Forum › Reconstitution & Math

Is it ok to dilute reta to a concentration of 15 mg per ml?

14 replies12 peopleOct 21, 2026☆ Follow
Summary

Can 30 mg reta vials be safely reconstituted with 2 ml BAC water without solubility issues?

Users report that 2 ml works fine for 30 mg reta and even higher concentrations are used without problems. Some prefer more water to reduce potential aggregation over time or to improve dosing accuracy at lower strengths. Factory fill volume is often around 1 ml, so doubling it is viewed as safe. People adjust volumes based on their weekly dose to keep injection amounts convenient.

What this discussion establishesWhere people disagree

Whether to follow COA values or just labeled mass when reconstituting, and how much precision matters at higher doses.

Still open

Exact minimum solubility limit for reta in BAC water.

Nothing here is advice.

14 replies · 12 people
AmberBeacon57archiveopening post14h

Got 30 mg freeze-dried reta vials. Thinking about adding 2 ml BAC water but wondering if solubility could be a problem. Only ended up with 2 ml sterile vials for the filtering step, which was an oversight. Smaller injection volumes would be nice though.

KeenSparrow66archive14h

Can't see any reason it would cause trouble.

BrightCompass57archive13h

Should be okay, and you could even use less water if wanted.

SharpCinder28archive13h

A compounding place once used 1 ml for 20 mg of tirz. These days I go with 3 ml for most things because it might cut down on molecules bumping into each other over time.

NorthWillow72archive13h
↳ replying to @AmberBeacon57 (opening post)

On my second round using 1 ml for 30 mg tirz and no problems so far. Someone mentioned minimum solubility numbers earlier, and 2 ml looks like it should work. Saw this online.

WarmBramble39archive13h

If you want smaller shots just go with 1 ml, that works fine.

SlowLedger42archive12h

When thinking about solubility, consider how much water the manufacturer originally added before freeze-drying. Gray-market 3 ml vials usually started with about 1 ml per vial. You can check this by the size of the dried puck. If the puck takes up roughly 1 ml space then about 1 ml of water was used at the start. Asking about 2 ml means you're using twice that amount, so solubility should be okay.

KeenThistle61archive9h
↳ replying to @SharpCinder28

Dosing mistakes or small variations also matter less. A one-unit error at 30 mg per ml is bigger than the same error at 10 mg per ml.

NorthWillow72archive9h
↳ replying to @KeenThistle61

Depends a lot on the dose. Pinning 15 mg weekly means 30 mg per ml gives two 15 mg shots of 0.5 ml each, which is simpler. At 5 mg I would probably use 3 ml per 30 mg to keep the shot at 0.5 ml.

PlainAlder11archive8h

I use 2 ml for a 30 mg vial. For the bigger ones I do 5 ml on 100 mg and 6 ml on 140 mg. People get mixed up on the ratios but the total weekly amount stays at 20 mg combined.

GreyThistle69archive6h

Been using 1.5 ml on 25 mg reta and it works out nicely.

SlowLantern29archive4h
↳ replying to @NorthWillow72

Most gray 30 mg tirz vials probably contain a bit over 30 mg. Since I stay on small doses I always mix according to the COA numbers. At 15 mg dosing maybe you don't need to be as exact, which is why 1 ml to 30 mg works for you?

NorthWillow72archive4h
↳ replying to @SlowLantern29

Right, I just go by the labeled amount instead of the COA and the difference doesn't add up to much overall.

↳ replying to @SlowLantern29

Lower strength reta kits seem easier to find than low strength tirz ones. The 20 mg reta vials are common and the math works best for me so I have several. Bought a couple 5 mg sema kits because my dose is 250 mcg and that will last well into next year.

↳ replying to @NorthWillow72

I always figured some of the difference was just from the filtering step.

Related discussions

Add your experience

If you have tried it, this topic is still open. Sign in to reply — it takes a minute.