SunStoke
The Journal
How SPF Actually Works (and What the Number Really Means)
SPF isn't a timer and it isn't a percentage of 'strength': it's a ratio measured in a lab. Here's what SPF 15, 30, and 50 really block, why 'broad spectrum' matters, why the FDA says SPF is not related to time in the sun, and why the number on the bottle is only half the story.
Chemical vs Mineral Sunscreen: Which Should You Use?
Chemical and mineral sunscreens protect your skin in different ways — one absorbs UV, the other reflects and absorbs it. Here's how each works, their real pros and cons, how they hold up in makeup and water, and how to pick the one you'll actually wear and reapply.
How Much Sunscreen to Apply — The Amount Almost Everyone Gets Wrong
The single biggest reason sunscreen underperforms isn't the SPF you chose — it's using too little. Here's the 2 mg/cm² rule in plain teaspoons and shot glasses, how far a bottle should actually last, and how to cover the spots people always miss.
Understanding the UV Index: How to Read It and What to Do
The UV index is a free daily forecast of how fast the sun can damage your skin — yet most people scroll past it. Here's what the 0-to-11+ scale means, where the forecast comes from, what raises it, and the simple actions each band calls for.
Tanning Myths, Debunked
A 'base tan,' the idea that tanning beds are safer, the belief that you can't burn on a cloudy day: the myths around tanning are stubborn and risky. Here's what the FDA, WHO and IARC actually say, and why shade and clothing are the only 'safe' part of the story.
Protecting Your Skin by Type: A Guide to the Fitzpatrick Scale
Not all skin responds to the sun the same way. The Fitzpatrick scale sorts skin into six types by how it burns and tans — here's what each type means for how you protect yourself, how to place yourself on it, and why no type is exempt from sun protection.
What a Sunburn Really Is (and Why Prevention Beats Any Cure)
A sunburn isn't just pink skin — it's a visible sign of DNA damage and an inflammatory response that has to run its own course. Here's what's actually happening under the skin, why redness shows up late, why it can't be undone once it starts, and why the tools on this site exist to help you avoid one in the first place.
How Much Sunscreen Each Body Area Actually Needs
'A shot glass for the whole body' is the right rule, but it hides how unevenly that shot glass should be split. Here's the rule-of-nines math behind the Sunscreen Amount Calculator, worked out region by region — face and neck, arms, torso, and legs — in grams and teaspoons.
Sunscreen Reapplication Timing for a Real Day Out
The two-hour rule is a starting point, not the whole story — swimming, sweating, and towelling off all reset the clock differently. Here's a full beach-day timeline, worked out on the SPF Reapplication Timer, showing exactly when each top-up actually falls.
Sun Protection for Babies and Kids: Clothing, Shade, and Sunscreen Basics
Children burn easily and a smaller body still needs at least one ounce of sunscreen for a whole-body coat, says the FDA. Shade and clothing come first. Here's how the site's calculators apply to a child, and where this article stops and a pediatrician's advice starts.