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Glossary

What is a lot number on a supplement?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

A lot number is the code of letters, numbers or symbols that ties a container to the batch it came from. Under FDA manufacturing rules, it must let the company trace that batch's full history of making, packaging, labeling and holding. Printing it on the container is one way to meet the tracing rule, not the only one.1,2

Key facts

  • FDA's definition: any distinctive group of letters, numbers or symbols from which the complete history of a batch or lot can be determined.1
  • A batch is a uniform quantity made under one manufacturing record in one cycle; a lot is a batch or an identified part of one.1
  • Makers must assign a batch, lot or control number to each lot of packaged and labeled supplement.3
  • They must be able to trace each packaged and labeled product's history through distribution.4
  • A reserve sample of each lot, identified by its number, is kept 1 year past the shelf life date or 2 years after the last batch is distributed.2

What the number connects

The batch production record must include the batch's own number and the number given to each lot packaged and labeled from it. The same record lists the equipment used, each component and its weight, and the yield, so the number on a container leads back to all of it.2,5

FDA uses the idea for nutrition labeling too: when it samples products to check a label, containers that share a common container code, or failing that a day's production, count as one lot.6

Is it always printed on the bottle?

Not necessarily. FDA's compliance guide says putting a batch, lot or control number on the packaged product is one way to meet the tracing requirement, but companies have flexibility. A firm that makes one product for a few customers might trace it by distribution dates or distinct containers instead.2

When FDA explains how to report a problem with a product, it asks for codes from the container, such as the lot number, expiration date and UPC code, along with photos of the label and lot code.7

When the number is useful to you

  • Reporting a problem to the company or to FDA: the number points to the batch.7,8
  • Asking the company a question about your container: the number says which production lot it came from.1
  • When the maker follows up: its batch records and reserve samples are filed under that number.2,5

Questions people ask

Is a lot number the same as a batch number?

Close. FDA's definition covers batch numbers, lot numbers and control numbers alike. A lot can be a whole batch or an identified part of one, so one batch may be packaged as several lots.1,3

Where is the lot number on a supplement?

FDA rules do not set a place, and do not strictly require one to be printed. Look for a code marked lot, batch or similar on the label, the container or the box.2

What should I do with the lot number if I have a reaction?

Stop taking the product and contact your health care provider. Keep the container, or take photos of the label and lot code, and include the lot number when you report to the company or to FDA's Safety Reporting Portal.7,8,9

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Sources

  1. Code of Federal Regulations, Title 21, Section 111.3: What definitions apply to this part (current good manufacturing practice for dietary supplements). Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
  2. U.S. Food and Drug Administration. Small Entity Compliance Guide: Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements. Content current as of September 20, 2018. Opened 2026-10-07.
  3. Code of Federal Regulations, Title 21, Section 111.415: What requirements apply to filling, assembling, packaging, labeling, and related operations. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
  4. Code of Federal Regulations, Title 21, Section 111.410: What requirements apply to packaging and labels. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
  5. Code of Federal Regulations, Title 21, Section 111.260: What must the batch record include. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
  6. Code of Federal Regulations, Title 21, Section 101.9: Nutrition labeling of food. Legal Information Institute, Cornell Law School (eCFR text). Opened 2026-10-07.
  7. U.S. Food and Drug Administration. Food Allergies. Content current as of March 11, 2026. Opened 2026-10-07.
  8. U.S. Food and Drug Administration. Questions and Answers on Dietary Supplements. Content current as of August 27, 2026. Opened 2026-10-07.
  9. National Center for Complementary and Integrative Health. Using Dietary Supplements Wisely. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.