# Mass Balance on a COA: Does It All Add Up to 100%?

_What mass balance on a peptide COA means, and why a gap below 100% is a red flag. Educational only._

Source: https://growthguyscanada.coupons/articles/reading-a-coa-mass-balance.html · Updated: July 10, 2026 · TorontoHealth — educational only, not medical advice.


> **The core idea:** Mass balance asks a simple question — do all the components reported on the COA add up to roughly one hundred percent? A missing chunk is unexplained material.

## What mass balance means

Peptide content, water, salts, and related substances should account for nearly the whole sample. A complete COA lets you see the whole picture, not just one flattering number.

## Why a gap is a red flag

If the numbers stop well short of one hundred percent, something in the vial isn't accounted for. That unexplained portion is exactly what you'd want explained.

## What to ask for

A full report — identity, purity, and the supporting fractions — not a single isolated purity figure.

Related: [purity vs identity](/articles/coa-purity-vs-identity.html) · [how to read a COA](/articles/how-to-read-a-peptide-coa.html).

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Related guides[How to read a peptide COA](/articles/how-to-read-a-peptide-coa.html) · [How to spot a fake testing lab](/articles/how-to-spot-a-fake-testing-lab.html) · [Buying peptides in Canada](/articles/buying-peptides-in-canada.html) · [The Growth Guys discount code](/articles/growth-guys-discount-code.html)

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_General educational information, not claims about any specific company. For research and educational purposes only. Not medical advice. Posts may contain affiliate links — the price you pay does not change._