Lanolin

Sheep grow wool. The wool is coated in a waxy secretion that waterproofs it, and when the fleece is scoured that wax is recovered. That is lanolin.

It is in lip balms, nipple creams, hand salves, nappy creams and a great deal of veterinary and industrial product besides, and it does its job by sitting on skin and slowing water loss.

The animal question, which has a real split in it

Lanolin is an animal product. It is not vegan, and no certification body treats it otherwise.

Vegetarian is where it gets interesting. The sheep is shorn rather than slaughtered, so lanolin is an animal byproduct in the same category as honey or wool itself, and many vegetarians accept it on that basis while others decline it on animal welfare grounds relating to the wool industry.

That is a real disagreement about values, not a labelling ambiguity, and it is not our place to settle it. The page for people avoiding animal ingredients sets out where the words are defined and where they are personal, and this is squarely in the second half.

Beeswax sits in the same position for the same reason, which is worth knowing if you have already made your decision about one of them.

The unusual thing: you can read the amount

Almost nothing on a cosmetic label tells you how much of an ingredient is present. Lanolin is an exception when it is used as a skin protectant, because that use is regulated as an over-the-counter drug rather than as a cosmetic.

The regulation permits it at 12.5 to 50 percent, and the labelling rule requires a topical product to state the proportion of each active ingredient in its Drug Facts panel.

So a nappy cream or a nipple cream using lanolin as its protectant prints a number. It is the same reason Zinc oxide products carry a percentage, and it is one of the very few places in personal care where the quantity question has an answer.

When lanolin appears further down an ordinary cosmetic ingredient list, as an emollient rather than an active, that number disappears and you are back to reading order rather than amount. The cosmetics label guide covers where that line falls.

The allergy, which is genuine and specific

Lanolin is a recognised contact allergen. It appears on standard patch test panels, usually under the name wool alcohols, because the alcohol fraction rather than the whole wax is generally responsible.

Two practical consequences.

The name on the panel and the name on the tube differ. A patch test result reading wool alcohols corresponds to lanolin and lanolin alcohol on an ingredient list, and a reader who does not know that will not connect them.

A wool allergy is not the same thing. Reacting to a jumper is usually irritation from coarse fibre, and it does not predict a lanolin reaction either way.