Plumb
A-

Subscription-funded independent lab-testing and review service for dietary supplements and health products

ConsumerLab.com

Independent (privately held; founded and led by Tod Cooperman, M.D.)

Hands-on tester Partly paywalled Visit ConsumerLab.com ↗

A genuinely independent, lab-driven supplement watchdog whose blinded retail testing earns trust, but most verdicts hide behind a paywall and it sells a paid seal on the side, so read the reviews and the certification business as two separate things.

What it's really for An independent supplement-testing lab; the full results sit behind a paid subscription.

What our grade covers The grade on this page is about its lab-tested supplement reviews, not everything the site does.

High Scoring Confidence Checked against primary sources. We are confident in the facts and the grade here.

Follow the money

By its own disclosure, the largest source of money is consumers and institutions paying membership/subscription fees (it says these "fund" the Product Reviews and that it does not accept advertising or free samples from makers of reviewed products). Manufacturers can pay separately for the Voluntary Certification Program, but ConsumerLab states paying the testing fee "in no way guarantees the product will pass," so payment does not appear to buy a passing review or rank in the independent Product Reviews.

Source →
Operating since
1999 (27 years) · source
What it costs you
Partly paywalled Some content is free, but the full reviews or detailed ratings sit behind a paid subscription.
How they make money
Primarily paid memberships and institutional subscriptions (about $69/year, 100,000+ members) that fund testing; secondary revenue from a separate opt-in Voluntary Certification Program (manufacturers pay a testing fee to license the "CL Seal"), survey-report sales, and PriceCheck/"Where to Buy" referral fees.
What they do
ConsumerLab buys supplements off retail shelves and sends blinded samples to independent contract laboratories to test identity, potency, purity and contaminants (heavy metals, etc.), then publishes pass/fail reviews and "Top Picks" behind a subscriber paywall. It does not run its own lab, instead commissioning accredited outside labs.
What to watch for
Most results and the actual brand-by-brand verdicts sit behind a membership paywall, so the testing is not freely reproducible; some reviews show missing or "N/A" contaminant data; and the same company that publishes "independent" reviews also runs a paid certification program selling the CL Seal, a structural conflict it discloses but readers should keep separate from the reviews.
Composite score
4.10 / 5.00 → grade A-

How the grade was reached

Independence · 30% weight 4 / 5

Does the site take money from the very entities it ranks? Pay-for-placement, vendor-funded data, and affiliate commissions all pull this down. The less the ranking can be bought, the higher the score.

Evidence basis · 30% weight 5 / 5

What is the ranking actually built on? Hands-on testing scores highest, then verified first-hand reviews, then opinion or popularity surveys and self-reported figures, then pay-to-rank, which scores lowest.

Method transparency · 20% weight 3 / 5

Is the methodology published, specific, and reproducible? Can a reader see how a given rank was reached, or is it a black box?

Conflict disclosure · 10% weight 4 / 5

Are commercial relationships, sponsorships, and affiliate arrangements disclosed clearly and near the rankings themselves, rather than buried?

Manipulation resistance · 10% weight 4 / 5

How hard is it to game? Controls against fake reviews, solicited reviews, and vendor gaming raise this; an open box anyone can stuff lowers it.

Evidence

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