WhySkin
The Journal
Choosing a Foundation Formula for Your Skin Type
Liquid, powder, stick, and cream-to-powder foundations each suit different skin types. Here's how to match format to your skin type quiz result.
Are Beauty Subscription Boxes Worth It? Doing the Math
A box's advertised "value" assumes you use every sample before it expires. Here's the real cost-per-item math and when a subscription is actually worth it.
Managing Frizz and Humidity, Based on Your Hair Type
Why the same anti-frizz product works differently across hair types — sealing oils for high-porosity, curlier hair vs. lightweight anti-humectants for low-porosity, straighter hair.
SPF 30 vs. 50 vs. 100: What the Numbers Actually Mean
SPF 30, 50, and 100 sound dramatically different, but the actual percentage of UV blocked barely moves between them. Here's the real math.
How to Treat Combination Skin as Two Zones, Not One Problem
Combination skin isn't one confusing skin type — it's an oily T-zone and a drier outer face that each need different products.
Why Your Foundation Looks Different in Every Light
The same foundation shade can look perfect indoors and off outdoors. Here's why warm bulbs, cool fluorescents, and daylight each change how a shade reads, and how to test one properly.
Budgeting for Sunscreen: The One Product Not to Skimp On
Cheap sunscreen isn't the problem — using too little of it is. Here's why stretching a bottle undermines its SPF and how to budget for correct application instead.
Protecting Your Hair From Heat Styling Damage
How to use heat protectant correctly, pick the right tool temperature by hair type, reduce styling passes, and use air-drying to cut cumulative heat exposure.
When to Reapply Sunscreen: A Timing Guide for Everyday Life
An office day, a beach day, and a swim session all need very different reapplication rhythms. Here's a practical timing guide for each.
Color-Correcting Concealer: How the Color Wheel Actually Works
Color correctors work on one simple principle: opposite colors cancel each other out. Here's how green, peach, and lavender correctors each apply that logic, with worked examples.
The Complete Dry Skin Routine, Step by Step
A full AM and PM routine for dry skin, built around the damp-skin humectant technique and rich, sealing moisturizers.
How Often You Should Deep Condition, Based on Hair Porosity
Deep-conditioning frequency and formula weight explained by porosity — low porosity needs lighter formulas plus heat every 2-3 weeks, high porosity needs richer, weekly treatments.