Frequently asked questions

About the certifications

Does no certification mean the product is unsafe?: No. Absence of certification means the product has not been independently verified by NSF, USP, the Informed family (Sport, Choice, Protein), IFOS, or IGEN. Many supplements without these certifications are perfectly fine. Certification adds assurance — it is not proof of safety, nor is it a requirement for a good product.
Which certifications does Certwell cover?: Five third-party schemes: NSF Certified for Sport, USP Verified, Informed Sport, IFOS (fish oil), and IGEN (non-GMO). Each subpage explains what is tested, how to verify a certificate, and where the scheme matters most.
What is the difference between NSF Certified for Sport and Informed Sport?: Both are batch-level testing programmes for substances banned in competitive sport. NSF Certified for Sport is run in the US and is the certification most often referenced by major US sports leagues. Informed Sport is run by LGC in the UK and has the deepest coverage of UK and European brands. For UK athletes, Informed Sport tends to be more practical because more of the products on UK shelves carry it; for US-recognised competitions, NSF tends to be the expected standard. Either is a strong signal.
What's the difference between Informed Sport, Informed Choice, and Informed Protein?: All three are run by LGC in the UK. Informed Sport tests every batch against the WADA banned-substance list — it is the relevant tier for athletes competing in a tested sport. Informed Choice tests a sample of products each month rather than every batch — same banned-substance scope, looser cadence. Informed Protein verifies that the protein content on the label is accurate and includes banned-substance screening — it targets the protein category specifically. For competition, look for Informed Sport. For routine quality assurance, Informed Choice is enough. For protein products, Informed Protein adds independent confirmation of the protein claim.
Is "tested in a GMP facility" the same as third-party certified?: No. Good Manufacturing Practice (GMP) is a baseline requirement for any supplement made for sale in the UK or US. It governs cleanliness, record-keeping, and process control at the factory — it does not check that what is on the label matches what is in the bottle, and it does not screen for banned substances or contaminants. Third-party certifications go further by independently testing the finished product against a defined standard.
Do these certifications mean the supplement actually works?: No. None of the schemes assess clinical efficacy. They confirm identity (the right ingredient), potency (at the stated dose), purity (free from contaminants and, in some cases, banned substances), and — for USP — dissolution. Whether a given supplement produces a measurable effect is a separate question that certification cannot answer.
Why might a certified product lose its certification?: Certification is not permanent. A brand can stop paying for ongoing testing, fail a re-audit, change a formulation, or move production to a non-audited facility. Certifying bodies remove the listing in those cases. This is one reason verifying the specific product and batch on the body’s database matters more than relying on the logo on the packaging.

Choosing a supplement

Should I always pick a certified product over a non-certified one?: Not automatically. Certification is most valuable in categories with documented quality problems — fish oil, protein powder, herbal extracts, and stimulant-containing pre-workouts — and for athletes subject to drug testing. For straightforward vitamins from large UK pharmacies, a non-certified product from a reputable brand is often comparable. Use certification as one signal among several.
I am an athlete — which certification matters most for me?: For UK competitive athletes, Informed Sport is the most widely recognised standard and has the broadest UK brand coverage. NSF Certified for Sport is equally trusted and is the standard most often referenced by US sports leagues. Either is a strong signal. Whichever you choose, always verify the specific batch on the certifying body's database — strict liability rules apply in most tested sports.
Is a more expensive certified product better than a cheaper one?: Not necessarily. Price reflects brand positioning, packaging, formulation choices, and certification fees, not just quality. A cheaper certified product from a contract manufacturer can carry the same testing rigour as a premium-priced equivalent. Comparing dose-for-dose pricing is more useful than comparing bottle prices.
Are these certifications recognised in the UK?: Yes. The Informed family (Sport, Choice, Protein) is UK-run and referenced in UK Anti-Doping (UKAD) athlete guidance. NSF Certified for Sport, USP Verified, IFOS, and IGEN are all internationally recognised and accepted by UK retailers, sports bodies, and consumers. None of them are themselves UK regulators — UK supplement safety is regulated by the FSA and DHSC — but the certifications operate independently of and complement that regulatory baseline.

Using Certwell

Why does my search return no results?: Search matches against product name, brand, and category. If a term is too narrow (a specific flavour or pack size, for example) it may not match anything. Try the brand on its own, or browse by category from the homepage. The catalog is also not exhaustive — see how it works for the limits of coverage.
Why is product X not in the catalog?: Coverage is broadest for sports supplements, fish oil, and common vitamins. Niche or non-certified categories are intentionally narrower. Some products are also temporarily hidden because their retailer URLs no longer resolve and we have not yet found a replacement listing. If you think a product belongs and is missing, send a note via the contact form.
Can I filter by both category and certification at the same time?: Yes. Combine a category filter with a certification filter to narrow results — for example, fish oil products with IFOS certification, or sports nutrition products with Informed Sport. The URL updates as you filter, so a filtered view can be bookmarked or shared.
Why are there fewer retailers listed than I expected?: Listings are marked active when the destination URL still resolves to the product. If a retailer has delisted the product or changed its URL structure, the listing is hidden until a fresh URL is found. The result is a catalog that prefers fewer accurate listings over more stale ones.
Can I suggest a product to add?: Yes. Email contact@certwell.co.uk with the product name and a link to its listing on the certifying body's database. Suggestions are reviewed periodically and added once the certification has been verified at the source.

Trust and money

How is the data kept up to date?: Certification links are reviewed periodically and the catalog is rebuilt from source files on every update. The freshness of any individual link is recorded against it, but listings can still lag the certifying body's own database between refreshes. For high-stakes use, always verify directly on the issuing body's site. See how it works for full detail on the build pipeline.
How do affiliate links work, and does this affect which products are shown?: Some retailer links are affiliate links. Certwell may earn a small commission if you buy through them, at no extra cost to you. Affiliate relationships do not influence which products appear in the catalog or how they are ranked. Retailer ordering on a product page is based on popularity signals (primarily customer review counts collected from the retailers), not on commission rate.
Does Certwell receive payment from certification bodies or supplement brands?: No. Certwell has no commercial relationship with any of the five certification bodies and does not accept payment from supplement brands for inclusion, ranking, or promotion in the catalog. The only commercial relationships are with retailer affiliate networks.
How do you decide which retailers to list?: Retailers are selected on the basis of stocking certified supplements relevant to the catalog, shipping to the UK, and being established enough to provide reliable order fulfilment and returns. Affiliate eligibility is not a selection criterion — Certwell lists retailers it has no commercial relationship with on the same footing as affiliate partners.

About the certifications

Does no certification mean the product is unsafe?

No. Absence of certification means the product has not been independently verified by NSF, USP, the Informed family (Sport, Choice, Protein), IFOS, or IGEN. Many supplements without these certifications are perfectly fine. Certification adds assurance — it is not proof of safety, nor is it a requirement for a good product.

Which certifications does Certwell cover?

Five third-party schemes: NSF Certified for Sport, USP Verified, Informed Sport, IFOS (fish oil), and IGEN (non-GMO). Each subpage explains what is tested, how to verify a certificate, and where the scheme matters most.

What is the difference between NSF Certified for Sport and Informed Sport?

Both are batch-level testing programmes for substances banned in competitive sport. NSF Certified for Sport is run in the US and is the certification most often referenced by major US sports leagues. Informed Sport is run by LGC in the UK and has the deepest coverage of UK and European brands. For UK athletes, Informed Sport tends to be more practical because more of the products on UK shelves carry it; for US-recognised competitions, NSF tends to be the expected standard. Either is a strong signal.

What's the difference between Informed Sport, Informed Choice, and Informed Protein?

All three are run by LGC in the UK. Informed Sport tests every batch against the WADA banned-substance list — it is the relevant tier for athletes competing in a tested sport. Informed Choice tests a sample of products each month rather than every batch — same banned-substance scope, looser cadence. Informed Protein verifies that the protein content on the label is accurate and includes banned-substance screening — it targets the protein category specifically. For competition, look for Informed Sport. For routine quality assurance, Informed Choice is enough. For protein products, Informed Protein adds independent confirmation of the protein claim.

Is "tested in a GMP facility" the same as third-party certified?

No. Good Manufacturing Practice (GMP) is a baseline requirement for any supplement made for sale in the UK or US. It governs cleanliness, record-keeping, and process control at the factory — it does not check that what is on the label matches what is in the bottle, and it does not screen for banned substances or contaminants. Third-party certifications go further by independently testing the finished product against a defined standard.

Do these certifications mean the supplement actually works?

No. None of the schemes assess clinical efficacy. They confirm identity (the right ingredient), potency (at the stated dose), purity (free from contaminants and, in some cases, banned substances), and — for USP — dissolution. Whether a given supplement produces a measurable effect is a separate question that certification cannot answer.

Why might a certified product lose its certification?

Certification is not permanent. A brand can stop paying for ongoing testing, fail a re-audit, change a formulation, or move production to a non-audited facility. Certifying bodies remove the listing in those cases. This is one reason verifying the specific product and batch on the body’s database matters more than relying on the logo on the packaging.

Choosing a supplement

Should I always pick a certified product over a non-certified one?

Not automatically. Certification is most valuable in categories with documented quality problems — fish oil, protein powder, herbal extracts, and stimulant-containing pre-workouts — and for athletes subject to drug testing. For straightforward vitamins from large UK pharmacies, a non-certified product from a reputable brand is often comparable. Use certification as one signal among several.

I am an athlete — which certification matters most for me?

For UK competitive athletes, Informed Sport is the most widely recognised standard and has the broadest UK brand coverage. NSF Certified for Sport is equally trusted and is the standard most often referenced by US sports leagues. Either is a strong signal. Whichever you choose, always verify the specific batch on the certifying body's database — strict liability rules apply in most tested sports.

Is a more expensive certified product better than a cheaper one?

Not necessarily. Price reflects brand positioning, packaging, formulation choices, and certification fees, not just quality. A cheaper certified product from a contract manufacturer can carry the same testing rigour as a premium-priced equivalent. Comparing dose-for-dose pricing is more useful than comparing bottle prices.

Are these certifications recognised in the UK?

Yes. The Informed family (Sport, Choice, Protein) is UK-run and referenced in UK Anti-Doping (UKAD) athlete guidance. NSF Certified for Sport, USP Verified, IFOS, and IGEN are all internationally recognised and accepted by UK retailers, sports bodies, and consumers. None of them are themselves UK regulators — UK supplement safety is regulated by the FSA and DHSC — but the certifications operate independently of and complement that regulatory baseline.

Using Certwell

Why does my search return no results?

Search matches against product name, brand, and category. If a term is too narrow (a specific flavour or pack size, for example) it may not match anything. Try the brand on its own, or browse by category from the homepage. The catalog is also not exhaustive — see how it works for the limits of coverage.

Why is product X not in the catalog?

Coverage is broadest for sports supplements, fish oil, and common vitamins. Niche or non-certified categories are intentionally narrower. Some products are also temporarily hidden because their retailer URLs no longer resolve and we have not yet found a replacement listing. If you think a product belongs and is missing, send a note via the contact form.

Can I filter by both category and certification at the same time?

Yes. Combine a category filter with a certification filter to narrow results — for example, fish oil products with IFOS certification, or sports nutrition products with Informed Sport. The URL updates as you filter, so a filtered view can be bookmarked or shared.

Why are there fewer retailers listed than I expected?

Listings are marked active when the destination URL still resolves to the product. If a retailer has delisted the product or changed its URL structure, the listing is hidden until a fresh URL is found. The result is a catalog that prefers fewer accurate listings over more stale ones.

Can I suggest a product to add?

Yes. Email contact@certwell.co.uk with the product name and a link to its listing on the certifying body's database. Suggestions are reviewed periodically and added once the certification has been verified at the source.

Trust and money

How is the data kept up to date?

Certification links are reviewed periodically and the catalog is rebuilt from source files on every update. The freshness of any individual link is recorded against it, but listings can still lag the certifying body's own database between refreshes. For high-stakes use, always verify directly on the issuing body's site. See how it works for full detail on the build pipeline.

How do affiliate links work, and does this affect which products are shown?

Some retailer links are affiliate links. Certwell may earn a small commission if you buy through them, at no extra cost to you. Affiliate relationships do not influence which products appear in the catalog or how they are ranked. Retailer ordering on a product page is based on popularity signals (primarily customer review counts collected from the retailers), not on commission rate.

Does Certwell receive payment from certification bodies or supplement brands?

No. Certwell has no commercial relationship with any of the five certification bodies and does not accept payment from supplement brands for inclusion, ranking, or promotion in the catalog. The only commercial relationships are with retailer affiliate networks.

How do you decide which retailers to list?

Retailers are selected on the basis of stocking certified supplements relevant to the catalog, shipping to the UK, and being established enough to provide reliable order fulfilment and returns. Affiliate eligibility is not a selection criterion — Certwell lists retailers it has no commercial relationship with on the same footing as affiliate partners.