How to judge a skin care claim in 60 seconds

You’re standing in the aisle, holding a cream that says “clinically proven to reduce redness in 2 weeks”. You have about a minute before your kid pulls something off the shelf. Here’s a checklist you can run in that minute: six questions, with answers usually hiding in the fine print, or missing entirely, which is itself an answer.

First, what the rules actually say

It helps to know the baseline. In Canada, the Competition Bureau explains that under the Competition Act, a company cannot make a claim about a product’s performance or effectiveness “unless you can prove that the claim is based on an adequate and proper test,” and the test must be done before the claim goes out. The Bureau describes a proper test as one done under controlled conditions, with subjectivity kept low, reflecting real-world use, and supporting the overall impression the ad creates.

The industry’s own rulebook, the Canadian Code of Advertising Standards administered by Ad Standards, says the same thing in its first clause: “All advertising claims and representations must be supported by competent and reliable evidence,” and what counts is “the general impression conveyed by the advertisement,” not the literal words.

So every claim is supposed to have evidence behind it. The catch is that for cosmetics, nobody checks in advance. Health Canada doesn’t pre-approve cosmetic claims; it acts on complaints. The six questions below are how you do the check yourself.

The six questions

1. Who tested it?

Was it an outside lab, a university clinic, or the company’s own team? Was a dermatologist or other specialist involved, and in what role?

“Dermatologist tested” only tells you a skin doctor was involved somewhere, usually in an irritation test. Health Canada’s guidance is clear that there are no rules standardizing what that test has to be. An independent lab is a better sign than an in-house test, but even that just tells you who held the clipboard, not whether the study was good.

Vague: “Tested by experts.” Better: “Tested at an independent clinical research centre under dermatological supervision.”

2. On how many people?

A number is the most useful thing a claim can give you. Twelve people is a pilot. Fifty is a reasonable cosmetic study. A few hundred is unusual for skin care and a sign someone took it seriously.

If there’s no number at all, assume it’s small. The Competition Bureau’s guidance warns against claims based on “statistically insignificant” or one-time results, and against generalizing from a narrow test group to everyone. A cream tested on 20 women aged 25 to 35 tells you little about your father’s winter-cracked hands.

Vague: “Clinically tested.” Better: “In a 4-week study of 62 adults with dry skin.”

3. What was measured?

This is where most claims quietly slip. There are two very different kinds of evidence:

• Measurements. An instrument reads skin hydration, water loss through the skin, redness, or a trained grader scores the skin on a scale.
• Opinions. Participants fill in a questionnaire: “Did your skin feel softer?”

Both are legitimate, but they answer different questions, and the claim should match. “87% said their skin felt smoother” is an opinion result, and the US Federal Trade Commission’s health products guidance says that consumer surveys “are never sufficient to substantiate claims about the effects” of a health product, because people’s experiences can reflect placebo effects (feeling better because you expect to) and other factors. That’s written for health claims, but it’s a fair standard for any claim that sounds like a result.

Also ask: measured compared with what? A change from day one is not the same as a change compared with a control group that used a plain cream.

Vague: “Visibly reduces the look of redness.” Better: “Redness score reduced by an average of 30% versus a plain moisturizer, graded by a blinded assessor.”

4. For how long?

Skin care results are time-stamped. A hydration jump one hour after applying almost any moisturizer is normal and says nothing about next week. Two weeks is enough to see a short-term effect. Eight to twelve weeks starts to tell you something about skin renewal and conditions like eczema (atopic dermatitis, the itchy inflamed rash) that come and go.

Check that the time in the claim matches the study. “Results in 2 weeks” backed by a 2-week study is fair. “Long-lasting hydration” backed by a 24-hour test is a stretch.

Vague: “Long-lasting.” Better: “Hydration remained above baseline at 24 hours.”

5. Was it published?

Published means it appeared in a scientific journal where outside reviewers checked the methods first. Most cosmetic studies never get that far, which isn’t a scandal on its own; it does mean nobody independent has looked at the data.

If a claim cites a study, see if it names a journal or just says “data on file”. “Data on file” means the company has a report it isn’t showing you. That doesn’t make it wrong, but you’re being asked to trust rather than verify.

A related check: the Ad Standards code says advertising must not “distort the true meaning of statements made by professionals or scientific authorities.” If a claim quotes a study, the study should actually say that.

6. Who paid?

Almost always, the company. That’s normal; nobody else will fund a study of a hand cream. It does mean the study was designed to show the product at its best, and a disappointing result may simply never appear in an ad.

The FTC guidance makes a useful demand of advertisers: any statement “about the amount, type, or strength of evidence” must itself be accurate. In plain terms, “proven” should mean proven. When you see that word, look for the study that earned it.

The words that should make you slow down

A few phrases are worth a second look every time:

• “Up to.” “Up to 80% less flaking” means the best participant got 80%; the average could be 20%. An FTC-commissioned study on “up to” claims found that many consumers read them as a promise of the maximum result. Treat “up to” as a ceiling.
• “Helps.” “Helps improve” promises nothing measurable.
• “Look of” / “appearance of.” “Reduces the appearance of fine lines” is a claim about how skin looks, often for a short time, not about the skin itself. It’s allowed precisely because it promises less than it sounds like.
• “Clinically” with no details. Without a number and a measurement, the word is decoration.
• Percentages without a base. “9 out of 10 agreed” — agreed with what, out of how many, and what did the other one say?

Putting it together

Here’s the whole checklist, ready for the aisle:

1. Who tested it? Independent lab or in-house?
2. How many people? Is there a number at all?
3. What was measured? Instrument, trained grader, or questionnaire? Compared with what?
4. For how long? Does the claim’s timeframe match the study’s?
5. Was it published, or is it “data on file”?
6. Who paid, and does the wording (“proven”, “up to”) oversell what they found?

A claim that answers four or more of these clearly is one someone was willing to be checked on. A claim that answers none is asking for your trust, not offering evidence. And if you’re buying for a real skin problem, a rash, persistent dryness, eczema that keeps flaring, no label replaces care: if it isn’t better after two weeks, see your doctor or pharmacist.

What to remember: specific beats vague. Numbers, measurements, timeframes and a named study are signs a company expects scrutiny. “Clinically tested”, “up to”, “helps” and “the look of” are signs it would rather you didn’t look too closely. Neither is proof, but in 60 seconds, it’s a very good sort.