Transfer-Resistant vs Water-Resistant vs Waterproof

Three words that sound like a scale — good, better, best — and only one of them is defined anywhere.

On mascara, foundation and eyeliner, none of the three has a legal definition, a threshold or a standardised test in either the US or the EU. On sunscreen, the picture is completely different, and different again depending on which side of the Atlantic the bottle came from. In the US, "waterproof" on a sunscreen is not merely unregulated — it is prohibited.

The reason those two worlds look nothing alike is a classification quirk worth understanding before anything else.

On makeup: nothing, anywhere

We looked for a term-specific rule for these words on cosmetics and did not find one in either market.

US. The only legal hook is the general misbranding standard at 21 U.S.C. 362(a) — a cosmetic is misbranded "if its labeling is false or misleading in any particular." No defined meaning, no threshold, no test for "waterproof mascara".

EU. Article 20(1) of Regulation (EC) No 1223/2009 forbids using labelling to "imply that these products have characteristics or functions which they do not have", and Regulation (EU) No 655/2013 requires claims be "supported by adequate and verifiable evidence". Neither defines, restricts or even mentions these three words. The Commission's technical document on cosmetic claims has dedicated annexes for "free from" claims and for "hypoallergenic" — and nothing on water resistance at all.

"Transfer-resistant" is the emptiest of the three. We found no definition and no standard test for it, for any product category, in either jurisdiction. The clearest evidence of that absence is commercial: L'Oréal holds a granted patent, US7258023B2, on a process for measuring the transfer resistance of a cosmetic product, whose own background notes that transfer resistance is "usually" assessed by ad-hoc in vivo evaluation. Companies patent measurement methods precisely when no standard one exists.

That does not make the claims meaningless — a brand will generally have run something before printing them. It means the something is theirs, and you cannot compare two brands' claims because they are not measuring the same thing.

On US sunscreen: "waterproof" is banned outright

This is the part most people have backwards. 21 CFR 201.327(g):

"(g) False and misleading claims. There are claims that would be false and/or misleading on sunscreen products. These claims include but are not limited to the following: 'Sunblock,' 'sweatproof,' and 'waterproof.' These or similar claims will cause the product to be misbranded under section 502 of the FD&C Act."

Note that the ban is wider than the one word everybody knows about — sunblock and sweatproof go with it.

FDA's stated reasoning, in the 2011 final rule, is evidentiary rather than chemical:

"These terms are essentially exaggerations of performance that FDA does not think can be substantiated."

That is a subtly different argument from the one usually offered. The common explanation is "no sunscreen is truly waterproof". What FDA actually said is that nobody could prove it either way, so the claim cannot be made.

In place of those words, US sunscreen gets exactly two permitted statements — "Water Resistant (40 minutes)" and "Water Resistant (80 minutes)" — each earned by a prescribed test.

What "40 minutes" actually measures

Two things about that number are not what they look like.

It is not forty minutes of swimming. The procedure at 21 CFR 201.327(i)(7)(i) reads:

"Step 2: Perform moderate activity in water for 20 minutes. Step 3: Rest out of water for 15 minutes. Do not towel test site(s). Step 4: Perform moderate activity in water for 20 minutes."

That is about 55 minutes elapsed, of which only the immersion counts. The 80-minute claim repeats the cycle to four immersions.

And the forty came from beach marketing data. FDA, explaining why it declined to change the periods in 2011:

"We based these time periods on marketing data indicating that individuals at the beach or the pool spend an average of 21 minutes in the water and go into the water an average of 3.6 times (43 FR 38206 at 38263, August 25, 1978). We have not received any other data supporting different time periods."

Two twenty-one-minute dips, rounded. It is a description of how people behaved at pools in the 1970s, not a physiological threshold.

The EU does not regulate this at all

This inverts the usual assumption that European cosmetics rules are the stricter ones.

The EU's dedicated instrument on sunscreen efficacy and claims is Commission Recommendation 2006/647/EC. It does prohibit implying total protection:

"No claim should be made that implies the following characteristics: (a) 100 % protection from UV radiation (such as 'sunblock', 'sunblocker' or 'total protection'); (b) no need to re-apply the product under any circumstances (such as 'all day prevention')."

But the word water does not appear in it anywhere. We checked the full text specifically for that.

So where does a European "Water Resistant" claim come from? Two voluntary ISO measurement standards — ISO 16217:2020 for the immersion procedure and ISO 18861:2020 for calculating how much SPF survived — plus a pass mark set by Cosmetics Europe, the industry's own trade association:

"A product may be labelled ´water resistant´ if the value for the 90% lower unilateral confidence limit [mean %WRR – d] is greater than or equal to 50%."

Neither ISO standard sets a threshold; they only say how to measure. The 50% comes from the trade body, and nothing legally compels a European manufacturer to apply it.

So the same two words are two different promises

This is the practical consequence, and it is roughly a factor of two.

The tests are not even physically comparable. FDA requires subjects to "perform moderate activity in water". ISO 16217 seats them in a circulating spa at 30 ± 2 °C, positioned so the jets "cannot impinge directly on the test sites". One is swimming; the other is sitting still in a warm bath, carefully avoiding the jets.

What to actually do with all this

1. On sunscreen, read the minutes, not the adjective. A US label gives you 40 or 80. An EU label gives you a phrase whose threshold is set by industry.
2. Treat any water-resistance figure as an upper bound. It was measured without towelling, on immersion time only.
3. On mascara and foundation, treat all three words as brand vocabulary. They are not a scale, they are not comparable between brands, and "transfer-resistant" is the least anchored of them.
4. Reapply after towel drying regardless of the number. That is what the FDA-mandated directions say, and the test is the reason they say it.

What we could not establish

• Whether any ISO or other standard exists for cosmetic transfer resistance. ISO's own catalogue refuses automated access, and ISO/TC 217 has roughly 66 published standards we could not enumerate. This is a documented absence after a genuine search, not a proof that nothing exists.
• The current text of OTC Monograph M020, which superseded parts of the 2011 sunscreen framework. FDA's document server returned errors on every attempt, so everything here about US sunscreen rests on 21 CFR 201.327 as currently codified and on the 2011 final rule preamble.
• Anything about Australian rules. Search results suggested Australia bans "waterproof" and uses a four-hour water-resistance category. We could not reach a single Australian primary source, so we are not repeating it.
• The complete ISO standards. We read the official ISO 16217:2020 and ISO 18861:2020 preview documents, which include the scope and the immersion procedure but truncate later clauses. Nothing here rests on a clause we could not see.
• Anything about FTC doctrine on these claims. The FTC's site refused every request this session.

Sources consulted, retrieved 28 July 2026:

• 21 CFR 201.327 — over-the-counter sunscreen labelling, via the eCFR versioner API. Quoted for the prohibited claims at (g) and the water-resistance procedure at (i)(7)(i).
• Federal Register 76 FR 35620 (17 June 2011) — FDA final rule on sunscreen labelling and effectiveness testing, via GovInfo. Quoted for the "exaggerations of performance" reasoning, the origin of the 40/80-minute periods, and the rejection of bare "very water resistant".
• 21 U.S.C. 362 — misbranded cosmetics.
• Commission Recommendation 2006/647/EC — on the efficacy of sunscreen products and the claims made relating thereto. Quoted for the prohibited-claims paragraph, and checked specifically for any mention of water resistance.
• Regulation (EC) No 1223/2009, Article 20 and Commission Regulation (EU) No 655/2013 — cosmetic claims.
• Cosmetics Europe Recommendation N°16: Water Resistance Labelling, revised June 2023 — quoted for the 50% threshold. This is a trade-association document, not law, and is cited as such.
• ISO 16217:2020 and ISO 18861:2020 — official preview documents. ISO's own site refuses automated requests; the previews carry the scope and immersion procedure quoted here.
• US7258023B2 — Process for measuring the transfer resistance of a cosmetic product, L'Oréal. Cited for the absence of a standard method, not for any product performance.

A patent argues for its own invention and is used here only for what the industry says about its own measurement practice. Regulation changes, and this describes it as we read it on the date above — general information, not legal or medical advice. GlowSteal has not tested any product for this article.