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About & Our Testing Methodology

Last updated: July 2026
isoproteinpowder.com
Independent Testing Publication

We're a testing publication, not a brand-affiliated review site. Every product on our list is purchased at full retail price and sent to a third-party lab — we do not accept free samples for anything that appears in our rankings, because free samples create an incentive to rate a product favorably.

How We Test

Every product on this list is purchased at full retail price — we do not accept free samples from manufacturers for products that appear in our rankings, because free samples create an incentive (conscious or not) to rate a product favorably.

  1. Sourcing: Each product is bought directly from the manufacturer's official store or a verified retailer, never from a third-party reseller where counterfeit risk is higher.
  2. Lab analysis: Samples are sent to a third-party lab for testing, including protein content verification (to catch "amino spiking" or "protein spiking," where cheap free-form amino acids are added to inflate the protein number on the label without providing equivalent nutritional value), heavy metal screening, and macro verification against label claims.
  3. Scoring: Each product is scored out of 10 across the criteria below, and we disqualify any product that fails heavy metal or label-accuracy screening — those products do not appear on this list regardless of how they'd otherwise score.
  4. Re-testing: We recheck pricing monthly and re-run the full lab panel whenever a brand announces a reformulation, changes manufacturing facilities, or after roughly 12 months, whichever comes first.

Our Scoring Criteria

Label Accuracy

Does the actual lab-tested protein content match what's printed on the label, within an acceptable margin?

Ingredient Quality

Whey source, filtration method (concentrate vs. isolate vs. hydrolysate), and presence of unnecessary fillers.

Digestive Tolerance

Lactose content, protein type, and sweetener choice — the factors most linked to bloating and GI discomfort. Meet Protein Buddy to get matched by digestion fit specifically.

Safety Screening

Heavy metal content and banned substance testing, especially relevant for competitive athletes.

Value

Cost per gram of verified protein — not just sticker price, since serving sizes vary widely.

Mixability & Taste

Assessed via blind panel testing across multiple flavors of each product.

Third-Party Certification

Whether the product carries independent certifications like NSF Certified for Sport or Informed Choice.

Our Two-Tier System: Trust Is the Product

Not every protein powder worth knowing about has been personally tested by us yet — but we'd rather tell you that clearly than blur the line. Every product on this site falls into one of two tiers, and we label which one, everywhere, always:

Independently Lab Tested

We purchased this product ourselves at retail and sent it to a third-party lab. The score, the pros/cons, and the ranking are our own findings — not the manufacturer's claims.

Research Profile

We have not personally tested this product. Everything shown is sourced from the manufacturer's published specifications and cited public sources — no taste, mixability, or quality score is invented. We say so directly on the page.

Protein Buddy, our recommendation tool, understands this distinction too — it tells you plainly which tier a recommendation comes from, rather than presenting a Research Profile with the same confidence as a product we've actually tested. As we purchase and test more products ourselves, they move from Research Profile to Independently Lab Tested — the underlying architecture doesn't change, only the depth of what we can honestly claim about that specific product.

Editorial Independence

This site earns revenue through affiliate commissions when you purchase through links on our pages — full disclosure is in the footer of every page. That commission rate does not vary by brand or product: our #1 ranked product earns us the same referral rate as our #10 ranked product, so there is no financial incentive to rank one above the other. No brand featured on this site has editorial approval over its review, score, or ranking.

Corrections

If you believe something on this site is factually inaccurate — a pricing error, an outdated formulation, or a lab result that doesn't match your own testing — please contact us with details and we will investigate and correct promptly where warranted.