Supplement Testing Requirements

Confirms that each incoming dietary ingredient is what the supplier says it is. Required by 21 CFR 111.75(a)(1) for dietary-ingredient components (FDA can exempt a manufacturer only via the petition process at 111.75(a)(1)(ii); other components may rely on a supplier COA with periodic confirmation under 111.75(a)(2)). Without identity testing, you could put the wrong ingredient in your product and never know until someone gets hurt. Methods include HPTLC, HPLC, and DNA barcoding for botanicals.

Verifies that the finished product contains the amounts listed on the Supplement Facts panel. If your label says 500mg of Vitamin C per serving, potency testing confirms it. Finished-batch verification is required under 21 CFR 111.75(c), for every batch or for a subset of batches chosen by a sound statistical sampling plan, and 111.75(c)(1) and (c)(3) permit testing a selected subset of specifications when the manufacturer documents why those checks verify the batch. Common methods: HPLC, UV-Vis spectrophotometry.

Screens for unwanted substances: pesticides, solvents, allergens, and adulterants. Purity and composition specifications must be established (21 CFR 111.70(e)) and confirmed for finished batches under 111.75(c), with the same documented-subset provision.

Tests for microbial contamination: total aerobic count, yeast and mold, and organisms such as E. coli, Salmonella, and Staphylococcus aureus. Part 111 requires limits on contamination that may adulterate the product (111.70(e)), and 111.75(c) lets finished-batch verification cover every batch or a subset of batches chosen by a sound statistical sampling plan. Inventory Ready recommends testing every batch. Contamination can occur during production even with clean raw materials.

Screens for lead, mercury, cadmium, and arsenic. Part 111 does not name a heavy-metals panel, but it does require you to set specifications with limits on contaminants that may adulterate the product, so this is not an area federal law leaves alone. California's Proposition 65 creates practical requirements on top of that, and some retailers require testing: Amazon's dietary supplement policy requires heavy metal and microbial contaminant testing for supplements intended for bodybuilding, joint health, sexual enhancement, sports nutrition, and weight management. Methods: ICP-MS, ICP-OES.

Determines shelf life by testing product at intervals under controlled conditions. The common reference is ICH Q1A(R2), a stability guidance whose scope is registration applications for new drug substances and products, not dietary supplements: accelerated testing at 40°C/75% RH for 6 months gives a preliminary shelf life estimate, and long-term testing at 25°C/60% RH (or 30°C/65% RH) continues through the full shelf life being proposed. FDA's supplement labeling guide says an expiration date is not required, but a firm that puts one on the label must be able to support it with valid data showing it is not false or misleading.