Browser-only ingredient tool
Paste any moisturizer ingredient list. The decoder sorts each ingredient it recognizes into occlusive, emollient, humectant, or a supporting role, tells you which of the three moisture functions is missing, and reads the declaration order to say whether the product is water-based or anhydrous. It gives no safety score and no personal verdict.
70 classified entries covering 262 ingredient names, reviewed August 9, 2026
Decode the declaration
Copy the full ingredient declaration from the package or the current manufacturer listing, commas and all. Do not paste medical details or personal history.
The three functions
Published dermatology reviews sort moisturizer ingredients into three functional classes. The names are unglamorous and the difference between them is the single most useful thing to understand about a product you are about to buy, because it explains why two moisturizers at the same price can behave nothing alike on the same skin.
Occlusives
Substances that physically block water loss by creating a hydrophobic barrier over the skin. This is the class with the clearest measured effect. Sethi 2016 reports that petrolatum at a minimum concentration of 5% reduces water loss by more than 98%, and that lanolin, mineral oil, and silicones sit lower, at 20% to 30%.
Typical names: petrolatum, mineral oil, dimethicone, lanolin, beeswax, and the animal fats and vegetable oils StatPearls groups here.
Emollients
Lipids that fill the spaces between surface skin cells so the skin feels softer, more flexible, and smoother. This is the class you feel immediately. Purnamawati 2017 highlights the physiological lipids in particular, ceramides, cholesterol, and free fatty acids, which are the same lipid families the skin barrier already uses.
Typical names: ceramides, cholesterol, squalane, isopropyl myristate, stearic acid, shea butter, and most plant oils.
Humectants
Hygroscopic compounds that attract water from two sources: from the dermis into the epidermis, and in humid conditions from the environment. Sethi 2016 calls them a double-edged tool, because water pulled into the outer layer can then be lost to the air unless something slows it down.
Typical names: glycerin, urea, hyaluronic acid, propylene glycol, sorbitol, lactic acid, sodium PCA, honey.
Why the missing class matters
This is the practical reason to run a decoder over a label rather than trust the front of the package. A product can be entirely reasonable and still be missing the function your situation calls for. StatPearls states the mechanism plainly: some humectants can increase water loss and make dryness worse without an occlusive used alongside them. In a humid summer that rarely shows up. In a heated room in February, or in a pressurized cabin, or after a long shift of handwashing, it shows up quickly.
The opposite gap is real too. A pure fat has no humectant in it at all, which is why the usual advice for that kind of product is to apply it to skin that is still slightly damp, so there is water present for the fat layer to slow the loss of. The decoder does not tell you which product is better. It tells you which of the three jobs the label actually covers, so the trade-off is visible before you spend money.
Reading the order
US cosmetic declarations are not arbitrary. Under 21 CFR 701.3(a), the label must list each ingredient in descending order of predominance. That is why the first three or four entries tell you most of what the product is: a list that opens with water is a water-based cream or lotion, and a list that opens with a fat or a wax is a balm or an ointment.
The rule stops applying partway down. 21 CFR 701.3(f) permits ingredients present at 1% or less to be listed without respect to order of predominance, and permits color additives to be listed in any order as well. On a list of twenty ingredients, the tail is effectively unordered. A famous ingredient sitting fourth from last does not mean the formula contains a meaningful amount of it, and a preservative near the end is exactly where a preservative belongs.
The decoder shows position because position is informative at the top of the list. It does not convert position into a percentage, because the regulation does not support that conversion.
Names are a second source of confusion. FDA accepts supplementary naming in parentheses after the common English name, which is why real labels say Water (Aqua) and Sweet Almond (Prunus Amygdalus Dulcis) Oil. The decoder reads both forms and both halves of a parenthetical, so a botanical name does not break the match.
Some ingredient names sound like one thing and do another. Cetyl alcohol and cetearyl alcohol are fatty alcohols that thicken and soften, and they are not the drying kind of alcohol. Caprylic/Capric Triglyceride is a light ester oil, not a preservative. Glycerin appears in nearly everything because it is cheap, effective, and well studied, not because it is filler.
When an ingredient is not in the dictionary, the decoder says so rather than guessing. An unrecognized name is a gap in this tool, not a mark against the ingredient.
Water-based or anhydrous
A water-first declaration
Water is the largest component. To stay one product rather than separating into layers, it needs emulsifiers. Because it contains water, it needs a preservative system. That is why water-based creams have longer ingredient lists: a good part of the list exists to hold the formula together and keep it stable, not to act on skin.
Expect to see a fatty alcohol, a gum or a carbomer, an emulsifier pair such as glyceryl stearate with a PEG stearate, a preservative, and often a chelator.
An anhydrous declaration
No water is declared. Everything present is fat, oil, or wax. There is no water phase, so there is nothing to emulsify and, in most cases, nothing for microbes to grow in, which is why these lists can be one line long. The trade-off is that there is no humectant water for the product to hold.
Balms, salves, ointments, and whipped fats sit here. The common application advice for them is to use a thin layer on slightly damp skin so the fat has water to work over.
Neither shape is better in general. A long list is not a warning sign and a short list is not a guarantee. What the decoder gives you is the ability to see which shape you are looking at in about five seconds, and then to check that against the thing you actually want the product to do.
Scope
It does not estimate a concentration. It does not score safety, rank quality, or rate a finished formula. It does not produce a comedogenic number, and our comedogenic ratings evidence guide explains why a raw ingredient score cannot predict a finished product anyway.
It does not diagnose anything, predict an allergic response, or tell you a product is suitable for you. It makes no medical claim about any ingredient or product, and a function label is a formulation description rather than a health outcome.
It also does not guess why an aromatic ingredient was added. When a fragrance-related term appears, it points you at the fragrance label checker instead, which handles that question narrowly and honestly.
Common questions
An occlusive sits on the surface as a hydrophobic layer and slows how fast water leaves the skin. An emollient is a lipid that fills the spaces between surface skin cells so the skin feels smoother and more flexible. A humectant is a water-attracting compound that pulls water from deeper skin and, in humid air, from the environment. Many real ingredients do more than one of these jobs, which is why the decoder can assign more than one label to a single ingredient.
Only partly. 21 CFR 701.3(a) requires ingredients in descending order of predominance, so the first few entries are the largest components. But 701.3(f) permits everything present at 1% or less to be listed in any order. On a long list, the tail is unordered, so a well-known ingredient near the end cannot be assumed to be present at any particular amount.
No, it is a different kind of product. Sethi 2016 describes humectants as double-edged, because they draw water from deeper skin into the outer layer where it can then be lost to the air, and StatPearls notes that some humectants can increase water loss when no occlusive is used alongside them. A humectant gel and a fat-based balm are answering different problems. The decoder reports which functions are present so you can see which one you are holding.
A declaration made entirely of fats, oils, and waxes with no water is an anhydrous product: a balm, a salve, or a whipped fat. Anhydrous products have no water phase for a humectant to hold, and because there is no water for microbes to grow in, they often carry no preservative system either. That is a formulation fact, not a quality ranking.
No. It classifies declared ingredients by cosmetic function. It gives no safety score, no comedogenic rating, no allergy result, no quality ranking, and no personal suitability verdict, and it cannot evaluate a finished formula from its ingredient names.
Run the decoder on ours
Paste the ingredient line from either product above and the decoder will read it as an anhydrous, fat-only declaration. Amazon shows the current product listing, package, price, availability, delivery options, and customer reviews.
Ingredients shown: 100% Grass-Fed New Zealand Beef Tallow.
Ingredients shown: Check the full ingredient statement on the current package.