How the 1% Rule in Skincare Works (And How to Spot It)
The 1% rule is the point in an INCI list below which ingredients no longer have to be ordered by concentration. Above it, the order is regulated and you can trust it. Below it, the brand arranges things however it likes.
That single distinction changes how you read a label. Without it, an ingredient list looks like a ranking from most to least, top to bottom. With it, you understand that the ranking stops somewhere in the middle — and that the useful skill is knowing where.
If you are new to this, start with the fundamentals of reading and decoding an INCI list. This article picks up once concentration order is familiar.
Where the 1% threshold comes from
The threshold comes straight from the EU Cosmetic Products Regulation. Article 19 requires ingredients to be listed in descending order of concentration, then adds an exception: below 1%, they may appear in any order¹.
The phrase "1% rule" is not regulatory. It is shorthand that grew out of the skincare community to describe the practical effect of that exception. You will not find it written anywhere in the law.
The reasoning behind the exception is straightforward: at very low doses, exact ordering stops telling a shopper anything useful, and enforcing it would effectively force brands to publish the fine detail of their formulas.
How to find the threshold on a real label
No brand marks where the 1% line falls. You have to infer it, and the best marker is the first preservative.
| Marker | What it tells you | Reliability |
|---|---|---|
| Phenoxyethanol | Capped at 1% in the EU² — everything after it is at 1% or below | Very high |
| Other preservatives (Sodium Benzoate, Potassium Sorbate) | Used at low doses, usually mark the same zone | Good |
| Parfum / Fragrance | Almost always near the end | Good |
| Declared allergens (Linalool, Limonene…) | Declared from 0.001%³, so always below the threshold | Very high |
| Colourants (CI 77491, CI 19140) | Consistently listed last | Very high |
Phenoxyethanol is the sharpest marker, for a specific regulatory reason: it cannot exceed 1%. Its position marks a boundary rather than an estimate.
A worked example: finding the line
Take a realistic serum list:
Aqua, Glycerin, Niacinamide, Propanediol, Sodium Hyaluronate, Phenoxyethanol, Ethylhexylglycerin, Panthenol, Tocopherol, Palmitoyl Tripeptide-1, Parfum, Linalool
Before Phenoxyethanol — Aqua, Glycerin, Niacinamide, Propanediol, Sodium Hyaluronate. These five are genuinely in descending order and all likely sit above 1%. Niacinamide in third position is credible at an active dose.
Phenoxyethanol — the boundary. It is at 1% maximum.
After — Ethylhexylglycerin, Panthenol, Tocopherol, Palmitoyl Tripeptide-1, Parfum, Linalool. All at 1% or less, in an order that carries no information. Panthenol could be at 0.9% and the peptide at 0.001%; nothing on the label lets you tell.
Verdict on this list: niacinamide is the only active you can confidently say is present at a serious dose. The peptide advertised on the front of the pack sits below the threshold — there is no way to know whether it does anything.
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Start for freeWhat the threshold does not tell you
This is where a lot of guides overreach. "End of the list means useless" is wrong, and believing it will make you dismiss good products.
Some ingredients are designed to work below 1%:
- Retinol — active from 0.1%, and often uncomfortable above 0.5%
- Peptides — dosed in fractions of a percent by design
- Tocopherol (vitamin E) — an effective antioxidant at low doses
- Fragrance allergens — provoke reactions at 0.001%, which is exactly why they must be declared
Conversely, these actives need volume to do their job, and finding them below the threshold is a genuine signal:
| Active | Dose usually needed | Below the 1% line? |
|---|---|---|
| Niacinamide | 2–5% | Probably not enough |
| Vitamin C (Ascorbic Acid) | 10–20% | Clearly not enough |
| Hyaluronic Acid | active from ~0.1% | Still useful |
| Glycerin | 3–10% | Not enough to hydrate on its own |
| Zinc Oxide (UV filter) | several % | Not enough |
So the useful question is not "where is this ingredient in the list" but "what dose does this particular ingredient need in order to do the job it is being sold for".
Using it while standing in a shop
Three steps, in order:
- Find the first preservative. That is your boundary.
- Check whether the advertised active sits before or after it. If it is after, the marketing claim rests on an unknown quantity.
- Ask what dose that active actually needs. Retinol after the preservative is normal. Niacinamide after the preservative, in a product sold on its niacinamide, is not.
This is the same reasoning you need to judge whether a skincare product is good, and it complements the step-by-step method for checking skincare ingredients before buying.
Frequently asked questions about the 1% rule
What is the 1% rule in skincare?
The 1% rule refers to the point in an INCI list below which ingredients no longer have to appear in descending order of concentration. Above 1%, the order is regulated and reliable. Below it, a brand can list ingredients in whatever order it likes. It is not written as a rule in the regulation itself — it is the practical consequence of Article 19, which only requires descending order above that threshold.
How do you find the 1% line on an ingredient list?
The most reliable marker is the first preservative. Phenoxyethanol is capped at 1% in the EU, so anything appearing after it is almost certainly at 1% or below. Colourants, fragrance and individually declared allergens are other dependable end-of-list markers. In a typical formula the threshold sits somewhere between the sixth and tenth ingredient.
Is an active at the end of the list always useless?
No, and this is the nuance that matters. Some actives work at very low doses: retinol is active at 0.1%, and peptides and fragrance allergens act well below 1%. What is questionable is a heavily marketed active — niacinamide, vitamin C, hyaluronic acid — that needs several percent to do anything and turns up after the preservative. The threshold is a signal, not a verdict.
Is the 1% rule an actual legal requirement?
The 1% threshold is genuinely in the EU Cosmetic Products Regulation: Article 19 requires descending order of concentration, then specifies that ingredients present at under 1% may be listed in any order. The phrase "1% rule", however, is skincare-community shorthand rather than regulatory language — you will not find it written that way in the legal text.
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References / Sources
¹ Regulation (EC) No 1223/2009 on cosmetic products — Article 19, labelling and descending order of concentration, including the exception that applies below 1%: eur-lex.europa.eu
² CosIng — the EU cosmetic ingredient database, including the EU concentration limit for Phenoxyethanol (Annex V): ec.europa.eu/growth/tools-databases/cosing
³ Regulation (EC) No 1223/2009 — Annex III, individual declaration thresholds for fragrance allergens (0.001% leave-on, 0.01% rinse-off), as amended by Regulation (EU) 2023/1545: eur-lex.europa.eu
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