A sunscreen label in the US can legally say only what the FDA's 2011 labeling rule allows: SPF numbers up to "100+", the words "broad spectrum" only if the product passes a documented test for UVA protection, water resistance stated as either 40 or 80 minutes, and never "waterproof" or "sweatproof" — both banned words. That rule is why every confusing thing on the bottle is the way it is. And the FDA's own guidance on SPF math: SPF 30 filters about 97 percent of UVB rays, SPF 50 about 98 — the jump from 50 to 100 is less than one percentage point.
And You publishes beauty culture, not medical advice — for skin conditions, a dermatologist beats a label, always.
What does SPF actually measure?
SPF — sun protection factor — measures UVB protection: the burning rays, per the FDA's labeling and effectiveness guidance. It's a ratio of how long protected skin takes to redden versus unprotected skin, under test conditions. Two things the number does not tell you: anything about UVA (aging, deeper-penetrating rays — that's the broad spectrum test's job) and anything about real beaches, since the FDA's test uses a fixed applied amount of 2 milligrams per square centimeter — considerably more sunscreen than people actually use, as dosing studies summarized by the American Academy of Dermatology have documented for years. Underapplication is why SPF 30 worn thinly performs below its label. The fix is not a bigger number; it's more product.
What does "broad spectrum" legally mean?
Per the 2011 rule, a product may claim broad spectrum only if its UVA protection is proportional to its UVB protection, verified by a standardized test — and only broad spectrum products with SPF 15 or higher may carry the skin-cancer/skin-aging prevention claim. Below SPF 15, the rule requires a warning that the product protects against sunburn only. So the label's fine print is doing real work: "broad spectrum SPF 15" and "broad spectrum SPF 30" are different legal categories, not just marketing tiers.
Why does it say "water resistant (80 minutes)"?
Because in 2011 the FDA banned "waterproof," "sweatproof," and "sunblock" as claims no product can prove, and replaced them with timed testing: a product passes 40 minutes or 80 minutes of water exposure and may state exactly that, and nothing more. The practical reading, straight from the rule: reapply after the stated time in water, after towel-drying, and at least every two hours regardless. The 80-minute claim is not a strength tier compared to other formulas' ingredients — it's a tested performance under standard conditions. Labels age too.
What about "mineral" versus "chemical"?
The FDA's sunscreen monograph recognizes two UV-filter categories: the two inorganic (often sold as "mineral") filters, zinc oxide and titanium dioxide, are generally recognized as safe and effective (GRASE) per the FDA's 2019 proposed rule; so are two organic filters, while 12 others were flagged for more data — the same 2019 proposal that noted the agency wanted absorption testing on the rest. That proposal is still the operative public document, and it's also why "reef-safe" on a label means nothing legally: no US regulator defines the term. Hawaii's 2021 state law banning two specific filters (oxybenzone and octinoxate) from sale is the closest thing to a rule, and it bans ingredients rather than certifying products.
Your label-reading checklist
- Broad spectrum, SPF 30 minimum — the AAD's stated baseline for daily use.
- Water resistance time (40 or 80 min) — plan reapplication around it, literally set a timer.
- Active ingredients list — zinc oxide and/or titanium dioxide if you want the GRASE-listed inorganic filters.
- Ignore: "dermatologist recommended" counts, SPF above 50 on the front (real differences shrink to decimals), and any "reef-safe" badge.
- Expiration date or no date: the FDA requires expiration dating unless a product is proven stable for three years — no date means the company asserted three-year stability, per the rule.
What the label still won't tell you
How much to apply (the answer is about a shot glass for a body, per AAD guidance), whether the texture suits your skin tone — a real gap the beauty industry has only recently addressed with cosmetically elegant mineral formulas — or your personal risk profile, which is a dermatologist conversation. The label is a regulated document, and now you can read it like one.
For more context, read Complete Guide to Building a Sustainable Wellness Routine.
For more context, read What the SPF Number on Your Sunscreen Label Actually Means.
For more context, read What the SPF number on your sunscreen actually means.