Amino Acid Label-Claim Testing

We measure how much of each free amino acid is in your product. We make no claims about what the product does. Each report gives concentrations in µM and mg/L, the chromatogram and a QC summary, so your QC or regulatory team can set a measured value beside a declared one.

The regulatory frame explains why that number matters. For dietary supplements, FDA requires the quantity by weight per serving of dietary ingredients that have no Daily Value ¹. FDA judges compliance on a composite of 12 consumer packages, or 10 % of the lot if smaller, and accepts reasonable excesses within good manufacturing practice ¹. Manufacturers must also set specifications for the identity, purity, strength and composition of each finished batch ². Our services support research, development and process monitoring. We are not a GLP, GMP or ISO 17025 laboratory, so check whether your quality system requires an accredited lab for release testing.

What we measure in supplements, beverages and pet food

Every analyte comes from the same chromatographic run, so a single declared ingredient is quantified alongside the rest of the free profile. The derivatization chemistry is described on our AQC method page.

Analyte	Panel	Why it comes up
Taurine	AA-2	Added mainly to food supplements, and also to energy drinks and other foods ³; a dietary requirement for cats ⁴
GABA	AA-2	Listed on 644 product labels in the US Dietary Supplement Label Database as of April 2021 ⁵
Ornithine, citrulline, hydroxyproline	AA-2	Quantified in the same run when a formula declares them
Leucine, isoleucine, valine	AA-1	Branched-chain amino acid declarations and blend ratios
Glutamine	AA-1	Changes in solution over time (see caveats)
Arginine	AA-1	Single-ingredient and blend declarations
14 other amino acids + ammonia	AA-1	The full free profile; see the analyte reference

Functional beverages. EFSA describes energy drinks as non-alcoholic beverages containing caffeine, taurine and/or vitamins ⁶. A Norwegian risk assessment evaluated taurine at 300–400 mg per 100 mL, levels chosen because taurine is an ingredient in energy drinks sold in Norway ³.

Supplements. GABA appears as a powder in capsules and in fermented milk and fermented soy products ⁵. In the US it meets the definition of a dietary ingredient ⁵.

Pet food. Cats have a dietary requirement for taurine, and plant-based protein sources are devoid of it ⁴. That makes taurine a formulation parameter, not an optional extra. A cat food labeled complete and balanced must meet an AAFCO cat food nutrient profile or pass feeding trials ⁷. Owens et al. report that AAFCO recommends a minimum of 0.1 % taurine on a dry-matter basis for extruded kibble and 0.2 % for canned diets ⁸.

Questions this answers

Does this lot contain the taurine per serving that our label declares?
Is the GABA in our supplier's raw material present at the stated strength?
How much glutamine is left in our ready-to-drink product after storage?
Did our cat food reach its taurine target after processing?
Are leucine, isoleucine and valine in our blend in the declared proportions?
Which free amino acids are present that the label does not mention?

Caveats for this matrix

Energy-drink concentrations need dilution

At 300–400 mg per 100 mL ³, taurine (125.15 g/mol ³) is about 24–32 mM. That is well above our 5 µM – 5 mM working range. AQC also needs a 4–6-fold molar excess of reagent over amines; too little reagent gives incomplete derivatization ⁹. We dilute every concentrated sample in-house and add an internal standard to every sample.

Acids, caffeine and flavor systems

AQC derivatization needs a pH of roughly 8.2–10.1, and strongly acidic samples must be neutralized first ⁹. We buffer and dilute beverages so the reaction runs in range. AQC reacts with any primary or secondary amine ⁹, so amine-containing ingredients can add peaks. Caffeine, at 70–400 mg/L or more in energy drinks ⁶, is routinely detected by HPLC with UV at 254 nm ¹⁰, close to our 260 nm wavelength. We check each chromatogram against a reagent blank. For a matrix type we have not seen before, a spike-recovery qualification (PREP-2, see pricing) checks whether the matrix distorts the result. Results below the quantitation limit are flagged, not reported as numbers. More on this at quality control.

Powders, capsules, gummies and kibble

Solids need an extraction step (PREP-1) before derivatization; see sample preparation. We measure free amino acids only. Taurine is not incorporated into proteins ¹¹, so a free result is the relevant one for it. Leucine or glutamine bound in whey, soy or meat protein is not counted. A free result will therefore not match a label that includes protein-bound amino acids; see free vs. total amino acids. The AAFCO taurine minimums above are on a dry-matter basis ⁸. Converting our result needs a moisture value, which we do not measure.

Glutamine and heat change the product over time

Glutamine in water degrades to pyroglutamic acid, with maximum stability between pH 5.0 and 7.5 and a rate that depends on temperature ¹². Amino acids also react with sugars on heating through the Maillard reaction, with lysine and glycine among the more reactive ¹³. A result therefore describes the product when we analyze it, not the batch sheet. For a label claim, that is usually the question.

Application notes

Application notes for this matrix are in preparation. The methods library covers the chemistry in the meantime.

Literature watch

New publications on supplements, beverages & pet food analysis are reviewed monthly; relevant findings and what they change for sampling or interpretation are added to this page.

Key references

21 CFR 101.36 — Nutrition labeling of dietary supplements — US Food and Drug Administration, Electronic Code of Federal Regulations, current.
21 CFR 111.70 — What specifications must you establish? — US Food and Drug Administration, Electronic Code of Federal Regulations, current.
Risk assessment of "other substances" – Taurine (VKM Report 2015:22) — Norwegian Scientific Committee for Food Safety (VKM), Panel on Food Additives, Flavourings, Processing Aids, Materials in Contact with Food and Cosmetics, 2015.
Nutritional Requirements of Small Animals — Sanderson SL, Merck Veterinary Manual, 2024.
United States Pharmacopeia (USP) Safety Review of Gamma-Aminobutyric Acid (GABA) — Oketch-Rabah HA, Madden EF, Roe AL, Betz JM, Nutrients, 2021.
"Energy" drinks report — European Food Safety Authority, 2013.
A Consumer's Guide: Overview of Pet Food Labels — Murphy CM, Schertz ON, Strawn LK, Virginia Cooperative Extension, 2022.
Rabbit Carcasses for Use in Feline Diets: Amino Acid Concentrations in Fresh and Frozen Carcasses With and Without Gastrointestinal Tracts — Owens TJ, Fascetti AJ, Calvert CC, Larsen JA, Frontiers in Veterinary Science, 2020.
Derivatization of Amino Acids Using Waters AccQ•Tag Chemistry — Waters Corporation, application primer.
Quantification of Caffeine in Energy and Cola Drinks via Rapid High Performance Liquid Chromatography Assays with Ultra Violet Diode Array Detection — Karlsen CE, Cravino JA, Soliven A, Mahon PJ, Li F, Shalliker RA, Beverages, 2025.
Taurine: new implications for an old amino acid — Schuller-Levis GB, Park E, FEMS Microbiology Letters, 2003.
Degradation kinetics of L-glutamine in aqueous solution — Arii K, Kobayashi H, Kai T, Kokuba Y, European Journal of Pharmaceutical Sciences, 1999.
Impact of Wort Amino Acids on Beer Flavour: A Review — Ferreira IM, Guido LF, Fermentation, 2018.

OpenChemWorks Laboratory · Reviewed by the laboratory director, PhD chemist · Updated September 23, 2026

Amino Acid Label-Claim Testing for Supplements, Beverages and Pet Food