Amino Spiking: What It Is and How to Spot Protein Quality

What Is Amino Spiking?

Amino spiking is a practice where manufacturers add cheap individual amino acids to protein powders to artificially inflate the declared protein content. Typical “spiking” amino acids include glycine, taurine, or creatine. Amino spiking is one of several questionable practices in the supplement industry. Another is Fairy Dusting (underdosing of active ingredients).

Why does it work?

In Switzerland, protein content is calculated from total nitrogen: protein = total nitrogen (Kjeldahl) × 6.25 (LIV, Annex 1, number 19). Nitrogen determination cannot distinguish between nitrogen from protein and nitrogen from other sources. The problem: free amino acids also contain nitrogen and are therefore counted, even though they don’t represent complete protein.

The result: A label might show 25g of protein per serving, but a significant portion doesn’t come from the actual protein source - it comes from added individual amino acids.

Why Is Amino Spiking a Problem for Protein Quality?

Amino spiking distorts the actual protein content of a product, leads to an incomplete amino acid profile, and lowers the share of essential amino acids in the declared protein. You pay for complete protein but partly receive cheap individual amino acids.

Incomplete Amino Acid Profile

The content of essential amino acids differs considerably depending on the protein source: pea protein contains comparatively little methionine, hemp protein little lysine. Combining several sources can balance out the profile. If part of the “protein” consists of pure glycine or taurine, the share of the other essential amino acids, such as leucine, in the declared protein decreases.

Lower Protein Quality

The quality of a protein depends not only on its quantity, but on the amount and ratio of indispensable amino acids, on digestibility and on the availability of the amino acids (FAO 2013). A protein that meets amino acid requirements less well is utilised less effectively.

Less Protein for Your Money

The declared protein content does not correspond to the actual complete protein in the product. With a 1kg bag, the difference adds up quickly.

Good to know: It’s normal for the sum of all amino acids on a certificate of analysis to be slightly lower than the declared total protein content. Depending on the food, the conversion factor 6.25 can overestimate protein content by up to 9% (FAO 2003), and certain amino acids like tryptophan are partially destroyed during hydrolysis (Adebiyi et al. 2005). A small difference is therefore not, on its own, an indication of amino spiking. It only becomes suspicious when cheap individual amino acids appear separately in the ingredients list.

How to Spot Amino Spiking

1. Read the Ingredients List Carefully

Watch for these warning signs:

• Glycine as a separate ingredient (not as part of a protein)
• Taurine in protein powders (it doesn’t belong there)
• L-Glutamine in large quantities
• Creatine used as a filler

Important: In a high-quality protein powder, the ingredients list should be short and easy to understand: the protein source (e.g. pea protein, hemp protein), other ingredients with a recognisable purpose, possibly natural flavourings.

2. Request the Amino Acid Profile

Reputable manufacturers publish the complete amino acid profile of their products. The profile differs considerably depending on the protein source: the leucine content of plant-based protein isolates ranges from 5.1% (hemp) to 13.5% (corn) of the protein (Gorissen et al. 2018). Therefore, compare the profile with the declared protein source.

If a manufacturer doesn’t provide an amino acid profile, that’s a red flag.

3. Price as an Indicator

High-quality protein sources have a market price - this applies to plant-based proteins just as much as animal-based ones. If a product is significantly cheaper than competitors with the same declared protein content, you should be sceptical. Individual amino acids are cheaper than real protein raw materials.

4. Check the Origin

Ask the questions: Where does the protein come from? Who produces the raw material? Are there organic certifications? Transparent manufacturers can answer these questions and disclose their supply chain.

Legal Situation

In Switzerland

Swiss food law (Lebensmittel- und Gebrauchsgegenständeverordnung, LGV) prohibits consumer deception. Under Article 12 paragraph 1 LGV (prohibition of deception), designations, statements, presentation, advertising and information about foodstuffs must correspond to the facts and must not give rise to deception, in particular as to composition and content.

The Food Information Ordinance (LIV) calculates protein content from total nitrogen (Annex 1, number 19).

In the EU

Regulation (EU) No 1169/2011 on the provision of food information to consumers likewise requires that food information must not be misleading. Total nitrogen determination cannot distinguish protein nitrogen from nitrogen from other sources. Detecting added individual amino acids therefore requires additional analytical methods (Lukacs et al. 2024).

What Makes a High-Quality Protein?

1. Transparent amino acid profile - The manufacturer publishes the exact composition
2. Short ingredients list: Protein source, other ingredients with a recognisable purpose, possibly natural flavourings
3. Traceable origin - Clear information about the protein source and supply chain
4. Realistic price - Quality has its price
5. Certifications - Organic seals, laboratory analyses, or independent third-party testing

Conclusion

Amino spiking diminishes the quality of the protein. You can spot declared individual amino acids in the ingredients list; undeclared additions only show up in additional laboratory analyses.

Look for transparency: a manufacturer with nothing to hide will show you exactly what’s in their product.

Further Reading

• Understanding Protein Quality: PDCAAS, Bioavailability & Amino Acids
• How Much Protein You Really Need
• Fairy Dusting: When Supplements Only Work on the Label
• Problematic Additives in Dietary Supplements
• Organic Protein Powder Nature: with a transparent amino acid profile
• Organic Hemp Protein

Sources:

• Lukacs M, Zaukuu JZ, Bazar G, Pollner B, Fodor M, Kovacs Z (2024). Comparison of Multiple NIR Spectrometers for Detecting Low-Concentration Nitrogen-Based Adulteration in Protein Powders. Molecules, 29(4), 781. DOI: 10.3390/molecules29040781
• Jiao X, Meng Y, Wang K, Huang W, Li N, Liu TC (2019). Rapid Detection of Adulterants in Whey Protein Supplement by Raman Spectroscopy Combined with Multivariate Analysis. Molecules, 24(10), 1889. DOI: 10.3390/molecules24101889
• Topal BN, Caglar-Andac S (2026). Counterfeiting in Protein Supplement: Spectroscopic and Chromatographic Analysis. Critical Reviews in Analytical Chemistry, 56(5), 1453-1465. Online 29.04.2025. DOI: 10.1080/10408347.2025.2496502
• Faller AC, Arunachalam T, Shanmughanandhan D, Kesanakurti P, Shehata HR, Ragupathy S, Newmaster SG (2019). Investigating appropriate molecular and chemical methods for ingredient identity testing of plant-based protein powder dietary supplements. Scientific Reports, 9, 12130. DOI: 10.1038/s41598-019-48467-9
• Gorissen SHM, Crombag JJR, Senden JMG, Waterval WAH, Bierau J, Verdijk LB, van Loon LJC (2018). Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids, 50(12), 1685-1695. DOI: 10.1007/s00726-018-2640-5
• House JD, Neufeld J, Leson G (2010). Evaluating the quality of protein from hemp seed (Cannabis sativa L.) products through the use of the protein digestibility-corrected amino acid score method. Journal of Agricultural and Food Chemistry, 58(22), 11801-11807. DOI: 10.1021/jf102636b
• Adebiyi AP, Jin DH, Ogawa T, Muramoto K (2005). Acid hydrolysis of protein in a microcapillary tube for the recovery of tryptophan. Bioscience, Biotechnology, and Biochemistry, 69(1), 255-257. DOI: 10.1271/bbb.69.255
• Mariotti F, Tomé D, Mirand PP (2008). Converting nitrogen into protein - beyond 6.25 and Jones’ factors. Critical Reviews in Food Science and Nutrition, 48(2), 177-184. DOI: 10.1080/10408390701279749
• FAO (2003). Food energy - methods of analysis and conversion factors. Report of a Technical Workshop, Rome, 3-6 December 2002. FAO Food and Nutrition Paper 77. Rome.
• FAO (2013). Dietary protein quality evaluation in human nutrition. Report of an FAO Expert Consultation, Auckland, New Zealand, 31 March-2 April 2011. FAO Food and Nutrition Paper 92. Rome.
• Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, OJ L 304, 22.11.2011, p. 18.
• Ordinance on Foodstuffs and Utility Articles (LGV) of 16 December 2016 (SR 817.02), Art. 12 (Prohibition of deception), status as of 1 July 2025.
• Ordinance of the FDHA on Food Information (LIV) of 16 December 2016 (SR 817.022.16), Annex 1, No. 19, status as of 1 July 2025.