Ordered Reta with a different Molecular Formula than PubMed - Thoughts?

[86Vision]

Hi,

Sorry for the long post.

First off, I want to mention I'm new to all of this, but I did spend a good amount of time trying to research and understand the basics before beginning my journey with Reta. Before I found this forum, I ordered from a vendor that was found and listed as "Great" on Finnrick. This was before I knew that this site isn't really trusted and that everyone recommends using Janoishik. Lesson learned. And yes, I now know that vendors overcharge. I plan on sourcing from a vendor here and hopefully getting in group buy testing in the future.

With that being said, I noticed the Reta I ordered has the molecular formula listed on the website as: C223H343F3N46O70 and Pubchem has it listed as C221H342N46O68. I didn't catch this before I ordered.

So I guess this is aimed at the peptide veterans in the community. Is this fairly normal or do you suggest I toss it and look for a vendor that offers the base formula? I don't plan on filtering. I don't have the most sterile environment for that. The vendor does have a COA on the website and I did reach out to them via email to ask if the COA is for the Reta I received and they claimed it is.

I'm just curios what people think about this and if its anything to concerned about? Would you use it for research without filtering?

I used ChatGPT (deep research) and gave it the molecular formula provided by the vendor website along with the COA and told it to compare against the molecular formula for Reta on PubChem and why they differ. ChatGPT seems to think its pretty standard. Here's a small portion of the research provided by ChatGPT:

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🧪 Verification of Retatrutide Authenticity and Analysis of COA Data​

🔬 Molecular Formula Comparison (COA vs. PubChem Reference)​

The molecular formula provided in the COA for the Retatrutide sample was:
C₂₂₃H₃₄₃F₃N₄₆O₇₀

This doesn't match the standard pharmaceutical-grade formula listed in PubChem and other literature sources:
C₂₂₁H₃₄₂N₄₆O₆₈ (no fluorine)

That base formula corresponds to a peptide molecular weight of approximately 4731.3 g/mol (average mass). The COA’s version, however, includes:

• 
  
• +2 carbon
• 
  
• +1 hydrogen
• 
  
• +2 oxygen
• 
  
• +3 fluorine

Those additions bring the average molecular weight to ~4845 g/mol — a difference of about 114 Da.
This discrepancy lines up almost exactly with the addition of C₂H₁F₃O₂, which is the formula for trifluoroacetate (TFA). In other words, the COA sample appears to be the TFA salt form of Retatrutide.

Here’s a breakdown:

Source	Molecular Formula	Approx. Molecular Weight
PubChem / Literature	C₂₂₁H₃₄₂N₄₆O₆₈ (no F)	~4731.3 g/mol
COA Sample	C₂₂₃H₃₄₃F₃N₄₆O₇₀ (with F₃)	~4845.4 g/mol

The COA also lists a monoisotopic mass of 4728.52 Da, which matches exactly with the known monoisotopic mass of C₂₂₁H₃₄₂N₄₆O₆₈: 4728.47 Da. This further confirms that the core peptide structure is consistent with literature values.

Legitimate Reasons for Formula Discrepancies​

Differences in listed formulas like this are actually very common in research peptides, and here’s why

• 
  
• Trifluoroacetate (TFA) salt form: Peptides are often purified using trifluoroacetic acid, and the resulting powder retains this as a counter-ion. That adds F atoms and bumps the molecular formula and mass — but doesn’t alter the actual peptide.
• 
  
• Other salt forms: Some versions might use acetate, chloride, or sodium salts instead. These change the formula too, but the active peptide remains the same.
• 
  
• Water of hydration or excipients: Lyophilized peptides often contain trace water or bulking agents (like mannitol), which may or may not be included in reported formulas or weights.
• 
  
• Monoisotopic vs. Average Mass: Databases like PubChem often report average mass, while COAs will report monoisotopic mass (the most precise value used for identity confirmation via mass spectrometry).

The COA even notes that “injectable peptides may contain salts and sugars to aid in solubility and act as pH buffers,” which are not considered impurities and may not be detected via UV.

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Bottom Line​

The peptide in question is chemically consistent with known Retatrutide, and the added fluorine atoms in the COA formula are explained by the presence of TFA as a counter-ion.

So while the formula looks different from PubChem, this is not a red flag — it’s a normal and legitimate difference between the base compound and its salted, purified form.

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[ZippityDooDah]

So I guess this is aimed at the peptide veterans in the community. Is this fairly normal or do you suggest I toss it and look for a vendor that offers the base formula? I don't plan on filtering. I don't have the most sterile environment for that. The vendor does have a COA on the website and I did reach out to them via email to ask if the COA is for the Reta I received and they claimed it is.

I'm just curios what people think about this and if its anything to concerned about? Would you use it for research without filtering?

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While the potential danger of TFA in humans is still a largely unsettled question, personally I wouldn't be inclined to take the risk when more common counter-ion forms are available. GLP-1's in general are readily available in the sodium salt form and while acetates aren't uncommon the anecdotal evidence suggests higher incidences of ISR's, cloudiness and other reconstitution issues. Honestly I'm not sure about reta, whether sodium or acetate is more common, but TFA is definitely not common. Anyone providing peptides with TFA as the counter-ion would seem to be doing little if any purification and post-processing and that alone is reason enough for me to avoid. The one thing I can guarantee is nobody is providing freebase GLP-1's other than the guys with the fancy patents.