Related

Class	Doing what	Names
Primary surfactant	Removes sebum and soil	Sodium laureth sulfate, sodium C14-16 olefin sulfonate, sodium cocoyl isethionate
Secondary / amphoteric	Softens the primary, builds foam	Cocamidopropyl betaine, coco-glucoside, lauryl glucoside
Emollient	The "moisturising" claim	Glycerin, shea butter, oils, dimethicone
Cationic polymer	Deposits emollient onto skin as it rinses	Polyquaternium-7, guar hydroxypropyltrimonium chloride
Thickener	Body and pour	Sodium chloride, carbomer, xanthan gum
Chelator	Prevents hard-water scum	Disodium EDTA, tetrasodium glutamate diacetate
Preservative	Essential	Sodium benzoate, phenoxyethanol, methylisothiazolinone (rinse-off only in the EU)

A rinse-off product has seconds of contact and is then washed away, so how can it moisturise?

The mechanism is real but small: deposition. Cationic polymers form a complex with the surfactant and the emollient, and as dilution rises during rinsing that complex precipitates onto the skin rather than washing away. It leaves a thin conditioning film — the same coacervation chemistry that makes 2-in-1 shampoo work.

What that achieves is less stripping, not moisturisation. The measurable benefit of a "moisturising" body wash is a milder surfactant system and a small deposited film. Applying a Body Lotion to damp skin afterwards does far more, and takes thirty seconds.

• pH. A body wash can be built at skin pH, and most are around 5–5.5. That is a genuine advantage over true soap, which cannot exist below pH 9.
• Fragrance is the leading cause of contact dermatitis in this category, applied over the whole body, daily, on skin that hot water has just stripped.
• Methylisothiazolinone is a significant contact allergen. The EU limits it to 15 ppm in rinse-off products and prohibits it in leave-on; the US has no equivalent restriction, so a US body wash may contain more.
• Antibacterial claims: FDA's 2016 rule banned nineteen ingredients, including triclosan, from consumer antiseptic washes, on the basis that manufacturers had not shown them safe for long-term daily use or more effective than plain soap and water.

Lukewarm rather than hot — heat strips lipids faster than any surfactant. Less product than the bottle implies. A washcloth or a hand rather than a plastic pouf, which holds moisture and skin cells and grows bacteria; if a pouf is used, it needs regular replacing and drying. Lotion within three minutes of getting out, on skin patted rather than rubbed dry.

Cosmetic in the US — FDA primary categories (12) personal cleanliness and (02) bath preparations. It becomes an OTC drug with an antibacterial or acne claim.

In the EU, preservatives must come from the Annex V closed positive list of 60 entries, with the MI restriction above; and Annex II prohibits 1,766 substances.

Two to three years unopened, 12–18 months after opening. High-surfactant products are among the more robust in a bathroom.

The two things that end a bottle: separation or thinning, and water dilution — topping up a nearly-empty bottle with water is common, and it contaminates the remainder from that moment.

• Bath and Body — the shelf this sits on, and the rest of it.
• Cosmetics — what the label is legally allowed to say, and the full catalogue.
• The rest of Washing — Bar Soap · Shower Gel · Shower Oil · Hand Soap.
• Body Lotion — the step that does the moisturising.
• Regulatory statements here follow the FDA and EU sources listed on Cosmetics, read 16 August 2026.