Mixing Two Different Brands (Suppliers) of Retatrutide in One Injection

MTSpace

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Has anyone combined the same peptide from two separate suppliers into a single shot?

I was pulling my normal retatrutide dose from Supplier A, and partway through I realized I only had roughly half the amount I wanted in the syringe. Instead of tossing it, I pulled the rest from Supplier B's retatrutide into that same syringe and injected.

Both suppliers' products have been fine for me in the past, but I've never before put two sources of the same peptide together in one injection.

Roughly three hours have passed now, and nothing seems off, but it made me think:

  • Anyone else tried this?
  • Could there be any theoretical concern with combining the same peptide from different suppliers in one syringe?
  • Would you have thrown out the partial dose, or handled it the way I did?

I'd like to hear real-world stories as well as any reasoning people have.
 
Yep, that's been my routine for roughly the past 6 weeks, today included 🤷 At first I kept the two separate, drawing each into its own syringe, though for the most recent couple I switched to combining them into a single syringe.

Nothing to flag, and nothing especially noteworthy either, aside from the weight loss continuing as I'd anticipate.
 
I don't think there's any danger in drawing your reta dose from two different suppliers' vials. That said, reusing the same syringe was a mistake. A fresh syringe should have been used for the new vial. By going back into it with the same needle, you may have introduced contamination into that vial.
 
Needles cost next to nothing. I always grab a fresh one when I go from one used vial to another, even if they came from the same kit, so I can draw and shoot whatever is left.

Beyond that, every time a needle goes through the rubber stopper it gets blunter. That means when it finally hits your skin it can feel rougher, hurt a bit more, or draw blood.
 
MTSpace said:

Has anyone combined the same peptide from two separate suppliers into a single shot?

I was pulling my normal retatrutide dose from Supplier A, and partway through I realized I only had roughly half the amount I wanted in the syringe. Instead of tossing it, I pulled the rest from Supplier B's retatrutide into that same syringe and injected.

Both suppliers' products have been fine for me in the past, but I've never before put two sources of the same peptide together in one injection.

Roughly three hours have passed now, and nothing seems off, but it made me think:

  • Anyone else tried this?
  • Could there be any theoretical concern with combining the same peptide from different suppliers in one syringe?
  • Would you have thrown out the partial dose, or handled it the way I did?

I'd like to hear real-world stories as well as any reasoning people have.

You should be fine

A lot of folks combine peptides into a single syringe, so as long as you sanitized both vials, drawing from two sources shouldn't cause a problem.

I don't see any reason for concern about the blend itself, provided the mass and purity of each were equal (or nearly so).

Whatever impurity worries exist would still be there on your following dose anyway, so that point doesn't really apply to mixing.

I have pinned 2x 1/2 doses before

If the reason you're considering this is that you have two smaller pens (for example, two 0.5 mg pens rather than a single 1 mg pen) and you want to use them together to hit your prescribed dose, that's generally safe as long as they go into different injection sites (such as opposite sides of the abdomen or different thighs, at least 2 inches apart). That said, firing two autoinjectors at once wastes pens and notably raises your needle exposure, which increases the chance of accidental sticks or improper administration
 
I can't see any issue with that, chances are they come from the same maker.

The sole variation might be the overall dose, since the vials could hold a slightly different quantity of Reta, though not by much.
 
angeliquereta said:

I can't see any issue with that, chances are they come from the same maker.

The sole variation might be the overall dose, since the vials could hold a slightly different quantity of Reta, though not by much.
Before offering advice that could mislead others, take the time to read up and learn a great deal.

Kits produced in different batches may differ substantially. Even when purchasing from a single vendor, you need to know the mass that third-party testing has confirmed for that specific batch.
 
indolent said:

angeliquereta said:

I can't see any issue with that, chances are they come from the same maker.

The sole variation might be the overall dose, since the vials could hold a slightly different quantity of Reta, though not by much.
Before offering advice that could mislead others, take the time to read up and learn a great deal.

Kits produced in different batches may differ substantially. Even when purchasing from a single vendor, you need to know the mass that third-party testing has confirmed for that specific batch.
That wasn't meant as guidance at all. The person already went ahead and injected the product, so there's nothing to be done now. When I said not a lot, I was only trying to point out that the mass differs from vial to vial. It doesn't reach a level where you'd risk taking a double dose. Apologies if it came across as advice, because it truly wasn't. And I'm fairly certain I picked up those mass variations from reading your posts across various threads.
 
angeliquereta said:

indolent said:

angeliquereta said:

I can't see any issue with that, chances are they come from the same maker.

The sole variation might be the overall dose, since the vials could hold a slightly different quantity of Reta, though not by much.
Before offering advice that could mislead others, take the time to read up and learn a great deal.

Kits produced in different batches may differ substantially. Even when purchasing from a single vendor, you need to know the mass that third-party testing has confirmed for that specific batch.
That wasn't meant as guidance at all. The person already went ahead and injected the product, so there's nothing to be done now. When I said not a lot, I was only trying to point out that the mass differs from vial to vial. It doesn't reach a level where you'd risk taking a double dose. Apologies if it came across as advice, because it truly wasn't. And I'm fairly certain I picked up those mass variations from reading your posts across various threads.
The bit about "not a lot"
 
indolent said:

angeliquereta said:

indolent said:

angeliquereta said:

I can't see any issue with that, chances are they come from the same maker.

The sole variation might be the overall dose, since the vials could hold a slightly different quantity of Reta, though not by much.
Before offering advice that could mislead others, take the time to read up and learn a great deal.

Kits produced in different batches may differ substantially. Even when purchasing from a single vendor, you need to know the mass that third-party testing has confirmed for that specific batch.
That wasn't meant as guidance at all. The person already went ahead and injected the product, so there's nothing to be done now. When I said not a lot, I was only trying to point out that the mass differs from vial to vial. It doesn't reach a level where you'd risk taking a double dose. Apologies if it came across as advice, because it truly wasn't. And I'm fairly certain I picked up those mass variations from reading your posts across various threads.
The bit about "not a lot"
Yeah, I understand. I wouldn't have made that remark to a person who was asking questions before they'd already injected peptides. I need to keep in mind to watch how I phrase things.
 
Rs ended up drawing 3 from 1 vial, then 5 from a vial that had just been mixed. This kind of thing occurs. To sidestep the rough onset, Rs injects at night and sleeps through it.
 
quicksilver80 said:

Rs ended up drawing 3 from 1 vial, then 5 from a vial that had just been mixed. This kind of thing occurs. To sidestep the rough onset, Rs injects at night and sleeps through it.
The warning against reusing one syringe definitely lands. Thinking back on it, my whole "whatever, I'll just shoot it" attitude was a bit sloppy.

If I could redo it, the smarter move would have been a half dose, then finishing vial number one, and only bringing in the other supplier at my following injection — that way I wouldn't be adding an extra variable.

Realistically the danger was small, surely not bigger than plenty of everyday risks we all shrug off, yet it showed me that I hadn't weighed every variable with the care I ought to have.

Lesson taken: when something looks trivial, it still pays to pause and walk through the steps before doing anything.
 
MTSpace said:

quicksilver80 said:

Rs ended up drawing 3 from 1 vial, then 5 from a vial that had just been mixed. This kind of thing occurs. To sidestep the rough onset, Rs injects at night and sleeps through it.
The warning against reusing one syringe definitely lands. Thinking back on it, my whole "whatever, I'll just shoot it" attitude was a bit sloppy.

If I could redo it, the smarter move would have been a half dose, then finishing vial number one, and only bringing in the other supplier at my following injection — that way I wouldn't be adding an extra variable.

Realistically the danger was small, surely not bigger than plenty of everyday risks we all shrug off, yet it showed me that I hadn't weighed every variable with the care I ought to have.

Lesson taken: when something looks trivial, it still pays to pause and walk through the steps before doing anything.
My germaphobia was so intense that when I first mixed an r20, I swapped to a fresh needle after every single 1ml of bac water. That initial session had me seriously on edge. These days I realize that wasn't needed, but even so, if a needle is headed for an injection, I won't put it back into a vial a second time—they dull quite quickly
 
I pick up 3ml syringes for the reconstitution step, and they don't cost much either. In fact, my pharmacy occasionally hands them over at no charge when I come in for my TRT script.
 
I left this out earlier, but my habit is to mix up the following vials roughly 7 days ahead of when I expect to require them.
 
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