Aroma chemicals and solvents: the questions perfume makers ask
By Omer Siton, founder of PerfuMate · Updated
Aroma chemicals are the single molecules a perfumer weighs, and solvents such as DPG are what the strong or solid ones are diluted in. Each answer below is the short version, with the figures from PerfuMate's catalog, and links to the page that goes into depth.
What are aroma chemicals?
An aroma chemical is a single odorous molecule, or a small group of closely related isomers, with its own CAS number, made by synthesis or isolated from a natural source. Linalool, Hedione, Iso E Super and vanillin are examples, and each smells the same from one bottle to the next. Aroma chemicals vs essential oils explains how they differ from naturals.
What chemicals are used in perfume?
Mostly ethanol, which is the bulk of an alcohol perfume, plus a concentrate of aromatic materials: aroma chemicals, and natural mixtures such as essential oils and absolutes, which are themselves made of molecules. Fragrance makers also use functional ingredients such as solvents and antioxidants; IFRA's Transparency List registers the materials used to make fragrance mixtures, natural and synthetic. There is no single chemical formula of perfume: every perfume is its own mixture. What is perfume made of goes through it.
Natural or synthetic perfume ingredients: which is better?
Neither, as a rule: safety and quality belong to each material and its dose, not to its origin. Naturals bring a rough, living texture and batch variation; aroma chemicals bring consistency, structure, radiance and notes no plant gives, and most perfumes use both. Aroma chemicals vs essential oils works through safety, cost and consistency.
Can I make perfume without essential oils?
Yes. A perfume can be built entirely from aroma chemicals, or from a ready-made fragrance oil; about half of the accords on PerfuMate's accords page contain no natural material, the Rose Accord and the Sandalwood Accord among them. The IFRA check and the allergen label still apply. Aroma chemicals vs essential oils has the details.
How do I make perfume with aroma chemicals?
The same way as with any material: weigh a concentrate in grams, keeping strong or solid aroma chemicals as 10% dilutions, dilute it in perfumer's alcohol, rest it and test it. The first formula on how to make perfume at home is mostly aroma chemicals: Hedione, Iso E Super, Ambroxan, Ethylene Brassylate and Vanillin beside two essential oils.
What is Iso E Super, and what does it smell like?
Iso E Super is IFF's woody-amber aroma chemical, OTNE by its chemical name: smooth, transparent and velvety, with a dry cedar-and-amber tone and a skin-like radiance. The catalog rates it 2 out of 10 for strength but gives it about 12 days on a blotter, and many people find it faint at first sniff. See Iso E Super in the catalog and how much Iso E Super to use.
How do I use Iso E Super, and can I wear it on its own?
By role: under 1% of the concentrate as a blender, roughly 5 to 15% as a heart support, 20% and beyond as the main idea. Worn alone it reads as a soft cedar-and-skin haze; IFRA's OTNE standard caps it at 20% of a finished fine fragrance, so a perfume of nothing but Iso E Super at 20% strength sits exactly at the line. How much Iso E Super to use has each role.
Is Timbersilk or Sylvamber the same as Iso E Super?
No. All three share a CAS number, but they are OTNE grades cut to different isomer ratios and smell different: Timbersilk drier, like sanded cedar plank, Sylvamber more mineral. None is a drop-in for the others. How much Iso E Super compares them.
What can I use instead of Iso E Super?
The substitutes engine ranks Bornafix first, at 92, noting that it is louder so you use a little less, followed by pairs such as Cedar Ketol with Teak. The catalog cannot tell Bornafix and Iso E Super apart by their notes, so smell them side by side before you swap. The full ranking is on Iso E Super's catalog page.
What is Ambroxan, and what does it smell like?
Ambroxan is Kao Corporation's trade name for ambroxide, an ambergris molecule Kao makes from sclareol from clary sage: dry, woody and ambery, with a labdanum warmth, a soft marine-mineral salinity and a light sweetness. It is loud, 7 out of 10 on the catalog's scale, and lasts about 17 days on a blotter. See Ambroxan in the catalog.
How do I dilute and dose aroma chemicals like Iso E Super and Ambroxan?
Dilute by weight: a 10% dilution is 1 g of material made up to 10 g with perfumer's alcohol or DPG, and every gram of it carries 0.1 g of the material. Iso E Super is usually weighed neat because its doses are large; Ambroxan, a solid, is weighed from a 10% solution, and its maker gives 0.1 to 10% as its dosage range. For a 100 ml eau de parfum at 18%, Ambroxan at 5% of the concentrate is 0.72 g, weighed as 7.2 g of a 10% solution in perfumer's alcohol, whose 6.48 g of alcohol then counts toward the bottle's alcohol. See how much Ambroxan and the dilution arithmetic.
What are Ambroxan crystals, and how do I use them?
They are Ambroxan in its normal form, a white solid sold as flakes or crystals that melts at 67 to 77 °C, according to Kao's safety data sheet. Dissolve 1 g in 9 g of perfumer's alcohol or DPG for a 10% solution, swirl until clear, label it and weigh from that. How much Ambroxan has the steps.
Ambroxan vs Cetalox, Ambrofix and Hedione: what is the difference?
Ambroxan, Ambrofix (Givaudan, made by fermenting sugarcane) and Ambrox Super (dsm-firmenich) are the same molecule, ambroxide; the substitutes engine scores Ambrofix 100 and Ambrox Super 93 as stand-ins. Cetalox has a different CAS number in the catalog and smells drier and less sweet, scored 72. Hedione is not an ambergris material at all but a jasmine-floral heart note. How much Ambroxan compares the grades in a table.
What can I use instead of Ambroxan?
Another ambroxide grade: Ambrofix or Ambrox Super, the same molecule under another name, or Cetalox if you want it drier and less sweet. The computed ranking is on Ambroxan's catalog page.
Is there a natural alternative to Ambroxan?
Not one that smells the same. Labdanum absolute, which the catalog calls the closest natural material to the smell of ambergris, clary sage absolute and sclareol cover the ambery side, ambrette seed the musky side, and real ambergris tincture is rare and restricted. Ambroxan itself is made from clary-sage sclareol, and Givaudan calls its fermented Ambrofix "100% naturally derived", but both are single molecules, not naturals. How much Ambroxan goes further.
Why can't some people smell Iso E Super or Ambroxan?
Specific anosmia, a blind spot for one molecule, is common, and the nose also adapts to a smell that stays around it. For Ambroxan, a 2025 study found that people without a working copy of the odorant receptor OR7A17 could still detect the molecule but found it less pleasant; Iso E Super is also simply quiet, 2 out of 10. Bench both on more than one nose. How much Ambroxan has the evidence.
Are Iso E Super and Ambroxan safe to use?
Within their limits, yes. Iso E Super falls under IFRA's OTNE standard, at most 20% of a finished fine fragrance, and is a declarable EU allergen; Ambroxan reaches no IFRA Category 4 limit, is not a declarable allergen, and its maker's safety data sheet classifies it as not hazardous. Handle both like any concentrated material, with gloves and good air. Aroma chemicals vs essential oils answers this in full; Iso E Super and IFRA and Ambroxan and IFRA give the limits, which are calculated reference checks, not a safety assessment.
Iso E Super vs Ambroxan: what is the difference?
Both are long-lasting base materials filed under amber and woody, but Ambroxan is far louder on the catalog's scale, 7 out of 10 against 2, and smells of ambergris, while Iso E Super is a velvety cedar-and-skin haze. Ambroxan lasts about 17 days on a blotter, Iso E Super about 12; Iso E Super has an IFRA cap, Ambroxan none. They mix well: three of PerfuMate's house accords use both. Iso E Super vs Ambroxan compares them side by side.
Iso E Super vs Galaxolide: what is the difference?
Iso E Super is a woody amber, not a musk; Galaxolide is the classic clean white musk, sweet and powdery, usually sold at 50% in a solvent. Galaxolide stays on a blotter about 4 days, Iso E Super about 12, and in the EU both must be named on the label above 0.001% of a leave-on product. Iso E Super vs Ambroxan covers Galaxolide too.
Iso E Super vs Hedione: what is the difference?
They share no family, Hedione being a jasmine-floral heart material and Iso E Super a woody-amber base, but both are quiet, 2 out of 10, and used in large amounts for their effect: Hedione for lift and bloom, Iso E Super for volume and reach. Hedione leaves a blotter after about 3 days, Iso E Super after about 12. Iso E Super vs Ambroxan has the comparison.
How do Hedione and Ambroxan work together in a perfume?
At opposite ends of a perfume: Hedione opens and spreads the heart and is gone from a blotter in about 3 days, while Ambroxan carries the drydown for about 17. Dose them differently, Hedione often at a tenth of a concentrate or more, Ambroxan mostly below that and from a 10% solution. None of PerfuMate's house accords pairs them, so find your ratio by trial, as the worked base on Iso E Super vs Ambroxan shows.
What is Hedione (and Hedione HC), and what does it do in perfume?
Hedione is dsm-firmenich's methyl dihydrojasmonate: a transparent, radiant jasmine, more an effect than a smell on the blotter, used at high levels to add lift and bloom to florals and citrus. Hedione HC is the high-cis grade, more radiant and used the same way at lower doses. See Hedione in the catalog, Hedione HC and the story of Hedione.
What is dipropylene glycol (DPG), and why is it used in perfume?
DPG is a practically odorless, colorless solvent, a co-product of making propylene glycol, that perfumers use to dilute strong or solid materials and to carry oil-based and functional fragrances. It barely evaporates and adds weight but no smell. DPG in perfume explains it in full.
How much DPG should I use in perfume?
As little as your dilutions need; an alcohol perfume needs none. Because DPG adds weight without strength, the 1.35 g it brings into the 10 g first formula on how to make perfume at home turns an intended 18% perfume into 15.6% unless you weigh more concentrate. DPG in perfume works it through.
Perfumer's alcohol vs DPG: which solvent should I use?
Perfumer's alcohol to dilute the finished perfume, DPG to dilute single materials and carry formats that should not evaporate. Alcohol flashes off and lifts the top notes; DPG stays on the skin with the perfume. DPG in perfume has a table of which solvent does which job.
Dipropylene glycol vs propylene glycol: what is the difference?
Related glycols, not the same material: propylene glycol is a single, smaller molecule that boils at about 188 °C, DPG a mixture of larger isomers that boils at about 231 °C. The catalog notes that PG dissolves very nonpolar aroma chemicals less well than DPG, so DPG is the usual perfume solvent. DPG in perfume compares them.
Is DPG safe?
As used in cosmetics and perfume, the assessments say yes: the US Cosmetic Ingredient Review concluded in 1985 that it is safe as presently used in cosmetics, and almost all companies notifying it to the EU's classification inventory report no hazard class. Its flash point, around 120 to 138 °C, is far above that of perfumer's alcohol. DPG in perfume gives the sources.
PerfuMate's catalog page for each material carries its strength, its blotter life and the published formulas that use it, free to browse; the free IFRA calculator checks a whole formula against the Category 4 limits in your browser.