Sunscreen 101: What's Actually In Your Sunscreen (And Why It Matters)
Everything you need to know to choose sun protection that works with your body, not against it.
If you're like most people, choosing a sunscreen comes down to one factor: SPF number. Higher SPF, better protection, right? Grab it and go. But here's what most people never stop to consider: what's actually IN that bottle, and what happens once it's on your skin?
Not all sunscreen is created equal and some of the most popular formulas on store shelves are doing a lot more than blocking UV rays.
Let's break down what's really going on and how to protect your skin without trading one risk for another.
Chemical vs. Mineral Sunscreen: Two Completely Different Mechanisms
This is the distinction almost nobody explains clearly, so let's start here.
Chemical sunscreens work by absorbing UV light. When that light hits your skin, the active chemical filters undergo a reaction, converting that UV energy into heat, which is then released from the skin. The ingredients responsible for this — oxybenzone, avobenzone, octocrylene, homosalate, to name a few — are lab-synthesized compounds. Many were developed decades ago, before researchers fully understood what their breakdown products would mean for long-term health.
Mineral sunscreens work through a completely different mechanism. Their active ingredients, zinc oxide and titanium dioxide, sit on top of the skin and physically reflect UV rays away from the body. There's no chemical reaction and no absorption into the bloodstream. It's a physical barrier, not a chemical one.
That distinction matters more than most people realize, because of what we now know about chemical sunscreen absorption.
What the Research Actually Shows
This isn't about fear-mongering away from sun protection. It's about making an informed choice. Here's what's been established:
Several common chemical UV filters are banned in Europe and Australia. These aren't fringe ingredients…they're found in many sunscreens sold in the U.S. but regulatory bodies in other countries have restricted them due to safety concerns.
Many of these chemicals mimic the body's natural hormone signaling. This means they can function as endocrine disruptors, potentially interfering with hormone communication in the body when absorbed repeatedly over time.
A study published in JAMA found significant systemic absorption after a single use. Researchers had participants apply chemical sunscreen under maximal use conditions. After just one application, blood plasma levels of the active ingredients exceeded the FDA's own threshold, the level at which the agency recommends additional safety and toxicology testing. This happened after one use, not months of cumulative exposure.
These chemicals are cumulative. Repeated exposure means they can build up in body tissue over time, similar to many other environmental toxins we're exposed to daily.
Children absorb more, more efficiently. Kids have a higher surface-area-to-body-weight ratio and thinner skin than adults, meaning topical products absorb more readily. This is part of why chemical sunscreens generally aren't recommended for infants.
The FDA regulates sunscreen as a drug, not a cosmetic. This classification alone signals how seriously the systemic effects of these products are treated at a regulatory level.
A Note on Spray Sunscreens
Beyond absorption through the skin, spray sunscreens carry an additional concern: inhalation.
Many spray formulas contain benzene derivatives, and breathing in fine aerosolized particles, especially with repeated use near the face, introduces its own exposure pathway. If spray is your preferred format, spray it into your hands first and rub it on rather than applying it directly to the body.
How to Build a Smarter Sun Protection Strategy
The good news: you don't have to choose between protecting your skin from the sun and avoiding unnecessary chemical exposure. Here's how to approach it in order of priority.
1. Physical barriers first
Before sunscreen even enters the conversation, lean on:
Shade
Shelter
Sun-protective clothing (look for UPF-rated fabric for extended time outdoors)
2. Choose mineral over chemical
When you do reach for sunscreen, check the active ingredient list for non-nano zinc oxide or titanium dioxide. These sit on the skin's surface instead of absorbing into it.
3. Support your skin from the inside out
Nutrition plays a meaningful role in your skin's resilience to UV stress. Foods and nutrients to prioritize:
Vitamin D — your body needs some sun exposure to produce this, so the goal is balance, not total sun avoidance
Astaxanthin — found in wild-caught salmon, trout, shrimp, crab, and krill (more on this below)
Green tea — rich in EGCG, an antioxidant studied for its skin-protective properties
Vitamin E — found in nuts, seeds, and leafy greens
Polyphenols — found in berries, apples, grapes, leafy greens, nuts, seeds, dark chocolate, and coffee
Polypodium leucotomos — a fern extract studied for its internal skin-protective effects
4. Be mindful of foods that work against you:
High-glycemic, ultra-processed foods
Seed oils and other non-biologic fats
Skim or non-fat dairy, which often contains emulsifiers
5.Morning sunlight exposure to build more tolerance
Getting regular sunlight exposure before 10am has been shown to rebalance and support the circadian rhythm as well as help build the bodies natural response to sunlight. This is called building your “sun callus”. It’s typically advised to minimize/moderate prolonged sun exposure during peak UV windows (typically from 10am-4pm).
Nature's Medicine Spotlight: Astaxanthin
If there's one nutrient worth adding to your radar this summer, it's astaxanthin. This deep-red pigment, found in wild salmon, trout, shrimp, and krill, is one of the most potent antioxidants studied for skin and sun resilience.
Research suggests astaxanthin may:
Reduce UV-induced oxidative stress and inflammation in the skin
Protect cell membranes, including mitochondrial membranes, from UV-related oxidative damage
Improve skin elasticity, texture, and hydration with consistent use
Wild-caught seafood is the most direct food source. For a more concentrated and consistent dose, a daily supplement throughout the summer months tends to offer more noticeable benefit than occasional use.
The Bottom Line
Sun protection isn't about choosing between "safe" and "effective." Mineral sunscreens, paired with physical barriers and a nutrient-supportive diet, give you real protection without the chemical trade-offs. The goal has never been to avoid the sun entirely. It's to protect your skin intelligently.
Frequently Asked Questions
Is mineral sunscreen actually better than chemical sunscreen?
Mineral sunscreen (non-nano zinc oxide or titanium dioxide) sits on top of the skin and physically reflects UV rays, while chemical sunscreen is absorbed into the skin and bloodstream. For people seeking to minimize chemical exposure, mineral sunscreen is the preferred choice.
Is chemical sunscreen safe to use?
The FDA has not banned the most common chemical UV filters, and sunscreen manufacturers maintain their products are safe when used as directed. However, research has shown that several active ingredients are absorbed into the bloodstream at levels exceeding FDA safety thresholds after a single application, and some are restricted in other countries. Individuals concerned about systemic absorption opt for mineral-based sunscreens.
What should I look for on a sunscreen label?
Check the active ingredients list. For mineral sunscreen, look for non-nano zinc oxide or titanium dioxide. For chemical sunscreen, the common active ingredients to be aware of include oxybenzone, avobenzone, octocrylene, and homosalate.
Is spray sunscreen safe?
Spray sunscreen carries an additional concern around inhalation risk, since many formulas contain benzene derivatives. Spraying into the hands and applying manually, rather than spraying directly onto the body, reduces this exposure.
Can diet really help protect skin from sun damage?
Nutrition doesn't replace sunscreen, but certain nutrients (astaxanthin, vitamin E, polyphenols, green tea) support the skin's resilience to UV-induced oxidative stress. These work best as a complement to topical protection, not a substitute for it.
Is chemical sunscreen safe for kids?
Children absorb topical products more readily than adults due to a higher surface-area-to-body-weight ratio and thinner skin. Mineral sunscreen is generally the recommended choice for infants and young children.
