Water (aqua) is the first ingredient. Is that a bad sign?

No. Most creams and lotions are water-based, so water comes first because there is the most of it. It says nothing about whether the product is good.

Does fragrance-free mean there is no scent ingredient at all?

Not always. Some products use masking agents, or plant extracts that contain the same kinds of substances as fragrance. If you have reacted to fragrance before, read the actual ingredient list, not the claim on the front of the box.

How many digits does a Thai cosmetic notification number have?

The Thai FDA says the number on the label has 10 or 13 digits. If it looks odd or you cannot find it in the system, do not use the product yet. You can ask the Thai FDA hotline on 1556.

How to read a cosmetic ingredient list: INCI order, fragrance, allergens

The ingredient list on the back of a bottle looks like unreadable chemistry, but it follows only a handful of rules. Once you know how it is ordered, which part tells you about amounts and which part does not, and which single word hides many substances, you can find the thing you react to in seconds. This lesson covers reading the list, and checking a Thai FDA notification number yourself.

What INCI names are

INCI stands for International Nomenclature of Cosmetic Ingredients, a shared naming system, so the same substance has the same name wherever the product is made. Water is aqua or water, glycerine is glycerin, and plant extracts usually appear as the Latin plant name plus the part used, such as …leaf extract.

The point of a shared name: if a dermatologist tells you which substance you react to, you can write that exact name down and look for it on the label of any brand.

The ordering rules

EU law and the US FDA use the same idea.

Ingredients above 1% are listed from most to least.
Ingredients at 1% or less follow them, in any order.
Colourants come last, in any order. Products sold in several shades may write “may contain” or ”+/-” followed by every colour used across the range.
A whole fragrance blend can be declared as one word: parfum or fragrance (flavourings in lip products appear as aroma or flavor).

What that means: the first three to five ingredients are usually the bulk of the product, while in the second half of the list, position no longer tells you which is more.

If the ingredient advertised in big letters on the box sits after the preservative, there is probably less than 1% of it.

Example: finding the 1% line in a real list

Say a moisturiser (an invented list, for teaching) reads:

aqua, glycerin, caprylic/capric triglyceride, cetearyl alcohol, dimethicone, niacinamide, phenoxyethanol, panthenol, centella asiatica leaf extract, parfum, linalool, CI 77891

Step by step:

Find an ingredient with a low legal cap. Phenoxyethanol is a preservative the EU allows at no more than 1%. Its position is a rough marker: everything after it is at 1% or less.
Count what comes after the marker. Five ingredients follow it: panthenol, centella leaf extract, parfum, linalool and CI 77891. All five are under 1%, and their order means nothing.
Pick out the fragrance. Parfum is the whole blend. Linalool is a fragrance allergen that has to be named separately.
Pick out the colour. CI followed by a five-digit number is a colour code. CI 77891 is titanium dioxide, used here to make the cream white.

Conclusion: this cream is mostly water, glycerin and oils. The centella extract that might be splashed across the box is under 1%, and it is fragranced. If you react to fragrance, this one is not for you.

After the 1% line, position no longer tells you the amount

Fragrance: the one to watch

Fragrance is one of the most common causes of allergic contact dermatitis, second only to nickel. One fragrance blend can contain dozens of substances, yet the label only says parfum.

To help people who react, the EU requires certain fragrance allergens to be named on their own when they are present above 0.001% in leave-on products and above 0.01% in rinse-off products. Names you will see often: limonene, linalool, geraniol, eugenol, cinnamal and citral.

Two cautions:

Fragrance-free or unscented does not always mean no scent ingredients. Some contain masking agents; some use plant extracts or essential oils, which contain the same kinds of substances as fragrance.
Below the threshold, nothing has to be declared. Tiny amounts may not appear on the label, so someone with a strong allergy cannot avoid everything with total certainty.

Common allergens worth knowing by name

Group	Names to look for	Often found in
Fragrance	parfum, fragrance, linalool, limonene, geraniol, eugenol	almost anything scented
Isothiazolinone preservatives	methylisothiazolinone (MI), methylchloroisothiazolinone (MCI)	shampoo, conditioner, wet wipes, mascara
Permanent hair dye	p-phenylenediamine (PPD)	permanent hair colour
Acrylates	HEMA and other acrylates	uncured gel nail polish

Preservatives usually sit near the end of the list, so read all the way to the last word. If you do gel nails regularly, see gel nail allergy for more on acrylates.

Labels that say hypoallergenic, natural or clean can still cause reactions. Those words do not tell you what is inside. The ingredient list does.

What a Thai-language label must show

Cosmetics sold in Thailand must carry a Thai label. The Thai FDA lists what it must include, such as:

the product name and trade name
the type of cosmetic
the names of all ingredients
directions for use
the name and address of the manufacturer or importer
net quantity
batch number
month and year of manufacture, or month and year of expiry
the notification number

No Thai label, or missing details, is the first sign not to buy.

Checking a notification number yourself

The notification number is what a manufacturer or importer receives after notifying the Thai FDA of the product’s details. By law, sellers may not sell cosmetics that have not been notified. The Thai FDA says the number is 10 or 13 digits long.

How to check:

Go to the Thai FDA website, www.fda.moph.go.th, and find the section “ตรวจสอบผลิตภัณฑ์” (product check). The search system lives at porta.fda.moph.go.th.
Choose cosmetics as the product type.
Enter the notification number or the product name.
Compare the result with the label in your hand. The product name and the manufacturer or importer must match. A real number that belongs to a different product is a red flag.

Other channels: the Oryor Smart Application, the FDAThai LINE account, and the Thai FDA hotline 1556, where you can also report a suspicious product.

A notification number tells you the product was notified to the Thai FDA. It does not prove the product is genuine or that your skin will not react. Match the details, and test before you use it.

Common mistakes

Trusting the front of the box over the list on the back. The advertised ingredient may be under 1%.
Reading only the first three ingredients. Frequent allergens like preservatives and fragrance usually sit in the second half.
Assuming natural means non-allergenic. Essential oils and plant extracts can cause allergies too.
Seeing a 10-digit number and stopping there. Search it and compare the product name.
Remembering your allergen vaguely. Ask your doctor for the exact INCI name and save it on your phone.

Still unsure after reading the label? The next step is testing on your skin before real use: see patch testing new products. If you get a rash, itching or swelling after using something, stop and talk to a doctor or pharmacist.

Sources

General guidance. Products differ between brands: always follow the label. If you react to a product, see a doctor.