Accelerated and real-time stability, packaging compatibility and preservative efficacy for cosmetics and personal care products
A stability study shows whether your lotion, serum, cleanser or balm still looks, smells and performs the way it should after months in its package, and through heat, cold and shipping. We store your product at set conditions, pull it on a schedule, and check it for separation, changes in color, odor, pH and viscosity, weight loss, and problems with the package itself. The results give you the data to set a shelf life, choose a package, and support safety substantiation for your formula.
12-week accelerated study from $750. In your packaging from $1,150.
$750
Storage: 40 C and 45 C, with a room-temperature and refrigerated control
Pulls: start, 4 weeks, 8 weeks and 12 weeks
Includes: three freeze-thaw cycles and a centrifuge test at the start
Samples: 8 units or about 400 g
$1,150
Everything in card 1, done in your final package, plus checks for leaks, weight loss, discoloration, deformation and pump or closure function
Samples: 12 filled units in your final package, plus one empty package
$850
Storage: room temperature, with pulls at 3, 6, 12, 24 and 36 months
Best started at the same time as an accelerated study so the real-time data can confirm the projected shelf life
Every package checks appearance, color, odor, pH, viscosity, specific gravity and phase separation at each pull. Microbial counts, preservative content and active ingredient assays can be added and are quoted with your study.
Physical and chemical stability: whether an emulsion stays together, whether a gel thins out, whether color or fragrance drifts, and whether pH moves far enough to affect skin feel, preservative performance or an active ingredient.
Microbial stability: whether the preservative system still holds up after the product has aged. This is where stability and preservative efficacy testing meet.
Package compatibility: whether the product and the package get along over time. Some formulas pull fragrance or water through plastic, some stain or soften the package, and some pumps stop working when a product thickens.
Real time at room temperature is the baseline. Accelerated storage at 40 C and 45 C speeds up the changes that would happen on a shelf, and a refrigerated control at 4 to 5 C gives a reference sample that barely changes.
Freeze-thaw cycling moves the product between about -10 C and room temperature. Three cycles is the standard screen and five is a harder test for products that will ship in winter. Emulsions that are going to break usually show it here first.
Centrifuge testing spins warmed product to force separation. It is a quick early warning for emulsions and suspensions, and we do it at the start of every study.
Light exposure is available for products in clear or translucent packaging.
Other conditions such as 30 C / 65% RH, 50 C or custom cycling can be set up on request.
A common rule of thumb is that 12 weeks at 40 C stands in for about a year at room temperature, and 12 weeks at 45 C for about two years. It is a useful estimate, not a guarantee. Heat doesn’t age every ingredient the same way, and some products (natural oils, certain actives, products with no added preservative) behave differently at high temperature than they do on a shelf. For that reason we recommend starting a real-time study alongside the accelerated one. The accelerated data gets you to launch, and the real-time data confirms the date.
A preservative that passes on a fresh batch can lose strength as the product ages, especially if pH drifts or a preservative binds to the package. Testing preservative efficacy at the start and again at the end of the accelerated study shows whether your product is still protected at the end of its shelf life. Ask for it with your quote, or see microbial challenge and preservative efficacy testing.
The Modernization of Cosmetics Regulation Act requires brands to have adequate substantiation that a product is safe. It doesn’t spell out stability testing, but stability and preservative data are part of showing that a product stays safe for as long as it is on a shelf and in use. US cosmetics don’t need an expiration date or a period-after-opening symbol, but sunscreens and other OTC drug products need an expiration date backed by stability data, and products sold in the EU need a date or a PAO symbol. If your product makes a drug claim, see pharmaceutical stability testing.
The study design follows the general approach in ISO/TR 18811 for cosmetic stability.
Tell us about the product, the package, and where it will be sold.
Accelerated, accelerated in your packaging, real time, or a combination, plus any add-ons.
Filled units from a real batch in your final package, and an empty package if you are testing compatibility.
We test the starting values, do the freeze-thaw and centrifuge tests, and put samples into storage.
Samples are pulled and checked on schedule, and you get a report at each pull.
Every result in one summary with the shelf life the data supports, from the laboratory director.
Not by name. It requires that you can substantiate your product is safe, and stability and preservative data are a normal part of that.
The accelerated study takes 12 weeks of storage plus a week or two for testing and the final report. Real-time studies run as long as the shelf life you want to support, up to 36 months.
They give you a good estimate to launch on. We recommend confirming it with a real-time study started at the same time.
If you have picked your package, yes. A lot of stability failures are really packaging failures: leaks, weight loss, stained or softened bottles, or pumps that stop working.
For the standard accelerated study, 8 units or about 400 g. For packaging compatibility, 12 filled units in the final package plus one empty package. We confirm exact numbers with your quote.
Yes. Testing at the start and again at the end of the accelerated study shows whether the preservative system still works on aged product.
Separation, color and odor changes, pH and viscosity drift, specific gravity, weight loss, and any change in the package. Microbial counts, preservative content and active assays can be added.
Period after opening, the open-jar symbol showing how many months a product is good for once it’s opened. It is required for many products sold in the EU and isn’t required in the US.
No. Products with drug claims are OTC drugs and need ICH-style stability data and an expiration date. See pharmaceutical stability testing.
Yes. We can test in glass first and repeat in your package once you’ve chosen it.
Tell us about your product and we’ll send back a quote. You can also email [email protected].
