Tryptophan dosage

Tryptophan testing quantifies this essential amino acid , a major precursor of serotonin and melatonin , involved in the regulation of mood, sleep and energy metabolism.
Essential for protein synthesis and the production of niacin (vitamin B3), tryptophan is a key indicator of the nutritional value of foods and nutraceutical formulations .

The analysis is carried out by high-performance liquid chromatography (HPLC) or mass spectrometry (LC-MS/MS) , after acid or enzymatic hydrolysis of the samples to release the free amino acid.

Analytical methods and protocols

The dosage is based on the chromatographic separation of amino acids after extraction and possible derivatization.

• In HPLC-DAD or HPLC-fluorescence , the detection of tryptophan is carried out at a specific wavelength (280 nm).
• In LC-MS/MS , the method offers excellent sensitivity and selective identification even in complex matrices.

The parameters measured include:

• The content of free or total tryptophan (mg/g or %),
• The amino acid profile of a sample,
• The stability and bioavailability of the compound in a given formulation.

Methods can follow ISO 13903 , AOAC 988.15 , or Commission Directive 98/64/EC for food and nutritional matrices.

Industrial and scientific applications

Tryptophan dosage is widely used in the following sectors:

• Human and infant nutrition : formulation of products enriched with essential amino acids.
• Animal nutrition : control of the tryptophan/lysine/methionine ratio in compound feed.
• Nutraceuticals : standardization of supplements promoting sleep, relaxation or emotional regulation.
• Research in plant biology : study of indole metabolism in plants and the biosynthesis of growth hormones (auxins).

This analysis guarantees the nutritional quality and traceability of the formulations , while supporting functional and regulatory claims.

Affected matrices

• Food products (vegetable proteins, milk, flours, legumes),
• Animal feed and nutritional premixes,
• Food supplements (powders, capsules, plant extracts),
• Fermented products or products enriched with amino acids,
• Plant extracts rich in tryptophan derivatives.

Further analyses recommended

For a complete understanding of the metabolism of tryptophan and its bioactive derivatives, YesWeLab recommends combining this assay with:

• Serotonin assay , to monitor metabolic conversion to the serotonergic pathway,
• Dosage of tryptophol , an indolic metabolite derived from tryptophan,
• Dosage of tryptamine , a derivative molecule involved in neurotransmission,
• Melatonin dosage , the final hormone of the tryptophan pathway,

YesWeLab expertise

YesWeLab relies on a network of ISO 17025 and COFRAC accredited laboratories , specialized in the chromatographic analysis of amino acids and indolic metabolites .
Our teams support manufacturers and formulators in the standardization of nutritional products , biochemical characterization and regulatory compliance .

Thanks to the YesWeLab digital platform , you can:

• Order your analyses online,
• Track your samples and results in real time,
• Compare your batches to ensure the stability and quality of your formulas.