How to choose a supplement manufacturer: the questions to ask
By British VitaTech, published , reviewed on
How to choose a supplement manufacturer comes down to evidence you can check: certificates whose scope names your format, every batch tested by accredited laboratories, and a written agreement that the formula and its data belong to your brand. Ask every candidate the same questions, check the answers against public directories and test reports, and audit the site before you sign.
At a glance
- Check each certificate in the issuer's online directory: certification covers the product range, operations and site in its scope (BSI, 2021).
- As of October 2026, an FDA registration number "does not in any way convey FDA's approval or endorsement" (21 CFR 1.242), and the 2026 renewal window closes on 31 December (21 CFR 1.230).
- BRCGS grades run from AA to D, and every certificated site has at least one unannounced audit every 3 years (BRCGS, 2022).
- US rules require an identity test on each dietary ingredient and reserve samples held 1 year past the shelf life date (21 CFR 111.75; 21 CFR 111.83).
Certificates: what each one proves and how to check it
A GMP certified supplement manufacturer in the UK or abroad should name the scheme, the certifier and the formats in scope. Rules are stated as of October 2026.
| Credential | What it proves | How to check |
|---|---|---|
| ISO 9001 | A quality management system to ISO's criteria, for any sector (ISO, 2026); ISO 22000 covers food safety management (ISO, 2018) | The issuer's directory; IAF CertSearch, a database of accredited certificates (ISO, 2025); UKAS CertCheck (UKAS, 2026) |
| HACCP | An audit of the HACCP-based procedures every GB food manufacturer must run (Regulation (EC) No 852/2004, Article 5) | The issuer's directory and scope |
| Food GMP | Hygiene and prerequisite programmes; BSI's GMP module covers 22 areas, including approved suppliers, allergen management, traceability and recall (BSI, 2021). Not the medicines GMP that MHRA certifies after inspection (MHRA, 2024) | The scope must name your format |
| BRCGS Food Safety | Issue 9, a GFSI-recognised standard (GFSI, 2026), graded, with unannounced audits (BRCGS, 2022) | The BRCGS Directory's public search of certificated sites (BRCGS, 2026) |
| FDA food facility registration | A registration US law requires of facilities making food for US consumption, supplements included, renewed every two years (21 CFR 1.225; 21 U.S.C. 321(ff); 21 CFR 1.230). Not an approval: FDA issues no certificate of registration and does not recognise private ones (FDA, 2024a) | Ask for the number in confidence: FDA's list is exempt from disclosure (21 U.S.C. 350d) |
| 21 CFR 111 | Compliance with the US supplement GMP rule, which covers anyone who makes, packs, labels or holds supplements, imports included (21 CFR 111.1). FDA does not approve supplements before sale (FDA, 2026) | FDA's inspection classifications, which are not a full list (FDA, 2024b); third-party audit reports |
Open each certificate in the issuer's directory, match the holder and address to the making site, check the dates, and read the scope word for word: "packing and distribution of food supplements" covers neither formulation nor manufacture.
Worked example: 1 major (not against a fundamental requirement's intent) and 12 minor non-conformities earn BRCGS grade C (C+ if unannounced) and a 6-month audit cycle; AA allows up to 5 minor and no major (BRCGS, 2022).
Formula and data ownership: what to get in writing
As of October 2026, UK law treats a formula as a trade secret if it is secret, has commercial value because it is secret, and has been subject to "reasonable steps under the circumstances" to keep it secret (Trade Secrets (Enforcement, etc.) Regulations 2018, regulation 2). An NDA sets out how you share information in confidence (IPO, 2015). Get in writing:
- Ownership of the formula: ingredients, grades, supplier codes, amounts per serving and overages.
- Ownership of the specification, process records, stability data and test reports, with copies.
- A mutual NDA, with access to your formula restricted.
- Exit terms: the documents handed over, any notice period or exclusivity, and any buy-out fee.
Our guide to white label, private label and custom formulation compares the routes.
Development: paid R&D or free samples
A stock sample shows a manufacturer's existing formula. A bespoke formula needs development: regulatory review, bench rounds, sensory panels, a pilot batch on production equipment and stability in the final pack. Ask what each stage delivers, how many sample rounds are included, and what happens if a target is missed.
Testing: every batch, accredited laboratories and certificates of analysis
In a US study of 30 immune-support supplements bought on Amazon, 17 had inaccurate labels: 13 listed ingredients that analysis did not detect, and 9 contained substances not on the label (Crawford and colleagues, 2022). As of October 2026, GB food businesses must ensure their food meets food law and "verify that such requirements are met" (Regulation (EC) No 178/2002, Article 17). Under the US rule (21 CFR 111.75):
- At least one identity test on each dietary ingredient, unless FDA grants an exemption.
- A supplier's certificate of analysis can replace tests on other components once the supplier is qualified, if it shows methods, limits and results.
- Finished batches verified against specification: every batch, or a subset chosen by a sound statistical sampling plan. Ask which.
Cover contaminants too: GB maximum levels for food supplements include 3.0 mg/kg lead and 0.1 mg/kg mercury (Regulation (EC) No 1881/2006, as it applies in GB).
ISO/IEC 17025 accreditation covers the tests on a laboratory's schedule of accreditation, so check that each analysis is listed (UKAS, 2019). On a certificate of analysis, match the batch number, check the method, limit and units, and look for results marked "Not UKAS accredited" (UKAS, 2022).
Stability and shelf life
European Commission guidance, which UK government guidance cites (DHSC, 2017), expects vitamins in food supplements to stay within 20% below and 50% above the declared value throughout shelf life, and minerals within 20% below and 45% above (European Commission, 2012). The US supplement GMP rule does not require an expiry date, but "you should have data to support any such date" (FDA, 2010).
Worked example: under this guidance, 25 µg of vitamin D means 20 µg to 37.5 µg throughout shelf life. With a measured 15% loss, a 10% overage releases at 27.5 µg and ends near 23.4 µg. A US label needs at least 25 µg throughout (21 CFR 101.9(g)(4)): about 18% overage. Ask for studies in the final pack at ICH conditions, borrowed from medicines: 25°C and 60% relative humidity (or 30°C and 65%) long term, and 40°C and 75% for 6 months accelerated (ICH, 2003), confirmed in real time. See stability and shelf life testing.
Regulatory and label support by market, as of October 2026
In GB, the business under whose name a food is marketed, or the importer if that business is based outside the British Islands, is responsible for its food information (Regulation (EU) No 1169/2011, Article 8).
| Market | What to check with your manufacturer |
|---|---|
| Great Britain | Authorised claims from the GB nutrition and health claims register (DHSC, 2026); a claim to treat or prevent disease makes a product a medicine by presentation (MHRA, 2025) |
| Northern Ireland and the EU | EU rules apply in Northern Ireland under the Windsor Framework, with claims from the EU Register (nibusinessinfo.co.uk, 2026); EU countries may request notification of placing on the market (European Commission, 2026) |
| United States | A "Supplement Facts" panel (21 CFR 101.36); structure/function claims carry FDA's disclaimer and are notified within 30 days of first marketing (21 CFR 101.93); a new dietary ingredient is notified at least 75 days before marketing unless already in the food supply, chemically unaltered (21 CFR 190.6) |
See our guide to supplement label requirements.
Traceability, mock recalls and retained samples
As of October 2026, GB food businesses must identify their suppliers and the businesses they supply (Regulation (EC) No 178/2002, Article 18), and withdraw food that fails food safety requirements, informing the authorities (Regulation (EC) No 178/2002, Article 19). FSA and FSS guidance advises reviewing traceability and the recall plan every year, which could include a mock exercise (FSA and FSS, 2019). Ask for the last mock recall: time taken, lots traced both ways, and a mass balance reconciling material received with product, stock and waste.
The US rule asks for a reserve sample of each lot, held 1 year past the shelf life date (or 2 years from distribution of the last batch without one), with at least twice the quantity needed for all specification tests (21 CFR 111.83). Worked example: a test panel using 30 capsules means at least 60 per reserve sample, kept until month 36 for a 24-month shelf life.
Supplier approval and allergen control
Ask how suppliers are approved before first use and reviewed afterwards, and for the site's matrix of the 14 regulated allergen groups (Regulation (EU) No 1169/2011, Annex II), its cleaning verification and its "may contain" policy. GOV.UK guidance ties precautionary allergen labelling to a cross-contamination risk you cannot control, and rules it out "as a substitute for food hygiene and safety practices" (GOV.UK, 2026).
Insurance, audits and communication
In England, Wales and Scotland, a business that puts its name or trade mark on a product, and so holds itself out as the producer, can be liable for damage caused by a defect (Consumer Protection Act 1987, section 2). Ask for the manufacturer's product liability limit, territory, period, exclusions and certificate of insurance.
Audit the site before you sign: in the US, a firm that sells a supplement made for it under its own label "has an obligation to know what and how manufacturing activities are performed" (FDA, 2010). Then sign a quality agreement: a named contact, a written plan for each stage, notice before any change of material, supplier or process, and who leads a complaint or recall.
Red flags
- A certificate you cannot confirm with the issuer, or a scope without your format.
- A certificate said to come from ISO, which does not certify companies (ISO, 2025).
- A site calling itself ISO 9001 accredited: sites are certified, not accredited (UKAS, 2026).
- Talk of FDA approval, an FDA registration certificate (FDA, 2024a), or US GMP certification with no named auditor.
- Certificates of analysis without methods or limits, or a shelf life without stability data.
- Free development with no written ownership terms.
How to choose a supplement manufacturer: a printable checklist
The questions to ask a supplement manufacturer: print this supplement manufacturer checklist and send the same contract manufacturer questions to every candidate.
Certificates
- Who issued each certificate, and does its scope name my format at the making site?
- For the US: when was your FDA registration last renewed, and what was your last FDA inspection outcome?
Formula and data
- Who owns the formula, specification, stability data and test reports, in writing?
- What do I receive if I move production, and on what notice?
Development
- What does each development stage deliver, and is the pilot batch made on production equipment?
Testing
- Is every batch tested, for what, and by which ISO/IEC 17025 accredited laboratory?
- How do you confirm raw material identity, and can I see a sample certificate of analysis?
Stability and labels
- Which storage conditions and pack does the stability study use, and how is overage set?
- Who checks ingredient status, claims and label wording for each market?
Traceability and recalls
- When was your last mock recall, how long did it take, and did the mass balance reconcile?
- How many retained samples do you keep per batch, and for how long?
Suppliers and allergens
- How are suppliers approved, and how is allergen cross-contact controlled and verified?
Insurance
- What product liability limit, territory and exclusions apply, and can we see the certificate?
Audits and communication
- Can we audit or visit the site before we sign, and who is our named contact?
- Will you give notice before changing a material, supplier or process, and sign a quality agreement?
How we approach it at British VitaTech
British VitaTech is ISO 9001, HACCP and GMP certified by BSI, and FDA registered. Both certificates are in BSI's online directory: ISO 9001 under FS 822806, and HACCP and GMP under HACCP 827076, whose scope names capsules, gummies, pouches and liquids, so those formats are GMP certified. Tablets, powders and sachets are made in the same facility. BRCGS implementation under way, certification expected in early 2027. See quality and accreditations, FDA registered facility, BRCGS certification and company facts.
Every batch is tested by accredited partner laboratories (ISO/IEC 17025), and batch testing is part of every order. Gummies get an active content assay on every batch as standard. Quality control releases each batch against its specification, with a certificate of analysis: see testing and batch release. We keep three retained samples per batch for shelf life plus one year, run a full mock recall with mass balance, and hold £5m product liability insurance with worldwide cover.
Development runs as a paid R&D stage: brief and feasibility, formulation, bench samples, sensory evaluation, regulatory and claims review per market, a pilot batch on production equipment, stability in the final pack at ICH conditions with partner laboratories, then release and handover. Your formula is yours: you receive the formula, specifications, stability data and test reports. See formula ownership, moving manufacturer, our UK facility and our project stories.
Sources
- BSI (2021). HACCP & GMP Certification Criteria (BSI Group, September 2021): scope statement, and Module 3, Good Manufacturing Practices (GMP), headings 3.1 to 3.22.
- Cornell Legal Information Institute (2026). 21 CFR 1.242: What does assignment of a registration number mean?
- Cornell Legal Information Institute (2026). 21 CFR 1.230: When must you register or submit a registration renewal? (renewal every other year, 1 October to 31 December of each even-numbered year).
- BRCGS (2022). Global Standard Food Safety Issue 9 (August 2022), Part III: audit protocol, section 2 (at least one unannounced audit every 3 years), section 2.3 (non-conformities; no certificate for a major against the statement of intent of a fundamental clause) and Table 2 (grades and audit frequency); Issue 9 text as published by BRCGS in January 2025 for the Issue 10 initial consultation.
- eCFR (2026). 21 CFR 111.75: What must you do to determine whether specifications are met? (up to date as of 23 October 2026).
- Cornell Legal Information Institute (2026). 21 CFR 111.83: What are the requirements for reserve samples?
- ISO (2026). ISO 9001 Quality management systems (web page, accessed October 2026).
- ISO (2018). ISO 22000:2018 Food safety management systems, published June 2018 (ISO web page 'ISO 22000 Food safety management', accessed October 2026).
- ISO (2025). How to verify an accredited certification (ISO Help Centre, 9 December 2025).
- UKAS (2026). Accreditation vs certification (web page, modified 23 July 2026).
- legislation.gov.uk (2004). Regulation (EC) No 852/2004 on the hygiene of foodstuffs, Article 5, HACCP principles (GB version; no outstanding effects shown in October 2026).
- Medicines and Healthcare products Regulatory Agency (MHRA) (2024). Good manufacturing practice and good distribution practice (GOV.UK guidance, last updated 13 May 2024).
- Global Food Safety Initiative (GFSI) (2026). Certification Programme Owners: 'BRCGS Global Standard for Food Safety issue 9' recognised against Benchmarking Requirements version 2020 (page modified 11 August 2026).
- BRCGS (2026). About the BRCGS Directory: public certificate search for currently certificated sites; certificated sites can choose to be removed from the public listing.
- Cornell Legal Information Institute (2026). 21 CFR 1.225: Who must register under this subpart?
- Cornell Legal Information Institute (2026). 21 U.S.C. 321(ff): definition of dietary supplement, deemed to be a food.
- US Food and Drug Administration (FDA) (2024a). Questions Regarding Whether Food Facilities are Required to Pay Registration Fees and Private Businesses Claiming or Suggesting an Affiliation with FDA (content current as of 5 March 2024).
- Cornell Legal Information Institute (2026). 21 U.S.C. 350d: registration of food facilities, paragraphs (a)(3) and (a)(5).
- eCFR (2026). 21 CFR 111.1: Who is subject to this part? (up to date as of 22 October 2026).
- US Food and Drug Administration (FDA) (2026). Questions and Answers on Dietary Supplements (content current as of 27 August 2026).
- US Food and Drug Administration (FDA) (2024b). Inspection Classification Database (content current as of 13 September 2024).
- legislation.gov.uk (2018). The Trade Secrets (Enforcement, etc.) Regulations 2018, SI 2018/597, regulation 2, definition of trade secret (no outstanding effects shown in October 2026; regulation 1(2): extends to England and Wales, Scotland and Northern Ireland).
- Intellectual Property Office (IPO) (2015). Non-disclosure agreements (GOV.UK guidance, published 12 March 2015, with example one-way and mutual NDAs).
- Crawford C, Avula B, Lindsey AT and colleagues (2022). Analysis of Select Dietary Supplement Products Marketed to Support or Boost the Immune System. JAMA Network Open 5(8), e2226040.
- legislation.gov.uk (2002). Regulation (EC) No 178/2002 (General Food Law), Article 17, responsibilities of food business operators (UK version; no outstanding effects shown in October 2026).
- legislation.gov.uk (2006). Regulation (EC) No 1881/2006, Annex, maximum levels for contaminants: entries 3.1.22 (lead, 3.0 mg/kg) and 3.3.3 (mercury, 0.1 mg/kg) for food supplements (GB version; no outstanding effects shown in October 2026).
- UKAS (2019). Choosing a UKAS Accredited Supplier (leaflet B33, November 2019; web page accessed October 2026).
- UKAS (2022). GEN 6: Reference to accreditation and multilateral recognition signatory status, Edition 2 (December 2022), section 6.3.
- Department of Health and Social Care (DHSC) (2017). Technical guidance on nutrition labelling (GOV.UK, last updated 3 March 2017), chapter 7, 'Tolerances', which refers to the European Commission's guidance on tolerances.
- European Commission (2012). Guidance document for competent authorities for the control of compliance with EU legislation on tolerances for nutrient values declared on a label (December 2012), sections 2.2 and 2.3 and Table 2.
- US Food and Drug Administration (FDA) (2010). Small Entity Compliance Guide: Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements (December 2010), section III.3 (question 2, Example 3) and section IX (IX.2.3 and IX.3.3).
- Cornell Legal Information Institute (2026). 21 CFR 101.9(g)(3)(i) and (g)(4)(i): a Class I (added) nutrient must be formulated to be at least equal to the value declared on the label; applied to dietary supplements by 21 CFR 101.36(f)(1).
- ICH (2003). Q1A(R2) Stability testing of new drug substances and products, section 2.2.7.1 (EMA copy, Step 5; listed by EMA as the current effective version in October 2026).
- legislation.gov.uk (2011). Regulation (EU) No 1169/2011 on the provision of food information to consumers, Article 8(1) (GB version, as amended 27 May 2021 by SI 2021/632; no outstanding effects shown in October 2026).
- Department of Health and Social Care (DHSC) (2026). Great Britain nutrition and health claims (NHC) register (GOV.UK, last updated 19 May 2026; applies to England, Scotland and Wales).
- Medicines and Healthcare products Regulatory Agency (MHRA) (2025). Guidance Note 8: A guide to what is a medicinal product (published September 2025), sections 4 and 10.
- nibusinessinfo.co.uk (2026). Nutrition labelling and claims about nutritional and health content (Northern Ireland business guidance, developed with the Food Standards Agency; accessed October 2026).
- European Commission (2026). Food supplements: Directive 2002/46/EC, including optional national notification under Article 10 (web page, accessed October 2026).
- Cornell Legal Information Institute (2026). 21 CFR 101.36: Nutrition labeling of dietary supplements.
- Cornell Legal Information Institute (2026). 21 CFR 101.93: Certain types of statements for dietary supplements.
- Cornell Legal Information Institute (2026). 21 CFR 190.6: Requirement for premarket notification.
- legislation.gov.uk (2002). Regulation (EC) No 178/2002 (General Food Law), Article 18, traceability (UK version; no outstanding effects shown in October 2026).
- legislation.gov.uk (2002). Regulation (EC) No 178/2002 (General Food Law), Article 19, withdrawal and recall of food (UK version; no outstanding effects shown in October 2026).
- Food Standards Agency and Food Standards Scotland (FSA and FSS) (2019). Guidance on Food Traceability, Withdrawals and Recalls within the UK Food Industry (March 2019), pages 10 and 36.
- legislation.gov.uk (2011). Regulation (EU) No 1169/2011, Annex II, substances or products causing allergies or intolerances (GB version; 14 items).
- GOV.UK (2026). Food labelling and packaging: precautionary allergen labelling (PAL) (GOV.UK guide; page metadata updated 5 October 2026, public update date 4 December 2014).
- legislation.gov.uk (1987). Consumer Protection Act 1987, section 2, liability for defective products (extent England, Wales and Scotland).