A batch code is the short string of letters and numbers printed on a supplement package that identifies the specific production run it came from. It is not the SKU, not the barcode, and not the expiry date. It is the number a factory uses when it needs to find out what went into that bottle, on which line, on which day, and who signed off on it.
If you are holding a bottle, look at the shoulder of the label, the bottom of the bottle, the crimp of a softgel, or the sealed edge of a stick pack. On most supplements the code sits within a few centimetres of the best-by date, because the two are stamped in the same operation.
The short answer
A batch code ties one physical unit back to one batch production record. That record lists the lot numbers of every raw material, the equipment used, the fill weights, the in-process checks, and the test results that released the batch. When something goes wrong — a customer complaint, a failed stability pull, a heavy metals result that lands late — the batch code is how a manufacturer finds every other unit from the same run instead of guessing.
Without it, a recall becomes a brand-wide recall. With it, a recall can be limited to one run of a few thousand bottles.
Batch code, lot number, expiry date: what is the difference
People use "batch code" and "lot number" interchangeably, and in most factories they are the same thing. The distinction matters mainly in documents.
| Term | What it identifies | Example |
|---|---|---|
| Batch code / lot number | One production run | `L2405A17` |
| Best-by / expiry date | The date the stability data supports | `05/2027` |
| SKU / item code | The product as sold | `ZS-MAG-GUM-60` |
| Barcode (UPC/EAN) | The retail listing | `8 12345 67890 3` |
A single SKU will have many batch codes over its life. A single batch code should never cover two different formulas, two different pack sizes, or two different fill dates. If a supplier tells you one batch code covers both a 60-count and a 120-count bottle, ask how the batch record is structured, because those are usually separate runs.
In the EU, Regulation (EU) No 1169/2011 Article 18 requires a lot mark on food supplements, preceded by the letter "L" unless the mark is clearly distinguishable from other label information. That is why you often see `L` at the start of European codes. The US has no equivalent label rule, but 21 CFR Part 111 requires batch production records that make the same traceability possible.
Where the code actually is
Manufacturers put the code where the packaging equipment can print it without a second pass. In practice that means:
- Bottles: shoulder of the label, side panel near the best-by, or the base. Sometimes ink-jetted on the bottom rim.
- Softgels: on the printed foil of the blister, or on the carton flap.
- Gummies: usually the bottom of the bottle, occasionally the neck.
- Stick packs and sachets: crimped into the seal, so it survives the fill.
- Tubs of powder: bottom or side, sometimes under the label.
If you cannot find a code, do not assume it is missing. Check the crimp, the fold of the carton, and the area under the cap. On small pilot runs, the code is sometimes printed on a separate label applied by hand, which can fall off in transit.
What the characters usually mean
There is no universal format. Every factory builds a code that suits its own records, and two codes that look similar can mean different things at different suppliers. That said, most codes carry four pieces of information in some order:
- Date — either `YYMMDD`, `YYDDD` (Julian day), or `MMYY`.
- Line or facility — a letter or number for the production line.
- Shift or operator group — sometimes a single letter.
- Sequence — the batch number within that day.
A code like `L2405A17` most likely reads as: lot, 2024, May, line A, seventeenth batch. A code like `24078B` might be 2024, day 78, line B. Only the manufacturer can confirm, and a good supplier will tell you the format in writing when you ask.
Ask for this at the quotation stage. It takes one email, and it saves an argument two years later when a retailer asks you to prove which run a complaint came from.
Why the code matters more than most brands realise
Recalls. If a raw material lot turns out to be contaminated, the factory traces it to every batch that used it. The batch code is the only reliable link between the material and the finished unit.
Certificates of analysis. A COA is issued per batch, not per product. If a buyer asks for the COA for the bottle in their hand, the batch code is how you find the right document. Marketplaces increasingly ask for this during disputes.
Stability and shelf-life claims. When a stability study pulls a batch at 6, 12 and 24 months, the results apply to that batch and the process it was made under. If a later batch changes filler or encapsulation conditions, the old data does not automatically cover it.
Customs and import. Some markets ask for lot-level documentation on import, particularly for products that make structure/function claims. A missing code can hold a shipment at the port.
Complaint handling. "The gummies in this bottle are gritty" is unanswerable without a code. With a code, a factory can pull the retention sample from the same run and check whether the problem is real, isolated, or a formulation issue that will repeat.
What a complete batch record contains
The code is the label on the box. The record inside it is what actually protects you. A GMP factory should be able to produce, for any code you name:
- The master formula and the actual weights used, including overage
- Lot numbers and certificates of analysis for every raw material
- Equipment identification and cleaning records
- In-process checks: fill weight, hardness, disintegration, seam integrity, water activity for gummies
- Environmental monitoring where relevant, especially for probiotics
- Finished-product test results: identity, potency, heavy metals, microbial, and where required, dissolution
- Who reviewed and released the batch, and when
- Retention samples and their storage location
Under 21 CFR Part 111, dietary supplement manufacturers in the US market must keep batch production records and retain them for at least one year past the shelf life of the batch. A supplier who cannot retrieve a record within a day or two for a code you give them is telling you something about how the next recall will go.
How to verify a batch code in one email
Send this to your supplier contact, not to a sales inbox:
Please confirm the batch code format you use, and send the COA and batch production record summary for the last three lots shipped to us. Also confirm how long records are retained and who signs batch release.
A serious OEM answers within two business days and sends documents without a fight. A trader will forward the email to a factory and come back with a PDF that has someone else's logo on it.
Three things to check in the reply:
- Does the COA batch number match the code on the bottle exactly?
- Is the COA issued by the factory or by a third-party lab, and is the lab named?
- Does the release date on the record precede the ship date?
Red flags worth taking seriously
- No code at all. Common with very small runs and repackaged stock. It also means no traceability.
- A sticker placed over the original code. Sometimes legitimate during a relabel, often a sign that two runs were merged.
- The same code on bottles with visibly different colour or texture. Either the batch was blended across runs, or the code is not a real batch code.
- A COA that lists a different batch number than the bottle. Ask for the correct document before you ship anything to a customer.
- A factory that cannot explain its own format. If the code is decorative, the records behind it probably are too.
What this means if you are building a brand
When you place a private label order, the batch code is one of the few things on the label that you do not control and cannot fake. It is also the first thing a serious buyer, a marketplace trust team, or an importer will ask about when something goes wrong.
At our facility in Guangzhou we print a lot code on every unit across our capsule, gummy and softgel lines, and keep the batch record for the full retention period. Standard MOQ is 1,000 units per SKU, and production runs 4 to 6 weeks after artwork approval — long enough that you should know exactly which code will be on the first shipment before you approve the artwork, not after.
If you want to see what a batch record and COA package looks like before you commit to a run, ask us for a sample set with a recent lot. It is a boring document. It is also the difference between a recall that costs you one run and one that costs you the brand.
FAQ
Is a batch code the same as an expiry date?
No. The expiry date tells you when the product stops meeting its label claim. The batch code tells you which production run it came from. They are printed next to each other but serve different purposes.
Can two bottles have the same batch code and different expiry dates?
Not legitimately. The expiry is calculated from the production date of that batch. If the dates differ, ask for the batch record.
Do I need a batch code to sell on Amazon?
Amazon does not require a specific format, but it does ask for lot-level documentation during quality or authenticity disputes. Products without traceable codes are harder to defend.
What if my supplier refuses to share the code format?
That is unusual and worth pushing on. The format itself is not confidential; the records behind it are. A refusal usually means the supplier is a trader without direct access to the factory.
How long should a manufacturer keep batch records?
In the US market, at least one year past the shelf life of the batch under 21 CFR Part 111. Most GMP factories keep them longer, often five years, because customers ask years later.
Can a batch code be reused?
It should never be reused for a different formula or a different fill date. Reuse destroys the entire point of traceability.
