All things SPF
May 29, 2026
How Swellies Was Influenced by K-Beauty
K-beauty changed what daily sunscreen could feel like. Here's how that influenced Swellies, and why a 5-ingredient zinc oxide formula gets to...
Read more →
May 25, 2026
How Much Zinc Oxide Does Sunscreen Need?
A zinc oxide concentration of 20 to 25% is what parents should look for in a mineral sunscreen. Below 15%, zinc oxide...
Read more →
May 20, 2026
Is My Sunscreen Safe for Freshwater?
The reef-safe conversation ignores lakes, ponds, and rivers. That's a problem. Everyone who's read a sunscreen label in the last five years...
Read more →
May 16, 2026
The Seed Oil Evidence Is Inconclusive. We Left Them Out Anyway.
The seed oil conversation started in food. Soybean oil, canola oil, corn oil, refined vegetable oils high in linoleic acid that became...
Read more →
May 15, 2026
Can You Use Diaper Rash Cream as Sunscreen? A Lab-Tested Answer.
Diaper rash cream has zinc oxide. So does sunscreen. The active ingredient is the same. But using diaper rash cream as sunscreen...
Read more →
May 14, 2026
Seed Oils Have No Meaningful SPF. Here's What the Data Shows.
A claim that will not die: raspberry seed oil has an SPF of 28 to 50. It shows up in DIY sunscreen...
Read more →
May 13, 2026
UVA Fades Tattoo Ink. Zinc Oxide Blocks UVA.
UV radiation breaks down tattoo ink. This is the same photodegradation that happens to any organic pigment exposed to UV light, occurring...
Read more →
May 10, 2026
Mineral Sunscreen and Body Hair: Why the White Cast Happens and How to Fix It
Most mineral sunscreens turn chest and back hair white. Here is why it happens, which ingredients are responsible, and what the formula...
Read more →
May 07, 2026
Iron Oxides in Sunscreen: The Blue Light Protection Some Formulas Skip
Iron oxides in sunscreen absorb high-energy visible (HEV) light, commonly called blue light, in addition to providing the tint that neutralizes white...
Read more →