20 Questions to Ask Supplement Manufacturers and Suppliers Before You Sign

Most sourcing problems in supplements are not surprises. They show up later as a missing COA, a label that doesn't match the bottle, or a reorder that takes three times longer than the first one. The fix is doing the homework before the first purchase order. Below are the questions to ask supplement manufacturers and distributors before you sign anything, grouped the way an experienced buyer actually works through them.

You won't need every answer in writing on day one. But a supplier that is slow, vague, or annoyed by these questions is telling you something about how the relationship will go once there's a problem.

Quality system questions to ask supplement manufacturers

Start with the foundation. In the U.S., anyone who manufactures, packages, labels, or holds dietary supplements is subject to the current Good Manufacturing Practice rule in 21 CFR Part 111. Certifications on top of that are useful signals, but they don't replace it.

1. Are you operating under 21 CFR 111 cGMP, and when was your last FDA inspection? Ask whether any Form 483 observations were issued and how they were closed out.
2. Is your facility registered with FDA as a food facility? Registration is required and renewed every two years. It is not an approval, so be wary of anyone who calls it one.
3. What third-party certifications do you hold? NSF/ANSI 455-2 is a GMP audit standard specific to dietary supplements. Ask for the certificate and check the scope and expiration date.
4. Who performs your testing, and is the lab ISO/IEC 17025 accredited? In-house testing is fine for some checks, but you want to know which tests are done where.
5. How do you qualify ingredient suppliers? Under Part 111, identity of each dietary ingredient must be verified by at least one appropriate test. A supplier's COA alone is not enough for identity.
6. What does your complaint and adverse event process look like? Brands have serious adverse event reporting obligations, and your supplier needs a way to feed information back to you.

Documentation and testing

This is where you learn how a supplier behaves when you ask for proof. A good partner hands these over without a fight. If you want a refresher on what to look for, our guide on how to read a certificate of analysis walks through a COA line by line.

1. Can I get a lot-specific COA for every lot I receive? Generic or "typical" COAs don't tell you what's in your product.
2. What does the finished product COA test for? Look for potency or identity of key actives, microbiology, and heavy metals at minimum.
3. How are lot numbers and expiration dates applied, and at what level? You want coding on both the unit and the case so recalls and rotation are traceable.
4. What stability data supports the expiration date? Real-time data is best. Accelerated data is common for newer products, but ask how the date was set.
5. Can you provide a Supplement Facts panel and full ingredient statement before I buy? You need these to build listings and check retailer requirements.
6. What allergen controls are in place, and what other allergens are handled in the facility? Major food allergen declaration rules apply to supplements, and sesame is now on the list.

A supplier that is slow or vague with documents before the sale will not get faster after it.

Commercial terms: MOQs, pricing, and lead times

Once quality checks out, get clear on the money and the calendar. These answers drive your cash flow more than the unit price does.

1. What is the minimum order quantity for stock product versus private label versus custom? MOQs vary a lot by format, and our breakdown of supplement MOQs covers why.
2. How is pricing tiered by volume? Ask for an itemized quote so you can see how product, packaging, and labeling each move as quantity goes up.
3. What is the realistic lead time for stock product, and for custom work? Get both the typical range and what happens when raw materials are short.
4. What payment terms are available after the first order? Many suppliers start new accounts on prepayment or deposit and open terms after a track record.
5. How much notice do you give on price changes? Ingredient costs move, and you need time to adjust retail pricing or promotions.

Logistics and fulfillment

Plenty of good product arrives damaged, late, or in a format a retailer's DC won't accept. Ask about the physical side early.

1. How is product packed, and can you meet retailer routing guides or Amazon prep requirements? Case packs, pallet configuration, and labeling all matter.
2. What carriers and ship methods do you use, and who handles freight claims? Know where responsibility shifts from supplier to buyer.
3. Can you hold inventory or ship on a release schedule? Some buyers prefer blanket orders released over time rather than one large delivery.

A simple supplement supplier checklist

If you're comparing several vendors, it helps to score them side by side. Here's a short supplement supplier checklist you can adapt.

How to vet a supplement supplier beyond the questionnaire

Answers are a starting point. Knowing how to vet a supplement supplier means checking what you can independently. Search FDA's warning letter database for the company name. Verify any certification on the certifier's public listing rather than trusting a PDF. Order a small quantity or samples and compare the physical product to the paperwork: does the lot number on the bottle match the COA, and does the label match the Supplement Facts panel you were sent?

References help too, though a supplier can't always share customer names. If they can't, ask how long their longest-running accounts have been with them and how they handled their last major quality issue. A specific, honest answer about a past problem is often more reassuring than a claim that nothing has ever gone wrong.

Finally, pay attention to how questions about regulation are handled. A supplier shouldn't be offering to put disease claims on your label or telling you that FDA "approves" supplements. Structure/function claims are allowed with the required disclaimer and a notification to FDA, but responsibility for substantiating those claims sits with the brand. A supplier that takes that seriously is one that will keep you out of trouble.

Putting it to work

Send the questions in writing before your first call, and ask the supplier to answer them in writing too. It saves time, gives you something to compare across vendors, and becomes a useful record if a dispute ever comes up. Then use the call to dig into anything that seemed thin.

RV Pharma is a wholesale nutraceutical distributor that supplies retailers, pharmacies, distributors, and e-commerce sellers across North America. We're happy to answer every question on this list, and our Buyer Resources page is a good place to start, including a redacted sample COA and details on lot coding and testing.