How the stars are calculated
We want you to be able to argue with a rating. So here is the whole recipe: what we look at, how much each piece counts, and the two hard rules that sit on top.
Editorial ratings, not user reviews.
Step 1: six factors, scored 0 to 100
| Factor | Weight | What we check |
|---|---|---|
| Testing & certificates | 30% | Does the supplier say an outside laboratory tests its products (yes, limited, no)? Can anyone open the certificates? Are they tied to a lot number? Is the laboratory named, and does it look accredited (ISO/IEC 17025)? Which methods appear on the certificate: HPLC, mass spectrometry, endotoxin, sterility. |
| Track record | 20% | Years in business, the score and volume of any trust-site profile, positive and negative signals from the fact sheet, forum presence, and a heavy deduction for a public FDA warning letter. A closed supplier scores zero here. |
| Transparency | 15% | Research-use-only labeling, a public email, phone number and street address, a stated location and founding year, a working certificate page, and a written returns policy. |
| Pricing | 15% | The supplier's price level, its listed price for the reference item (BPC-157, 5 mg) against the median of the field, its free-shipping threshold, and whether prices are shown openly. |
| Catalog | 10% | Roughly how many listings, how many formats (vials, pens, capsules, nasal, bulk, blends), and how broad the range of notable items is. |
| Ordering & service | 10% | Card acceptance and the number of ways to pay, a stated dispatch time, international shipping, named carriers, and published returns and guarantee policies. |
Every factor begins at zero and earns fixed points for each fact we could confirm, up to a ceiling of 100. In Testing, for example, stating outside testing is worth 55 points, open certificates add 15, per-lot certificates add 10, naming the laboratory adds 8, an accredited-looking laboratory adds 4, and each method shown adds a point or three. A fact we could not confirm earns nothing: if certificates sit behind a login, they count as not public.
Step 2: weight and add
Multiply each factor by its weight (30 / 20 / 15 / 15 / 10 / 10), add them up and round. That gives a score out of 100. Divide by 20 and round to one decimal and you have the star rating: 76 points is 3.8 stars, 90 points is 4.5.
Step 3: two hard rules
- A public FDA warning letter caps the score at 59. However well a supplier does elsewhere, a letter on the record holds it to 3.0 stars at most. The cap lifts only if the letter is withdrawn.
- A supplier we could not verify is not rated. If the site was down, redirected, or showed nothing checkable, it gets no stars and sits in a separate list. Closed suppliers are also not rated.
The four sub-ratings
On review pages we also show four buyer-facing sub-ratings, each out of 5, built from the same factor points: Quality is the Testing factor; Trust is the average of Transparency and Track record; Value is the Pricing factor; Experience is the average of Ordering & service and Catalog. They are a quick way to read the shape of a supplier, not a second formula.
What we deliberately ignore
- Our own lab results. We do not run tests. A certificate from an independent laboratory you can look up is better evidence than anything we could ask you to take on faith.
- Customer reviews and ratings. We collect none, show none and mark up none. See the editorial policy.
- Anything to do with use. Every supplier here sells materials labeled for laboratory research only. Nothing in the formula touches any other topic.
- Whether a link pays us. Referral links are disclosed and have no place in the maths.
Where the facts come from
We read each supplier's own public pages (home, product, testing, about, contact, shipping, policies) and public records (FDA warning letters, trust-site profiles, business registries). Each review lists where we looked. Facts are re-checked on a rolling schedule, and the site is rebuilt whenever the data changes; the month on each page is the last rebuild.
The complete dataset, including every factor score, is on the download page as CSV and JSON, so you can rerun the maths yourself.
Questions buyers ask
Can a supplier buy a better rating?
No. The formula is public and identical for every supplier. The only way a rating moves is when a checkable fact changes, such as a supplier starting to publish per-lot certificates or a regulator issuing a letter.
Why don't you use customer reviews?
Because in this market they are easy to fake and easy to lose: several suppliers have had their trust-site profiles removed outright. Where a profile exists we use its score and volume as one input into track record, and we never collect reviews ourselves. Every star on this site is editorial.
Do you test products in a lab?
No. We rate what suppliers publish and what regulators publish. A certificate from a named independent laboratory for a specific lot is the strongest evidence a supplier can offer, and it is what the formula rewards most.
How do I get a fact fixed?
Use the contact page and include a link to the page on the supplier's site that shows the correct information. Fixes land at the next rebuild and the page's updated date changes.
What does 3.8 stars actually mean?
That the supplier scored 76 out of 100 points on the weighted formula. Stars are the score divided by 20, rounded to one decimal. They are editorial, not user reviews.