We use two scoring systems, because a supplement and a research peptide are different things and are judged on different evidence. Both give a 0-100 score, both use the same principle - we score what is disclosed and verifiable, and a claim on its own only ever earns partial credit and is always labelled as a claim - and neither is ever influenced by affiliate commission.
Supplements
Every supplement receives a 0-100 score built from six weighted categories. Default weights are testing & evidence 20%, ingredient/formulation quality 25%, value 20%, dose transparency 15%, manufacturer transparency 10%, and label transparency 10%. Some supplement categories use adjusted weights where relevant (for example, oxidation testing matters more for omega-3 than for creatine).
Testing evidence earns credit by tier: a verified recognised certification earns full credit, a verified independent laboratory report 95%, a batch-specific manufacturer certificate of analysis 80%, a specific testing claim we could not independently check 45%, and no public evidence located 20%. Value compares the cost of a daily serving with other products in the same category: the lowest-cost product earns full credit and a typical product about 70%. Where we have not yet researched a brand's manufacturing details we use a neutral midpoint rather than a penalty. Formulation, dose and label scores are calibrated so that a well-made, transparent product can reach the high 70s or 80s; a score of 90 or more needs published, batch-specific testing evidence and strong results in every other category.
A category that has not yet been researched for a given product is treated as pending and excluded from that product's score, rather than being counted as an average or a zero - the remaining categories' weights are redistributed proportionally so the score still reflects what is actually known. Testing specifically is only ever excluded this way when evidence review is genuinely unfinished, not when a product has simply been found to lack public evidence.
Our current supplement scoring framework
Supplement scores combine six categories. We normalise the weights to a total of 100. A supplement may have a category-specific weighting; its product analysis displays the actual breakdown.
Compare like with like
Daily cost divides the price by the number of days supplied at the label serving. Tables show daily cost alongside the relevant active amount. Some categories also use a comparable-unit calculation in their value score, such as cost per 100 mg elemental magnesium; the product analysis explains the category basis. Missing amounts are shown as unavailable.
A high score is not a medical recommendation. Price convenience, Prime status and affiliate commission do not establish quality or individual suitability.
What our picks mean
Best Overall uses the highest overall score in the current comparison. Cheapest Per Day uses the lowest disclosed daily cost among eligible products. Best Tested uses the highest testing-evidence score among eligible reviewed products with supporting evidence; its badge identifies whether that evidence is a claim, a manufacturer report or independently verified evidence. Ties use overall score, then product ID. Each award is ranked independently, so the same product can win more than one. No testing award is assigned if qualifying evidence is unavailable.
We keep testing claims distinct from independently checked evidence and show provenance where it is recorded.
Research peptides
Research peptides are sold for laboratory research only. Their score compares the documentation and characteristics of the research product - it says nothing about whether a peptide is safe, effective or suitable for human or veterinary use, and a high score is not an endorsement of any kind. Research peptides are covered on the UK site only.
Testing & analytical evidence (45 points)
This is the biggest part of the score, but it is deliberately fair to an industry that is largely unregulated. Purity evidence matters most: a stated HPLC purity result from an actual report earns up to 13 points. The rest is made up of the source of the report (up to 8), whether it is tied to a batch (up to 6), an identity or mass-spectrometry check (up to 6), a measured content figure (up to 4) and how recent it is (up to 3). Verification with the laboratory, microbiology/endotoxin results and contaminant panels are bonuses (up to 5 in total) - they can lift a score but their absence does not sink it.
Reports without a named lab still count. Many laboratories will not put their name on reports for research peptides, so a supplier-issued certificate of analysis with real results is accepted and scores well - an independent, named, verifiable laboratory simply scores a little higher. A certificate that is merely “signed” earns no extra credit.
Claims earn something too. If a supplier says a product is tested but we could not find a report, we take that partly at their word: a generic “lab tested” earns a few points, a specific claim (for example a stated purity and method) earns more, and “certificate of analysis available on request” earns the most - but always far less than a real report. We only score what is actually documented; one tested sample does not guarantee every vial is identical.
Value (25 points)
Price per mg is compared against equivalent products: the same peptide and the same chemical form (for example CJC-1295 with DAC is never compared with No DAC). Vial size is not matched, because a larger vial legitimately gives better unit value. The benchmark is the median price per mg, with every supplier carrying equal weight so a shop with many sizes cannot dominate it. A product priced at the median earns 18 of 25; cheaper earns more and dearer earns less. Coupon codes, crossed-out “RRP” prices, subscription prices and our own affiliate links are ignored. Value is never adjusted by testing quality, so it stays a pure price measure.
Product identity, supplier and listing transparency (30 points)
Identity (15): the exact peptide, the relevant form, mg per vial, vial count, molecular identifiers such as CAS number or sequence, physical formulation, storage information and a stable product code. Supplier (10): who is actually selling it - legal company name, verifiable Companies House registration, UK address, contact details, shipping and returns policies, and an explanation of how batches are tested and traced. Unsupported medical claims, promoting human self-use, or misleading testing statements lose points. Listing (5): whether the title, quantity and description agree, the price basis is clear, the stock status is clear and the image genuinely shows the product.
Not yet reviewed is not the same as zero
A product we have not finished researching shows Score pending rather than a low score. Only once the identity, price, supplier and testing reviews are complete (and at least 80% of the weighted inputs have been reviewed) does a number appear. If we have looked properly and found no evidence, that legitimately scores zero for that item.
Caps on the overall score
So that a product with a polished website can never outrank one with genuine batch-level evidence, the overall score has a ceiling that depends on the strongest testing evidence found: no analytical report at all (claims only), maximum 65; a supplier-issued report or one with no named laboratory, 88; an independent report that is not tied to a batch, 90. Independent, batch-specific reports have no testing ceiling. If the exact compound, form or vial quantity cannot be established, no score is shown at all.
Score labels
90-100 Very strong evidence & value; 80-89 Strong; 70-79 Good; 60-69 Mixed; 40-59 Limited; 0-39 Weak evidence. The number is the primary result; the label only describes it.
Keeping scores current
Prices and stock are refreshed on every check and the score recalculates automatically. A new batch invalidates the previous batch’s test report until the new one has been reviewed. Out-of-stock products keep being scored from their last in-stock price but sit at the bottom of the table, and are not used to set the value benchmark.
Research use only. Research peptides are not medicines, supplements or personal-use products. A high score does not mean a product is approved, clinically effective, sterile, safe to administer or suitable for human or veterinary use.