How to use musks in a perfume formula

A musk is dosed by its job: a clean white musk can be a tenth or more of a concentrate, a powdery musk a few percent, an animalic musk a trace. Use two musks rather than one, because a large share of people cannot smell any single musk at all.

What kinds of musk are there?

The word covers three different jobs, and the catalog files them under separate sub-categories of the musk family.

• White or clean musks. Galaxolide is the definitive laundered white musk, sweet and powdery with a faint woody-floral side and enormous substantivity. Habanolide is the metallic, hot-iron, clean-linen musk of modern laundry accords. Helvetolide adds a fruity pear sparkle rather than depth.
• Powdery and sweet musks. Ethylene Brassylate is soft, sweet, slightly waxy and forgiving. Exaltolide is warm, powdery-clean with a discreet animalic edge close to the lactonic side of real deer musk. Ambrettolide is radiant and slightly fruity-vegetal, the classic exalting musk. Tonalide is the harder-edged, ambery, retro polycyclic.
• Animalic musks. Muscenone is a powerfully diffusive, warm, slightly dry-woody animalic musk; a small dose makes a whole base vibrate. Velvione is velvety and civet-like, plush skin-warmth where a hint of dirtiness is welcome. Muscone is the warm, sweet odorant of natural Tonkin musk.

Cashmeran sits at the edge of the family: a musky-woody indane ketone, spicy and red-fruity, that bridges musks and woods rather than doing either job alone.

Why can I not smell my musk?

Specific anosmia. Musks are large molecules, and a meaningful share of people are blind to one or another of them while smelling the rest perfectly. If you cannot smell a musk, that says nothing about the bottle and nothing about your nose in general, but it does mean a perfume built on that one musk is a perfume with no base for part of its audience.

The fix is structural: always blend two musks of different chemistry. A polycyclic such as Galaxolide beside a macrocyclic such as Habanolide or Exaltolide covers most noses, because the blind spots do not overlap. The pair also smells better than either alone, since a single musk is a smooth, featureless surface and two of them have a texture.

How much musk goes in a formula?

• Clean musks: 5 to 20% of the concentrate. The catalog note on Ethylene Brassylate says it is used generously, often 5 to 20% of a formula, and Galaxolide can form a large share as a fixative bed. This is the floor the rest of the perfume stands on.
• Powdery musks: 1 to 5%. Enough to soften and fix, not enough to turn the drydown into talc.
• Animalic musks: 0.1 to 1%. Muscenone and Velvione are dosed from a 10% dilution and judged the next morning, because their warmth only reads in the drydown and too much reads as unwashed.

Watch the bottle strength. Galaxolide is usually supplied at 50% in IPM or benzyl benzoate, so 10 g from the bottle is 5 g of musk, and any ratio you set without correcting for that is not the ratio you think it is. Musks also leave a strip last, days after the top has gone, so a dose approved on a fresh strip has told you nothing yet.

Which musks are banned?

The nitro musks, the sweet, powdery, vintage fixatives of early twentieth century perfumery, are mostly gone. In the IFRA 51st Amendment dataset PerfuMate ships, Musk Xylene, Musk ambrette, Musk moskene and Musk tibetene are all prohibited outright, cap zero. Musk Ketone survives only as a specification standard: no Category 4 percentage cap, but it may be used only if it holds less than 0.1% musk xylene. Separately, EU cosmetics law lists musk ambrette, moskene and musk tibetene in Annex II, and the catalog marks each of those rows with its EU ban beside the CAS. The catalog keeps the nitro musks for reading old formulas, and the substitutes engine will never offer a prohibited bottle, alone or inside a blend.

The macrocyclic and polycyclic musks above are the replacements, and the catalog says so on each row: Ambrettolide is described as a natural-feeling alternative to nitro musks.

A worked example: a musk accord

For 100 g of concentrate: Galaxolide 50% 12 g (6 g of musk), Habanolide 4 g, Ethylene Brassylate 8 g, Exaltolide 2 g, and Muscenone 0.5 g weighed from a 10% dilution (0.05 g neat). Two clean musks of different chemistry cover the anosmias, the brassylate rounds them, Exaltolide brings the powdery-animalic warmth, and the trace of Muscenone is the pulse under the whole thing. Smell it at hour one and it is almost nothing; smell the strip the next morning and that is the accord. If it reads too clean, raise the Muscenone before you touch anything else; if it reads unwashed, halve it.

On the bench, PerfuMate corrects every musk line for the strength of the bottle it is weighed from, marks the EU-banned rows in red and keeps every IFRA-prohibited musk out of the substitutes engine, so a stand-in it ranks over your shelf is one you can actually use. The AI that builds and refines formulas is handed the catalog and your shelf on every run, never trained on either. See how the bench works, or browse the substitutes for any musk in the catalog.