Ferric Ammonium Citrate is commercially available in brown and green forms. The distinction appears simple, but buyers often find that selecting the correct material involves more than choosing a color.
Brown and green Ferric Ammonium Citrate normally have different iron-content ranges and physical appearances. However, the supplied form does not by itself confirm the applicable grade, impurity limits, regulatory status or suitability for a particular formulation.
For purchasing purposes, “brown” or “green” should therefore be treated as the beginning of specification review—not as the complete purchasing specification.
This guide explains the practical differences between the two forms, the limits of color-based selection and the information buyers should confirm before requesting a sample or bulk quotation.
What Is Ferric Ammonium Citrate?
Ferric Ammonium Citrate, also known as Ammonium Ferric Citrate, Ammonium Iron Citrate or Ammonium Iron(III) Citrate, is a complex salt composed of iron, ammonia and citric acid.
The FAO/JECFA specification describes Ferric Ammonium Citrate as a complex salt of undetermined structure and recognizes two types—brown and green—containing different amounts of iron. It is therefore not best understood as one simple compound with a single universally fixed molecular composition.
This is commercially important because buyers may encounter:
- different product names;
- brown or green appearance descriptions;
- different iron-content ranges;
- different referenced standards;
- different test methods;
- different intended-use statements.
These differences do not automatically mean that one supplier is correct and another is incorrect. They mean the buyer must compare the complete specification rather than relying on the product name alone.
Buyers reviewing available forms, documentation and bulk packaging can also visit our Ferric Ammonium Citrate powder product page.
The Main Difference: Iron Content
The clearest distinction between brown and green Ferric Ammonium Citrate is the typical iron-content range.
According to the FAO/JECFA specification, brown Ferric Ammonium Citrate contains 16.5%–22.5% iron, while green Ferric Ammonium Citrate contains 14.5%–16.0% iron. The same specification also gives different appearance descriptions and functional uses for the two forms.
| Item | Brown Ferric Ammonium Citrate | Green Ferric Ammonium Citrate |
|---|---|---|
| Typical Iron Content | 16.5%–22.5% Fe | 14.5%–16.0% Fe |
| Typical Appearance | Brown, reddish-brown or garnet-red scales or granules; brownish-yellow powder | Green scales, granules, powder or transparent green crystals |
| JECFA Functional Uses | Nutrient; dietary supplement | Nutrient; dietary supplement; anticaking agent for sodium chloride |
| Practical Buying Focus | Confirm iron assay, applicable grade, impurity limits and documentation | Confirm iron assay, intended application, applicable grade and regulatory conditions |
These ranges provide a useful starting point, but the buyer should still verify the actual supplier specification and batch COA. A general reference range is not a substitute for an agreed commercial specification.
For example, buyers should clarify whether the quoted iron percentage is based on:
- elemental iron content;
- an as-is or dried basis;
- a referenced compendial or supplier method;
- an internal release specification;
- an agreed customer specification.
Comparing prices without first confirming the assay basis can result in an inaccurate supplier comparison.
Does Brown Mean Pharmaceutical Grade and Green Mean Food Grade?
Not necessarily.
Brown and green forms are associated with different iron-content ranges, but color alone does not determine whether a product is food, pharmaceutical, nutritional or technical grade.
Grade is determined by the complete specification, referenced standard, manufacturing controls, impurity limits, documentation and intended market.
A brown product is not automatically pharmaceutical grade simply because it is brown. A green product is not automatically suitable for every food application simply because it is green.
One clear U.S. regulatory example applies specifically to green ferric ammonium citrate. Under 21 CFR §172.430, green ferric ammonium citrate may be used as an anticaking agent in salt for human consumption, provided that the level does not exceed 25 ppm, or 0.0025%, in the finished salt. This is a narrowly defined authorization and should not be interpreted as general approval for all food applications.
For buyers, the safer review sequence is:
- Confirm the intended application.
- Confirm the destination market.
- Identify the applicable standard or regulatory route.
- Confirm the required brown or green form.
- Review the full specification and COA.
- Complete internal technical and regulatory evaluation.
This avoids the common mistake of using color as a shortcut for grade or regulatory suitability.
Brown Ferric Ammonium Citrate
Brown Ferric Ammonium Citrate normally has the higher iron-content range. Depending on the applicable specification, its appearance may be described as brown, reddish brown, garnet red or brownish yellow.
From a purchasing perspective, brown material may be considered when a project requires a particular iron range, physical form or referenced specification.
Before purchasing brown Ferric Ammonium Citrate, buyers should confirm:
- required iron-content range;
- referenced specification or standard;
- appearance limits;
- moisture or loss-on-drying requirements;
- heavy-metal limits;
- solubility requirements;
- packaging and storage controls;
- required COA, TDS and SDS documentation.
The final decision should be based on the agreed specification rather than assumptions about the typical market use of brown material.
Green Ferric Ammonium Citrate
Green Ferric Ammonium Citrate normally contains less iron than the brown form. Official descriptions may include thin green scales, granules, powder or transparent green crystals.
The green form may be evaluated for food, nutritional or selected technical applications, but suitability still depends on the relevant specification, destination-market requirements and intended use.
Buyers should not assume that all green material is identical. Two green products may differ in:
- iron assay;
- shade and physical appearance;
- moisture content;
- particle form;
- impurity limits;
- referenced standard;
- documentation scope;
- approved or intended use.
When possible, buyers should provide an existing specification or current supplier COA. This allows a meaningful technical comparison instead of quoting material based only on the word “green.”
Why Color Alone Is Not Enough
Brown and green are useful commercial identifiers, but neither one provides enough information to release a purchase order.
A complete review should answer the following questions.
What Iron Content Is Required?
Iron content is usually the first technical distinction between the two forms.
A buyer who only requests “Ferric Ammonium Citrate powder” may receive quotations based on different forms and assays. Those quotations are not directly comparable until the iron specification is aligned.
What Standard Is Required?
The buyer should state whether the project requires:
- a specific compendial standard;
- a food-related specification;
- an internal manufacturer standard;
- a technical-grade specification;
- a customer-approved specification or reference COA.
Terms such as USP, BP or FCC should not be treated as broad marketing labels. Buyers should confirm the exact tests, limits and document references included in the supplier’s specification.
What Is the Intended Application?
The application affects which tests and supporting documents matter.
For example, a food-related project may require different contaminant, microbiological and regulatory documentation from a technical or laboratory application.
The intended use should therefore be disclosed early in the sourcing process rather than reviewed only after sample receipt.
What Is the Destination Market?
Permitted uses and documentation requirements differ between countries and product categories.
A material that meets one compositional specification may still require additional regulatory review before use in another market. The buyer’s regulatory team should confirm permitted use, use level and labeling requirements.
What Documentation Is Required?
Typical sourcing documents may include:
- batch COA;
- product specification;
- TDS;
- SDS/MSDS;
- country-of-origin statement;
- allergen statement;
- manufacturing-flow information;
- heavy-metal or microbiological data;
- market-specific regulatory statements.
The required documentation package should be clarified before commercial production or shipment.
How to Read a Supplier COA
A COA should be reviewed as a batch document, not merely as proof that the supplier sells a product with the correct name.
For Ferric Ammonium Citrate, buyers should pay particular attention to the following fields.
Product Identity
Check whether the document clearly identifies:
- Ferric Ammonium Citrate;
- brown or green form;
- relevant product code;
- batch or lot number;
- production date and/or test date, where applicable.
A COA that does not identify the supplied form may create uncertainty when the supplier offers more than one specification.
Appearance
The appearance result should correspond with the agreed form and specification.
Minor wording differences may be acceptable, but the result should not conflict with the material ordered.
Iron Content
Confirm:
- the specification range;
- the actual batch result;
- the test method or referenced standard;
- whether the result is reported on an as-is or another defined basis.
Iron content is one of the most important values for determining whether the batch matches the required form.
Moisture or Loss on Drying
U.S. regulatory text describing Ferric Ammonium Citrate as a drug color additive notes that the brown and green complexes are deliquescent in air and reducible by light. In commercial handling, buyers should therefore review moisture control, sealed packaging and light-protection requirements against the supplied grade and TDS.
Impurities and Contaminants
Required tests depend on the grade and intended use. They may include:
- heavy metals;
- lead;
- arsenic;
- sulfate-related limits;
- microbiological testing;
- other application-specific impurities.
Not every test is required for every grade, but the test scope should match the project’s quality and regulatory expectations.
Batch Traceability
A commercial COA should be linked to the actual supplied batch.
Buyers should ensure that a generic or sample COA is not mistaken for the final batch COA issued against the shipped material.
CAS Number and Naming Differences
The WHO JECFA database lists CAS No. 1185-57-5 and recognizes several names, including Ferric Ammonium Citrate, Ammonium Ferric Citrate, Ammonium Iron Citrate and Ammonium Iron(III) Citrate.
In practical sourcing, the CAS number should be reviewed together with:
- the full product name;
- brown or green form;
- iron-content range;
- referenced standard;
- supplier specification;
- intended application.
The CAS number alone is not sufficient to confirm that two supplier quotations represent the same commercial grade.
Common Purchasing Mistakes
Ordering Only by Product Name
“Ferric Ammonium Citrate” does not indicate whether the buyer requires brown or green material.
The inquiry should include the required form and iron-content range.
Treating Color as the Complete Grade
Brown or green appearance does not automatically confirm food, pharmaceutical or technical suitability.
The complete specification and intended regulatory route still need to be reviewed.
Comparing Prices Before Aligning Specifications
A lower quotation may represent a different iron range, grade, testing scope or documentation package.
Price comparison should begin only after the key specifications have been aligned.
Using an Old COA Without Checking the Test Basis
An existing supplier COA is useful, but buyers should confirm whether its test methods, standard references and specification ranges match the proposed new supply.
Assuming the Sample and Bulk Batch Use the Same Release Standard
The sample should represent the proposed commercial specification.
Before ordering, buyers should confirm that future bulk material will be released against the same agreed quality limits.
Confirming Documentation Too Late
Market-specific documents, additional testing and formal statements may affect cost and lead time.
The complete document list should therefore be discussed during quotation or sample evaluation.
A Practical Buyer Checklist
Before requesting a Ferric Ammonium Citrate quotation, prepare the following information:
- Required form: brown or green
- Target iron-content range
- Required grade or referenced standard
- Intended application
- Destination market
- Current specification or COA, if available
- Required test items
- Required documentation
- Trial and commercial quantity
- Packaging preference
- Target delivery schedule
Providing this information allows the supplier to quote the correct material and reduces repeated clarification during sample evaluation.
Practical Selection Summary
The main commercial distinction between brown and green Ferric Ammonium Citrate is their typical iron-content range.
Brown material generally contains more iron, while green material generally contains less. However, this does not mean that form alone determines grade or application.
A reliable sourcing decision should combine:
- brown or green form;
- iron-content requirement;
- applicable specification;
- impurity limits;
- intended use;
- destination-market requirements;
- batch documentation;
- packaging and storage conditions.
The most important purchasing principle is:
Do not order Ferric Ammonium Citrate by color alone. Order against an agreed specification.
Ferric Ammonium Citrate Bulk Supply
Lifeworth supplies Ferric Ammonium Citrate powder in brown and green forms for qualified commercial projects.
Supply discussions may include:
- brown or green form confirmation;
- target iron-content review;
- specification comparison;
- sample arrangement;
- batch COA review;
- TDS and SDS/MSDS support;
- export packaging;
- labeling and shipping documentation;
- trial and bulk quantity planning.
Buyers with an existing specification or current supplier COA can send it to us for comparison before requesting a sample or commercial quotation.
Review the available product information on our Ferric Ammonium Citrate powder page or contact our ingredient sales team with your required form, specification, quantity and destination market.
References
- FAO/JECFA. Ferric Ammonium Citrate – Food Additive Specification. FAO JECFA Monographs 1.
- World Health Organization. JECFA Database: Ferric Ammonium Citrate.
- Electronic Code of Federal Regulations. 21 CFR §172.430 – Iron Ammonium Citrate.
- Electronic Code of Federal Regulations. 21 CFR §73.1025 – Ferric Ammonium Citrate.
