Understanding Use Percentages
In the description section of many of our products, you will see a ‘Use up to’ or ‘Average’ percentage. When you see ‘Average,’ the material is unrestricted and you can use as much as you like. For beginners, it is a great idea to use aroma chemicals and naturals that are unrestricted.
However, many aroma chemicals and natural materials used in perfumery have safety-in-use recommendations expressed as a maximum percentage of the material allowed to be in contact with the skin. This is to reduce to almost zero the risk of allergy, sensitization reactions or carcinogenic potential. The allowed amount will be different depending on whether the perfumed end product is a lotion, soap, perfume, etc., and we try to provide the ‘Use up to’ percentage for perfume, Category 4 in the IFRA standards. The IFRA restrictions are mandatory for the EU and other IFRA members and reflect best practices elsewhere, and if you are selling your perfumes it is up to you to know what your local rules are.
While we try to stay current with product limits as determined by IFRA, we may miss some and it is up to you the perfumer to know which materials
have use restrictions by checking. Here is the website you would go to to find the restricted items. IFRA International Fragrance Association. The SDS can be helpful in knowing the chemical names and finding out if there are restrictions on the chemicals
How to Calculate Usage Percentages
For the aromas that are restricted, the maximum percentage listed is on a weight by weight basis, not volume, and reflects the maximum allowed in the final, dilute product.
If the given maximum percentage of an aroma chemical is, for example, 5%, that means the finished perfume product can have no more than 5% of that aroma chemical in its makeup. To know the upper limit you may have in your concentrate before dilution, you take your final allowable 5% and divide by your intended dilution. An
parfum might dilute a perfume concentrate to 20% or .20 in alcohol, an eau de toilette might dilute the concentrate even more to 10% or .10. In our example, if you will be making a
parfum, you would divide 5% by .20 and get 25% allowed in your concentrate:
5%/.20= 25% or 25 parts maximum of aroma chemical in every 100 parts of concentrate, which then becomes 5 parts in every 100 of diluted perfume.
If you were planning on an eau de toilette, you would divide 5% by the .10 dilution to get 50% maximum allowed in your concentrate.
5%/.10 = 50%.
Once you dilute your 50% concentrate to a tenth, you will end up at that 5% upper limit. You needn’t use the maximum allowed, but now you know what you are limited to. As long as you stay below your calculated limit in your concentrate, you are good to go!
If you need to see if your current concentrate will be safe when diluted, multiply the current percentage of the aroma chemical by the intended dilution. If the answer is less than the allowable upper limit, you are OK! From the above example, if you have used 7 grams of aroma in 100 grams total undiluted and will be making a 20% EdP, you would take 7% x .20= 1.4%, which is less than the 5% upper limit so you are fine.