Proprietary blends: what they actually hide

What it is

Under the Dietary Supplement Health and Education Act (DSHEA) of 1994, the Supplement Facts panel must list every dietary ingredient and its weight. There is one carve-out: when ingredients are listed as part of a "proprietary blend," only the total weight of the blend has to be disclosed. Individual ingredient amounts within the blend can be withheld.

On a label this looks like a single line — "Metabolic Support Blend, 1,727 mg" — followed by an indented sub-list of the blend's component ingredients. The component ingredients are listed in descending order by weight, but the actual mg of each is the formulator's private information.

Almost every multi-ingredient supplement in the affiliate channel uses a proprietary blend. That includes most of the products reviewed on this site.

What the marketing claims

The phrasing on a supplement label or sales page tends to recycle a few patterns. Proprietary blends usually shows up wearing one of these:

• "Our proprietary formula is a closely guarded trade secret."
• "Decades of research went into the exact ratios."
• "Synergy that can't be matched by single-ingredient products."
• "Patented blend" — used loosely, often without an actual patent.

What the published evidence actually says

There is no published evidence that any specific proprietary blend in the affiliate supplement channel produces an outcome unobtainable from disclosed-dose individual ingredients. The "synergy" argument is a marketing premise, not a clinical finding.

The structural problem is auditability. When the trial base for an ingredient says 400 mg of EGCG, 200 mg of L-theanine, and 200 mcg of chromium produced an effect, and the blend on the label is 1,727 mg total across five ingredients, you cannot verify whether any individual ingredient hits its studied dose. The math usually says it doesn't.

Trade-secret defences for proprietary blends do not generally hold up to scrutiny. Modern analytical chemistry can reverse-engineer a supplement formulation in a competent contract lab in a few weeks. The blend isn't hiding the recipe from competitors. It's hiding it from buyers.

Patents are public documents. A "patented blend" can be looked up on Google Patents in two minutes. In most affiliate supplements, the patent — when it exists — covers a specific manufacturing process, not the ingredient ratios.

Effective dose vs typical supplement dose

There is no "effective dose" of a proprietary blend per se — the structural fact is that you cannot assess effective dosing of the individual actives.

A useful heuristic: take the total blend weight, divide by the number of listed ingredients, and assume even distribution. If that average is below the studied dose for any active in the blend, you can be confident that ingredient is below threshold.

A 1,500 mg blend across five ingredients gives you 300 mg per ingredient on average. If two of those ingredients have studied doses above 400 mg, at least one is sub-clinical. Usually more than one.

Safety profile

Proprietary blends do not introduce direct safety hazards by themselves. The hazard is that you cannot verify the dose of an ingredient that does have a hazard threshold (EGCG, mucuna, ashwagandha at high doses, etc.).

For drug interactions, the inability to verify the dose of an individual ingredient inside a blend means you cannot reliably assess interaction risk with prescription medication. That is a meaningful clinical issue.

Pregnancy, breastfeeding, paediatrics: a proprietary blend is exactly the wrong format for any population where individual ingredient dose matters for safety.

This is general information, not medical advice. Anyone on prescription medication, pregnant or breastfeeding, or managing a chronic condition should bring an ingredient like Proprietary blends to their clinician before starting it.