There is one famous proverb 'all things are good at particular dose level' so either its medicine or alcohol, should be consumed at a particular dose level.
The same thing applied to perfumery also, no doubt there are so many world-famous fragrances that claim overdose of some important particular ingredients like Tresor by Lancome, Tuscan Leather by Tom Ford, etc.
Out of 1487 aroma chemicals; 259 and out of 312 natural oil; 239 oils are classified as Dermal allergen.
(There are more than 9000 aroma chemical are used in the perfumery, but here I mention 1487 only as IFRA IOFI till 2016 labeled only 1487 aroma materials)
Note: Aroma ingredients which cause skin allergen their dose level is not fixed it get change as per
Environment
skin type
Ecology
There are two types of phase before someone get allergic
Induction Phase
Elicitation Phase
Induction Phase: As the name indicate the time when the allergy is induced. During the induction phase, the person comes in contact with a substance and may have no visible reaction to it. But, inside, the body is preparing a defense against the substance, by preparing for an allergic response.
Elicitation phase: After the Induction phase, elicitation may come or may not come. As it depends on the immunity and exposure level of the person. But in some people after the Induction phase – it could be days, weeks, months or years-the person start to have allergic reactions when exposed to a small amount of the substance, or even a different substance. This is elicitation; the body has become allergic and a small amount of a substance elicits an allergic reaction.
The induction of allergy relates to the following things:-
1. Strength of sensitizer: A strong sensitizer even at a lower dosage will induce allergy and the same way a week sensitizer even at a higher concentration may not induce allergy.
2. The concentration of material or Purity: A more concentrated and pure application of fragrance material has a higher chance of passing through the skin to reach and interact with lymph nodes.
3. Different people have different skin as per different Ecology so their pre-dispositions to allergy will also be different.
IFRA and Allergy Prevention:
International Fragrance Association categories the different type of products based on the ingredients are limited to a level below which the induction is expected to happen; IFRA QRA (Quantitative Risk Assessment)
QRA is established to safe use level with intention of preventing skin sensitization i.e. preventing directly from the induction phase.
This QRA use 11 categories to incorporating all type of products having fragrance in it and table are as follow:-
Note: Category 1, Lip products and Category 6, Mouthwash: Due to potential of ingestion here Flavors are used or Raw material approved by flavor use.
SAF number directly proportional to sensitization, menace higher the value more likely the application to contribute sensitization.
Calculating IFRA QRA limits:-
Formulation IFRA limit= (RM QRA limit / RM% present in Formula)*100
For Example: If Eugenol is used in formula at 5%, and fragrance intended for Hydroalcoholic for shaved skin i.e. Category 4
Then as per Formulation:-
IIFRA limit = (RM QRA limit / RM% present in Formula)*100
Therefore, 0.5/5*100= 10
This means that formulation containing 10% of Eugenol can be used at up to 10% in category 4 products.
Apart from the IFRA limit there are so many other factors also decide % of aroma chemical in the formula, I will discuss this more elaborately in some other article.
All Rights Reserved | The Perfumer's Valley
Archana Shandilya
References -
https://ifrafragrance.org/