In this article, read about:
How stability testing determines a health, beauty, and wellness product's shelf life
When an expiration date is required, by subcategory
How date and lot data drive retailer acceptance
On a typical package, shelf life seems like the simplest thing: A date, printed small, easy to skim past. But that single number is the output of three separate disciplines, which most brands manage in three different departments.
An expiration date gets determined through stability testing, expressed on the label or left off depending entirely on a product's subcategory, and then enforced by retailers the moment a shipment hits the dock.
The trouble starts when a brand treats these as one problem, or assumes the rules that apply to one product apply across the whole catalog. An OTC drug, a face cream, and a supplement can sit side by side on the same shelf and follow three different sets of rules for whether that date is even required. Miss the rule on one end and you carry regulatory exposure. Miss the data on the other and you get rejected shipments, chargebacks, and write-offs on stock that was fine when it left the building.
This piece examines all three links: what stability testing actually measures, when a date has to go on the label, and what happens to that date once it becomes supply-chain data your trading partners check on receipt.
The Lab: Stability Testing
Before a date can go on a label or into a shipment, someone has to prove its efficacy. That proof comes from stability testing, which measures whether a product maintains its quality after time passes and conditions change.
Stability testing measures four properties:
Identity: Has time caused the active ingredient to change into something else?
Strength: Is the active ingredient still present at the labeled potency, or has it degraded?
Quality: Has the product changed in ways you can see or measure, like color shift, separation, clumping, or microbial growth?
Safety: Have any chemical compounds formed or broken down in a way that could harm the person using it?
A product holds its shelf life only as long as all four stay within spec. The expiration date is the point where the testing can no longer promise they do.
There are two common ways to perform stability testing.
Real-time studies, also called long-term studies, store the product under the conditions it will actually live in and test it at intervals across its expected life. This results in the definitive answer regarding expiration, but the testing takes as long as the shelf life itself. You cannot confirm a two-year date in under two years.
Accelerated studies solve the timing problem by stressing the product on purpose, holding it at elevated temperature and humidity to speed up the chemical reactions that cause degradation. That gives an early, supportable estimate a brand can act on now, which the real-time data then confirms or corrects as it comes in.
Most stability programs run both at once: accelerated studies to support launch and real-time studies to verify shelf-life over time.
The output is the part brands tend to misread. Stability testing does not hand back a generic number for a category. It produces a shelf-life duration tied to a specific formulation, specific packaging, and specific storage conditions. Change the bottle, change the closure, reformulate, or store it warmer than tested, and the date no longer applies.
Brands who outsource manufacturing frequently assume their contract manufacturer ran that testing and owns those records, and sometimes that is true. When a retailer, auditor, or recall investigation asks what backs the date, a brand should be able to point to the underlying stability study on file. That documentation is what turns the printed number from a claim into a defensible one.
The Label: Determining the Subcategory
Here is where brands with a mixed catalog get caught. Two products can look identical on the shelf, sit in the same store, ship through the same door, and still follow completely different rules about whether a date has to appear at all. Classification, not chemistry, is what decides what the label owes the customer.
Here are the three subcategories that brands most often deal with:
OTC drugs: For over-the-counter drug products, expiration dating is generally required, and the date has to be backed by stability data. The number is not optional and is a regulated claim that a study has to support.
Cosmetics: For most cosmetics, there is generally no federal requirement to print an expiration or shelf-life date. That absence is where brands relax too early. Period-after-opening guidance, "best by" conventions, and individual retailer expectations can still apply, and a product that is technically compliant with no date can still get turned away by a buyer who wants one. No legal requirement does not mean no expectation.
Supplements: Dietary supplements sit in between. Dating is generally not mandated the way it is for OTC drugs, so in practice it tends to be a manufacturer and quality-team decision shaped by retailer expectation rather than a blanket federal rule. But the moment a brand chooses to print a date, that date should be supported by data.
Note: The descriptions above are general orientation, not legal or regulatory advice. Dating requirements vary by product, by the claims a product makes, and by jurisdiction, and they change over time. Before you set dating policy for a specific product, route the specifics to qualified regulatory counsel or the appropriate internal team rather than treating any summary, including this one, as the final word.
The Supply Chain: Retailer Enforcement
Up to this point, the date has been a lab result and a labeling decision. The moment the product ships, the date becomes operational data that other companies act on. A retailer's receiving system does not care how carefully the stability study was run, but rather cares what date is on the carton, what date is in the file, and whether the two agree.
The first thing brands run into is minimum remaining shelf life. Most retailers will not accept a product just because it has not yet expired. Instead, they require a minimum percentage of its shelf life to be still remaining on the day it arrives, often expressed as a rule like "at least 75 percent of stated shelf life left on receipt." A product with a valid, unexpired date can still be rejected at the dock for arriving too close to that date.
This means that the expiration or best-by date and the lot code have to travel accurately through the advance ship notice and the item data, and they have to match what is physically printed on the carton. When the ASN says one lot and the pallet holds another, or the date in the item record does not line up with the date on the package, the shipment fails verification.
Accurate date and lot data are also what makes rotation and recall work. First-expired-first-out and first-in-first-out only function when every unit's date and lot are known and trustworthy, both in the warehouse and in the data moving ahead of the shipment. The same is true for recalls: When a specific lot has to come off shelves fast, clean lot data is what lets a brand and a retailer isolate exactly what is affected instead of pulling everything and eating the difference.
The Risks of Disconnected Shelf-Life Data
The three links share one number but rarely share one owner. When different groups work in isolation, the failures surface downstream, at a receiving dock or in a deduction. Three failure modes account for most of it:
If the lab is skipped: The date goes on the product without a study behind it, borrowed from a similar item or an industry rule of thumb. For OTC drugs, that is direct regulatory exposure, since the date is a claim a study is required to support. For everything else, it is quality risk: a number nobody can defend if a retailer, an auditor, or a recall asks what backs it.
If you assume one subcategory's rules apply to the whole catalog: A brand who dates everything the way they date their OTC line ends up mis-dating across a mixed catalog. Some products carry a date they were never required to make and may not be able to defend. Others are missing a date they were required to carry. The stability work may have been fine; the classification behind the labeling decision was not.
If the data doesn't carry through accurately between systems: The date on the physical product is correct, but the ASN or item data carries a wrong date, a mismatched lot, or nothing at all. The result shows up as receipts rejected for failing verification, chargebacks for non-compliant data, and write-offs on stock that gets returned or ages out because it couldn't be received or rotated in time.
A Practical Shelf-Life Checklist for Brands
Shelf life is manageable once you treat it as three linked jobs instead of one number. Work the chain in order, and confirm each link before you rely on the next:
Establish a supported date for every product. Run or source stability data for each product, tied to its actual packaging and storage conditions. Don't inherit a number from a similar item or a category rule of thumb, and if a contract manufacturer ran the testing, get the study and the records in hand rather than assuming they exist.
Date each product by its own subcategory. Apply the dating rule that fits how the product is classified, not one blanket rule across the catalog. Confirm which items are required to carry a date, which are not, and which sit in between, and route anything uncertain to regulatory or the appropriate internal team before it goes to label.
Carry the date and lot data through to your trading partners. Make sure the expiration or best-by date and the lot code travel accurately through your ASNs and item data, and that both match what is physically printed on the carton. The digital record and the physical product have to tell the same story, because the receiving dock reads both.
Build rotation and recall on top of clean data. Use that accurate date and lot data to drive first-expired-first-out rotation and to isolate specific lots fast when a recall hits. Clean data is what makes both precise; bad data turns rotation into guesswork and a targeted recall into a blanket one.
Run top to bottom, the checklist is also a diagnostic: if a shipment gets rejected or a date can't be defended, the failure traces back to whichever link was skipped. Fix it at the source, where it's cheap, instead of at the dock, where it isn't.
Keep Your Date and Lot Data Accurate with SPS Assortment
Keeping expiration dates, best-by dates, and lot details accurate and consistent everywhere they travel is exactly the problem SPS Assortment solves. SPS Assortment helps ensure the item data sent to each retailer is complete, standardized, and aligned with that retailer’s requirements.
That means the date and lot data in your item records matches what you determined in the lab and printed on the label, checked for errors before it ever reaches a receiving dock. Connect with SPS to keep every trading partner working from the same accurate product record and stop losing shipments to data that doesn't line up.