If you make fragranced soap or cosmetic products, you’ve probably bumped into “IFRA Standards.” Let’s dig into what they are, where they come from, how the categories work, what you should be getting from fragrance suppliers—and then walk through a real, numbers-based example using essential oils so you can see exactly how to check compliance.
What IFRA Standards are (and where they come from)
IFRA is the International Fragrance Association—the industry body that sets safety rules for how fragrance ingredients may be used in finished consumer products. IFRA doesn’t act alone: safety assessments are produced by RIFM (the Research Institute for Fragrance Materials) and reviewed by an independent Expert Panel. Those assessments feed into IFRA Standards, which set maximum acceptable concentrations (MACs) for specific fragrance ingredients by product category.
IFRA is an association of fragrance manufacturers, so to them each of the substances in the IFRA standards is an ingredient; it’s what they use to make their fragrance oils.
When we talk about meeting IFRA standards, we are usually dealing with essential oils that have these substances as components of the ingredient (essential oil) we are using.
For clarity, I will refer to them as components in this article.
The current framework (the 51st Amendment) reviews three factors when determining the limits of a component: dermal sensitization, systemic toxicity, and phototoxicity. All three also take into account multiple potential sources of exposure. The lowest relevant limit becomes the maximum usage rate.
What is a Restricted Component?
In IFRA language, a “restriction” means a specific component (such as: eugenol, citral, methyl eugenol, furocoumarins) has a category-specific maximum in the finished product.
If your product contains that component—whether you added it neat or it arrived “inside” an essential oil or fragrance oil—you must keep the total amount of that component at or below the category limit. IFRA also has “prohibitions” (not allowed) and “specifications” (quality/purity requirements), but since most day-to-day calculations that small makers will do are about the restricted components and their category caps, I won’t be addressing those in this article.
The IFRA Product Categories
IFRA sets limits by category, which reflect where and how the product is used (lips vs. underarm, rinse-off vs. leave-on, etc.). Here’s the quick view of the 12 categories (51st Amendment):
| Category | Name | Examples |
|---|---|---|
| 1 | Products applied to the lips | Lip balm; Lipstick |
| 2 | Products applied to the axillae (underarm) | Deodorant |
| 3 | Products applied to the face/body using fingertips | Eye cream; Serum |
| 4 | Fine fragrance products | Eau de parfum; Body spray |
| 5A | Body lotion products applied with the hands (leave-on) | Body lotion; Body butter |
| 5B | Face moisturizer products applied with the hands (leave-on) | Face cream; Face lotion |
| 5C | Hand cream products applied with the hands (leave-on) | Hand cream; Cuticle cream |
| 5D | Baby creams, baby oils, and baby talc | Baby lotion; Baby oil |
| 6 | Products with oral and lip exposure | Toothpaste; Mouthwash |
| 7A | Rinse-off hair products with some hand contact | Shampoo; Rinse-off conditioner |
| 7B | Leave-on hair products with some hand contact | Leave-in conditioner; Hair styling cream/serum |
| 8 | Products with significant anogenital exposure | Intimate hygiene wipes; Feminine deodorant spray |
| 9 | Rinse-off body/hand exposure products | Bar soap; Body wash |
| 10A | Household care products with mostly hand contact | Hand dishwashing liquid; Laundry detergent |
| 10B | Household care aerosol/spray products (potential leave-on skin contact) | Fabric refresher spray; Furniture polish aerosol |
| 11A | Intended skin contact with minimal transfer from an inert substrate (no UV) | Scented facial tissues; Scented cotton rounds |
| 11B | Intended skin contact with minimal transfer from an inert substrate (with potential UV) | Scented clothing accessories (e.g., perfumed scarf); Scented wristband |
| 12 | Products not intended for direct skin contact (minimal/insignificant transfer) | Scented candle; Plug-in air freshener |
When you see a limit like “Citral—Category 5C: 0.15%,” that means your finished hand cream (Category 5C) can contain no more than 0.15% citral total from all sources.
IFRA Certificate of Conformity
When you’re buying a fragrance oil (a compound), your supplier should provide you with:
- An IFRA Certificate of Conformity, showing the maximum usage rate for that fragrance mixture in each IFRA category (they’ve already done the component math internally).
- A Safety Data Sheet (SDS).
- Details of any fragrance allergens in the fragrance(they are a separate thing from IFRA)
IFRA even publishes a template for the Certificate of Conformity, and the Guidance explains how certificates map to categories. Practically, you use the supplier’s “max for your category” as your upper limit for that fragrance mixture.
Important: Fragrance suppliers ensure their mixture meets all component limits and then give you a single “max use by category.” If you’re blending essential oils yourself, you are effectively the “fragrance supplier,” so you must do the component-level math yourself (covered below).
Where to Get the Percentages of Components in an EO
The BEST source of information about the components in your essential oil(s) is testing on the actual essential oil you have. Assuming you aren’t going to pay to have the testing done yourself, you may be able to obtain the information in a Certificate of Analysis from your supplier, which may show the results of the testing conducted on that particular batch.
If you don’t have reliable information from either of those sources, you can use studies or other compiled information giving the typical range or a reliable estimate of the percentage of a component in an essential oil, such as:
- IFRA’s Annex on contributions from other sources is a downloadable spreadsheet that compiles typical/indicative concentrations of restricted components in natural complex substances (NCS), including many essential oils. It’s probably the best place to start.
- Essential Oil University‘s extensive database of studies for specific essential oils (free registration required);
- International Standards (ISO) has published ISO Monographs for many specific essential oils (these monographs may be purchased individually) which give the expected range of components;
How to Calculate IFRA Compliance When Using Essential Oils
- List IFRA-restricted components present in each essential oil you are using. Use whatever sources you have to identify which restricted components are present and at what typical percentage in that oil. If you have a range, use the higher end to be sure you are safe.
- For each restricted component, compute its level in the finished formula:
[% of oil in formula] times [% of component in that oil] equals [% of component in formula] - Combine the amounts of each restricted component. If the same restricted component is contained in more than one essential oil you are using, add the % of the component in formula from each calculation (Step 2, above), to get the total percent in your formula.
- Identify your product’s IFRA category. (Example: a hand cream is Category 5C.)
- Compare to the IFRA Maximum Acceptable Concentration. For each restricted component, compare the % of component in formula (from steps 2 and 3) to the maximum acceptable concentration of that component in the product category,.
- If you are over the maximum acceptable concentration for any component in an essential oil, reformulate as necessary to get down within the acceptable range.
Example:
Let’s say you want an Orange Spice hand cream (Category 5C) with:
- Clove bud oil (Syzygium aromaticum) at 1.00% of the formula
- Lemongrass Oil (Cymbopogon flexuosus) at 1.00% of the formula
From the IFRA Annex, typical major restricted constituents include:
- Eugenol in clove bud oil
- Citral (neral + geranial) in lemongrass oil
Keep in mind that exact percentages vary by source/season; use your Certificate of Analysis when available. The Annex provides indicative ranges you can use when you don’t have test data. (Note that in this example, I’m not going through all the steps for all the components, just the major ones.
For our illustrative math, we’ll use commonplace mid-range values consistent with the Annex’s intent:
- Clove bud oil: eugenol approximately 80%
- Lemongrass oil: citral approximately 75%
Step 1: Compute the constituent levels in the finished product
Remember the formula:
- [% of oil in formula]
- times [% of component in that oil]
- equals [% of component in formula]
Eugenol contributed by clove bud oil:
- 1.00% clove oil in the formula
- times 80% eugenol in clove oil
- equals 0.80% eugenol in the finished hand cream
Citral contributed by lemongrass oil:
- 1.00% lemongrass oil in the formula
- times 75% citral in lemongrass oil
- equals 0.75% citral in the finished hand cream
Step 2: Look up the IFRA Maximum Acceptable Concentration for Category 5C
- Eugenol : Category 5C limit 0.64% maximum in the finished product.
- Citral: Category 5C limit 0.15% maximum in the finished product.
Step 3: Compare
- Eugenol present at 0.80% → over the 0.64% limit → not compliant.
- Citral present at 0.75% → over the 0.15% limit → not compliant.
Step 4: How much can you use?
It’s a different formula:
- % of the component allowed in the finished product
- divided by % of component in the essential oil
- equals Maximum amount of essential oil allowed in formula
Eugenol:
- 0.64% Eugenol allowed in the finished product
- divided by 0.80% Eugenol in Clove Oil
- equals 0.80% maximum amount of Clove Oil allowed in formula
Lemongrass Oil:
- 0.15% Lemongrass allowed in the finished product
- divided by 0.75% Citral in Lemongrass Oil
- equals 0.20% maximum amount of Lemongrass Oil allowed in formula
These limits are independent because eugenol and citral are different restricted components. If you set your formula to 0.80% clove bud + 0.20% lemongrass, you’d be right at both maximum allowed concentrations (0.64% eugenol and 0.15% citral respectively).
Also check for other restricted components in each oil (e.g., isoeugenol, methyl eugenol, geraniol, etc.) and add contributions across all sources of the same component. For example, if this formula also contained cinnamon leaf oil (which has 74% eugenol), you would add the amount of eugenol from both the clove oil and the cinnamon leaf oil into your calculations.
Putting it all together (your workflow)
- Pick the right category for your product. (Use IFRA’s category table and examples.)
- Fragrance oil? Obey the supplier’s IFRA Certificate max for your category.
- Essential oils?
- Use your Certificate of Analysis where possible; otherwise, consult IFRA’s spreadsheet “Annex on contributions from other sources” or other reliable sources to estimate typical restricted-constituent levels.
- Calculate each of the percentages of every restricted component in the finished product and compare to the IFRA Standard for that component in your product category.
- Adjust percentages, swap materials, or move the product to a less-stringent category (e.g., rinse-off) if appropriate for the use case.
If you are in the R & D stage, you can go the other way. Figure out the maximum allowed amount for each of the essential oils you want to use. Watch for any restricted components contained in more than one essential oil. Adjust the amounts of the essential oils based on what’s allowed (and how you want it to smell).
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