Enzyme Activity
What Does SPU Mean in Serrapeptase?
SPU measures functional enzyme activity rather than weight. What the unit describes, how the assay determines it, and why per-capsule and per-serving figures cannot be compared directly.
The iSerra Journal
Evidence, explained clearly.
Plain-language guides to enzyme activity, finished-product testing, delayed-release performance, and the questions worth asking before choosing a serrapeptase product.
Featured
What Does SPU Mean in Serrapeptase?
SPU measures functional enzyme activity rather than weight. What the unit describes, how the assay determines it, and why per-capsule and per-serving figures cannot be compared directly.
Read the guide →The library
6 articlesEnzyme Activity
Declared Potency vs. Measured Enzyme Activity
A declared specification is what a product is formulated to. A measured result is what an assay found in one lot. Why the two are constantly conflated, with Lot 6798 as a labeled example.
Testing & Verification
The 14 Tests Behind an iSerra Production Lot
Identity and potency, heavy metals, microbial limits, and USP disintegration — what each of the four categories confirms, where the documentation lives, and what a per-lot panel was never designed to tell you.
Buying Guides
What to Compare Before Choosing a Serrapeptase Product
Eight questions to ask of any label — activity basis, declared vs. measured, lot-specific documentation, laboratory accreditation, delivery format, finished-product testing, other ingredients, and what you can verify before buying.
Delivery Science
Delayed-Release Disintegration: What USP <2040> Actually Tests
A physical test on a finished capsule, run in a gastric-phase medium and then an intestinal-phase medium. What a two-phase result establishes — and why it cannot be converted into a conclusion about the body.
Testing & Verification
How to Read a Serrapeptase Certificate of Analysis
Five questions that determine whether a COA is evidence about your bottle: whose document it is, which lot it names, what was tested, whether potency is declared or measured, and whether it covers the finished product. Plus the red flags.
A different kind of supplement content
Traceable
Claims are separated by evidence type and tied to the document that supports them.
Specific
Declared specifications and measured lot results are never treated as the same thing.
Useful
Every article ends with practical questions a reader can apply to any label.