Sunscreen Basics

Sunscreen is one of the most effective tools to prevent skin cancer, sunburn, and premature aging. But not all sunscreens are equal — and not all claims are reliable.

Summary
Choose a broad-spectrum SPF 30+ or higher, apply generously, and reapply often. Physical blockers like zinc are highly reliable, while chemical filters are also safe when tested properly.

What SPF Really Means

SPF 30 filters ~97% of UVB rays.
SPF 50 filters ~98% of UVB rays.
No sunscreen blocks 100%.
The biggest factor is application — most people apply only half the recommended amount.

Types of Sunscreens

Chemical filters (oxybenzone, avobenzone, octocrylene, etc.)
- Pros: Lighter feel, easier to spread, often invisible on skin.
- Cons: May irritate sensitive skin; some degrade faster in sun/heat.
Physical/mineral blockers (zinc oxide, titanium dioxide)
- Pros: Very stable, broad-spectrum, effective immediately, lower irritation risk.
- Cons: Thicker texture, can leave a white cast (though tinted formulas help).

👉 Zinc sunscreens are often recommended by dermatologists, especially for sensitive skin and children, because their UV protection is consistent and reliable.

Which Sunscreens Can You Trust?

Independent testing by Choice (Australia) and Consumer Reports (US) shows not all products match their label claims.
Zinc-based sunscreens generally perform well, including those marketed as “reef safe.”
Some brands — like Kokua Sun Care (Hawaii, zinc-based, backed by pro surfer Kelly Slater) — build reputations on transparent testing.

⚠️ Always look for independent reviews and third-party testing, not just the label.

Sunscreen and Coral Reefs

Myth: Sunscreen causes coral bleaching.
Truth: Coral bleaching is primarily caused by warming oceans from climate change.
Some chemical UV filters (oxybenzone, octinoxate) may harm coral larvae in lab studies at high concentrations.
Real-world reef exposure is far lower, but many people choose reef-safe (zinc-based) sunscreens when swimming in sensitive areas.

How to Use Sunscreen Effectively

Apply at least a teaspoon per limb (~30–40ml for full body).
Reapply every 2 hours, or after swimming, sweating, or toweling off.
Use daily when the UV index is 3 or higher (common in Australia year-round).
Combine with hats, clothing, and shade for full protection.

FAQs

Q: Is zinc sunscreen better?
A: Zinc is stable, broad-spectrum, and very reliable. But high-quality chemical sunscreens are also safe and effective. The best sunscreen is the one you’ll actually use consistently.

Q: Do higher SPF sunscreens last longer?
A: No. SPF is about the level of protection, not duration. All sunscreens need reapplication.

Q: Can darker skin tones skip sunscreen?
A: No. While melanin provides some protection, darker skin can still develop sun damage, aging, and skin cancer.

Q: Can sunscreen prevent melanoma?
A: Yes. Regular daily use of SPF 30+ significantly lowers the risk of melanoma and other skin cancers.