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Soap Math

IFRA Categories Explained

Which category covers your product — and why it matters for fragrance safety compliance

What IFRA Is and Why It Has Categories

The International Fragrance Association (IFRA) publishes safety standards for fragrance materials based on toxicology research from the Research Institute for Fragrance Materials (RIFM). These standards set maximum usage levels for individual fragrance ingredients across 48 product categories in the current 51st Amendment.

The reason there are categories instead of one universal limit is that dermal exposure varies enormously by product type. A fragrance ingredient at 1% in a leave-on facial cream is absorbed into skin all day. The same ingredient at 1% in a bar soap is heavily diluted with water during use and rinsed off within seconds. The actual dose delivered to the body is completely different — so one limit would either over-restrict or under-protect depending on the product.

At a Glance

  • 48 product categories in the 51st Amendment (2022)
  • Categories set limits based on exposure — not product preference
  • Leave-on = stricter limit; rinse-off = higher limit
  • Face / lips / mucous membranes = strictest limits
  • US compliance is voluntary; EU compliance more directly regulated

The 48 Categories — Major Groups

The 48 categories are grouped by exposure type. The table below shows the major groups and representative product types. For the full list, consult the IFRA 51st Amendment standard document or use the IFRAMath calculator.

Category GroupCategoriesProduct ExamplesLeave-on or Rinse-off
Lip products1Lip balm, lipstick, lip glossLeave-on (mucous membrane)
Deodorant / intimate2–3Deodorant, intimate wash, body sprayLeave-on / rinse-off
Face leave-on4A, 4B, 4C, 4DFacial moisturizer, eye cream, sunscreen, anti-aging serumLeave-on
Body leave-on5A–5CBody lotion, hand cream, hair products (scalp)Leave-on
Facial rinse-off6A, 6BFace wash, facial scrubRinse-off
Hair products7A, 7BShampoo, conditioner, hair dyeRinse-off / leave-on
Fragrance8A, 8BFine fragrance (EDT, EDP), aftershaveLeave-on
Rinse-off body9, 10A, 10BBar soap, body wash, bath bombsRinse-off
Household / non-skin11A, 11BBaby wipes, feminine hygiene wipesLeave-on (sensitive)
Ambient / inhalation12Candles, diffusers, room spraysInhalation exposure

Categories Change Between Amendments

The 49th Amendment used only 11 categories. The 51st Amendment expanded to 48 by splitting previous categories into more specific exposure types. A limit from a supplier's 49th Amendment Certificate of Conformance is not the same as a 51st Amendment limit. Always confirm which amendment you are working from.

How Limits Are Set

Each IFRA limit is derived from a Quantitative Risk Assessment (QRA). RIFM's toxicologists identify the No Observed Adverse Effect Level (NOAEL) for a given fragrance material from animal or human study data. This is then divided by safety factors and adjusted for expected consumer exposure in each product category to arrive at the maximum safe concentration in the finished product.

The factors that determine how strict a category's limit is:

FactorLower Limit (stricter)Higher Limit (more lenient)
Contact typeLeave-onRinse-off
Body areaFace / eye area / lipsArms, legs, torso
Skin conditionDamaged, compromised barrierIntact healthy skin
User groupInfant, elderly, sensitiveGeneral adult population
FrequencyDaily useOccasional use
Concentration at useUndiluted (fine fragrance)Highly diluted (rinse-off)

Pro Tip

When choosing which category to apply to your product, always pick the category that most closely matches how your customer actually uses the product — not the one with the highest limit. A leave-on body lotion is Category 5B, not Category 9 (rinse-off body wash), even though soap limits are more generous. Misclassifying your product to get a higher limit defeats the purpose of compliance.

Common Products and Their Categories

Here are the most common small-batch product types and their correct 51st Amendment categories:

  • Cold process bar soap: Category 9 (rinse-off body, hand, and face)
  • Liquid hand soap / body wash: Category 9
  • Shampoo: Category 7B (hair products, rinse-off)
  • Conditioner (rinse-out): Category 7B
  • Leave-in conditioner: Category 7A
  • Body lotion / hand cream: Category 5B (body leave-on)
  • Facial moisturizer / serum: Category 4A
  • Eye cream: Category 4B
  • Lip balm: Category 1
  • Deodorant (underarm): Category 3A
  • Fine fragrance (body spray, EDT): Category 8A or 8B
  • Baby products: Category 11A or 11B (highest restriction)

Using IFRAMath

The IFRAMath calculator on this site lets you build a fragrance blend, enter each material and its IFRA limits, and calculate the maximum safe usage rate for up to 48 categories simultaneously. It flags prohibited ingredients and identifies EU allergens that require label disclosure.

To use it correctly: enter each fragrance component individually with its IFRA 51st Amendment limit for the relevant category. If a supplier provides limits for multiple categories in their Certificate of Conformance, use the category that matches your product. The calculator outputs the maximum total fragrance percentage that keeps each component within its limit.

Frequently Asked Questions