Animal notes in perfume: musk, ambergris and their substitutes

Musk, ambergris, civet and castoreum are four materials perfumery once took from animals: the musk deer, the sperm whale, the African civet and the beaver. Since the late 19th century, chemistry has replaced almost all of them with synthetic molecules, starting with musk. On a list of notes today, "musk" nearly always means a family of lab-made molecules, not an animal secretion.

These materials shared a few traits: a powerful smell, often harsh until diluted, a high price, and the ability to make other scents last. Getting them usually meant killing the animal, or relying on luck along a shoreline. The substitutes have been sorted since then too: several early synthetic musks are now banned under the IFRA Standards.

Where did perfumery's animal materials come from?

Perfumery's animal materials came from the glands or the gut of a handful of species, each with a main odour molecule. The table sums up where the four materials of this Class came from and what replaces them; each row is explained further down, with its source.

Material	Animal	What was collected	Key odour molecule	Replaced by
Musk	Male musk deer, from Tibet and Nepal to Siberia	The musk pod, a preputial gland, usually taken by killing the deer	Muscone	Synthetic musks: nitro, polycyclic, macrocyclic, alicyclic
Ambergris	Sperm whale	A waxy substance from the digestive system, found floating at sea or washed ashore	Ambrein, which breaks down into ambroxide	Ambroxide (Ambroxan), made from sclareol
Civet	African civet	Civet oil, a glandular secretion	Civetone	Synthetic civetone
Castoreum	Beaver	The exudate of the castor sacs, dried and tinctured in alcohol	At least 24 known compounds	Synthetic musks designed to emulate it

Musk: from the musk deer to synthetic musks

Natural musk comes from the musk pod, a preputial gland in a pouch under the skin of the male musk deer's abdomen, and according to Wikipedia's article on musk it is normally obtained by killing the deer with traps laid in the wild. The name goes back through Late Greek and Persian to a Sanskrit word for testicle, because the gland was thought to resemble one. Trade in natural musk is now controlled under CITES, the convention on international trade in endangered species, though the same article notes that poaching and illegal trading continue.

Natural musk was used extensively in perfumery until the late 19th century when economic and ethical motives led to the adoption of synthetic musk, which is now used almost exclusively.

Chemistry got there by accident. In 1888 Albert Baur, trying to produce a more effective form of TNT, obtained an artificial musk; the nitro musks that followed include musk xylene, musk ketone and musk ambrette. The main odorant of deer musk, muscone, is a large-ring ketone, and Wikipedia's article on synthetic musks records that Leopold Ruzicka managed to synthesise it in 1926, in very small quantities. Polycyclic musks such as Galaxolide came next, while macrocyclic musks, the closest to muscone, were not commonly produced until the late 1990s because they were hard and costly to make. The Class on what chemistry has brought to perfumery since the late 19th century places these molecules in the wider story.

Not all of these molecules lasted. The IFRA Standards library lists musk ambrette as a prohibition published in 2006, musk moskene and musk tibetene in 2008 and musk xylene in 2009, while musk ketone carries a specification published in 2010. Wikipedia's article on musk adds that concerns over nitro and polycyclic musks led to bans or reduced use in many regions, and that macrocyclic musks, which appear safer, are expected to replace them.

Why did ambergris give way to Ambroxan?

Ambergris is a waxy substance produced in the digestive system of sperm whales, found floating at sea or washed up on coastlines. Fresh, it has a marine, faecal smell; it turns sweet and earthy as it ages, according to Wikipedia's article on ambergris. The article explains the chemistry: oxidation breaks down ambrein, a relatively scentless terpenoid, into ambroxide and ambrinol, the main odour components of ambergris.

Finding ambergris was always down to luck, and the trade is legally tangled. Although it is not harvested from whales, the same article lists the United States, Australia and India among countries where its trade is illegal, and the United Kingdom, France and Switzerland among those where it is legal. The slim chances of finding it and that legal ambiguity led perfumers away from ambergris and chemists towards alternatives.

The main alternative is ambroxide, widely known by the brand name Ambroxan. Wikipedia's article on ambroxide describes it as one of the key constituents of the smell of ambergris, with woody, musky and slightly salty nuances, and explains that it is made from sclareol, a component of clary sage essential oil. The club keeps separate pages for ambergris, the whale material and Ambroxan, the molecule that stands in for it. Sclareol is also one of the substances the EU's 2023 rules require on cosmetic labels above a threshold, as the Class on fragrance allergens on the label and the IFRA Standards explains.

Civet and castoreum: what became of the other two animal notes?

Civetone is the main odorous constituent of civet oil, sourced from the African civet. Wikipedia's article on civetone describes a strong musky odour that only becomes pleasant at extreme dilution, a structure closely related to muscone, both worked out by Leopold Ružička, and a modern synthesis from precursor chemicals found in palm oil.

Castoreum is a yellowish exudate from the castor sacs of mature beavers, which use it with urine to mark their territory. In perfumery, according to Wikipedia's article on castoreum, the word refers to a resinoid extract of the dried sacs tinctured in alcohol, usually aged for two years or more to mellow, and it is largely used for a note suggesting leather. Wikipedia's article on synthetic musks explains that these molecules were designed to emulate deer musk and the other animal musks, castoreum and civet, with a clean, smooth, sweet scent that lacks their faecal notes. For the leather side of the story, open the leather note page.

What does "musk" mean on a list of notes today?

On a list of notes, "musk" today almost always means one or more synthetic musks. Nearly all musk fragrance used in perfumery is synthetic, sometimes called "white musk", says Wikipedia's article on musk, and beauty magazines such as Mademoiselle Bulle list "white musk" among a perfume's notes in that sense. The musk note page covers the families of molecules behind the word.

A few plants smell musky too. The same article names angelica (Angelica archangelica) and musk seeds (Abelmoschus moschatus), which produce macrocyclic lactones that perfumery uses as substitutes for animal musk or to adjust a blend of other musks.

Synthetic musks also reach far beyond perfume bottles. Galaxolide, a polycyclic musk, is commonly used in laundry detergents to mask the smell of the detergent chemicals, according to Wikipedia's article on musk. Your clean washing may well be where you smell musk most often.

Exercise: find the musk in your laundry

You need a towel, your usual detergent and two days; nothing goes on your skin. The point is to notice how a base note stays once everything else has gone.

1. Smell the cap of your detergent or fabric softener and write down three words for what you notice.
2. Wash a towel with it, let it dry, then smell it and write three words again.
3. Keep it folded and smell it the next day and the day after. Note what lasts longest. Synthetic musks, used in detergents as base notes, are good suspects.
4. Ask someone else to smell the towel without telling them anything, and write down their words next to yours. If you disagree, keep both descriptions.
5. Finally, compare with a paper blotter dipped in a perfume whose notes list musk, smelled the next day.

Share what lasted longest in the Ambers, Spices & Gourmands circle, next door to the amber family where musk has its page.