Fixative
In perfumery a fixative slows the evaporation of a fragrance's volatile notes so it lasts longer — and isn't the same as a base note. The materials that do it.
Updated
In perfumery, a fixative is a material that slows the evaporation of a fragrance's more volatile parts so the whole composition holds together and lasts longer. (The same word turns up in hairspray and art supplies — an aerosol that stops your hair or a charcoal drawing from moving — but those are unrelated; here it always means the perfumery sense.) A perfume is a mixture of materials that fly off the skin at very different speeds: a citrus top note is gone in minutes, a resin can linger for a day. Left alone, the light materials race off first and the scent collapses into its heavy base within an hour. A fixative is what keeps that from happening — it drags the evaporation curve out so the opening, heart, and base unfold in sequence rather than falling apart.
The mechanism is physics, not magic. Fixatives tend to be heavier, less volatile molecules with a low vapor pressure, so they evaporate slowly themselves and, mixed into the formula, lower the effective volatility of everything around them — the textbook framing is that they equalize the vapor pressures across the blend (Raoult's law, for the chemically inclined). Benzoin resin's heavy constituents have boiling points well above 300°C; a bright citrus terpene like limonene boils around 176°C and is gone almost as fast as it lands. Stir the slow material through the fast one and the fast one leaves the skin more gradually. Classic naturals that do this work include oakmoss, labdanum, benzoin, myrrh and frankincense, orris, and the animalic materials — musk, civet, and ambergris. The modern toolkit leans on synthetics: ambroxan (an ambergris stand-in), the white musks like Galaxolide, and Iso E Super, which is as much a diffusion booster as a fixative.
Here is the part that trips people up: a fixative is not the same thing as a base note. A base note describes when a material shows up — late, after the top and heart have burned off. A fixative describes what a material does — slow the whole blend down. The two overlap heavily, which is why they get used interchangeably, but they aren't synonyms. Most fixatives sit in the base, yet plenty of base notes are poor fixatives, and a fixative needn't smell of much at all (some, like the odorless fractions of ambergris or a near-scentless carrier, do the work without adding a note). Vanilla and sandalwood are base notes that also smell loudly; a good fixative is judged on tenacity, not aroma.
- Fixative
- A material added to a perfume to reduce the rate at which its volatile components evaporate, increasing the fragrance's tenacity on skin. Wikipedia's standard phrasing is "a substance used to equalize the vapor pressures, and thus the volatilities, of the raw materials in a perfume oil." Fixatives are usually low-volatility, higher-molecular-weight materials; they may carry a strong scent of their own (oakmoss, labdanum) or almost none (some ambergris fractions, near-odorless carriers). It names a function, not a fixed list of ingredients.
- Fixative vs. base note
- A base note is a position in the fragrance's timeline — the materials that emerge last and linger longest. A fixative is a role — anything that slows the blend's overall evaporation. They overlap (most fixatives live in the base) but are not the same: many base notes fix poorly, and a fixative is rated on holding power rather than on how it smells. The cleanest way to keep them straight: base note answers "when?", fixative answers "what job?".
- Natural fixatives
- The classic anchors are resins and balsams — benzoin, labdanum, myrrh, frankincense, tolu and storax — plus orris and oakmoss, the workhorse base of chypre and fougère structures. Animalic materials (musk, civet, and ambergris) were prized fixatives historically. Several of these are now limited or replaced: oakmoss is restricted as an allergen (limited to about 0.1% in finished products under IFRA standards, with the EU banning its key allergen compounds outright in 2021), and animal-derived musk, civet, and ambergris are largely avoided on ethical and supply grounds in favor of synthetics.
- Synthetic fixatives
- Modern perfumery mostly fixes with lab-made molecules. Ambroxan reproduces the warm, salty anchor of ambergris; the white musks such as Galaxolide and Exaltolide (cyclopentadecanolide) supply long, low-volatility hold; Iso E Super adds a transparent woody glow that fixes and boosts diffusion at once. Near-odorless carriers like benzyl benzoate and diethyl phthalate also slow evaporation without adding a scent of their own.
- Tenacity
- A perfumer's word for how long a material or a finished fragrance holds its character on skin or paper — the property a fixative is meant to improve. It is related to but distinct from sillage (how far a scent projects) and longevity (how long you can still detect it): a tenacious base can keep a fragrance readable for hours while its sillage has long since dropped to a skin scent.