer each year in the U.S. than all other cancers combined!
Skin cancer doesn’t just show up where you’d expect, either. It can appear on your scalp, ears, lips, and even under your nails. There are three types of skin cancers: Basal cell carcinoma, squamous cell carcinoma, and melanoma. Melanoma is the one to watch—it’s fast-moving and can spread to other organs. More than two people die from it every hour in the U.S. The good news? If detected early, the 5-year survival rate is 99%.
As for the sun ☀️, well, about 90% of nonmelanoma skin cancers and 86% of melanomas are linked to UV exposure. And just five or more sunburns in your life? That doubles your risk of melanoma. 😬
While it seems everyone is more aware of the risks and wearing SPF, researchers expect melanoma rates to rise nearly 6% in 2025. To me, that’s even more reason to double down to avoid sunburns, practice sun protection (more on that next), and get your skin checked by your dermatologist at least once a year.
Oh, and please avoid tanning beds. They can hit your skin with UV radiation 10-15x higher (!) than the sun at its peak intensity. More people develop skin cancer because of indoor tanning than develop lung cancer because of smoking. Let that sink in. Like, wow.
The Bright Road Ahead
#9 Practicing smart sun protection
If you do just one thing for your skin, let it be this: Wear sunscreen. Daily use of an SPF 15 or higher has been shown to reduce the risk of developing that squamous cell carcinoma by 40%. Buuut there’s a lot about sunscreen that’s misunderstood. Let’s clear a few things up 👇
SPF math is weird. SPF 30 ≠ twice SPF 15. It’s actually only 4% stronger. SPF 15 blocks ~93% of UVB rays. SPF 30? ~97%. SPF 50? ~98%. WHAT? 🤯
SPF isn’t waterproof. No sunscreen is "waterproof" or "sweatproof", and the FDA no longer allows these labels. What you now see is “water-resistant,” and even that has limits (often 40 or 80 minutes).
Darker skin tones still need sunscreen. Darker skin tones may have more melanin, offering some natural protection, but it’s not a complete shield. Doctors urge those with black and brown skin to use sunscreen.
Most people under-apply. To get the full benefits of SPF, use about a shot glass for your body and a nickel-sized amount for your face. Reapply every two hours. Brands are jumping in to simplify it: Skin + Me’s patented doser packaging ensures the correct “dose” of SPF, while Beame’s UV Detection Stickers change color when it’s time to reapply (genius).
Mineral vs. Chemical. Mineral sunscreen (also called physical or organic sunscreen) is made with minerals like zinc oxide or titanium dioxide. This sunscreen sits on top of your skin and acts like a shield—reflecting UV rays away. Often leaves a white cast when applied. Chemical sunscreen contains, well, chemical ingredients. These chemical compounds absorb UV rays, turn them into heat, and release that heat from your skin. But, as usual, chemical mostly = bad. Some of the active ingredients in chemical sunscreens have been flagged as endocrine disruptors, meaning they may mess with your hormones. Go with the mineral one.
You cannot DIY your sunscreen. The above stirred a lot of chatter online, especially among MAHA, whose influencers now preach shea butter and watermelon juice as natural alternatives. And while it’s smart to be ingredient conscious, I side with what Dr. Oma Agbai, a board-certified dermatologist, told the HuffPost: “When people ask me which is riskier—sunscreen or the sun—the answer is always the same: the sun, hands down.”
What do I trust? My go-to is EltaMD’s sunscreen + moisturizer, which I’ve used for years. It’s one of the few products I recommend universally—and yes, it’s Bryan Johnson-approved too. (More on my skincare stack here). Wirecutter, where I often turn for recommendations, also suggests sunscreen from brands Thrive and Badger. And then here’s a list for darker skin tones (which unfortunately are not always considered).
What about sun protection that’s not SPF? Beyond sunglasses and hats, here are a few others to consider:
Sun-protective foods. Certain foods, like blueberries and cauliflower, are said to offer internal sun protection thanks to their antioxidants, vitamins, and anti-inflammatory compounds. While I get some benefits, part of me thinks it’s BS. I mean, will eating more carrots really prevent a sunburn? Come on.
Sun-protective clothing. More brands are making clothes with UPF ratings. UPF (Ultraviolet Protection Factor) basically tells you how much of the sun’s UV rays can pass through the fabric. I’ve been seeing this pop up more lately, so it feels important to mention, buuut it’s another thing I think is overrated. If you have a UPF piece you swear by, I’d love to be proved wrong. 🙏 But broadly, wear hats, long-sleeved shirts, etc. at the beach, okay?
Shade. I try to stay in the shade whenever I’m in the sun for long stretches. (Even got into a minor standoff with a boat captain in Barcelona this summer over putting up the canopy.) And, of course, when in doubt, bring shade with you.
Oh, and one more tip: Use digital tools to track the UV index (which ranges from 0-11+) so you know when more protection is needed.
Apple Weather includes a detailed breakdown of the UV index AND—get this—you can add a widget to your home screen to easily check the sun’s intensity. (Learn how in this video.) Jack Dorsey’s latest app also shows you the UV index for your location and helps you see how long you can expose your skin to sunlight before it starts to burn by inputting your skin type (of six options) and the clothes you’re wearing. Very cool.
#10 Our future with the sun
Is it hot in herre? Objectively, yes. According to NASA, the Earth was about 2.65 degrees Fahrenheit warmer in 2024 than in the late 19th century. The last decade was the hottest on record, and this summer continues to break records—from Tampa to Turkey. 🥵
No, the sun isn’t getting hotter. What’s happening is a direct result of climate change. Buuut instead of focusing on that (which is its own urgent topic with huge health implications), let’s talk about how we can adapt and harness the power of the sun.
☀️ Residential solar is rising. Panels can lower energy bills and protect you from rising utility costs. While growth dipped slightly in 2024, global residential solar additions jumped 30% annually between 2020 and 2023. Countries across the EU now offer direct financing or incentives to support adoption. With prices dropping and incentives coming, I think/hope this will only get more accessible.
🌇 Smarter cities, cooler streets. Some cities, like LA and Phoenix, use reflective paint on their roads to reduce heat absorption and make the city cooler. In other places, solar benches are appearing in parks and playgrounds. These benches double as charging stations, making access to power more accessible and enabling people to be in public spaces longer (double win)!
❄️ Cooling as a human right. Access to air conditioning isn’t equal—and that gap is widening. Up to 4 billion people may lack AC by 2050. Some cities are stepping in with cooling centers (think libraries, gyms) equipped with AC during heatwaves. Others are piloting district cooling systems that pull from cold bodies of water to cool buildings, especially in dense or low-income neighborhoods.
🌱 Rooftop gardens doing the most. Rooftop “agrivoltaics” are sprouting up in cities—these rooftop systems combine solar panels and plants into one clever design. The panels shade the crops (improving yield and saving water), while the greenery cools the panels (boosting efficiency). They use up to ⅓ less water than full-sun rooftop farms. So cool (literally).
🚍 Transit’s getting a solar glow-up. Solar-powered buses and trains are gaining traction, helping cities reduce emissions, expand access, and cut operating costs. More equitable transportation = more equitable cities.
To me, the future with our sun is bright (pun intended)—as long as we keep banding together and taking an inclusive, proactive, and science-forward approach to harnessing what is inarguably one of our most powerful resources. If we do that, then maybe, just maybe, we can turn our hottest problem into one of our brightest opportunities.
Now, go get some sun. Here’s your prescription: 10 minutes of morning sunlight, a hat, some SPF, and a walk outside. No pill or app required. 🌞
Did this add some brightness to your day 🌞 or was it a total eclipse 🌒? We’d love your feedback! Hit reply if you have thoughts on how we can make these Special Reports more valuable, or any topics you’re burning to read.
👋 Who are you again? I’m Derek Flanzraich—founder of two venture-backed startups in Greatist (👍) and Ness (👎). I’ve worked with brands like GoodRx, Parsley, Midi, Ro, NOCD, and Peloton. I now run Healthyish Content, a premium health content & SEO agency (among other things).
Every Thursday, I share 5 health things I feel strongly about so you can live healthyish. And this is a special edition: One health topic, 10 parts, for 5HT+ members only. (As a reminder: I’m more your friend with health benefits. None of this is medical advice.)