What IFRA actually restricts, and why
Of the 406 materials on the bench, exactly one is prohibited and 323 carry no limit at all. IFRA is not the list of forbidden things people expect.
Most people meet IFRA as a rumour. Somebody says oakmoss is banned, or that you cannot use bergamot any more, and a beginner concludes that the interesting materials have been taken away and what is left is a careful, dull middle. It is worth knowing what the Standards actually say before a rumour starts shaping your formulas.
So start with a count. The bench in this studio holds 406 materials. Exactly one of them is prohibited outright: massoia lactone. Eighty-two carry a numbered limit. The remaining 323, four out of every five, carry no restriction at all, at any dose, in anything you might make.
What a limit is actually for
There are three reasons a material ends up with a number against it, and only three.
The first and by far the commonest is sensitisation. Some molecules can teach a person's immune system to treat them as a threat. The trouble is that the lesson does not fade. Someone sensitised to a material at twenty will still react to it at sixty, to that material in anything, not only in your perfume. That is why these limits are strict in a way that feels disproportionate to the smell.
The second is phototoxicity. A few materials react with sunlight once they are on skin, and the result is a burn rather than a rash.
The third is ordinary systemic toxicity, and it is rare in perfumery at the doses anybody actually uses.
A limit is not a verdict on a material. It is the dose below which the thing that went wrong stops happening.
Bergamot is both answers at once
Bergamot expressed carries a category 4 limit of 0.4 %. Bergamot FCF carries no limit at all. Same fruit, same cold press, two completely different entries.
The difference is a small group of molecules called furocoumarins, bergapten chiefly, which sit in the peel and are the part that reacts with sunlight. FCF stands for furocoumarin free. Take them out and the restriction goes with them, because the reason for it has gone.
That pair is the whole logic of the Standards in two numbers. The limit was never about bergamot. It was about one thing inside bergamot, and when that thing is removed the oil is unrestricted again.
Oakmoss is not banned either
Oakmoss absolute sits at 0.1 %, and the low-atranol grade is the one on this bench. The two sensitisers in classical oakmoss are atranol and chloroatranol, and the modern absolutes are processed to remove most of them.
A tenth of a per cent of a finished perfume is not nothing. It is enough to build a recognisable mossy base around, which is what a chypre needs. What you cannot do any more is pour it, and the perfumes that poured it were being made before anybody had counted the people reacting to them.
The number you are comparing against is probably the wrong one
This is where most beginners frighten themselves, and it is worth getting straight.
IFRA limits apply to the finished product, not to your concentrate. Your formula is the oil. The perfume is that oil diluted in alcohol, usually to somewhere between 15 and 25 %.
Take the damascones, which are among the tightest things on the bench at 0.043 %. Read that against your formula and it looks impossible. But at 20 % concentration, your oil is only a fifth of what reaches skin, so you can carry roughly 0.215 % damascone in the oil itself and still sit inside the limit. Five times what the number appeared to allow.
Compare a concentrate percentage against a finished-product limit and you will cut good materials out of good formulas for no reason. The studio does this conversion as you type, which is the entire point of the compliance panel.
Why the same formula has four different limits
Everything above quotes category 4, which is fine fragrance on skin. The same material has a different limit in a face cream and a different one again in a candle, because the question is always how much reaches skin and for how long. That is a longer story, and it has its own post.
Put oakmoss on the bench at 0.3 % of the oil and watch the compliance panel. Then change the concentration from 20 % to 30 % without touching the formula at all. The same oil goes from compliant to over the limit, and nothing about the recipe changed. That is the clearest demonstration there is that these numbers live on the skin rather than in your beaker.
Open the bench →Every number in the Standards is a record of something that happened to somebody. Read that way, IFRA stops being a list of things taken away from you and becomes the only honest account the craft keeps of its own mistakes. You are allowed to disagree with a particular number. You are not really allowed to pretend nobody got hurt.