Getting to know your cosmetics from the label

In Thai law a cosmetic is any substance intended to be applied, rubbed, massaged, sprinkled, sprayed, dropped, inserted, steamed or otherwise used on the external parts of the human body — including the teeth and the mucous membranes of the mouth — for cleansing, beautifying, altering appearance, controlling body odour, or keeping those parts in good condition, together with skin preparations generally, but excluding jewellery and clothing worn on the body (Cosmetics Act B.E. 2558).

Cosmetics range from soap, shampoo, toothpaste and mouthwash to moisturisers, sunscreens, hair-removal creams, hair dyes, hair straighteners, nail polish remover and every kind of make-up. What matters is that skin is a richly vascular organ — so a harmful ingredient in a cosmetic can reach the baby. On top of that, the raised hormone levels of pregnancy change the skin in several ways, which means a mother-to-be's skincare routine should differ from anyone else's.

How the skin changes during pregnancy

The enormous rise in hormones makes pregnant skin prone to acne, dark patches, melasma and freckling. A dark line runs from below the navel to the pubis — the linea nigra. The abdominal skin, stretched as the uterus grows, develops stretch marks. And there is an itchy rash specific to pregnancy: pruritic urticarial papules and plaques of pregnancy (PUPPP).

Acne
Melasma
Linea nigra
Stretch marks
PUPPP

How to read the ingredient label

The law requires every cosmetic on sale to list its ingredients. Quantities need not be given, but the ingredients must be listed from most to least. So on a moisturiser whose first listed ingredient is water, water is the largest component — and the last name on the list, say ethylhexylglycerin, is the smallest.

Ingredients to avoid during pregnancy

These are the ingredients to avoid, because they may harm the mother or the baby. If you cannot remember any of it and are unsure — just avoid, it is simpler.

Ingredient	Other names on the label	Why avoid it
Retinol	Vitamin A, retinoic acid, retinyl palmitate, retinaldehyde, adapalene, tretinoin, tazarotene, isotretinoin	Vitamin A derivatives, usually found in anti-wrinkle creams and night-time acne treatments. They can cause birth defects across several body systems and restrict fetal growth
Salicylic acid above 2%	BHA, 3-hydroxypropionic acid, trethocanic acid, tropic acid	At high concentrations it can disturb the baby's blood clotting and cardiovascular function
Aluminium chloride hexahydrate	Aluminum chlorohydrate	Used in deodorants and antiperspirants. It may slow the mother's weight gain, restrict fetal growth, and cause abnormalities especially of the skeleton
Toluene	Methylbenzene, toluol, antisal 1a	A solvent found in mothballs and nail polish. It restricts fetal growth, lowers birth weight, and may impair development after birth
DEA	Diethanolamine, oleamide DEA, lauramide DEA, cocamide DEA	A petroleum-derived ingredient that makes skin feel moist and smooth; common in soaps, shampoos and hairsprays. It affects fetal brain development and may raise the risk of miscarriage
Formaldehyde	Quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, sodium hydroxymethylglycinate, bronopol (2-bromo-2-nitropropane-1,3-diol)	Formalin, a solvent commonly found in nail polish and hair straighteners. It is linked to cancer and to respiratory and neurological harm
Hydroquinone	Idrochinone, quinol, 1,4-dihydroxybenzene, 1,4-hydroxybenzene	Already banned in cosmetics in Thailand. It is normally a prescription melasma treatment with substantial side effects, used under dermatological supervision. It is well absorbed into the bloodstream and may harm the fetus
Parabens	Propyl-, butyl-, isopropyl-, isobutyl- and methylparaben	Cosmetic preservatives — which is why so many brands advertise themselves as paraben-free. Exposure in pregnancy is associated with miscarriage, restricted fetal growth and low birth weight
Phthalates	Diethyl phthalate, dibutyl phthalate, often hidden under “FRAGRANCE”	Solvents used in perfumes and pesticides; on a cosmetic label they may hide behind the single word “FRAGRANCE”. They lower birth weight, harm development, and raise the risk of autism and ADHD
Thioglycolic acid	Acetyl mercaptan, mercaptoacetate, mercaptoacetic acid, thiovanic acid	Used in hair-removal creams; associated with low birth weight

Beauty procedures to skip while pregnant

Skip hair dyeing and straightening, Botox, thread lifts, fillers, laser treatments, LASIK, chemical peels and dermabrasion. Besides, many pregnant women already have the radiance the English call a “pregnancy glow”.

So what is safe to use?

Ingredient	What it does
Glycolic acid (AHA)	A fruit acid that sloughs off dead skin cells and dark spots. Very little is absorbed into the bloodstream, so it is safe
Azelaic acid	Reduces pore blockage and skin inflammation, and lowers the chance of acne
Benzoyl peroxide	Found in acne treatments applied before washing, such as Panoxyl and Benzac. It kills bacteria in the pores and calms inflamed acne, and is barely absorbed into the bloodstream. Do take care with fabrics and pillowcases — it bleaches them
Ascorbic acid (vitamin C)	An antioxidant that reduces pigment formation, helps filter UV, and doubles as a natural preservative
Lactic acid	Renews skin cells and keeps the skin hydrated
Niacinamide (vitamin B3)	Hydrates the skin and brightens it
Mandelic acid	Antibacterial, exfoliating, evens skin tone and softens fine lines
Kojic acid	Inhibits pigment formation in the skin, inhibits bacteria and acts as an antioxidant

Skincare advice for pregnancy

Skip hair dyeing, hair straightening, Botox and laser treatments
Drink enough water and use a moisturiser to keep the skin hydrated
Avoid scrubbing the skin — it thins the keratin layer
Use sunscreen regularly

Questions?

Watch the explainer on YouTube, or book online. Opening hours Monday–Saturday, 1:00–7:00 pm.

Cosmetics and pregnancy