Vetting Questions for Supplement Manufacturers and 3PLs

Last reviewed: July 7, 2026 | Next review: October 5, 2026

By Greg Huang, founder since 2009 in the dietary supplement and nutrition industry

These questions come from years of real sourcing conversations with manufacturers and fulfillment providers. They are organized the way vetting actually runs: what you can learn before first contact, what to ask once you are talking, and what to have ready when the questions turn back on you.

Inventory Ready is independent. We help you ask better questions; the decision stays yours.

Dietary supplement manufacturers must comply with 21 CFR Part 111 (Current Good Manufacturing Practice for dietary supplements). This includes requirements for personnel, facilities, equipment, production, laboratory operations, and record-keeping.

The short answer

Vetting a manufacturer or 3PL runs in three passes. First, a public-record screen you complete before any contact: registration, FDA compliance records, reviews, and history. Second, structured questions on capability, commercial terms, and accountability, asked the same way of every candidate. Third, your own prepared answers to the questions they will ask you, given in ranges, never as exact figures. The question bank below covers all three.

The vetting posture

Good vetting is structured skepticism. Companies present their best face, claims sometimes stretch, and circumstances change, so every important claim gets checked against a surface the company does not control. That posture is not hostility; it pairs with genuine respect.

The relationship habits matter as much as the checks. Recognize the other side's expertise and ask for their input rather than dictating terms. Signal that you are building a long-term relationship, not shopping a one-off order. Keep confidences both ways: never share one partner's information with another, and expect the same discretion in return. And respond to everyone, including the candidates you decline; the company you reject this year may be the right fit in two years.

Before you reach out: the research screen

Every question below can be answered without contacting the company. Run the screen first and spend your outreach time only on candidates that pass.

Question	Where to look
Is the business registered and in good standing?	State business registry
How does the company describe its cGMP posture, and does anything contradict it?	Company website, FDA public records
Does the company or its leadership appear in FDA compliance records?	FDA public databases (inspections, warning letters)
What do employees say about operations and turnover?	Employer-review sites
What do the brands they serve and industry peers say?	Search, review platforms, trade forums
How long has the company operated, and who owns it?	Company website, registry, stock listings
Does the website look current and professionally maintained?	Company website
Where are the facilities relative to your logistics?	Company website, search

On the compliance rows: dietary supplement manufacturing falls under current good manufacturing practice rules in 21 CFR Part 111, and FDA publishes searchable inspection and enforcement records. Treat what you find as conversation input, not an automatic verdict; how a manufacturer explains a record tells you as much as the record itself.

Questions to ask a manufacturer

Capability

Which dosage forms and sizes do you run in-house, and where are your capability limits?
What lab testing is part of your standard quality process, and what is billed as an extra?
Can you stamp expiration dates on units, and what do you need from us to support the date?
Do you run pilot batches before full production, and on what cost basis?
What happens when demand grows: where does your capacity top out?

Commercial

What are your MOQ tiers, and is there flexibility for a first run?
Do you offer staggered ordering: a bulk-price order shipped in smaller lots over time?
Does this quote depend on ordering other products, or does it stand alone?
What is the deposit and balance schedule, and which payment methods do you accept?
What is your current lead time from purchase order to shipment, minimum and maximum, and how do you communicate delays?

Accountability

Do you review labels before printing, and do you accept accountability for errors your team approved?
What documentation ships with every lot: a certificate of analysis, a finished-product spec sheet, packing lists?
Are your purchase-order terms fair to both sides, and are you open to a quality agreement?
Can you provide references from brands you serve that we may contact?

The full request-for-quotation version of these questions, with the product brief and comparison structure, lives in the manufacturer RFQ template.

Questions to ask a 3PL

The fulfillment version of vetting runs on its own checklist, but the core questions are: What does the complete fee schedule look like, line by line? Does the warehouse system track expiration dates and lots? Which sales channels integrate natively? How often do you cycle count, and when are the blackout periods? Who is our named contact and how fast do you respond? Can we run a trial shipment first?

The complete version, including the operational profile a 3PL needs from you, is in the 3PL RFQ template and the 3PL vetting guide.

Questions they will ask you

Serious manufacturers and 3PLs vet you back. Preparing these answers before outreach is the single cheapest way to speed up quotes and be treated as a serious brand.

Where do you sell? List your channels: your own store, marketplaces, wholesale. Manufacturers and 3PLs price and plan differently for each.
What are your volumes? Have order-size and frequency estimates ready, in ranges. Exact figures are not required and are not wise to share at this stage.
Domestic or international? Know whether you need export documentation before the question comes up.
Branded ingredients or substitutes? Decide in advance whether ingredient brands are required or generic equivalents are acceptable, and ask for both quotes when you are open to either. The branded vs generic ingredients guide covers the trade-off.
What is your target pricing? Give a range, never a single number. A range keeps negotiating room while telling the manufacturer whether you are in a realistic band.
Why are you looking for a new manufacturer? Keep it positive: growth, capacity, a second source. Never talk down your current partner; it signals how you may talk about them next.
What is your timeline? Share a realistic window and whether it is fixed or flexible.

Recording what you learn

Vetting produces value only if the answers survive. Keep one decision record per sourcing round: every candidate, every answer, and every gap. When information is missing, write the gap down rather than skipping the row, so it becomes a follow-up instead of a surprise. Move commitments to email, and normalize everything into one comparison sheet before you decide.

Put the questions to work

Browse independently assessed manufacturers, labs, and 3PLs in the directory, or start with the manufacturer readiness quiz to see where your own preparation stands.

Frequently Asked Questions

How do I vet a supplement manufacturer before contacting them?

Run a public-record screen first. Check business registration with the state registry, look for the company in FDA public compliance databases, read employee reviews on employer-review sites alongside reviews from brands they serve, confirm years in business, and check whether the facility and website look current. A candidate that fails this screen never needs an email; a candidate that passes gets your structured questions.

What questions will a manufacturer ask me?

Expect questions about where you sell, your order size and frequency, whether you need branded ingredients or accept substitutes, your target pricing, why you are looking for a new manufacturer, and your timeline. Preparing these answers before outreach speeds up every conversation and signals that you run a serious brand.

What should I say when asked why I am switching manufacturers?

Keep it positive and forward-looking, for example business growth or adding a second source. Never criticize your current partner to a prospective one. The supplement manufacturing world is smaller than it looks, and a brand owner who talks down one partner signals to the next partner how they may be treated later.

Should I share target pricing with a manufacturer?

Share a range, not a number. A range keeps the conversation moving and lets the manufacturer tell you whether you are in a realistic band, without anchoring the quote to a single figure. The same discipline applies to volumes: estimates in ranges are enough at the vetting stage.

How do I check a manufacturer's FDA compliance history?

FDA publishes searchable public records, including inspection outcomes and warning letters, on fda.gov. Search the company name and its facility locations. What you find is a conversation input, not an automatic verdict: ask the supplier about anything you see and judge how they respond.

Greg Huang, founder since 2009 in the dietary supplement and nutrition industry

Founder of Inventory Ready. Previously founded and operated multiple consumer brands in the dietary supplement and nutrition industry since summer 2009.

Concepts Covered

COA (Certificate of Analysis)Quality Agreement MOQ (Minimum Order Quantity)Lead Time

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