How I Vet a Dietary Supplement Manufacturer (My 3-Gate Process)
Summary (Key takeaways)
Don’t start with a factory tour—start with a screen. Shortlist by format capability, MOQs, lead times, and rough pricing first.
Use a three-gate process: (1) detailed questionnaire, (2) document review, (3) on-site or virtual audit. Each gate filters fast.
Evaluate both doing (what they say they do) and proving (how they document it). FDA cares about both.
Your product concept drives the bar: claims, allergens, “free-froms,” and date codes change what the co-man must prove.
Build verification into the relationship (testing, audits, KPIs). Trust—but verify.
Who this approach is for (and how to adapt it)
National / fast-growing brands: You’re choosing a partner for multi-year growth. Run the full, gated process.
Brand-new launchers: Your first orders are transactional. You can simplify—but still use the gates to avoid obvious risks.
Step 0 — Pre-screen to a top 3
Before any deep vetting, filter on the basics:
Formats & capabilities (capsules, powders, gummies, liquids; blending, encapsulation, filling; in-house vs. outsourced testing)
MOQs & lead times (be honest about your run size)
Rough pricing (same spec basis when you compare)
Location (local/regional is easier to visit and manage)
If the basics don’t fit, don’t waste time “vetting.”
Gate 1 — The screening questionnaire
Purpose: confirm there’s a real quality system—not just marketing.
What I ask about:
GMP program (21 CFR 111): training, deviations/CAPA, change control
Environmental Monitoring: zones, swab frequency, organisms, actions
Allergen control: segregation, labeling checks, dedicated tools/lines
Food defense & security: access control, CCTV, visitor policies
Supplier qualification: raw-material vetting, approval/denial criteria
Testing philosophy: every-lot vs. skip-lot; component vs. finished-product; third-party labs and accreditation
Stability approach: release overages, date-code rationale, studies
Packaging controls: component approval, line clearance, tamper-evident
Pass criteria: Specific, consistent answers that show mature systems (not “we do as needed”).
Gate 2 — Document request (prove it)
Now we ask for redacted copies. “We have it” isn’t enough.
Request list (redacted is fine):
Finished-product specification (identity, purity, strength, composition + micro/chemical limits)
Sample COA for a similar product (methods, acceptance criteria, lab accreditation, lot traceability)
Key SOPs/Policies: deviations/CAPA, recalls, allergen control, environmental monitoring, sanitation, change control, training
Registrations/Certs: FDA registration, dietary supplement GMP audit reports/cert letters, any retail/customer approvals
Terms & Conditions: payment, label responsibilities, indemnities, retention samples, storage fees, rework rules
What I look for:
Procedures that guide action (not “notify manager” and stop).
Specs that include fit-for-purpose methods and acceptance ranges.
COAs that tie to the spec and show accredited labs.
T&Cs that don’t shove all risk and cost to you.
Gate 3 — Audit & tour (virtual or on-site)
Two lenses: design and discipline.
Design (reducing risk by layout):
Material & people flows, zoning, air handling, allergen segregation
Line clearance and label control (UPC/lot/date, over-label risks)
Storage conditions, pest prevention, tamper-evident features
Discipline (are they living the SOPs?):
Batch records filled in real time; corrections per SOP
Sanitation logs, swab results, corrective actions with root cause
Release documentation that matches COAs/specs
Ingredient receiving: ID tests, status tagging, quarantine controls
Deliverable: an observation report with severity, required corrections, and due dates. How they respond tells you a lot.
Match the co-man to your product
Bring a draft label (yes, before production). Your claims and callouts drive the bar:
“Gluten-free,” “vegan,” “sugar-free,” “non-GMO,” sports-tested? The plant must prove it.
Sensitive populations (e.g., pregnancy, diabetes) require tighter controls.
Date codes? Then we need a stability plan and overages.
Verification plan (trust, but verify)
Bake this into your PO/Master Service Agreement:
Release tests and acceptance criteria (potency, micro, heavy metals, any claim-critical “free-from” tests)
Lab accreditation and method class (e.g., HPLC/ICP-MS)
Retention samples: quantity, storage, access
Ongoing verification: periodic third-party testing, annual audit cadence, CAPA follow-up
Performance KPIs: on-time release, deviation rate, right-first-time lots
If it’s not in the PO, it probably won’t happen.
Quick red flags vs. green lights
Red flags
“We only test when a customer asks.”
No finished-product spec (or potency-only spec).
Vague methods on COAs; non-accredited lab.
Skip-lot micro on high-risk botanicals.
SOPs that are one page and manager-dependent.
Indemnity/T&Cs that push all risk to you.
Green lights
Mature environmental monitoring with trends & CAPA.
Clear allergen zoning and documented line clearance.
Product-specific specs with fit-for-purpose methods.
Every-lot micro for risk-prone inputs; validated ID testing.
Transparent documentation access and prompt corrective action.
Summary
A good manufacturer is more than shiny equipment. Vet for systems, documentation, and behaviors—then align quality expectations in writing. Your label and claims set the bar; your gates and verification keep it there.
Next steps (work with us)
Signature 1-on-1 Consultations — We’ll pressure-test your product concept and label content, map your manufacturer search, and define the specific questions, documents, and PO quality terms to use in your vetting. Clients also get access to our curated manufacturer list (primarily US & some Canada).
SSET: Supplement Startup Essentials Training — Learn which regulations apply to your product, how to build a practical market brief, and how to find and vet co-manufacturers and labs with confidence.