Reduced L-Glutathione (GSH) CAS 70-18-8

What Is Reduced L-Glutathione?

Reduced L-glutathione, commonly abbreviated as GSH, is a naturally occurring tripeptide composed of L-glutamic acid, L-cysteine and glycine. Its chemical name is γ-L-glutamyl-L-cysteinylglycine.

Commercial reduced glutathione is normally supplied as a white or almost white crystalline powder. Its CAS number is 70-18-8, molecular formula is C₁₀H₁₇N₃O₆S, and molecular weight is 307.32 g/mol.

The cysteine residue contains a reactive sulfhydryl group responsible for the reducing properties of GSH. Exposure to oxygen, elevated temperature, unsuitable pH or trace metals can convert reduced glutathione into oxidized glutathione, also known as GSSG.

The term “glutathione” should not be used without identifying whether the supplied material is reduced GSH or oxidized GSSG.

Reduced L-Glutathione Quick Facts

The exact grade, production route, specification and regulatory suitability should be confirmed in the AOZUN quotation and batch documentation.

Reduced Glutathione vs Oxidized Glutathione

Reduced and oxidized glutathione are related but different substances.

A high total-glutathione result does not necessarily prove a high reduced-GSH content. Buyers should request a method capable of distinguishing GSH from GSSG.

Why Does the GSH-to-GSSG Difference Matter?

Reduced glutathione can oxidize during manufacturing, drying, storage, solution preparation and formulation.

If the analytical method does not separate GSH and GSSG, the result may not accurately describe the amount of reduced glutathione in the product.

For quality-sensitive applications, the specification should separately address:

• Reduced glutathione assay

• GSSG

• Individual related compounds

• Total organic impurities

• Water or loss on drying

• Solution clarity and color

How Should Reduced Glutathione Quality Be Verified?

Reduced glutathione quality should be evaluated using identity testing, a validated quantitative assay and impurity-specific analysis. HPLC or another suitable separation method can distinguish the desired reduced form from oxidized glutathione and related compounds more effectively than a nonspecific total assay.

Why HPLC and GSSG Testing Matter

Testing only appearance and total assay may miss oxidation or closely related impurities.

An appropriate chromatographic method can support evaluation of:

• Reduced glutathione content

• Oxidized glutathione

• Individual related substances

• Total organic impurities

• Batch-to-batch consistency

• Stability changes

The analytical method and reference standard should be stated in the specification or test procedure.

Typical AOZUN Reduced Glutathione Specifications

For food, nutritional, cosmetic or pharmaceutical qualification, buyers may also require GSSG, related compounds, elemental impurities and microbiological limits.

Final acceptance criteria must be confirmed using the current AOZUN specification and batch COA.

Recommended Additional Quality Tests

Depending on the application, the following tests may be requested:

Reference limits are not automatically part of the standard AOZUN specification. They must be agreed before order confirmation.

What Do the Main Specifications Mean?

Assay

The assay indicates the measured glutathione content. The result should state whether it is calculated on an as-is or dried basis.

A reported value above 100% can occur because of analytical uncertainty and dried-basis calculation. It does not mean that the sample physically contains more than 100% material.

Specific Optical Rotation

Glutathione contains chiral amino-acid residues. Specific optical rotation helps confirm stereochemical identity and can reveal major differences in composition.

The concentration, solvent, temperature and optical path used in the test must be stated.

GSSG

GSSG is the oxidized form of glutathione. Elevated GSSG may indicate oxidation during processing or storage.

A dedicated GSSG limit is more informative than relying only on total assay.

Loss on Drying

Loss on drying estimates moisture and other volatile matter. Excess moisture can affect assay, stability, flowability and oxidation rate.

Chloride and Sulfate

These inorganic ions may originate from raw materials, fermentation, purification or pH adjustment. Limits help establish purification consistency.

Ammonium

Residual ammonium can be associated with fermentation nutrients or downstream processing. Sensitive food, cosmetic and pharmaceutical applications may require a controlled limit.

Iron

Trace iron and other transition metals can catalyze oxidation. A low iron level can therefore support both purity and stability.

Sulfated Ash

Sulfated ash estimates nonvolatile inorganic residue. A high result may indicate salts or other inorganic contamination.

Elemental Impurities

A generic “heavy metals as Pb” test may not be sufficient for every regulated application. Modern qualification may require individual results for lead, arsenic, cadmium and mercury.

Microbiological Quality

Material intended for food, nutritional or cosmetic formulations may require defined microbial limits.

A high chemical assay does not demonstrate acceptable microbiological quality.

How Is Reduced Glutathione Manufactured?

Commercial reduced glutathione is commonly produced through controlled microbial fermentation followed by separation, purification, concentration, crystallization and drying.

A typical manufacturing sequence may include:

1. Preparation of the fermentation medium

2. Controlled microbial fermentation

3. Cell separation or extraction

4. Purification

5. Concentration

6. Crystallization

7. Drying

8. Milling or sieving

9. Quality testing

10. Moisture- and oxygen-protective packaging

The actual production organism, fermentation substrate and processing aids should be confirmed with the supplier.

Fermentation-Derived vs Synthetic Glutathione

Fermentation is widely used for commercial reduced glutathione because it can provide the required stereochemical form and support industrial-scale production.

Buyers should still verify:

• Microorganism identity

• GMO or non-GMO status

• Fermentation substrate

• Animal-origin status

• Allergen risks

• Processing aids

• Residual solvents

• Purification controls

• Batch traceability

“Fermentation-derived” does not automatically establish food, pharmaceutical, vegetarian, vegan, non-GMO, halal or kosher compliance.

Available Reduced Glutathione Grades

Nutritional or Food-Ingredient Grade

Material intended for supplements or food products may require:

• Appropriate food-manufacturing controls

• Microbiological limits

• Elemental-impurity limits

• Allergen statement

• GMO statement

• Residual-solvent controls

• Compliance with destination-country rules

Permission to use glutathione in foods or supplements varies by country.

Cosmetic Grade

Cosmetic-grade GSH should have controlled color, odor, purity, GSSG, metals and microbiological quality.

The finished cosmetic manufacturer remains responsible for formulation safety, stability, claims and regulatory notification.

Pharmaceutical Grade

Pharmaceutical applications may require:

• Compliance with an applicable pharmacopeial monograph

• GMP manufacturing

• Validated analytical methods

• Impurity profiling

• Elemental-impurity evaluation

• Stability data

• Change control

• Regulatory support

A 98% or 99% assay alone does not establish pharmaceutical grade.

Reagent and Biochemical Grade

Laboratory applications may prioritize:

• Identity

• Assay

• GSSG

• Enzyme-assay suitability

• Solution clarity

• Trace metals

• Consistent analytical performance

Reagent grade is not automatically suitable for food, cosmetic or clinical use.

Oenological Grade

Glutathione may be used in certain wine-production applications where permitted. Oenological material may require defined GSH content, moisture, elemental impurities, labeling and production-source information.

Use must comply with the applicable OIV standard and local wine regulations.

Reduced Glutathione Applications

Nutritional Formulations

Qualified reduced glutathione may be used as an ingredient in capsules, tablets, powders, beverages or other supplement formats where legally permitted.

Formulators should evaluate:

• Permitted ingredient status

• Maximum or recommended use level

• Product stability

• Interactions with minerals and oxidizing ingredients

• Taste and odor

• Finished-product testing

• Permitted label claims

This raw-material page does not provide dosing or medical advice.

Food and Beverage Formulations

Glutathione may be used in certain food, beverage and oenological applications, subject to local regulations.

Its reducing character may influence oxidation, color and flavor stability, but the effect depends on the complete formulation and processing conditions.

Generic industrial or reagent-grade material should not be used in food.

Cosmetic Formulations

Reduced glutathione may be incorporated into qualified cosmetic formulations as an antioxidant or skin-conditioning ingredient where legally permitted.

Formulators should verify:

• Ingredient regulatory status

• Concentration

• pH

• Oxidation stability

• Color development

• Odor

• Preservative compatibility

• Packaging

• Finished-product safety

• Permitted cosmetic claims

A raw-material supplier should not guarantee skin whitening, removal of pigmentation, wrinkle reduction or a specific time to visible results.

Pharmaceutical Manufacturing

Qualified pharmaceutical-grade glutathione may be used as an API, excipient or processing material in approved pharmaceutical applications.

Bulk ingredient material must not be represented as an injectable or finished medicine. Sterile products require separate manufacturing, sterilization, container-closure and regulatory controls.

Biochemical and Research Applications

Reduced glutathione is used in:

• Biochemical assays

• Enzyme research

• Redox-system studies

• Protein chemistry

• Buffer formulations

• Cell-culture research

• Analytical standards

• Laboratory reducing systems

Researchers should select a grade appropriate for the test method and required purity.

Formulating with Reduced Glutathione

GSH contains a reactive sulfhydryl group and can oxidize in solution.

Important formulation variables include:

• pH

• Temperature

• Dissolved oxygen

• Light exposure

• Trace iron and copper

• Water activity

• Other oxidizing ingredients

• Packaging headspace

• Processing time

• Preservative system

A high-quality raw material cannot compensate for an unstable finished formulation.

Why Does Glutathione Oxidize?

Two reduced glutathione molecules can form a disulfide bond, producing oxidized glutathione.

Oxidation may accelerate when GSH is exposed to:

• Air

• Elevated temperature

• Alkaline conditions

• Light

• Trace metals

• Oxidizing agents

• Long solution-holding times

• Repeated container opening

The change may not always be visible, so chemical testing is required.

How to Improve GSH Stability in Formulations

Depending on the intended product, formulators may evaluate:

• Suitable pH control

• Low-oxygen processing

• Nitrogen headspace

• Chelating agents

• Low-metal raw materials

• Light-protective packaging

• Reduced processing temperature

• Shorter solution-holding time

• Compatible antioxidants

• Appropriate water activity

• Finished-product stability studies

Any stabilization system must comply with the applicable food, cosmetic or pharmaceutical regulations.

Reduced Glutathione Solution Preparation

For analytical or manufacturing use:

1. Use suitable-quality water.

2. Use clean, low-metal equipment.

3. Prepare only the amount required.

4. Minimize air exposure.

5. Avoid unnecessary heating.

6. Control pH.

7. Protect the solution from light where appropriate.

8. Use the solution promptly unless validated stability data support storage.

9. Monitor GSH and GSSG during stability studies.

Aqueous GSH solutions generally oxidize more readily than the sealed dry powder.

Compatibility Considerations

Before commercial formulation, test compatibility with:

• Copper and iron salts

• Peroxides

• Strong oxidizers

• Alkaline ingredients

• Mineral premixes

• Botanical extracts

• Flavor systems

• Preservatives

• Surfactants

• Packaging materials

Metal-containing ingredients may significantly affect oxidation.

How to Evaluate a Reduced Glutathione Supplier

A qualified supplier should be able to confirm:

1. Reduced form, GSH

2. CAS number

3. Production method

4. Assay method and calculation basis

5. GSSG limit

6. Related-substance limits

7. Optical rotation

8. Moisture or loss on drying

9. Elemental impurities

10. Microbiological limits

11. Fermentation organism

12. GMO and allergen status

13. Animal-origin status

14. Packaging

15. Storage and shelf life

16. COA, TDS and SDS availability

17. Change-control procedure

18. Regulatory suitability for the intended market

A supplier should not rely solely on a purity result when offering material for regulated applications.

Recommended Incoming Quality Checks

Depending on the grade, buyers may verify:

• Packaging integrity

• Label and batch number

• Appearance

• Solution clarity

• Identification

• Assay

• Specific optical rotation

• GSSG

• Related compounds

• Loss on drying

• Residue on ignition

• Chloride

• Sulfate

• Ammonium

• Iron

• Elemental impurities

• Microbiological quality

• COA compliance

Retained samples should be protected from moisture, heat, light and oxygen.

Packaging

A typical industrial package may use:

• Double food-compatible PE inner bags

• Light- and moisture-resistant outer bag

• Sealed fiber or cardboard drum

• 25 kg net weight

• Smaller foil bags for samples or specialty orders

Actual package size and liner material should be confirmed in the quotation.

For regulated uses, packaging materials may require food-contact, pharmaceutical or other application-specific documentation.

Storage and Shelf Life

Store reduced glutathione in a tightly sealed container in a cool, dry place protected from:

• Direct sunlight

• Heat

• Moisture

• Oxygen

• Strong oxidizers

• Trace-metal contamination

• Repeated container opening

Some reagent grades are stored at 2–8°C, while other validated bulk grades may have different labeled conditions. Follow the storage instructions and shelf life stated for the purchased product.

After opening, reseal the inner bag promptly and minimize headspace exposure.

Safety and Handling

Reduced glutathione is generally handled as a low-hazard solid, but normal industrial hygiene remains necessary.

Avoid:

• Generating airborne dust

• Breathing powder

• Eye contact

• Prolonged skin contact

• Contamination of food or production areas

• Mixing with unidentified oxidizing materials

Use suitable gloves, protective eyewear and dust control according to the current SDS and workplace risk assessment.

Transport Information

Reduced glutathione is commonly transported as a non-dangerous good.

Final transport status should be confirmed using:

• Current supplier SDS

• Product grade

• Package size

• Transport method

• Destination-country requirements

Temperature or moisture protection may still be commercially important even when the product is not classified as dangerous goods.

Regulatory Considerations

Regulatory status varies according to country and application.

Before using glutathione in a food, supplement, cosmetic or pharmaceutical product, confirm:

• Permitted ingredient status

• Required grade

• Use-level restrictions

• Labeling requirements

• Permitted claims

• Manufacturing requirements

• Import registration

• Finished-product testing

• Pharmacopoeial requirements, when applicable

A CAS number or UNII listing does not itself establish regulatory approval for a specific use.

What Documents Should a Supplier Provide?

Depending on application, buyers may request:

• Certificate of Analysis

• Safety Data Sheet

• Technical Data Sheet

• Product specification

• Manufacturing-flow summary

• GMP statement

• Country of Origin

• Allergen statement

• GMO statement

• Animal-origin or BSE/TSE statement

• Residual-solvent statement

• Elemental-impurity report

• Microbiological report

• Pesticide-residue statement

• Halal certificate

• Kosher certificate

• Stability or retest information

• Change-control statement

Only request or advertise certificates that apply to the actual supplied grade and manufacturing site.

Why Source Reduced L-Glutathione from AOZUN?

AOZUN supports international buyers seeking reduced L-glutathione for qualified nutritional, food, cosmetic, biochemical and pharmaceutical-manufacturing applications.

Commercial support may include:

• Grade and specification review

• Batch-specific COA

• GSH and GSSG requirement discussion

• Packaging options

• Sample evaluation

• Documentation coordination

• Export support

• Third-party inspection

• International shipment planning

• Technical communication during supplier qualification

Product grade, specification, manufacturing source, regulatory status and intended-use suitability must be confirmed in the final quotation and contract.

Information to Include in Your RFQ

For an accurate quotation, provide:

• Product name: Reduced L-Glutathione

• CAS number: 70-18-8

• Intended application

• Required grade

• Assay requirement

• Maximum GSSG

• Related-substance limits

• Elemental-impurity limits

• Microbiological requirements

• Required certificates

• Order quantity

• Packaging requirement

• Destination

• Sample requirement

• Delivery schedule

If you are replacing an existing supplier, attach the current specification or representative COA.

Frequently Asked Questions

What is reduced L-glutathione?

Reduced L-glutathione is a tripeptide composed of glutamate, cysteine and glycine. It is commonly abbreviated as GSH.

What is the CAS number of reduced glutathione?

Its CAS number is 70-18-8.

What is the molecular weight of glutathione?

Reduced glutathione has a molecular weight of 307.32 g/mol.

Is glutathione the same as reduced glutathione?

The word “glutathione” is sometimes used generically. A purchase specification should state whether the product is reduced glutathione, GSH, or oxidized glutathione, GSSG.

What is GSSG?

GSSG is oxidized glutathione formed when two GSH molecules create a disulfide bond. It is an important quality and stability indicator.

Is reduced glutathione soluble in water?

Yes. Reduced glutathione is soluble in water and should produce a clear, colorless solution at an appropriate test concentration.

Why should GSSG be tested separately?

A total assay may not distinguish reduced glutathione from its oxidized form. Separate GSSG testing provides better information about oxidation and active GSH content.

Is 98% glutathione pharmaceutical grade?

Not automatically. Pharmaceutical grade also depends on the pharmacopoeial specification, GMP system, impurities, stability, documentation and intended regulatory use.

Can food-grade glutathione be used for injection?

No. Food or bulk ingredient grade must not be used as an injectable product. Injectable use requires an approved sterile pharmaceutical product.

Does glutathione guarantee skin whitening?

No. A raw-material supplier should not guarantee whitening or a specific time to visible results. Cosmetic performance depends on formulation, concentration, stability, use conditions and permitted claims.

Is glutathione vegan?

It may be produced by fermentation, but vegan status must be supported by information about the microorganism, fermentation medium, processing aids and manufacturing facility.

Is fermentation-derived glutathione automatically non-GMO?

No. GMO status must be confirmed using supplier documentation.

How should reduced glutathione be stored?

Keep it tightly sealed, cool, dry and protected from light, moisture, oxygen and oxidizing materials. Follow the storage conditions printed on the supplied product.

Is an aqueous glutathione solution stable?

GSH solutions can oxidize to GSSG. Prepare solutions fresh unless validated stability data support a defined storage period.

What packaging is available?

A common bulk package is 25 kg per drum with moisture-resistant inner liners. Smaller packages may be discussed during quotation.

Can AOZUN provide a sample and COA?

Sample and documentation availability can be discussed during quotation. Include your grade, GSSG, microbiological and regulatory requirements in the inquiry.

Request a Reduced L-Glutathione Quote

Contact AOZUN for reduced L-glutathione pricing, specifications, packaging and export information.

Send us your required grade, assay, GSSG limit, application, quantity, packaging, destination and documentation requirements. Our team will review the request and confirm an appropriate commercial specification.