Proprietary blend

21 CFR 101.36(c) creates a narrow exception to the general rule that every dietary ingredient on the Supplement Facts panel must declare its quantity per serving. The exception lets a manufacturer declare a 'proprietary blend' (or a synonym — 'proprietary formula', 'unique blend', a brand name) as a single line with one total weight, followed by the constituent ingredients in descending order of predominance by weight. The per-ingredient amounts can be withheld. The conditions:

• The word 'blend' or 'proprietary' (or a synonym indicating a multi-ingredient mixture) must appear in the line.
• The total weight of the blend must be declared next to the line.
• Constituent ingredients must be indented or otherwise visually subordinate to the blend line.
• Constituents must be listed in descending order of predominance by weight.
• Any constituent for which a Daily Value is established (e.g. magnesium, vitamin B6) must still be broken out separately with its own amount and %DV — those cannot hide inside the blend.

When FDA finalised the Supplement Facts rule in 1997 (62 FR 49826), the industry argued that requiring individual amounts on every constituent of a complex botanical or sports-nutrition formula would force disclosure of trade-secret formulations that competitors could replicate within weeks. FDA accepted that argument narrowly: the exception preserves the total weight (so consumers and regulators can compute serving-level exposure) and the ordering (so the dominant ingredient is identified) while protecting the relative proportions. It was never intended to let manufacturers hide active ingredients at sub-therapeutic doses — but in practice that is precisely what has happened.

The classic amount-spiking scheme: a sports-nutrition product lists a 'Performance Blend 5,000 mg' with seven constituents, the first being beta-alanine. The marketing leans heavily on beta-alanine's clinically-effective dose (3.2 g/serving for muscular endurance). The actual content, revealed only by third-party HPLC assay, is 200 mg beta-alanine and 4,800 mg of cheap maltodextrin and citric acid. The product is technically lawful — beta-alanine is first by weight inside the blend — but the consumer has been misled. Class-action lawsuits under state UDAP statutes (California's Sherman Law, New York GBL §349, Massachusetts 93A) have produced eight-figure settlements on this pattern.

Any constituent of a proprietary blend for which a Daily Value has been established in 21 CFR 101.9 must be declared separately, outside the blend, with its own quantitative amount and %DV. This applies to: all 13 vitamins (A, C, D, E, K, B1, B2, B3, B6, B12, folate, biotin, pantothenic acid), the 15 DV-listed minerals (calcium, iron, magnesium, zinc, selenium, copper, manganese, chromium, molybdenum, sodium, potassium, chloride, phosphorus, iodine, fluoride if added), and the macro-nutrients with DVs (total fat, saturated fat, trans fat, cholesterol, total carbohydrate, dietary fibre, total sugars, added sugars, protein). A multivitamin attempting to declare 'Vitamin Blend 100 mg' with vitamins A, C, B6 inside is automatically misbranded — those three must be broken out individually with their %DV.

101.36(c) requires constituents listed in descending order of predominance. FDA Warning Letters routinely cite blends where the order is alphabetised, or grouped by 'type' (botanicals first, amino acids second), rather than by weight. This is an automatic 403(a)(1) misbranding finding. The discipline that prevents it:

1. Lock the Master Manufacturing Record (111.210) charge sheet to a numeric weight for every constituent — no 'as needed' ingredients in a blend.
2. Generate the label artwork constituent list mechanically from the MMR, sorted descending by per-serving weight.
3. Block label artwork revisions where the on-label order does not match the MMR-derived order.
4. Re-derive on every formula change (re-formulation, supplier swap with different concentration, overage change).

Major retailers and marketplaces increasingly require full per-ingredient amount disclosure regardless of 101.36(c):

Build the label artwork pipeline to full-disclosure as the default and you get retailer access and 403(a)(1) protection in one step.

The labelling exception in 101.36(c) does NOT relax the cGMP rule in 21 CFR 111.75: per-lot identity testing must still be performed on EACH dietary ingredient in the blend before it is used. There is no 'blend identity test' — you cannot HPLC the finished blend and call it identity confirmation. Each constituent lot, at receipt or before charge, must be confirmed individually using a scientifically valid method. This is one of the most-cited 483 observations on contract manufacturers who buy pre-blended raw materials from upstream suppliers.

• formula_components has an optional blend_id grouping constituents into one declared blend.
• Each constituent stores per-serving weight; the blend total is derived, not entered manually.
• label_artwork_revision is generated from the MMR; any drift triggers an artwork-vs-formula NCR.
• DV-bearing constituents (vitamins, minerals, macros) are auto-flagged for individual breakout.
• Per-lot identity tests (111.75) are enforced per constituent — buying a pre-blend from a supplier does not satisfy 111.75 unless documented under the (a)(1)(ii) exemption petition.