Ketone esters

Ketone esters suppliers and sourcing guide

Ketone esters are esters of the ketone body D-beta-hydroxybutyrate (or acetoacetate) with an alcohol, most often (R)-1,3-butanediol. The best known is the monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, made by transesterifying (R)-3-hydroxybutyrate, typically obtained from the bacterial polymer poly-(R)-3-hydroxybutyrate, with (R)-1,3-butanediol, then purifying by distillation. They are clear to pale liquids with a strong bitter taste, used in drinks, shots and gels.

See suppliers What to ask for on the COA

Category: Specialty nutrients
Also known as: D-beta-hydroxybutyrate ester · (R)-3-Hydroxybutyl (R)-3-hydroxybutyrate · Ketone monoester · BHB ester
Facts checked: November 2026

Forms and grades of ketone esters

Suppliers sell different products under the same name. Specify the one you need.

Ketone monoester liquid
(R)-3-hydroxybutyl (R)-3-hydroxybutyrate as a neat liquid at high purity, the form supplied for ready-to-drink shots.
Diesters and other esters
Other esters, such as butanediol diesters of acetoacetate or of hexanoic acid, sold by a few suppliers with different taste and composition.
Formulated concentrates
Ester pre-blended with flavors, sweeteners and water or other carriers to mask bitterness for beverages and gels.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Ester assay: Ester content by GC or HPLC against a reference standard.
Stereochemical purity: Chiral GC or HPLC to confirm the (R) configuration of both the acid and the alcohol parts, since racemic material is a different product.
Related substances: Free 1,3-butanediol, free 3-hydroxybutyric acid and oligomers by GC or HPLC, which rise as the ester hydrolyzes.
Water: Water by Karl Fischer, which drives hydrolysis in storage.
Residual solvents and heavy metals: Process solvents by headspace GC and lead, arsenic, cadmium and mercury by ICP-MS.
Microbiology: Total plate count and yeast and mold, mainly for diluted or formulated grades.

Storage, lots and expiry

Storage and shelf life

Keep ketone esters in tightly closed containers at the temperature the supplier specifies, protected from moisture and heat, which speed hydrolysis back to the acid and alcohol. Headspace can be nitrogen-flushed for opened drums. Shelf life is set by the supplier's specification, with retest of assay and free acid for older stock.

Lots and expiry dates

Record ester assay, stereochemical purity and free acid for each lot. Because free acid and butanediol change taste and pH, check older lots before using them in flavor-sensitive drinks.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

FDA's GRAS Notice Inventory lists GRN 515, for a D-beta-hydroxybutyrate ester notified by TdeltaS Limited for use in bars, gels and beverages; it closed on March 5, 2015 with FDA having no questions. The notice applies to that notifier's substance and intended use.
Source: hfpappexternal.fda.gov (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Ketone esters suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking ketone esters suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

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Frequently asked questions

What forms of ketone esters can brands buy?

Common forms include ketone monoester liquid, diesters and other esters and formulated concentrates. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for ketone esters include?

Expect ester assay, stereochemical purity, related substances, water, residual solvents and heavy metals and microbiology, each with its method, specification and result for that lot.

How should ketone esters be stored?

What is the regulatory status of ketone esters?

FDA's GRAS Notice Inventory lists GRN 515, for a D-beta-hydroxybutyrate ester notified by TdeltaS Limited for use in bars, gels and beverages; it closed on March 5, 2015 with FDA having no questions. The notice applies to that notifier's substance and intended use.

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