Not sure where to start when it comes to adding fragrance oil in your recipes? Let’s talk about IFRA usage rates. IFRA stands for the International Fragrance Association. The usage rates that are provided for each fragrance is there to help you determine how much fragrance oil you can safely use in your recipes. You want to make sure to pay attention to usage rates to avoid miss-use, and potential skin irritation if used in body products. There are 11 different IFRA categories, determining which category your product falls under is important, as usage rates vary from product to product. Below is a chart of the IFRA categories. The categories that are most commonly referred to in the handmade industry are Category 9- Soaps, Bath Bombs and Rinse-Off products. Category 4 is leave on products, such as lotions and body sprays. And Category 10, which is for the use in Candles, Room sprays and other non-skin contact items.
Let’s get technical. Now trust me when I say that math is not one of my greatest strengths in life, but hear me out when I say that learning how to calculate your usage rates will save you time and money in the long run by avoiding just ‘dumping’ in some fragrance oil and hoping for the best. By guessing how much fragrance oil should be in a product you are not only setting yourself up for failed batches, you are potentially creating a product that could harm one of your customers. The important thing to remember with IFRA usage rates is that although you never want to exceed the usage rate, you often will find yourself using less than the deemed ‘safe’ amount. Let me show you.
Let's say we are making a batch of Body Wash. Our Stephenson's 3-in-1 Body Wash Base will yield 3lbs (48oz) for this particular recipe and the fragrance oil I am using has the usage rate listed as 7.10%. Stephenson's 3-in-1 Body Wash Base recommends not exceeding 1% fragrance oil to avoid a cloudy appearance. Let’s do the first calculation using the IFRA usage rate.
Take your usage rate and convert to a decimal. (7.10 = .071)
Calculate: 48oz x .071 = 3.4oz fragrance oil.
Technically it would be safe to use this much fragrance oil in my body wash base, meaning it would not cause irritation to the skin, however it would ruin the body wash base. As mentioned, the Stephenson's Body Wash Base recommends up to 1% of the total body wash base, to avoid a cloudy soap. Now let’s calculate again now that we know this information.
Calculate: 48oz x .01 = 0.48oz fragrance oil.
Now that is a big difference. Make sure to always double check usage rates when creating products in different IFRA categories.