Microbial & Preservative Test
We test your product for microbial contamination in our own lab, alongside an accelerated stability test, so you know it's clean as made and holds up on the shelf.
Formulation & Development
200+ founders have built with us.
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Where our clients sell
Sounds familiar?
01
You switched to a 'gentler' preservative and don't know if it's enough.
02
A retailer or distributor wants microbial test results.
03
A batch came back with mould or an off smell.
04
You don't know if the product will still be clean a year from now.
We run cosmetic microbial testing in our own lab, alongside accelerated stability testing.
Every time a customer dips a finger into a jar, they add bacteria. A microbial test checks that the batch is clean to begin with, and our accelerated stability test shows how the product holds up over the equivalent of a year on the shelf.
You get results you can act on and a straight answer about whether the formula is ready. If a retailer asks for a preservative efficacy test, also called a challenge test, we’ll tell you when it’s worth sending the product out for one.
A good fit if
✓ Brands launching water-based products
✓ Founders who changed preservatives or reformulated
✓ Teams that need results for a retailer or market entry
Not the right fit if
✕ Anhydrous products with no water phase, in most cases
✕ Formulas still changing every week
✕ Shelf-life testing only (see Stability & Compatibility Test)
What you walk away with
01
Microbial results
Whether the product meets microbial limits as made.
02
Stability read
How the product holds up under accelerated conditions, the equivalent of about a year on the shelf.
03
Ready or not
A clear answer on whether the results meet the criteria used.
04
Next steps
What to change if it isn't ready, and whether a challenge test is worth running.
How it works
Intake
You send samples and we confirm which tests apply.
Test
The lab runs the microbial test.
Read
We review the results against the criteria.
Report
You get the results and what they mean for launch.
Timeline
4 months
Revisions
None
Meetings
2 meetings
Ready to start?
Pick a time that suits you and we'll confirm by email.
Start with a free discovery call
Every Microbial & Preservative Test project starts with a short free call, so we can understand what you need and scope it properly.
Book a free discovery call
Questions, answered.
What is a preservative efficacy test?
A preservative efficacy test, also called a challenge test, deliberately adds bacteria, yeast and mould to a product and measures how quickly the preservative system brings their numbers down over about four weeks. We don't run it in our lab. If you need one, we'll tell you when it's worth sending the product out.
What's the difference between microbial limits and challenge testing?
Microbial limits testing checks how many microorganisms are already in the product. Challenge testing checks how well the product fights off new contamination during use. Our lab runs the first one.
Do all cosmetics need a preservative?
Most water-based products do, because water lets microorganisms grow. Anhydrous products like oils and balms, or products in airless or single-use packaging, may need less or none, but that still has to be confirmed by testing.
What happens if the microbial test fails?
It means there are more microorganisms in the product than the limits allow. The fix is usually the preservative, the pH, the packaging or how the batch was made, and then you test again.
Is a preservative-free product safer?
Not necessarily. A product without an effective preservative can grow bacteria, yeast or mould once it's opened, which is a bigger risk to skin than a well-chosen preservative.
When should I test?
When the formula is final, ideally in its final packaging, and before production. Any change to the formula or preservative usually means testing again.
Which methods do you use?
We run a basic microbial test, and our accelerated stability test covers the equivalent of a year on the shelf. If you want a longer shelf life on top of that, you can send the product to an outside lab for a preservative efficacy test (PET).
How long does it take?
About 8 weeks.
Know it's clean before it ships.
Microbial & Preservative Test