In short
A restricted substance may enter a formula through natural oils as well as through a pure line, so a proper check adds every contribution. You need a table with one row per formula line, using the best composition data available and clearly flagging what is estimated. Then you compare each total with its limit, and the first limit reached sets your maximum dose. This goes further than the Level 10 practice problems, by dealing with the messy reality of composition data.
What you will learn
- Build a contribution table across lines
- Handle ranges and missing composition data
- Identify the limiting substance and the maximum dose
Before this lesson: Building a Fragrance Compliance File
The data problem
| Source | Strength | Limit |
|---|---|---|
| Lot-specific supplier statement or analysis, calibrated for that substance | Strongest | One lot |
| Supplier's grade statement of maximums | Often what you'll get | May be conservative or general |
| Certificate of analysis in area percent | Weak for quantity | See area percent |
| Published typical composition | A provisional estimate | Chemotype, origin and method |
| A general web figure | Weakest | Don't rely on it |
Note that some Standards also address specifications, or apply to named natural extracts. Read the actual Standard. A rule written about a named extract may be applied differently from one about a single constituent.
A worked contribution table
All limits and compositions here are invented. Product: 15% concentrate. Substance Z, with an invented limit of 0.60% in the finished product.
| Line | Share of concentrate | Z in material | Data source | Z in concentrate |
|---|---|---|---|---|
| Oil A | 6% | 30% (maximum) | Grade statement | 1.80% |
| Oil B | 2% | 10% (estimate) | Published | 0.20% |
| Pure Z | 1% | 100% | Specification | 1.00% |
| Compound C | 4% | Unknown | Requested | Flag |
| Total | 3.00% + unknown |
In the finished product, that gives 3.00% × 0.15 = 0.45% plus an unknown from compound C. Without C, you'd have some margin against the invented 0.60%. If C held an invented 30%, it would add 1.20% to the concentrate, and the total would be 0.63%, over the limit. So you cannot conclude anything until you have C's data. An honest status is "open".
Finding the limiting substance
Repeat this for each restricted substance. For each, the maximum concentrate is approximately:
maximum concentrate % = limit in product % ÷ (substance share in concentrate, as a fraction)
With Z at 3.00% of the concentrate and a 0.60% limit, the maximum concentrate is 0.60 ÷ 0.03 = 20%. If substance Y allows only 12%, then Y sets your dose at 12%. This is a useful thing to know before you commit to a dose. And it also shows which line to reduce, since cutting a small contributor won't help.
Special cases
- Groups. Some rules treat a group or the sum of isomers together. Read the wording. Citral and its isomers are an example of grouping in allergen rules.
- Schiff bases. A base may be counted according to the aldehyde it can release. See the Schiff base guide.
- Phototoxic combinations. Combined rules apply. See phototoxicity.
- Purchased compounds. Your supplier's certificate gives you a maximum dose. If you blend it with other things, you have to account for what you've added.
- Dilutions. Use the actual content of the material supplied.
- Oxidation. Some Standards address peroxide values. A good calculation doesn't remove the need for a good material.
Reviewing your work
Errors in these tables are often simple: a share used as a fraction, a percent entered twice, or a dilution ignored. Add a check: do your lines total 100%? Have someone else recalculate your largest contributor by hand. Test any software you're using with a problem you've already solved, as the Lab's software testing guide explains. RUŌOD Lab's own flag only compares relative share to a limit you've recorded. It holds no IFRA data and it doesn't do constituent tracing for you.
Practical exercise: A contribution table for one formula
- Choose one formula with at least two natural materials.
- Identify three restricted substances likely to be present.
- Build a contribution table for each, using the best available data, and labeling each source.
- Use upper values where you have only a range, and mark unknowns "flag".
- Calculate each maximum concentrate, and name the limiting one, if you can.
- Write to a supplier for the most important missing figure, and record the reply.
You have done this well if unknowns stay visible, your arithmetic has been checked, and your conclusion is honestly "open" where data are lacking. Use real limits from current sources, and date them. This doesn't confirm compliance.
Common mistakes
- Counting only pure lines. Naturals contribute too.
- Using a typical figure as if it were your lot. Mark it as an estimate.
- Treating an unknown as zero. Flag it.
Key terms
- Contribution table
- A table showing, for each restricted substance, how much each formula line adds, so that the total can be compared with a limit.
- Worst-case figure
- Using the highest credible composition value when an exact one isn't known, to avoid understating a substance.
Knowledge check
Written and reviewed by the RUŌOD Lab team. This is general education, not legal, regulatory, medical or safety advice. Example dilutions and exercises are for learning, are not validated products, and have not been safety-assessed. Completing a lesson confers no qualification. How we check these lessons.