The ingredient list on a moisturiser or serum looks like noise: thirty words, half of them chemical names, in six-point type on the back of the box. It is in fact one of the most regulated pieces of text on the product. In the United States, the Food and Drug Administration sets rules under 21 CFR 701.3 for what goes in the list, in what order, in what type size and on which panel. Those rules do not tell you the exact percentage of anything, but they let you infer a lot: which ingredients dominate the formula, where the active you are paying for probably sits, and what the word 'fragrance' is standing in for. This note explains the rules as published on FDA's cosmetics labeling guide, as of October 2026, and how to use them at the shelf.
Ingredients are listed by amount, until the 1 percent line
The core rule is simple. Per FDA's labeling guide, ingredients must be declared in descending order of predominance under 21 CFR 701.3(a). The first ingredient is present in the largest amount, the second in the next largest, and so on. For most water-based creams and serums the first word is water (often written as Aqua), followed by the humectants, emollients and emulsifiers that make up the bulk of the formula. If a product is marketed on a particular ingredient and that ingredient appears tenth, the order is telling you something the front of the box does not.
The descending order has a floor. FDA's guide states that ingredients present at 1 percent or less may be listed in any order after those present at more than 1 percent, under 21 CFR 701.3(f)(2). This creates an invisible line somewhere in the list. Above it, order means concentration. Below it, order is the manufacturer's choice. Finding that line is the single most useful skill in reading a label, and the next section shows how to estimate it.
Why the 1 percent line matters for actives
Many well-known skincare actives are used at low concentrations. Preservatives, some peptides, plant extracts and several antioxidants typically sit at or under 1 percent. A practical way to locate the line is to look for an ingredient that is almost always used at very low levels, such as a preservative like phenoxyethanol, and treat everything after it as being in the any-order zone. That is an estimate, not a measurement, because the regulation sets the rule for order and does not require the brand to mark where the 1 percent boundary falls. Where a brand does not publish a concentration, the label alone cannot confirm one.
Some brands sidestep the guesswork by putting the percentage in the product name. The Ordinary's Niacinamide 10% + Zinc 1% is a clear example: the name states the concentrations, and the ingredient list then follows the standard order rules. Our review of The Ordinary Niacinamide 10% + Zinc 1% discusses what that stated concentration does and does not tell you. Where a brand does not state a figure, the honest reading is that the active is present at an undisclosed amount, which may be meaningful or may be a trace.
'Fragrance' is one word for many ingredients
Per FDA's guide, under 21 CFR 701.3(a) fragrance and flavor compounds may be declared collectively as 'fragrance' or 'flavor' rather than listing each component, and disclosure of the individual components is optional. A single word on the label can therefore represent dozens of substances. For readers with sensitive skin or known reactions, this is the most important line on the list to notice, because the individual compounds are not required to be shown. A product labelled 'fragrance free' is making a marketing claim about the finished product rather than a regulated ingredient declaration, so read the list as well as the front.
Note also that the position of 'fragrance' in the list follows the same order rule as everything else. Fragrance near the top of a list means the formula contains more of it than of the ingredients that follow; fragrance at the end, below the preservatives, suggests a small amount. Neither position is a safety judgment. It is simply information the brand is required to provide and most people never use. Essential oils, by contrast, are usually named individually in the list, so a product can carry no 'fragrance' line and still be scented; reading the whole list catches both cases.
Where colour additives and 'other ingredients' fit
Two more exceptions to the descending order appear at the bottom of most lists. First, FDA's guide states that colour additives may be listed in any order after the non-colour ingredients, under 21 CFR 701.3(f)(3). This is why you will often see a cluster of CI numbers or names such as Red 40 at the very end, regardless of amount. Second, where FDA has accepted an ingredient's identity as a trade secret under 21 CFR 720.8, the manufacturer may substitute the phrase 'and other ingredients' in place of the name, per the same guide. That phrase means a component is present that the brand is permitted not to disclose; it does not mean the list is incomplete by error.
Products that are both cosmetics and over-the-counter drugs, such as a moisturiser with a sunscreen filter, follow an additional rule: FDA's guide states that active drug ingredients are listed first under a separate 'Active Ingredients' heading before the cosmetic ingredients. If you see two lists, the first is the drug part and the second is the cosmetic part. The recent approval of bemotrizinol as a sunscreen filter, which this site covered separately, will appear in that first list on any product that uses it.
Front-of-pack claims are not the ingredient list
The regulated part of the label is the ingredient declaration. The words on the front, such as 'hypoallergenic', 'natural', 'dermatologist tested' or 'clean', are claims. FDA's cosmetics labeling claims page states that labeling, including claims, must be truthful and not misleading, and that FDA does not have the authority to approve claims before cosmetics go on the market. The same page notes that advertising claims are regulated by the Federal Trade Commission rather than FDA. In practice, this means a front-of-pack claim has no fixed regulatory definition the way the ingredient order does, and the ingredient list is the better source when the two seem to disagree.
The type size rule is also worth knowing when you are squinting at a box. FDA's guide gives a minimum letter height of 1/16 inch for the ingredient declaration, with a 1/32 inch minimum allowed when the total labeling surface is under 12 square inches, under 21 CFR 701.3(b) and (p). Small jars genuinely are allowed smaller type. The declaration must appear on an information panel of the outer container, or on the immediate container if there is no outer packaging, so a product whose box you discarded may carry the list only on the box. Our affordable skincare routine guide links to the full ingredient lists for each product for that reason.
A sixty-second way to read any label
At the shelf, do four things. Read the first five ingredients; they are the body of the formula. Find the ingredient you are buying the product for and note how far down it sits. Look for a preservative to estimate where the 1 percent line falls, and treat everything after it as unordered. Finally, scan for 'fragrance', 'parfum' and any 'and other ingredients' phrase, and decide whether an undisclosed component is acceptable to you. That is enough to tell a formula built around its headline ingredient from one that mentions it. A product such as CeraVe Moisturizing Cream, whose selling points are its base ingredients rather than a low-dose active, reads very differently under this method from a serum sold on a single extract.
Bottom line
The ingredient list follows public rules: descending order of amount down to the 1 percent line, free ordering below it, colour additives at the end, one word allowed for fragrance, and a trade-secret phrase for anything FDA has agreed to keep confidential. Those rules, published in FDA's cosmetics labeling guide as of October 2026, do not reveal percentages, but they reveal structure, and structure is usually enough to judge whether a product is built around the ingredient on the front. Read the back first, then the front, and let the regulated list settle any disagreement between them.
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