Bac water/peptide ratio

[ultima thule]

Wondering how people handle vials that are more concentrated. From what I gather, the usual guideline is 1-2 ml of bac water for every 10mg of compound. That works fine with 10mg or 20mg vials. Say you put 1ml into 10mg and you want 2mg, then you draw 20 units on a 1ml syringe. But take a 40mg vial: if you only add 3ml of bac water and you're after 10mg, that's 60 units - a fair amount. Yet the bac water/peptide ratio there is under 1ml per 10g. So now I've got 2 wrinkles...what's the largest volume of solution you can inject subcutaneously in one go? And does it cause any trouble to reconstitute a peptide using less than 1ml of bac water per 10mg?

 

[Calm Logic]

A tool that calculates in reverse might be useful:

Reverse Peptide Calculator: Smart Reconstitution for a Clean Syringe Draw | PepRecon



This reverse calculator starts from the draw you want and determines how much BAC water is required. It is designed so reconstitution puts each dose on a clear syringe marking.

Image unavailable


reverse.peprecon.com

My typical BAC amount is 2-3 mL, but for peptides that sting or feel spicy, such as NAD+ or glutathione, I add more liquid to dilute them. Other exceptions exist too, for instance VIP, which can involve doses as small as 50 mcg (0.05 mg).

For peptides that do not sting, I generally target roughly 20 units (0.2 mL) for each dose, which makes measuring easier. Insulin syringes are marked up to 30 units (0.3 mL), 50 units (0.5 mL), and 100 units (1 mL), so all of those appear to be safe volumes for subq.

 

[randompersonrandom]

ultima thule said:

Wondering how people handle vials that are more concentrated. From what I gather, the usual guideline is 1-2 ml of bac water for every 10mg of compound. That works fine with 10mg or 20mg vials. Say you put 1ml into 10mg and you want 2mg, then you draw 20 units on a 1ml syringe. But take a 40mg vial: if you only add 3ml of bac water and you're after 10mg, that's 60 units - a fair amount. Yet the bac water/peptide ratio there is under 1ml per 10g. So now I've got 2 wrinkles...what's the largest volume of solution you can inject subcutaneously in one go? And does it cause any trouble to reconstitute a peptide using less than 1ml of bac water per 10mg?

That's the piece that doesn't hold up. Once you accept that no single common rule covers every peptide, most of the leftover confusion clears up. The answer to "how much" is "it depends."

My preference is to keep pins at 10 units minimum and 35 units maximum whenever possible. Some peps react too much at the site for that, though I avoid most of those. Back when I reconstituted KLOW, I went very dilute — 12 ml into 70mg of ghk-cu — yet the most recent one worked fine at 3 ml into 50 mg, which I'd guess is because the other components were better proportioned than my overfilled kits.

I've got Epitalon vials at 7.5 mg (they were meant to be 10 but came back underfilled on testing). For those, since the cycle runs 20 days, I put 2.25 ml into three vials and filter them into 1 pen cartridge, because I take 1 mg per day across 21 days and my units-per-pin sit at 10.

For Tirz, I mix to 22 mg/ml. That's the concentration my original Brello-acquired compound vials arrived at, and I simply never switched it up.

 

[ultima thule]

Next thing I'm wondering about: is concentration actually something to worry over, or not? Would 40mg of Reta in 2ml of bac water be a safe mix?

 

[Calm Logic]

ultima thule said:

Next thing I'm wondering about: is concentration actually something to worry over, or not? Would 40mg of Reta in 2ml of bac water be a safe mix?

It's basically safe to use a whole lot of BAC water—way more than you'd expect—so dilution isn't something you need to stress over.

As for reta/tirz, 20 mg per mL works just fine. @randompersonrandom pointed this out regarding the tirz concentration from Brello Health, and reta would behave the same way.

 

[BNLFL]

My next run is R60. With 2ml of BAC added, and pins at 7mg, each shot comes to 2.3mg. That works out to slightly more than 8 doses per vial, which is ideal. Since the pin mg are higher now, I'm going with 2 ml of BAC. It beats the 7-8mg pins. Drawing from the vial is simpler as well. I'll apply the same approach to my R30mg.

 

[ultima thule]

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

 

[EAM9112]

ultima thule said:

Wondering how people handle vials that are more concentrated. From what I gather, the usual guideline is 1-2 ml of bac water for every 10mg of compound. That works fine with 10mg or 20mg vials. Say you put 1ml into 10mg and you want 2mg, then you draw 20 units on a 1ml syringe. But take a 40mg vial: if you only add 3ml of bac water and you're after 10mg, that's 60 units - a fair amount. Yet the bac water/peptide ratio there is under 1ml per 10g. So now I've got 2 wrinkles...what's the largest volume of solution you can inject subcutaneously in one go? And does it cause any trouble to reconstitute a peptide using less than 1ml of bac water per 10mg?

What I do is move the contents into a bigger vial, maybe 5ml, and then dilute with extra BAC water. Say there's a 3ml vial containing 50mg GHK — I'll mix it with 2.5ml of BAC, move it through a filter into a 5ml sterile vial, and top it up with another 2.5ml, bringing the overall dilution to 5ml.

 

[RicFlair]

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

yeah, honestly the amount of bac water you're planning to inject matters, and so does the degree of dilution you're after—just like another user mentioned above, particularly for those “spicy” peps. As for me, I used 2 ml for tesa because that one stings too, though I figure where you pin also plays a role.

 

[Grogu]

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

I'm not convinced it's accurate to frame peptide concentration purely as a comfort issue.

Regarding what you asked specifically — tirzepatide at 40mg/2mL — there's no problem there, because Lilly sells tirzepatide in 15mg/.5mL vials, and that works out to 30mg/mL, a higher concentration than Brello's 22mg/mL. That gives us a "precedent" that 30mg/mL is safe. So mixing to 20mg/mL is obviously acceptable.

Where the line sits for "too concentrated" is still unresolved, in my view. And different peptides may behave differently. Take that 40mg tirzepatide vial — could you physically reconstitute it with .5mL of bac? Likely yes. But you'd end up at 80mg/mL. Same logic: a 60mg vial with .5mL of bac gives 120mg/mL. Whether either of those is wise, I can't say. It'll be worth watching what Lilly does if they eventually bring higher-dose tirzepatide to market.

Certain peptides — semaglutide and cagrilintide among them — tend to aggregate more readily when concentration goes up. With those, I'd avoid pushing toward the high end of the concentration range.

With the newer higher dose, semaglutide seems safe up to 9.6mg/mL. NN held the mL per pen constant (they made the brew more concentrated), yet it remains a fairly weak concentration.

 

[ultima thule]

Grogu said:

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

I'm not convinced it's accurate to frame peptide concentration purely as a comfort issue.

Regarding what you asked specifically — tirzepatide at 40mg/2mL — there's no problem there, because Lilly sells tirzepatide in 15mg/.5mL vials, and that works out to 30mg/mL, a higher concentration than Brello's 22mg/mL. That gives us a "precedent" that 30mg/mL is safe. So mixing to 20mg/mL is obviously acceptable.

Where the line sits for "too concentrated" is still unresolved, in my view. And different peptides may behave differently. Take that 40mg tirzepatide vial — could you physically reconstitute it with .5mL of bac? Likely yes. But you'd end up at 80mg/mL. Same logic: a 60mg vial with .5mL of bac gives 120mg/mL. Whether either of those is wise, I can't say. It'll be worth watching what Lilly does if they eventually bring higher-dose tirzepatide to market.

Certain peptides — semaglutide and cagrilintide among them — tend to aggregate more readily when concentration goes up. With those, I'd avoid pushing toward the high end of the concentration range.

With the newer higher dose, semaglutide seems safe up to 9.6mg/mL. NN held the mL per pen constant (they made the brew more concentrated), yet it remains a fairly weak concentration.





View attachment 11122

My focus was actually Reta, though it looks like we're heading toward the same point. I'm curious whether specific peptides come with any recommended concentration guidelines. Beyond that, does the final concentration of the solution actually matter? Could certain concentrations offer better stability, a longer shelf life, or perhaps be more or less effective? I haven't come across any studies on this, which is why I started this thread.

 

[Troposphere]

A factor nobody has brought up so far: as peptide concentration goes up, your syringe loading has to get that much more exact. Tiny differences in the amount you draw can translate into a noticeably bigger swing in the dose you actually get.

 

[Calm Logic]

ultima thule said:

Grogu said:

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

I'm not convinced it's accurate to frame peptide concentration purely as a comfort issue.

Regarding what you asked specifically — tirzepatide at 40mg/2mL — there's no problem there, because Lilly sells tirzepatide in 15mg/.5mL vials, and that works out to 30mg/mL, a higher concentration than Brello's 22mg/mL. That gives us a "precedent" that 30mg/mL is safe. So mixing to 20mg/mL is obviously acceptable.

Where the line sits for "too concentrated" is still unresolved, in my view. And different peptides may behave differently. Take that 40mg tirzepatide vial — could you physically reconstitute it with .5mL of bac? Likely yes. But you'd end up at 80mg/mL. Same logic: a 60mg vial with .5mL of bac gives 120mg/mL. Whether either of those is wise, I can't say. It'll be worth watching what Lilly does if they eventually bring higher-dose tirzepatide to market.

Certain peptides — semaglutide and cagrilintide among them — tend to aggregate more readily when concentration goes up. With those, I'd avoid pushing toward the high end of the concentration range.

With the newer higher dose, semaglutide seems safe up to 9.6mg/mL. NN held the mL per pen constant (they made the brew more concentrated), yet it remains a fairly weak concentration.





View attachment 11122

My focus was actually Reta, though it looks like we're heading toward the same point. I'm curious whether specific peptides come with any recommended concentration guidelines. Beyond that, does the final concentration of the solution actually matter? Could certain concentrations offer better stability, a longer shelf life, or perhaps be more or less effective? I haven't come across any studies on this, which is why I started this thread.

When it comes to grey, our main goal is simply steering clear of a hospital trip down the line, so if I had to pick a direction, I'd lean toward using a larger amount of BAC rather than a smaller one. A greater volume of BAC helps keep the peptide from clumping together (it gives the reta more space) and may also provide extra preservative.

 

[BNLFL]

Calm Logic said:

ultima thule said:

Grogu said:

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

I'm not convinced it's accurate to frame peptide concentration purely as a comfort issue.

Regarding what you asked specifically — tirzepatide at 40mg/2mL — there's no problem there, because Lilly sells tirzepatide in 15mg/.5mL vials, and that works out to 30mg/mL, a higher concentration than Brello's 22mg/mL. That gives us a "precedent" that 30mg/mL is safe. So mixing to 20mg/mL is obviously acceptable.

Where the line sits for "too concentrated" is still unresolved, in my view. And different peptides may behave differently. Take that 40mg tirzepatide vial — could you physically reconstitute it with .5mL of bac? Likely yes. But you'd end up at 80mg/mL. Same logic: a 60mg vial with .5mL of bac gives 120mg/mL. Whether either of those is wise, I can't say. It'll be worth watching what Lilly does if they eventually bring higher-dose tirzepatide to market.

Certain peptides — semaglutide and cagrilintide among them — tend to aggregate more readily when concentration goes up. With those, I'd avoid pushing toward the high end of the concentration range.

With the newer higher dose, semaglutide seems safe up to 9.6mg/mL. NN held the mL per pen constant (they made the brew more concentrated), yet it remains a fairly weak concentration.





View attachment 11122

My focus was actually Reta, though it looks like we're heading toward the same point. I'm curious whether specific peptides come with any recommended concentration guidelines. Beyond that, does the final concentration of the solution actually matter? Could certain concentrations offer better stability, a longer shelf life, or perhaps be more or less effective? I haven't come across any studies on this, which is why I started this thread.

When it comes to grey, our main goal is simply steering clear of a hospital trip down the line, so if I had to pick a direction, I'd lean toward using a larger amount of BAC rather than a smaller one. A greater volume of BAC helps keep the peptide from clumping together (it gives the reta more space) and may also provide extra preservative.

Now you've got me second-guessing whether 2ml or 3ml was the right call.

 

[Grogu]

ultima thule said:

Grogu said:

ultima thule said:

Understood, thanks everyone. So ultimately it isn't the concentration that's the issue. It only comes into play with certain peptides that sting, and then it's purely a comfort question.

I'm not convinced it's accurate to frame peptide concentration purely as a comfort issue.

Regarding what you asked specifically — tirzepatide at 40mg/2mL — there's no problem there, because Lilly sells tirzepatide in 15mg/.5mL vials, and that works out to 30mg/mL, a higher concentration than Brello's 22mg/mL. That gives us a "precedent" that 30mg/mL is safe. So mixing to 20mg/mL is obviously acceptable.

Where the line sits for "too concentrated" is still unresolved, in my view. And different peptides may behave differently. Take that 40mg tirzepatide vial — could you physically reconstitute it with .5mL of bac? Likely yes. But you'd end up at 80mg/mL. Same logic: a 60mg vial with .5mL of bac gives 120mg/mL. Whether either of those is wise, I can't say. It'll be worth watching what Lilly does if they eventually bring higher-dose tirzepatide to market.

Certain peptides — semaglutide and cagrilintide among them — tend to aggregate more readily when concentration goes up. With those, I'd avoid pushing toward the high end of the concentration range.

With the newer higher dose, semaglutide seems safe up to 9.6mg/mL. NN held the mL per pen constant (they made the brew more concentrated), yet it remains a fairly weak concentration.





View attachment 11122

My focus was actually Reta, though it looks like we're heading toward the same point. I'm curious whether specific peptides come with any recommended concentration guidelines. Beyond that, does the final concentration of the solution actually matter? Could certain concentrations offer better stability, a longer shelf life, or perhaps be more or less effective? I haven't come across any studies on this, which is why I started this thread.

When it comes to the TRIUMPH trials, Lilly hasn't released the exact strength of the retatrutide solution publicly, unlike approved medications that list their formulations in prescribing information. Because retatrutide hasn't received FDA approval, the complete formulation details are still proprietary and not published. I'm with @Calm Logic — better to use more bac water than too little.