Subject: Tesamorelin Degradation Baseline vs Month 1 | Room Temp vs Refrigerated | Peptide Crafters
From: Derek from Peptide Price <[email-masked]>
To: [email-masked]
Date: Thu, 19 Mar 2026 19:01:33 +0000
List-Id: <derekpruski.substack.com>

View this post on the web at https://derekpruski.substack.com/p/tesamorelin-degradation-baseline

Earlier today I shared a sneak peek at the first month of Peptide Crafters’ Tesamorelin degradation study. Shortly after they got back to me with the baseline COA, so now we can do a proper comparison. Here’s the full breakdown.
Most people in this space know they should store their peptides properly but have never actually seen data showing what happens when you don’t. This study starts to answer that question with real numbers from a controlled comparison.
Study Setup
Same batch (PC-G2-TS10), three samples tested by Janoshik on February 16, 2026 to establish a starting point — think of this as the “before” snapshot. Two months of additional testing still to come.
Here’s how the timeline worked before that baseline test even happened: the samples were produced, spent about a week in dry storage at the facility, then shipped to Janoshik which took another week. So by the time Janoshik tested them for baseline, they had already been sitting in lyophilized (freeze-dried powder) form for roughly two weeks. Once baseline was confirmed, each sample was assigned to its storage condition and the clock started.
Storage conditions:
Sample B — room temperature at 68–70°F
Sample C — frozen at -39°F
Sample A — held for later timepoints in the study
One thing worth flagging for context: most researchers store peptides in a standard household fridge running around 35–40°F. The “refrigerated” condition here is actually a freezer at -39°F, which is colder than what most people are working with at home. The real-world difference between room temperature and a standard fridge may be a bit smaller than what this study shows — but the direction of the results will almost certainly be the same.
Baseline — February 16, 2026
Sample A — 10.76 mg | Purity: 99.894%
Sample B — 11.46 mg | Purity: 99.876%
Sample C — 10.90 mg | Purity: 99.861%
All three samples started in essentially the same place — purity right around 99.86–99.89%. That’s a clean, consistent starting point across the board.
Month 1 Results — March 16, 2026
Sample B (Room Temperature — 68–70°F)
Baseline: 11.46 mg | 99.876%
Month 1: 10.81 mg | 98.184%
Content loss: 0.65 mg (-5.67%)
Purity loss: 1.692 percentage points
Sample C (Frozen — -39°F)
Baseline: 10.90 mg | 99.861%
Month 1: 10.59 mg | 99.732%
Content loss: 0.31 mg (-2.84%)
Purity loss: 0.129 percentage points
What The Numbers Actually Mean
Think of purity as how much of what’s in the vial is actually the peptide you want versus broken down byproducts. The higher the number the better.
After one month in the freezer, Sample C dropped only 0.129 percentage points in purity and lost 0.31 mg of content. That’s essentially nothing — the peptide is nearly identical to where it started.
Sample B stored at room temperature is a different story. It lost 0.65 mg of content — more than twice what the frozen sample lost — and dropped 1.692 percentage points in purity. That’s over 13 times more purity degradation than the frozen sample over the exact same period from the exact same batch.
In plain terms: if your Tesamorelin sits at room temperature for a month, it is measurably less potent and less pure than when you started. Cold storage largely prevents that.
The narrative that refrigerating or freezing Tesamorelin causes degradation has never had real data behind it. One month in, the frozen sample is sitting at 99.732% purity with minimal content loss. That talking point should be put to rest — and two more months of data will make it even more definitive.
Where The Study Goes From Here
This is month one of three. The real value here is the full progression — two more months of data will show whether the degradation rate stays steady, speeds up, or levels off. Peptide degradation doesn’t always move in a straight line, which is exactly why tracking it over multiple months matters.
If the gap between room temperature and frozen continues to widen through months two and three, the cumulative difference is going to be substantial. I’ll share the data as each round comes in.
Big shoutout to Peptide Crafters for running this properly and letting me share it with the community in real time.

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