In short
Reformulation means changing an existing formula, usually because a material has been restricted, has become unavailable or costs too much, while keeping its character as far as you can. Good reformulation follows a route: find what the material was doing, rebuild those effects, match blind against a retained standard, and report honestly what remains different. In practice you will rarely get a perfect match, so the skill lies in choosing what to protect.
What you will learn
- Work out what a removed material was doing
- Rebuild its effects with one or several materials
- Run a blind match and report the remaining difference
Before this lesson: Supplier Quality: Study Guide
The route
- Retain a standard. Keep a sample of the current version from a known batch, stored away from light and heat.
- Do the removal test. Remove the material, rebalance to 100%, and compare it blind. Write down exactly what is lost, and at which stage.
- List its jobs. A material might give lift at the top, body in the heart and a tail in the drydown. A single replacement rarely does all of this.
- List candidates per job. Check each for restrictions, allergens, availability and cost. Our substitution lesson gives the method.
- Trial one change at a time. Keep a table of versions.
- Match blind. Use a triangle test against the standard for the closest version.
- Recheck everything downstream. Restrictions, allergens, stability, cost, the label and the certificate.
- Record the change. See formula change control.
A worked outline, with no quantities
Say a muguet heart relied on Lilial, which the EU prohibited under Regulation (EU) 2021/1902. The removal test shows that the formula loses its soft, airy floral body, and some of its radiance after two hours. You might then list:
| Job lost | Candidates to test | Watch for |
|---|---|---|
| Soft floral body | Florhydral, Majantol, Mayol | A sharper, greener or thinner character |
| Air | More Hedione | Shifts toward jasmine |
| Tail in the drydown | A clean musk adjustment | Laundry effect |
You would then record which combination came closest, what stayed different, and whether a person who knew the original would notice. See the history in the muguet study guide.
Reporting a match
Avoid "identical". Report what you did: "In a triangle test on strips at 2 hours, one assessor out of three chose correctly." That tells a reader how much you know, which with three assessors is very little. For a commercial decision, a larger panel and a test on the final product may be justified. The sample-size lesson in the Research and Innovation track explains why. If a client or brand is involved, tell them plainly that the fragrance will change, and how.
When not to chase a perfect match
Sometimes a formula's character depended on what you have just removed. Then the honest options are to accept a change, present a new interpretation, or withdraw the product. Each is a decision for the owner, and you should bring evidence to help them make it.
Practical exercise: Remove one material and rematch
- Choose one of your formulas, and one material that matters to it. Treat it as unavailable from today, whatever the real status is.
- Retain a standard, then follow the route above, recording each trial.
- Reach a best version within three rounds.
- Run a blind test with at least one other person, using coded samples.
- Write a half-page change note: what changed, why, what you tested, what still differs and what needs rechecking.
You have done this well if you listed the material's jobs before choosing a substitute, your test was blind, and your note says what is still different. Say whether the removal was a drill, so your record cannot be mistaken for a regulatory finding.
Common mistakes
- Looking for one like-for-like replacement. It usually takes several small adjustments.
- Comparing against memory. Retain a standard before you start.
- Forgetting downstream documents. The old certificate no longer applies to the new formula.
Key terms
- Reformulation
- Changing an existing formula to meet a new requirement, such as a restriction, a cost target or a supply problem, while keeping its character as far as possible.
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.