Procedure guide
How to Reconstitute a Peptide
The physical procedure, quoted from the approved lyophilised products that have one — and the arithmetic deliberately left to the calculators.
- Reviewed by
- Alpha Health Finder Editorial Team
- Last reviewed
This page is the procedure and nothing else. How much water to add, how many micrograms land in a unit mark, how much benzyl alcohol a draw carries and how long the mixed vial keeps are all answered elsewhere on this site, and the links at the top of this page go straight to them. What follows is the part none of those pages covers: the physical sequence, in order, with the source of every step named.
There is an obvious problem with writing it, and it is better stated than hidden. The compounds most people reading this are reconstituting have no FDA-approved label, which means they have no reconstitution instructions — not vague ones, none. What does exist is a set of approved lyophilised medicines that are reconstituted in exactly the same way: a powder in a stoppered vial, a diluent that is frequently the identical bacteriostatic water, and a user doing it at a kitchen table. Four of those labels carry real technique. Every step below is quoted from one of them or from the water’s own label, and every quote is attributed to the product it belongs to rather than turned into a general rule.
What that means in practice: take the technique and leave the numbers. SEROSTIM tells you to aim the stream at the glass wall to stop it foaming, and that is a fact about how proteins behave at an air-liquid interface rather than a fact about somatropin. SEROSTIM also tells you to use 0.5 to 1 mL, and that is a fact about somatropin and has nothing to do with your vial. The first transfers. The second does not.
What this page does not cover
These live elsewhere on the site and are not restated here.
- Peptide reconstitution chart
The whole of the arithmetic: vial strength against diluent volume, micrograms per unit mark, units to draw for a given dose, and how many doses a vial holds. This page computes nothing.
- Peptide reconstitution calculator
The same conversion for any vial and any diluent volume, including the quarter-unit rounding and the delivered dose when a target does not land on a mark.
- Bacteriostatic water calculator
Solves for the diluent volume itself — how much water to add to reach a concentration, and the benzyl alcohol that volume carries with it.
- Bacteriostatic water mixing chart
Benzyl alcohol per injection and per week, the difference between the 0.9% and 1.1% presentations, and the neonatal contraindication. All the preservative arithmetic lives there.
- Peptide storage and beyond-use dates
Everything about the clock after mixing: what six approved labels state, why they disagree by more than eightfold, where the 28-day figure actually comes from, and why no beyond-use date can be given for an unapproved compound.
- Peptide blend calculator
Two compounds in one vial, and what one draw delivers of each. This page does not cover combining compounds and does not advise on whether they are compatible.
The procedure
- 1
Establish which diluent the drug is supposed to have
This is a step rather than an assumption, and it is the first place the procedure can go wrong. The diluent belongs to the drug: SEROSTIM’s 4 mg vial is reconstituted with bacteriostatic water and its 5 mg and 6 mg vials with sterile water, on the same label, because the first is a single-patient multiple-entry vial and the others are single-dose. Bacteriostatic water is what lets a vial be entered more than once; sterile water contains no preservative and is supplied only in single-dose containers. If the compound in front of you has no label, then there is no instruction to consult and the choice you make is a convention rather than a direction — which is worth knowing rather than pretending otherwise.
FDA label“Consult the manufacturer’s instructions for choice of vehicle, appropriate dilution or volume for dissolving the drugs to be injected, including the route and rate of injection.”
Bacteriostatic Water for Injection, USP — FDA prescribing information, Hospira, Inc., NDA 018802, via DailyMed. The diluent’s own label: aseptic technique at every entry, the conditional indication, and the instruction not to store reconstituted solutions absent a direction from the solute’s manufacturer. - 2
Hands, then both stoppers, then let them dry
Hand hygiene first, then swab the rubber stopper of the water bottle and the rubber stopper of the powder vial with alcohol and let both air dry rather than wiping them. The water label’s requirement covers every entry into every container, not just the first, and it applies to the bottle you have already opened four times as much as to the one you have not. Use a fresh needle for each entry: a preservative limits bacterial growth, it does not sterilise what you push into the vial.
FDA label“Use aseptic technique for single or multiple entry and withdrawal from all containers.”
Bacteriostatic Water for Injection, USP — FDA prescribing information, Hospira, Inc., NDA 018802, via DailyMed. The diluent’s own label: aseptic technique at every entry, the conditional indication, and the instruction not to store reconstituted solutions absent a direction from the solute’s manufacturer. - 3
Equalise the pressure, in the direction the label actually specifies
A stoppered vial is a closed system, and pulling liquid out of one and pushing it into another changes the pressure in both. PREGNYL is the one approved label that spells out the order, and it is the reverse of what most people do: air is drawn from the powder vial and injected into the solvent vial, which pressurises the diluent rather than the drug. Doing it the other way round leaves the powder vial under pressure and the diluent fighting you on the way in. If you skip the step entirely you will feel it — the plunger pulls back against you as the solvent leaves its vial.
FDA label“Withdraw sterile air from vial with lyophilized powder and inject into vial with solvent. Remove 1 to 10 mL of solvent and add to vial with lyophilized powder”
PREGNYL (chorionic gonadotropin) for injection — FDA prescribing information, Organon LLC, via DailyMed. Directions for Reconstitution, the only approved label we found that specifies the air-transfer step and its direction. - 4
Aim the stream at the glass wall, not at the cake
The single most useful sentence in American labelling on this subject, and the only one that gives the reason. Angle the needle so the diluent runs down the inside wall of the vial rather than jetting directly onto the powder. The reason is foaming: a protein solution driven through air at speed denatures at the interface, and foam is what that looks like. It is also slow. Let the diluent run in under gravity rather than pushing it, and the cake will start dissolving before the last of it has arrived.
FDA label“Aim the stream of diluent against the glass vial wall to prevent foaming.”
SEROSTIM (somatropin) for injection — FDA prescribing information, EMD Serono, Inc., BLA 020604, via DailyMed. Carries the most complete reconstitution technique in US labelling: aim the stream at the glass wall to prevent foaming, swirl with a gentle rotary motion, do not shake. - 5
Swirl, roll or invert gently — and do not shake
All four approved labels we read say do not shake, and only one says why. GENOTROPIN supplies the mechanism: shaking may cause denaturation of the active ingredient. That is the whole argument, and it is a better argument than the folklore version, because it explains why gentle motion for longer is preferable to vigorous motion for less time. SEROSTIM specifies a gentle rotary motion of the vial; HUMATROPE specifies gently moving the cartridge up and down ten times. The specific motion is product-specific, the prohibition is not.
FDA label“Do not shake; shaking may cause denaturation of the active ingredient.”
GENOTROPIN (somatropin) — FDA prescribing information, Pfizer Laboratories Div Pfizer Inc, via DailyMed. The only label we found that states why shaking matters: shaking may cause denaturation of the active ingredient. - 6
Wait, rather than agitating harder
The reflex when a cake has not dissolved is to shake it, which is the one thing every label prohibits. The labelled alternative is time. HUMATROPE sets out the escalation explicitly — mix gently, then let it stand, then if it is still not clear mix gently again and let it stand longer, and only then discard it. The specific intervals belong to that product and are not transferable, but the shape of the instruction is: gentle motion, then patience, then more gentle motion, then stop.
FDA label“If the liquid is cloudy or contains particles, gently mix the medicine in the Cartridge 10 more times. Let the Cartridge sit for 5 more minutes. If the liquid still remains cloudy or contains particles, do not use the Cartridge.”
HUMATROPE (somatropin) — FDA prescribing information and Instructions for Use, Eli Lilly and Company, via DailyMed. Source of the mix-wait-remix-discard sequence and of the sharps disposal instruction quoted here. - 7
Look at it before you draw anything
Hold it to the light and check that it is clear and that there is nothing floating in it. SEROSTIM sets a usable standard — clear or slightly opalescent is acceptable, cloudy or particulate is not — and that is about as close to a general specification as this subject gets. Be honest about the limit of this step for an unapproved compound: you are inspecting against no published description of what a correct solution looks like, so you can detect an obviously wrong vial and you cannot confirm a right one.
FDA label“SEROSTIM must not be injected if the solution is cloudy or contains particulate matter. Use the reconstituted solution only if it is clear or slightly opalescent.”
SEROSTIM (somatropin) for injection — FDA prescribing information, EMD Serono, Inc., BLA 020604, via DailyMed. Carries the most complete reconstitution technique in US labelling: aim the stream at the glass wall to prevent foaming, swirl with a gentle rotary motion, do not shake. - 8
Write the date on the vial, knowing what that date is and is not
Mark the vial with what it now is, how much diluent went in, and the date you did it. Two of those are for you and one of them is a practical necessity, because a reconstituted vial looks identical to every other reconstituted vial. Be clear about what the date is: it is a record of when you mixed it, not a beyond-use date, because no beyond-use date has been established for an unapproved compound. What the approved labels state — and they disagree with each other by more than a factor of eight — is on the storage sheet linked at the top of this page.
Common practice — not establishedNothing in any label we opened instructs a user to date a reconstituted vial of an unapproved compound, for the straightforward reason that no label covers one. This step is practice, and the date it produces is a record rather than an expiry.
- 9
Put the sharps away before you put anything else away
Reconstituting produces at least two used needles before a dose has been drawn — one into the water, one into the powder — and both go straight into the container. The HUMATROPE instructions for use put it as a sequence rather than a suggestion: into an FDA-cleared sharps container right away after use, and never loose into household rubbish. Recapping is where most needlestick injuries happen, so the used unit goes in assembled.
FDA label“Put your used Diluent Syringes in a FDA-cleared sharps disposal container right away after use. Do not throw away (dispose of) loose needles and syringes in your household trash.”
HUMATROPE (somatropin) — FDA prescribing information and Instructions for Use, Eli Lilly and Company, via DailyMed. Source of the mix-wait-remix-discard sequence and of the sharps disposal instruction quoted here.
What four approved lyophilised-product labels actually say about mixing
Every sentence of physical technique we could find in American labelling for a powder the user reconstitutes. Transcribed rather than merged: each row is one product, and none of these instructions was written about a research peptide.
| Product | Diluent the label specifies | Adding the diluent | Mixing | Before you use it |
|---|---|---|---|---|
| SEROSTIM 4 mg (somatropin) | Bacteriostatic Water for Injection with 0.9% benzyl alcohol | Aim the stream of diluent against the glass vial wall to prevent foaming | Swirl the vial with a gentle rotary motion until contents are dissolved completely. Do not shake. | Use the reconstituted solution only if it is clear or slightly opalescent |
| PREGNYL 10,000 USP units (chorionic gonadotropin) | Co-packaged solvent: water for injection with 0.56% sodium chloride and 0.9% benzyl alcohol | Withdraw sterile air from vial with lyophilized powder and inject into vial with solvent | agitate gently until powder is completely dissolved in solution. Do not shake. | If there is a discoloration or particulates, do not use |
| GENOTROPIN (somatropin) | Two-chamber cartridge, reconstituted by the device | Follow the directions for reconstitution provided with each device | Do not shake; shaking may cause denaturation of the active ingredient. | Make sure the solution is clear, and that the growth hormone powder is completely dissolved |
| HUMATROPE (somatropin) | Prefilled diluent syringe supplied with the cartridge | Reconstitute each cartridge of HUMATROPE using only the diluent syringe that accompanies the cartridge | Mix the medicine in the Cartridge by gently moving it in an up and down motion 10 times. Then let the Cartridge sit for 3 minutes. Do not shake. | The reconstituted solution should be clear |
All four say do not shake and none of them says why except GENOTROPIN, which supplies the mechanism: shaking may cause denaturation of the active ingredient. Only SEROSTIM states where to aim the stream and gives the reason — foaming. Only PREGNYL describes an air step, and it runs in the direction people usually get wrong: air is withdrawn from the powder vial and pushed into the solvent vial, not the other way round. Only HUMATROPE gives a waiting time, and it is specific to that cartridge. Take the technique; do not take the volumes, the timings or the storage periods, which belong to those products and not to yours.
What the diluent’s own label requires, and what it means when the drug has no label
The Bacteriostatic Water for Injection label is the one document in this procedure that definitely applies to you, because it is the thing you are actually holding. Read the right-hand column: several of its requirements point at something that does not exist for an unapproved compound.
| What the water label says | What it means when the drug has an approved label | What it means when it does not |
|---|---|---|
| indicated only for diluting or dissolving drugs for intravenous, intramuscular or subcutaneous injection, according to instructions of the manufacturer of the drug to be administered | Use the volume and vehicle that drug’s label specifies | There is no manufacturer instruction to follow, so the diluent’s own indication does not reach the use |
| Consult the manufacturer’s instructions for choice of vehicle, appropriate dilution or volume for dissolving the drugs to be injected | Bacteriostatic or sterile water is chosen by the drug, not by you | Nothing to consult; the choice becomes a convention rather than an instruction |
| Use aseptic technique for single or multiple entry and withdrawal from all containers | Swab before every entry, and use a sterile needle each time | Identical — this requirement belongs to the container and is unaffected by what is in the other vial |
| Do not use unless the solution is clear and seal intact | Inspect before drawing; discard a cloudy bottle | Identical |
| Inspect reconstituted (diluted or dissolved) drugs for clarity (if soluble) and freedom from unexpected precipitation or discoloration prior to administration | The approved label usually also says what the finished solution should look like | You are inspecting against no stated standard — nobody has published what normal looks like for your compound |
| Do not store reconstituted solutions of drugs for injection unless otherwise directed by the manufacturer of the solute | Store it exactly as that drug’s label directs, and no longer | There is no direction, so the water label’s own default applies — and the default is not to store it |
| When diluting or dissolving drugs, mix thoroughly and use promptly | Read against the product’s own in-use period, which overrides it | Nothing overrides it |
The last two rows are the uncomfortable ones and they are printed because the alternative is pretending they are not there. Read literally, the diluent label’s position on a compound with no manufacturer instruction is that the reconstituted solution should not be stored at all. Almost nobody follows that, and this page is not going to tell you that everyone is wrong — what it will not do is quote the convenient sentences from this label and skip these two. What the beyond-use question actually turns on, and the six approved products whose in-use periods disagree with each other by a factor of more than eight, is set out on the storage sheet linked at the top of this page.
Where each step on this page comes from
One row per step, so you can see at a glance which instructions have a document behind them and which are here as convention. Nothing on this page is sourced to a research peptide, because no research peptide has a source.
| Step | Document it is quoted from | Kind of instruction |
|---|---|---|
| Choose the diluent the drug specifies | Bacteriostatic Water for Injection, USP — Precautions | FDA label |
| Aseptic technique at every entry | Bacteriostatic Water for Injection, USP — Precautions | FDA label |
| Equalise the pressure before transferring | PREGNYL — Directions for Reconstitution | FDA label |
| Aim the stream at the glass wall | SEROSTIM — Reconstitution | FDA label |
| Swirl gently; do not shake | SEROSTIM, PREGNYL, GENOTROPIN and HUMATROPE all say it | FDA label |
| Wait rather than agitate harder | HUMATROPE — Instructions for Use | FDA label, product-specific timing |
| Inspect the finished solution | SEROSTIM and the Bacteriostatic Water label | FDA label |
| Label and date the vial | Nothing states it for an unapproved compound | Common practice — not established |
| Dispose of the sharps immediately | HUMATROPE — Instructions for Use, Disposing of used Diluent Syringes | FDA label |
Eight of the nine rows name a document. The ninth says so. That ratio is the point of the table — on this subject most of what circulates as instruction has nothing behind it at all, and the honest thing a page can do is show which sentences it can defend.
When it does not go to plan
The powder will not dissolve, or the solution stays cloudy
Do not shake it. The labelled response is more gentle mixing and more time, in that order, and then abandonment — HUMATROPE runs mix, wait, mix again, wait longer, discard. Two things make this worse before it gets better: a cold vial straight from a fridge dissolves more slowly than one at room temperature, and foam produced by shaking looks exactly like a failure to dissolve while actually being denatured protein. If it is still not clear after two rounds of gentle mixing, the labelled instruction for every approved product here is to stop using that vial.
“Mix the medicine in the Cartridge by gently moving it in an up and down motion 10 times. Then let the Cartridge sit for 3 minutes.”HUMATROPE (somatropin) — FDA prescribing information and Instructions for Use, Eli Lilly and Company, via DailyMed. Source of the mix-wait-remix-discard sequence and of the sharps disposal instruction quoted here.
The plunger fights me — it pulls back, or the vial sprays when I withdraw the needle
That is a pressure problem and PREGNYL’s label describes the fix as a step rather than a troubleshooting tip. Move air the way the label specifies: out of the powder vial and into the solvent vial before the transfer. If you have already created the problem, the recoverable version is to let the pressure equalise slowly rather than forcing the plunger, and to withdraw the needle with the vial upright.
“Withdraw sterile air from vial with lyophilized powder and inject into vial with solvent.”PREGNYL (chorionic gonadotropin) for injection — FDA prescribing information, Organon LLC, via DailyMed. Directions for Reconstitution, the only approved label we found that specifies the air-transfer step and its direction.
I shook it and now there is foam on top
GENOTROPIN’s label gives the reason to care and it is not cosmetic: shaking may cause denaturation of the active ingredient. Foam is protein at an air-liquid interface, and the part of the dose involved in it may no longer be the molecule you paid for. Nothing in any label we read describes a way to recover a foamed vial — there is no "let it settle and it will be fine" instruction anywhere — so what this page can honestly say is that the labels prohibit the action and none of them offers a remedy for having done it.
“Do not shake your pen, as this might stop the growth hormone from working.”GENOTROPIN (somatropin) — FDA prescribing information, Pfizer Laboratories Div Pfizer Inc, via DailyMed. The only label we found that states why shaking matters: shaking may cause denaturation of the active ingredient.
Can I go back into the same water bottle for a second vial?
That is what a multiple-dose container is for, and it is the entire reason the water contains benzyl alcohol — the label describes it as supplied "in a multiple-dose container from which repeated withdrawals may be made to dilute or dissolve drugs for injection". The conditions are the ones in the step above: aseptic technique at every entry, a fresh sterile needle each time, and do not use it if the solution is not clear or the seal is not intact. What the label does not state anywhere is a period after which an opened bottle should be discarded — no bacteriostatic water label we have read states one, and where a figure would go this site prints "not stated".
“It is supplied in a multiple-dose container from which repeated withdrawals may be made to dilute or dissolve drugs for injection.”Bacteriostatic Water for Injection, USP — FDA prescribing information, Hospira, Inc., NDA 018802, via DailyMed. The diluent’s own label: aseptic technique at every entry, the conditional indication, and the instruction not to store reconstituted solutions absent a direction from the solute’s manufacturer.
The peptide came with no instructions at all — what volume and what diluent?
Then you have hit the actual problem with the subject rather than a gap in this page. The volume is arithmetic and the calculators linked above will solve it for whatever concentration you want, but nothing establishes what concentration you should want, because nobody has run a stability study on your compound in your diluent. The diluent label itself is conditional on an instruction that does not exist. FDA has put several of the commonly compounded peptides into category 2 of its bulk substances list on the basis that it lacks the information to know whether they would cause harm — which is the regulator saying, in its own words, that the missing document is missing for everyone.
“FDA has identified no, or only limited, safety-related information for the proposed routes of administration. Therefore, the agency lacks sufficient information to know whether the drug would cause harm when administered to humans.”U.S. Food and Drug Administration — Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, category 2 of the Bulk Substances Nominated Under Sections 503A or 503B. Read for this page: the entries for BPC-157, CJC-1295, ipamorelin acetate, GHRP-2, GHRP-6, AOD-9604 and kisspeptin-10.
How long does the mixed vial keep, and does it go in the fridge?
Not answered here, and not because it is unimportant. It is the single most-asked question about reconstitution and this site has a whole printable sheet on it, because the honest answer needs six approved labels side by side to make sense — their in-use periods run from 7 days to 60 and one of them forbids the refrigeration that four others require. The one thing worth carrying over from the diluent label is its own default position, which almost nobody quotes.
“Do not store reconstituted solutions of drugs for injection unless otherwise directed by the manufacturer of the solute.”Bacteriostatic Water for Injection, USP — FDA prescribing information, Hospira, Inc., NDA 018802, via DailyMed. The diluent’s own label: aseptic technique at every entry, the conditional indication, and the instruction not to store reconstituted solutions absent a direction from the solute’s manufacturer.
What we could not source
Widely taught techniques we went looking for and could not anchor to a label, a public-health body or a trial. Each entry names what was searched and what this page does instead.
How long to wait for a cake to dissolve
Searched: The SEROSTIM, PREGNYL, GENOTROPIN and HUMATROPE labels in full, and the Bacteriostatic Water for Injection and Sterile Water for Injection labels. HUMATROPE is the only one that gives a time and it is 3 minutes for its own cartridge, with 5 more if it is still cloudy.
What this page says: No general figure exists and this page prints none. Dissolution time depends on the compound, the mass, the volume and the temperature, and borrowing somatropin’s three minutes for a different molecule would be inventing a specification. The step says to wait and to repeat gentle mixing rather than naming an interval.
Letting a refrigerated vial reach room temperature before reconstituting
Searched: All four approved product labels above plus both diluent labels. None of them instructs the user to warm a lyophilised vial before adding diluent; the only warming instruction on any label in this area is DEPO-Testosterone’s, and it is about redissolving crystals in an oil, not about reconstitution.
What this page says: Not established, and not printed as a step. Cold solutions do dissolve more slowly, which is physics rather than labelling, so the page mentions temperature in the troubleshooting section as an explanation and does not turn it into an instruction.
A needle gauge for drawing and transferring the diluent
Searched: The four product labels, both diluent labels, and the manufacturer listings and FDA device records already worked through for the insulin syringe conversion chart.
What this page says: No manufacturer or agency states one. This is the same finding the injection guide reached about drawing gauges for an oil, and this page agrees with it: the commonly supplied ranges are a supply convention and are not printed here as instruction.
Venting the vial with a second needle while the diluent goes in
Searched: The four product labels. PREGNYL is the only one that addresses vial pressure at all, and its instruction is an air transfer with the same syringe rather than a vent.
What this page says: Not documented anywhere we looked. The page prints the air-transfer step PREGNYL specifies and says nothing about venting, because a second puncture is an additional entry into a sterile container and no label asks for one.
A discard date for a punctured bacteriostatic water bottle
Searched: All seven standalone Bacteriostatic Water for Injection labels on DailyMed, searched for the strings that would carry such a period. This work was already done for the bacteriostatic water mixing chart and is recorded there.
What this page says: Not stated on any of them. The widely quoted 28 days is CDC’s figure citing USP General Chapter 797 and is about multi-dose vials in general, not about this product. This page prints no figure and points at the storage sheet, which sets out where the number comes from and what it does and does not govern.
A beyond-use date for the reconstituted peptide itself
Searched: Six approved lyophilised products with published in-use periods, the diluent labels, and FDA’s category 2 bulk substances list. The full comparison is on the storage sheet.
What this page says: None exists for an unapproved compound, and the approved figures disagree by more than a factor of eight, so none of them can be borrowed. The only sourced position available is the diluent label’s own default, which is not to store a reconstituted solution absent a direction from the solute’s manufacturer — printed on this page in the second table rather than quietly dropped.
Whether a particular compound is stable in bacteriostatic water at all
Searched: The Bacteriostatic Water for Injection label, which raises the question and does not answer it, and FDA’s category 2 entries for the commonly compounded peptides.
What this page says: Unknowable from published sources for an unapproved compound. The water label’s own warning is that some drugs "may be incompatible in a given vehicle, or when combined in the same vehicle or in a vehicle containing benzyl alcohol", and its advice is to consult a pharmacist. There is no test you can perform at a kitchen table that distinguishes a stable solution from a degraded one, and a clear solution is not evidence of an intact molecule.
Frequently asked questions
- Should you shake a peptide vial to dissolve it?
- No, and all four approved lyophilised-product labels we read say so explicitly. Only GENOTROPIN gives the reason, and it is the one worth knowing: "Do not shake; shaking may cause denaturation of the active ingredient." The labelled alternatives are gentle motion and time — SEROSTIM specifies swirling the vial "with a gentle rotary motion until contents are dissolved completely", HUMATROPE specifies moving the cartridge gently up and down 10 times and then letting it stand 3 minutes. If it is still cloudy the instruction is to repeat the gentle mixing, not to increase the force.
- Where should the water go in — onto the powder or down the side?
- Down the side, and this is the one piece of technique that has an FDA label behind it with a stated reason. SEROSTIM’s reconstitution section says: "Aim the stream of diluent against the glass vial wall to prevent foaming." Foam is protein denaturing at the air-liquid interface, which is the same mechanism GENOTROPIN’s label invokes to prohibit shaking. Let the diluent run down the wall under gravity rather than jetting it in — it is slower to push and faster to dissolve.
- Do I need to inject air into the vial first?
- PREGNYL is the only approved label that describes an air step, and it runs in the direction most people get wrong: "Withdraw sterile air from vial with lyophilized powder and inject into vial with solvent." Air comes out of the powder vial and goes into the diluent vial, which pressurises the liquid you are about to remove. Doing it the other way round pressurises the vial you are about to add to. If you notice the plunger pulling back against you as you draw the diluent, that is the step you skipped.
- How much bacteriostatic water should I add?
- That is arithmetic, not procedure, and it is answered in full on the three linked pages at the top — the reconstitution chart runs vial strengths of 1 to 50 mg against diluent volumes of 0.5 to 5 mL and gives the micrograms per unit mark for each combination. What this page can add is the constraint the labels put around the choice: the volume is supposed to come from the drug’s own label. SEROSTIM’s 4 mg vial is 0.5 to 1 mL; EGRIFTA WR’s 11.6 mg vial is 1.3 mL. For a compound with no label there is no specified volume, and the number you pick is a convenience rather than a specification.
- Bacteriostatic water or sterile water?
- Whichever the drug specifies, and the difference is about the container rather than the chemistry. Bacteriostatic Water for Injection contains 0.9% or 1.1% benzyl alcohol as a preservative and is "supplied in a multiple-dose container from which repeated withdrawals may be made". Sterile Water for Injection has no preservative and comes only in single-dose containers. SEROSTIM’s own label uses both — bacteriostatic water for the 4 mg single-patient vial that will be entered repeatedly, sterile water for the 5 mg and 6 mg single-dose vials that will not. If your vial will be entered more than once, the preservative is the entire point of it.
- How do I know if I have ruined the vial?
- The labelled standard is visual and it is narrower than people assume. SEROSTIM: "SEROSTIM must not be injected if the solution is cloudy or contains particulate matter. Use the reconstituted solution only if it is clear or slightly opalescent." PREGNYL: "If there is a discoloration or particulates, do not use." HUMATROPE gives one retry — 10 more gentle movements and 5 more minutes — and then says to discard the cartridge. Be honest about the limit for an unapproved compound, though: you can detect an obviously wrong vial and you cannot confirm a correct one, because nobody has published what a correct solution of your compound looks like, and a clear liquid is not evidence of an intact molecule.
Sources
- [1]SEROSTIM (somatropin) for injection — FDA prescribing information, EMD Serono, Inc., BLA 020604, via DailyMed. Carries the most complete reconstitution technique in US labelling: aim the stream at the glass wall to prevent foaming, swirl with a gentle rotary motion, do not shake.
- [2]PREGNYL (chorionic gonadotropin) for injection — FDA prescribing information, Organon LLC, via DailyMed. Directions for Reconstitution, the only approved label we found that specifies the air-transfer step and its direction.
- [3]GENOTROPIN (somatropin) — FDA prescribing information, Pfizer Laboratories Div Pfizer Inc, via DailyMed. The only label we found that states why shaking matters: shaking may cause denaturation of the active ingredient.
- [4]HUMATROPE (somatropin) — FDA prescribing information and Instructions for Use, Eli Lilly and Company, via DailyMed. Source of the mix-wait-remix-discard sequence and of the sharps disposal instruction quoted here.
- [5]Bacteriostatic Water for Injection, USP — FDA prescribing information, Hospira, Inc., NDA 018802, via DailyMed. The diluent’s own label: aseptic technique at every entry, the conditional indication, and the instruction not to store reconstituted solutions absent a direction from the solute’s manufacturer.
- [6]U.S. Food and Drug Administration — Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, category 2 of the Bulk Substances Nominated Under Sections 503A or 503B. Read for this page: the entries for BPC-157, CJC-1295, ipamorelin acetate, GHRP-2, GHRP-6, AOD-9604 and kisspeptin-10.
Next steps
- How to inject testosterone — the injection procedure
- Peptide mcg to mg converter
- Syringe selector
- Insulin syringe conversion chart
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Educational reference, not medical advice. Every technique on this page is quoted from the label of an approved medicine that happens to be reconstituted the same way. None of it was written about a research peptide, because no research peptide has a label and several are on FDA’s category 2 list precisely because the agency says it lacks the information to know whether they would cause harm. This page contains no dose, no frequency and no cycle for any compound, and reconstituting something correctly says nothing about whether it should be injected.