Glabridin vs Kojic Acid Dipalmitate: A Formulation, Stability & Sourcing Comparison for Buyers

Quick Answer

Glabridin and Kojic Acid Dipalmitate (KAD) should not be selected by one purity number, one tyrosinase result or a supplier claim that one ingredient is "more stable."

Both can create formulation challenges in water-rich systems, but for different reasons. Free Glabridin has poor aqueous solubility. Commercial Glabridin may also be sold as high-assay raw powder, oil-compatible material, alcohol/polyol-compatible material, water-compatible/solubilized material or another carrier-based delivery system. KAD is a different molecule: a lipophilic Kojic Acid derivative commonly supplied under CAS 79725-98-7. Peer-reviewed literature describes it as almost insoluble in water, and the exact oil phase, heating, cooling, crystallization behavior and stability conditions matter.

For a professional buyer, compare:

1. Exact identity.
2. Exact commercial grade / delivery format.
3. Phase and solubility requirements.
4. Stability evidence under relevant conditions.
5. Assay method and batch-specific COA.
6. Physical-property consistency.
7. Destination-market regulatory scope.
8. MOQ, processing burden and effective project cost.

There is no universal winner. The useful question is which exact supplier material your formulation, QC system and commercial model can support.

Glabridin vs KAD: Buyer Comparison Table

They Are Different Ingredients - and KAD Is Not Kojic Acid

Glabridin is commonly identified as:

• CAS 59870-68-7
• formula C20H20O4
• molecular weight about 324.4

KAD is commonly identified as:

• CAS 79725-98-7
• formula C38H66O6
• molecular weight about 618.94

KAD is also not the same molecule as Kojic Acid, CAS 501-30-4. This matters because search results often compare Glabridin with Kojic Acid and then introduce KAD as if it simply inherits every Kojic Acid property and regulatory conclusion.

It does not.

Before comparing a Glabridin offer with a KAD offer, match:

• exact product name
• CAS
• supplier product code
• assay grade
• specification
• batch COA
• analytical method
• commercial formulation format

Do not compare: "98% Glabridin"

with: "98% KAD"

as though the shared percentage makes the products equivalent in activity, quality or dose. They are different molecules and can also be tested by different analytical methods.

Both Are Difficult to Treat as Simple Water-Phase Actives

This is a major difference from Alpha-Arbutin. Free Glabridin has documented poor aqueous solubility. KAD is described in peer-reviewed literature as almost insoluble in water. But that does not mean they create the same formulation problem.

For Glabridin, the main sourcing question may be:

What commercial delivery format are you actually buying?

For KAD, the main formulation question may be: Can the exact crystalline/lipophilic grade remain dissolved and stable in the selected oil/emulsion system through processing and storage?

That distinction should be resolved before potency or price comparisons.

Glabridin: The Commercial Delivery-System Problem

Glabridin should not be treated as one single commercial format. Current supplier portfolios may offer different assay levels and different formulation formats.

Examples can include:

• high-assay raw Glabridin
• oil-compatible grades
• alcohol/polyol-compatible grades
• water-compatible or solubilized grades
• cyclodextrin or other carrier/delivery systems

The exact carrier is important. A lower-assay Glabridin delivery system is not necessarily the same product as a high-assay raw powder with less Glabridin. It may be solving a different formulation problem. Published research supports this principle.

A peer-reviewed Glabridin / hydroxypropyl-beta-cyclodextrin study reported a large improvement in aqueous solubility under its experimental conditions. That is evidence that delivery design can materially change Glabridin behavior. It is not evidence that every commercial "water-soluble Glabridin" uses the same carrier or achieves the same result.

Before buying a modified / solubilized grade, ask:

• What is the Glabridin assay?
• What is the carrier / matrix?
• Is the assay based on the complete commercial product?
• What solvents / phases were tested?
• What concentration was tested?
• Does the grade remain clear after cooling and storage?
• Does the carrier affect labeling, natural-origin claims or formulation restrictions?
• Does the current lot COA match this exact format?

Buyer rule: Evaluate water-compatible Glabridin as a complete delivery system, not as raw Glabridin with a different purity number.

KAD: The Oil-Phase and Crystallization Problem

KAD is lipophilic and almost insoluble in water in the cited peer-reviewed literature.

Current technical reference material from TCI K0050 lists:

• CAS 79725-98-7

• 98% HPLC

• solid physical state
• melting point 94-98 C

This is a useful reference-product profile. It is not a universal cosmetic-grade processing specification.

Commercial suppliers often describe KAD as "oil soluble."

For the exact supplier grade, ask:

• Which oils or esters have been tested?
• At what KAD loading?
• What heating temperature is required?
• How long is heating required?
• Does the material remain dissolved during cooling?
• Does it recrystallize after 24 hours, one week or accelerated storage?
• Which emulsifier system was used?
• What storage temperature was tested?
• Does the supplier have microscope / appearance / assay data after stability?

"Oil soluble" is not enough information for scale-up. A material that dissolves in a hot oil phase but recrystallizes during storage has not solved the formulation problem.

What Does "More Stable" Actually Mean?

KAD is frequently marketed as more stable than Kojic Acid. That claim cannot be used as a condition-free fact. A 2022 peer-reviewed study compared Kojic Acid and KAD under liquid hydrogen-peroxide oxidative stress. Under the study's defined conditions, KAD degraded faster than Kojic Acid.

This does not prove: "KAD is always less stable."

It does prove: "KAD is always more stable" is also not defensible.

Stability depends on the test system.

For either Glabridin or KAD, ask for:

• exact grade tested
• formulation or solvent system
• concentration
• temperature
• light exposure
• oxygen / oxidative conditions
• antioxidants / chelators
• packaging
• time points
• assay / degradation method
• pass/fail criterion

For Glabridin, a carrier-based or solubilized grade can behave differently from free high-assay material. For KAD, the oil phase and protection from oxidative stress can materially affect the result.

The useful comparison is not:

Which molecule has the better stability adjective?

It is:

Which exact commercial grade has relevant stability data for your exact formula?

What Does the Evidence Say About Efficacy?

Glabridin has independent experimental evidence related to melanogenesis and tyrosinase activity. A 1998 study reported anti-melanogenic / tyrosinase-related and anti-inflammatory effects under its experimental conditions. A 2026 mechanistic study reported additional effects involving melanogenesis and melanin-transfer-related pathways in cell and co-culture models. KAD also has experimental and delivery-system evidence related to anti-hyperpigmentation / tyrosinase endpoints in specific formulations.

These evidence sets are not directly interchangeable.

Do not create a universal claim such as:

• "Glabridin is X-times stronger than KAD"
• "KAD is more effective because it is oil soluble"
• "Use X% Glabridin instead of Y% KAD"

unless the exact conversion has been validated for the same assay, formulation and endpoint. One IC50 or one finished-formulation study is not a purchasing formula.

Evidence should answer:

• What exact material was tested?
• Raw active or delivery system?
• What concentration?
• What formulation?
• What endpoint?
• What model?
• Is the supplier grade equivalent to the tested material?

Do Not Use Purity as a Cross-Ingredient Potency Scale

Current reference products illustrate why. TCI G0534 lists Glabridin above 98% using GC for that reference product. TCI K0050 lists KAD above 98% using HPLC. Sigma also lists a >=98% HPLC Glabridin reference product.

The important buyer lesson is not that one method is better.

It is that: "98%"

is not a complete analytical statement.

Ask:

• What method?
• What reference standard?
• What calculation/reporting basis?
• Is the result a specification or actual lot result?
• Does the COA belong to the exact lot?

And across two different molecules, do not infer equal potency from equal assay percentages.

Regulatory Comparison: Avoid Two Opposite Mistakes

For KAD, do not copy the Kojic Acid rule. The SCCS opinion SCCS/1637/21 assessed Kojic Acid, CAS 501-30-4. The opinion explicitly states that derivatives including Kojic Acid Dipalmitate were not included because no derivative data were submitted. Commission Regulation (EU) 2024/996 now restricts Kojic Acid, CAS 501-30-4, to 1% in face and hand products.

That identity-specific rule should not automatically be transferred to KAD, CAS 79725-98-7. But the opposite conclusion is also wrong.

Do not say: "KAD is unrestricted because the Kojic Acid opinion did not assess it."

For Glabridin, this article likewise does not assert "unrestricted" status simply because the Kojic Acid-specific rule is irrelevant to Glabridin.

For both ingredients, verify:

• exact chemical identity
• INCI / regulatory name
• intended product category
• destination market
• use level
• impurity / carrier context
• current legal framework

Regulatory asymmetry is a due-diligence issue, not a safety ranking.

How Do the COA and QC Questions Differ?

Glabridin QC

Focus on:

• exact Glabridin identity vs generic licorice extract
• exact assay grade
• actual batch assay result
• analytical method
• reference standard / reporting basis where relevant
• carrier / matrix / solubilized format
• lot-specific COA
• current specification / TDS / SDS

A 40% carrier-based Glabridin format is not described fully by "40%."

The buyer may need to know what the other 60% is and why it is present.

KAD QC

Focus on:

• exact KAD identity vs Kojic Acid
• CAS / product code consistency
• assay specification
• actual batch result
• HPLC method context
• melting point / physical-property fields
• appearance
• lot-specific COA
• current specification / TDS / SDS

Public KAD COAs show why physical-property review matters. Several public documents and current TCI reference information place melting behavior around the mid-90 C range, while one current public supplier COA has reported a much higher range. That discrepancy does not prove fraud. It is a document-sanity red flag that should be clarified before qualification.

How Should Buyers Compare Supplier Grades?

First qualify the material within each ingredient.

Glabridin:

• identity
• assay
• raw vs carrier/solubilized format
• analytical method
• actual lot result
• supplier documents

KAD:

• identity
• assay/HPLC
• physical-property consistency
• formulation behavior
• actual lot result
• supplier documents

Then compare project fit.

Do not compare:

• a highly engineered water-compatible Glabridin delivery system with
• raw crystalline KAD

and treat that as a simple molecule-level comparison.

Likewise, do not compare:

• poorly documented Glabridin with
• fully documented KAD

and call KAD the better ingredient. Supplier quality, commercial format and ingredient choice are separate variables.

How Should Cost Be Compared?

Do not compare raw $/kg alone.

Glabridin effective project cost may include:

• raw-material or delivery-system price
• assay
• carrier / matrix
• solubilization work
• formulation reformulation
• analytical verification
• stability testing
• MOQ
• freight
• regulatory review
• reject risk

KAD effective project cost may include:

• raw-material price
• assay
• oil / ester system
• heating / processing
• recrystallization troubleshooting
• HPLC / identity testing
• stability testing
• MOQ
• freight
• regulatory review
• reject risk

Across different ingredients, do not calculate a universal "$ per gram active" or "$ per brightening potency" and call that the answer. A better project metric is:

Effective project cost = qualified raw material

• delivery / formulation work
• analytical testing
• stability work
• regulatory work
• MOQ / freight
• reject / reformulation risk

The lowest raw-material quote is not automatically the lowest-cost project. It is not proof that an ingredient or supplier is bad.

Current Sourcing Links

Before ordering either material, confirm the destination product, exact identity/grade, current specification and batch COA, MOQ, price, packaging and lead time. These are current sourcing entries, not permanent supplier endorsements or ingredient rankings.

Buyer Decision Scenarios

Scenario 1: Mostly water-based serum

Neither raw free Glabridin nor raw KAD should be assumed to dissolve directly into the water phase. A purpose-designed water-compatible / solubilized Glabridin grade may be a candidate if its carrier, assay and stability data fit the project. KAD usually requires a suitable oil/delivery strategy. The buyer should compare the actual delivery systems, not the molecular names alone.

Scenario 2: Oil-rich or anhydrous system

Both can be candidates depending on exact commercial grade. For KAD, validate oil/ester compatibility, heating and cooling / recrystallization. For Glabridin, verify whether the offered product is truly oil-compatible and whether a carrier is present.

Scenario 3: Conventional emulsion

Either material can be placed in a designed emulsion system.

The decision should come from:

• exact grade
• phase
• processing temperature
• solubility / crystallization
• stability data
• QC burden
• regulatory review
• effective cost

Scenario 4: Supplier says its KAD is "more stable"

Ask:

More stable than what, under which conditions, for how long, measured how?

Scenario 5: Supplier says its Glabridin is "water soluble"

Ask:

What is the complete commercial composition, carrier, Glabridin loading and test condition?

Scenario 6: Procurement wants the ingredient with the higher purity number

Stop.

The purity percentages are not a cross-ingredient efficacy scale.

Scenario 7: Brand wants a licorice-derived active story

Glabridin may be relevant to that positioning, but marketing origin does not replace identity, assay, carrier disclosure, batch evidence or destination-market review.

Can Glabridin and KAD Be Used Together?

They can appear together in designed multi-active formulation examples and patents. That is not proof of universal synergy.

A combined formula still needs to solve:

• phase allocation
• solubilization
• oil compatibility
• heating / cooling process
• precipitation / recrystallization
• stability
• total active system
• analytical control
• claim substantiation
• destination-market compliance

Treat a combination as a new formulation project. Do not assume that evidence for each ingredient separately proves the combination.

Questions to Ask Before Choosing Between Glabridin and KAD

1. What exact Glabridin and KAD grades are being compared?
2. Are names, CAS numbers and supplier product codes confirmed?
3. Are assay percentages specifications or actual batch results?
4. What analytical method supports each result?
5. Is the Glabridin raw, solubilized or carrier-based?
6. What is the complete Glabridin matrix / carrier?
7. Which phase is recommended for the exact Glabridin grade?
8. For KAD, which oils / esters and processing temperatures have been tested?
9. Does the KAD grade remain dissolved after cooling and storage?
10. What melting-point / physical-property specification is used for KAD?
11. What condition-specific stability data exist for both exact grades?
12. What current destination-market requirements apply to each exact identity?
13. What sample MOQ and commercial MOQ apply?
14. What formulation / testing work will each option require?
15. What is the effective project cost after those differences?
16. Does the supplier provide lot-specific documents and change notification?

Red Flags

Investigate further when you see:

• Glabridin treated as identical to generic licorice extract
• KAD treated as identical to Kojic Acid
• 98% Glabridin and 98% KAD treated as equal active strength
• "water-soluble Glabridin" with no carrier / loading disclosure
• "oil-soluble KAD" with no exact grade / solvent / process guidance
• "KAD is always more stable" with no test conditions
• one supplier potency number used to claim a universal winner
• the EU Kojic Acid 1% rule automatically applied to KAD
• KAD described as "SCCS approved" or "unrestricted"
• Glabridin described as "unrestricted" without a market-specific review
• a public/sample COA presented as the current shipment COA
• a major KAD physical-property inconsistency left unexplained
• marketplace $/kg presented as the universal cost winner
• patent/formulation co-presence described as proven synergy

A red flag means the comparison needs better evidence.

• Compare Glabridin bulk pricing
• Compare Kojic Acid Dipalmitate bulk pricing

References

1. Ingredexa GLABRIDIN_EVIDENCE_SHEET_V1.
2. Ingredexa KAD_COA_EVIDENCE_SHEET_V1.
3. Ingredexa KOJIC_ACID_VS_KAD_EVIDENCE_SHEET_V1.
4. Ingredexa BRIGHTENING_ACTIVES_COMPARISON_EVIDENCE_SHEET_V1.
5. Tokyo Chemical Industry. Glabridin G0534. CAS 59870-68-7; current reference-product specification reviewed 2026-09-18.
6. Tokyo Chemical Industry. Kojic Acid Dipalmitate K0050. CAS 79725-98-7; >98% HPLC; melting point 94-98 C; current page reviewed 2026-09-18.
7. Wei Y, et al. Characterization of glabridin/hydroxypropyl-beta-cyclodextrin inclusion complex with robust solubility and enhanced bioactivity. Carbohydr Polym. 2017. PMID 28038744.
8. Tazesh S, et al. Comparative Stability of Two Anti-hyperpigmentation Agents: Kojic Acid and Its Di-Palmitate Ester, Under Oxidative Stress. Adv Pharm Bull. 2022;12(2):329-335. PMID 35620332; PMCID PMC9106968.
9. Yokota T, et al. The inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation. Pigment Cell Res. 1998;11(6):355-361. PMID 9870547.
10. Li L, et al. Glabridin Inhibits Melanogenesis and Melanin Transfer via Wnt/beta-Catenin Pathway and Rho Family GTPase-Mediated Dendritic Formation Suppression. Pharmaceuticals. 2026;19(3):469. PMID 41901315.
11. Scientific Committee on Consumer Safety. Opinion on Kojic Acid. SCCS/1637/21.
12. Commission Regulation (EU) 2024/996 of 3 April 2024.
13. Sigma-Aldrich. Glabridin G9548, >=98% HPLC reference product; current page reviewed 2026-09-18.
14. Current supplier/SERP pages reviewed 2026-09-18; commercial claims treated as dated market observations rather than universal facts.
15. Alibaba current sourcing entries: Product IDs 1601271409005 and 1600980251526; link URLs user-verified via Alibaba Deep Link Generator.