How to Read An Ingredient List Like Someone Who Makes Skincare:

Analyzing the Viral Laneige Sleeping Mask, Science Degree not Required.

Feb 02, 2025

Hello, I’m Adeline. I write Ginseng & Tonic to deliver a straight shot of cultural & skincare analysis to your inbox most Sundays. Subscribe for deep dives into the intersections of culture and beauty by a former cultural studies professor and current skincare formulator.

Formulating various versions of a skincare product at Sabbatical Beauty.

Pasta sauce, an energy drink and a moisturizer: what do they all have in common? Ingredient lists. Just like how most processed food and drink come laden with additives that you may not want to ingest, skincare products are often more dilute in formulation than in marketing.

Learning to read an ingredient list is one of the most empowering actions you can take.

Hi, I’m Adeline, former English professor and founder and formulator behind Sabbatical Beauty. I’ve formulated Sabbatical Beauty products for almost a decade and my work has been featured in in Forbes, Elle, Buzzfeed, Popsugar & more. I also regularly contribute opinions to Beauty Independent.

Welcome to my Read an Ingredients List Like Someone Who Makes Skincare series, where I show you simple tools to make your smartest skincare purchasing decisions. I started deciphering ingredient lists early in my skincare journey because I was suspicious: many brands will shout the powers of a hero ingredient from the rooftops, but where this ingredient sits on the ingredient list tells another story.

My annoyance at the smoke and mirrors of skincare marketing made me to teach myself how to read ingredient lists.

This irritation also propelled me into becoming a skincare formulator, someone who develops and creates skincare products through a deep understanding of skin science and ingredients.

Here are some rules of thumb that I now follow as a skincare formulator when I examine an ingredient list. These rules will help you to figure out if the skincare product you’re examining is really worth the price tag.

Have skincare obsessed friends who would be interested in learning how to read an ingredients list? Share this post with them ⬇️

Teaching Example

Let’s examine the ingredient list for one of the products that I used regularly before I started my own skincare line— the Laneige Water Sleeping Mask — for our teaching example.

Ingredient List:

Product Claims To Treat:

Dryness,
Dullness
Loss of Firmness and Elasticity

Claim Ingredients:

Probiotic-Derived Complex (Lactobacillus Ferment Lysate and Trehalose): Delivers a hydrated glow while supporting skin's moisture barrier.
Squalane: Is a hydrating ingredient that mimics skin’s natural lipids.
Niacinamide and Saururus chinensis Extract: Help skin appear revitalized.

Now, let’s examine the ingredients and claims using my Rules of Thumb.

Rule 1: What Are In The First 5 Ingredients?

You probably already know that ingredients on a list are listed in descending order — that the 1st ingredient is the highest percentage, and the last ingredient the smallest.

But did you know the 1st 5 ingredients of a product are the ones most likely to have the biggest impact on your skin? These are also called functional ingredients, meaning that they ensure the product achieves its function (e.g. hydration, soothing properties).

Functional ingredients have the biggest impact on your skin’s reaction to a product, and often are the cause of skin reactions. They also greatly affect the product’s appearance, texture and feel.

Let’s examine the first 5 ingredients in this product:

Water/Aqua/Eau (ingredient #1)
As a rule of thumb, I would prefer my skincare product not have water as a first ingredient, but this is being sold as a “water sleeping mask” — so I’ll make an exception.
Butylene Glycol (ingredient #2)
Butylene Glycol (and other glycols) are often the second, third and/or fourth ingredients in the majority of skincare products. They are not harmful to skin. It appears so high on many ingredient lists because:
1. glycols are cheap humectants (moisturizing agents which attract moisture to your skin)
2. they help limit water activity within a product, improving preservative efficacy
3. they can also be used as solvents in creating plant extracts—meaning, they are used to extract beneficial properties of the plant so they can be used in skincare products.
Glycerin
This skincare ingredient is currently having a social media moment. The truth, however, is that it’s used in just about every skincare product because its an inexpensive humectant. It’s not a premium ingredient.
Trehalose
It’s nice to see a claims ingredient actually appearing in the first 5 ingredients! I rarely see this in most mainstream products, but this is an inexpensive ingredient so it isn’t hugely impressive.
Methyl Trimethicone
This is a type of silicone. Some folks really hate silicones, but they have their use. This particular one is an emollient and provides a light, weightless and elegant textural feel.

Analysis of the first 5 ingredients

This is a pretty standard functional ingredient list you can find in the majority of mass market products. This category does not generally deliver high concentrations of quality ingredients in their formulations. But for the price (this retails for $32 at Sephora), this product should deliver an elegant texture that will adequately hydrate your skin without suffocating it.

Unexpectedly, trehalose is actually in the first 5 ingredients (yay!) which means there’s enough of it in the product to impact your skin.

But where are the other ingredients used for marketing claims on the ingredient list?

Have friends who also feel suspicious of the beauty industry? Equip them with ingredient list knowledge by sharing this post.

Rule 2: Where Are The Claims Ingredients?

Claims ingredients are used to make marketing claims. In this product, the claims ingredients are Lactobacillus Ferment Lysate, Trehalose, Squalene, Niacinamide and Saurusus chinesis extract, all of which are supposed to help dry, dull skin that needs firming and lifting.

I’ve circled where these appear on the ingredients list:

As you can see, 2 of the claims ingredients appear relatively high on the ingredients list, 1 somewhere in the middle, and 2 near the bottom.

Is there enough Lactobacillus Ferment Lysate in this product to have an effect on your skin? Possibly.

But what about the last 2 ingredients, niacinamide and Saurusus Chinensis extract?

Rule 3: Where Are Claims Ingredients Relative to Preservatives or Fragrance?

To answer this question, first identify where the preservatives and fragrance/fragrance components are.

Next, see where the claims ingredient sits next to these two ingredient categories, noting:

Most preservatives and fragrance/fragrance components have a maximum usage level of 1%, and usually appear at less than 1% as they can cause sensitivity.
In the United States and many other countries, you can list ingredients at less than 1% of the formulation in any order you would like. So if rice extract is at 0.001% and linalool is at 0.5% you can still list rice extract before linalool.

Sadly, both niacinamide and Saurusus Chinensis extract are listed under both the preservatives and fragrances in this formula.

I’ve highlighted the preservatives (ethylhexylglycerin and disodium EDTA) and fragrances (fragrance/parfum) in blue.

Given that ethylhexylglycerin is normally not used at more than 1%, and noting that disodium EDTA should not be used at more than 0.2%, it is clear that there is less than 0.2% of niacinamide and Saurusus Chinensis extract in this product.

Rule 4: Most Plant & Animal Extracts Should Be High On Your Ingredients List

Honestly, this annoys me. Plant and animal extracts are generally quite safe to formulate with, and in my experience can - and should - be used at high concentrations to see skin effect.

There’s no excuse for Saururus chinensis extract to be so low on the ingredients list other than cost. There is not enough of it to affect your skin. It’s just being used for a marketing claim.

But what about niacinamide?

Rule 5: Some Ingredients Are Effective In Lower Percentages (But This Is Too Low For Niacinamide!)

Niacinamide is also too low for the ingredient to have noticeable effect on your skin. For niacinamide to start being effective, it should be used at a minimum of 4% - but here it is at less than 0.2%.

There are exceptions to this rule. There are ingredients can appear at 1% or less in a formulation and still be effective (niacinamide is just not one of them). These exceptions include:

Hyaluronic acid. High molecular hyaluronic acid cannot be used at more than 2% in formulation or it will render the product texture too thick, solid and unusable. You can however combine lighter weights of hyaluronic acid with the high molecular weight variety to achieve higher percentages in the formulation.
Ceramides and Peptides. These are often prohibitively expensive to use at more of a fraction of a percent, and peptides in particular often come encapsulated within a delivery mechanism that will allow effective skin penetration at low percentages.

Finally: My Summary Assessment of the Laneige Sleeping Mask Ingredient List

In my final assessment, let me return to the start of this piece where we evaluated the Laneige Sleeping Mask and the claims ingredients used for marketing.