What does a "restricted" ingredient actually mean?
Short answer: almost never a ban. "Restricted" is a regulator's concentration or use-condition rule — a maximum percentage, a pH floor, a leave-on/rinse-off distinction — attached to an ingredient that's still considered safe within those limits. In our own catalog, 2,304 live-offer products (about 1 in 4 of the 8,501 we track) carry at least one ingredient flagged on Health Canada's Cosmetic Ingredient Hotlist, and the single biggest contributor — citric acid, in 1,439 of them — is an ordinary pH-adjuster used at levels the Hotlist itself permits.
Where do these Hotlist flags in our catalog actually come from?
Most of them trace to one regulatory category: alpha-hydroxy acids. Health Canada's Hotlist entry for AHAs caps them at 3–18% total mono-AHA-equivalent concentration and a pH of 3.5 or higher for products meant for general consumer use, with looser limits (18–30%, pH down to 3.0) reserved for professional-use formulas, plus a required sunscreen-use advisory on the label. Citric acid, lactic acid, glycolic acid, and gluconolactone all fall under that single entry, which is why they dominate our numbers: citric acid appears in 1,439 live-offer products, lactic acid in 368, gluconolactone in 338, and glycolic acid in 130. None of those four ingredients is prohibited — they're regulated the way sunscreen SPF numbers are regulated, as a labeling and concentration standard, not a safety verdict against the molecule itself.
Salicylic acid is next at 337 products, capped at 2% under a separate Hotlist entry. Retinol shows up in 146 products under a 0.2%–1.0% cap depending on whether the product is a leave-on, full-body formula or something more localized like an eye cream. The two smallest of our top eight, methylisothiazolinone (94 products) and methylchloroisothiazolinone (90 products), are the ones where the restriction is genuinely strict — MI is barred from leave-on products entirely and both preservatives are capped at a combined 0.0015% in rinse-off formulas, reflecting a real, well-documented contact-allergy risk that's stricter than the AHA entries above it. That's the pattern worth internalizing: "restricted" isn't one severity level, it's a category that spans "ordinary active with a labeling rule" all the way to "narrowly permitted because of a known sensitization risk" — the Hotlist doesn't distinguish the two in its yes/no flag, so the flag alone tells you almost nothing about which end an ingredient sits on. (Full ingredient-level detail, including source citations, is on each ingredient's page — see citric acid, salicylic acid, and retinol.)
How is "restricted" different from "prohibited"?
Prohibited means Health Canada or the FDA has decided no permitted use exists — the ingredient cannot legally go into a cosmetic sold in that market, full stop. Restricted means the ingredient can be used, but only inside a defined envelope: a maximum percentage, a required pH, a rinse-off-only rule, a mandatory warning statement. Every one of the eight most-flagged ingredients in our catalog is in the restricted category, not the prohibited one, and every product we could check that carries one of these flags is formulated within — or below — the concentration or pH limit that applies to it; that's the condition the Hotlist sets, not a call about whether the ingredient belongs in skincare at all.
What is the Health Canada Hotlist, legally?
It's the enforcement reference for Canada's Cosmetic Regulations, which run on notification rather than premarket approval: manufacturers and importers must send Health Canada a cosmetic notification — product name, function, and a full ingredient list with INCI names and concentrations — within 10 days of first selling a product in Canada, under section 30 of the Regulations. Health Canada doesn't clear formulas before they hit shelves; it reviews the notifications, and under section 29 it can separately demand safety evidence from a company at any time, with a mandated stop-sell if that evidence isn't produced. The Hotlist itself isn't a law — it's Health Canada's own published interpretation of what a notified formula needs to satisfy under the Food and Drugs Act and Regulations to avoid being flagged for that follow-up scrutiny [1]. Reading a Hotlist entry is closer to reading a nutrition-label rule than reading a criminal statute: a bright line for compliance, not a toxicology verdict on the molecule.
Is the U.S. list actually shorter?
Yes, by a wide margin, and it uses a different structure entirely. The FDA's prohibited-and-restricted cosmetic ingredients sit in 21 CFR Part 700 Subpart B, and it names roughly nine substances or substance categories total: bithionol, certain mercury compounds, vinyl chloride as an aerosol propellant, halogenated salicylanilides, zirconium in aerosols, chloroform (fully prohibited as a cosmetic ingredient), methylene chloride, chlorofluorocarbon propellants, and a rule on prohibited cattle materials tied to BSE risk [3]. Most of these are legacy entries from decades-old safety findings, not an active, expanding list the way Canada's Hotlist is. That's a structural difference, not proof either country is more or less careful: the U.S. framework leans on the Federal Food, Drug, and Cosmetic Act's "adulterated" standard, which lets FDA act against a specific product found to contain "any poisonous or deleterious substance which may render it injurious to users" after the fact, and — since the 2022 Modernization of Cosmetics Regulation Act amended that same section — now also requires manufacturers to keep "adequate substantiation for safety" on file for each product [4]. Neither the U.S. nor Canadian system runs ingredients through a government safety trial before they can be sold; both are post-market systems that differ mainly in how much they spell out in advance.
So what should a restricted flag change about what I buy?
Mostly nothing, if the product is otherwise formulated the way you'd expect — a listed active near the top or middle of an ingredient list at a plausible over-the-counter concentration, sold through a legitimate retailer. A Hotlist flag on citric acid, lactic acid, or gluconolactone is not a reason to avoid a cleanser or toner; it means the formula is one Health Canada has a defined concentration rule for, which most compliant products already sit inside by default because that's how the acid is dosed for cosmetic use in the first place. Where it's worth paying closer attention is the narrower end of the restricted category — retinoids, at concentrations that climb toward or past the 0.2%–1.0% cap, or preservatives like MI/MCI in a leave-on product, where the restriction reflects a specific, tighter risk profile rather than a routine labeling rule. If you want to check a specific product or ingredient against these thresholds yourself rather than trust a marketing claim either way, our ingredient safety checker runs the same rule set used to generate these flags.
Key sources
Catalog counts are a live snapshot of our own database (August 2026) and will drift as offers rotate; treat the numbers above as directional, not permanent.