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Reading a Protein Powder Label: Serving Size, Protein per Scoop, Added Ingredients and Testing

How to read a protein powder label in the United States: serving size versus scoop, protein per serving, other ingredients, allergens, blends and what a testing statement can show.

Content last updated . This page has not been medically reviewed.

Quick answer
A protein powder label is a set of separate claims: how big a serving is, how much protein is in it, what else is in it, who made it and whether anyone outside the company tested it. Each part answers a different question, and none of them proves a product is right or safe for a particular person. This page uses US rules; other countries differ. It describes what labels show and does not recommend products or amounts. For the general label basics see Reading Supplement Labels.

Which kind of label is it?

FDA says a dietary supplement can be a powder, and that to be one it must be labeled as a dietary supplement. [1] FDA's reporting page lists whey protein and amino acids among dietary supplements. [2] A supplement-style product carries a "Supplement Facts" panel that must show the serving size, the servings per container and each dietary ingredient. [1] Products marketed as foods use a Nutrition Facts label instead. [3]

Reading the label, line by line

Label partWhat to checkWhat the source says
Serving sizeIs it one scoop, two, or a weight in grams? Is your scoop the same as the label's?For a supplement, one serving equals the maximum amount the label recommends per eating occasion. [4]
Servings per containerNeeded to compare price or amount between tubsMust appear unless it matches the net quantity statement. [4]
Protein per servingGrams of protein, not grams of powderA 30 g scoop with 24 g of protein is 80% protein by weight (arithmetic example).
Percent Daily Value for proteinOften missing, which is allowedRequired only with a protein claim or for products for infants and children under 4. [5]
Other ingredientsFlavors, sweeteners, gums, fillersIngredients that are not dietary ingredients are listed in a separate ingredient statement below the panel. [1]
AllergensMilk, soy, egg, peanut, tree nuts, wheat, sesame, fish, shellfishThe law requires major allergen sources to be named, for example "whey (milk)". [6]
BlendsA named blend with one total weightIndividual amounts inside a proprietary blend need not be given. [4]
Contact lineA way to report problemsSupplement labels must give a domestic address or phone number for serious adverse events. [1]

For sweeteners, thickeners and other added items, see Protein Powder Ingredients.

How the protein number is worked out

For foods, US regulation says protein content may be calculated as 6.25 times the nitrogen content found by laboratory analysis. [7] That is an estimate from nitrogen, not a count of whole-protein grams. A 2016 analytical paper described adulteration of milk-derived ingredients, including whey protein concentrate, with nitrogen-containing compounds such as melamine to raise the nitrogen content. [8] FDA's guide also says a product containing only individual amino acids may not declare protein. [4] The question of whether label protein is really there is covered in Amino Spiking and Label Accuracy. Protein quality, meaning how well a protein supplies amino acids, is a separate matter: see Protein Quality Scores.

What a testing statement can and cannot show

  • Regulation. FDA is not authorized to approve dietary supplements for safety and effectiveness before they are sold. [9]
  • Label claims. NCCIH notes the phrase "not evaluated by the Food and Drug Administration" must accompany structure and function claims. [10]
  • Third-party testing. NCCIH states that labels showing testing by independent groups are a good way to help ensure a supplement contains what is on the label and is not contaminated. [11] A statement on a label is not the same as a test result for the tub in your hand. The general types of programs are described on Quality Testing and Certifications.
  • Sport. UK Anti-Doping states there are no guarantees that any supplement product is free from banned substances. [12] See Sports Certification and Banned-Substance Contamination.
  • Heavy metals. Consumer Reports tested 23 protein powders and shakes in 2025 and reported that more than two-thirds had more lead per serving than its experts consider safe in a day. [13] That is one consumer organization's test, and it does not describe every product. Details are on Heavy Metals in Protein Powders.
  • Other nutrients. A 2025 laboratory paper on sports supplements found creatine and taurine amounts that deviated from label claims by up to about 66% and 142%. [14] It did not study protein powders, so it shows only that label and content can differ.

Frequently asked questions

Is protein per scoop the same as scoop size?

No. The scoop or serving size is the weight of powder; protein per serving is how much of that weight is protein. For supplements, FDA's guide says one serving is the maximum amount the label recommends per eating occasion. [4]

Why does my label not show a percent Daily Value for protein?

FDA says the percentage is required only when a protein claim is made or the product is for infants or young children. [5]

Does "third-party tested" mean a product is safe?

NCCIH says independent testing is a good way to help ensure a supplement contains what is on the label and is not contaminated. [11] It does not by itself show a product is safe or right for you.

What does "proprietary blend" mean?

FDA requires the blend's name and total weight, with ingredients listed in descending order by weight, but not each ingredient's own amount. [4]

How do I report a problem with a powder?

FDA asks consumers who had a serious reaction to stop using the product and file a report through its Safety Reporting Portal. [2]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Safety and who should ask a clinician
Anyone with a food allergy, kidney disease or liver disease should ask a clinician or dietitian before adding a powder. [15] [16] People with phenylketonuria, in which phenylalanine from foods and some artificial sweeteners can build up, need clinician guidance as well. [17] Mention every supplement to a pharmacist or doctor, because supplements can interact with medicines. [18] Pregnant or breastfeeding people and parents of children should ask first as well, since many supplements have not been tested in these groups. [10] See Protein Powder Safety and the medication interactions guide.
References
  1. FDA, Questions and Answers on Dietary Supplements. Read 2026-10-22.
  2. FDA, How to Report a Problem with Dietary Supplements. Read 2026-10-22.
  3. FDA, Daily Value on the Nutrition and Supplement Facts Labels. Read 2026-10-22.
  4. FDA, Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling. Read 2026-10-22.
  5. FDA, How to Understand and Use the Nutrition Facts Label. Read 2026-10-22.
  6. FDA, Food Allergies. Read 2026-10-22.
  7. eCFR, Title 21 CFR 101.9 Nutrition labeling of food (text version dated 2026-10-01). Read 2026-10-22.
  8. Determination of emerging nitrogenous economic adulterants in milk proteins by high-performance liquid chromatography/compact mass spectrometry. Rapid Commun Mass Spectrom, 2016. Read 2026-10-22.
  9. FDA, Information for Consumers on Using Dietary Supplements, content current as of 10/21/2022. Read 2026-10-22.
  10. NCCIH, Using Dietary Supplements Wisely. Read 2026-10-22.
  11. NCCIH, Know the Science: Tips on Reading Supplement Labels. Read 2026-10-22.
  12. UK Anti-Doping, Managing Supplement Risks. Read 2026-10-22.
  13. Consumer Reports, Protein Powders and Shakes Contain High Levels of Lead, published 14 October 2025, updated 8 January 2026. A consumer organization's own testing, not a regulator's. Read 2026-10-22.
  14. Development and validation of a qNMR method for the simultaneous quantification of creatine and taurine in sports supplements. Pharmazie, 2025. Read 2026-10-22.
  15. NIDDK, Eating, Diet, & Nutrition for Chronic Kidney Disease. Read 2026-10-22.
  16. NIDDK, Eating, Diet, & Nutrition for Cirrhosis. Read 2026-10-22.
  17. MedlinePlus Genetics, Phenylketonuria (U.S. National Library of Medicine). Read 2026-10-22.
  18. FDA, Mixing Medications and Dietary Supplements Can Endanger Your Health, content current as of 06/02/2022. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.