- Research peptides ship as lyophilized powder because solid-state material is far more stable than solution: properly stored at −20 °C or below, a lyophilized peptide holds for years, while the same peptide in solution can degrade measurably within weeks.
- Concentration is one calculation: peptide mass in milligrams divided by solvent volume in milliliters. A 10 mg vial reconstituted with 2 mL of bacteriostatic water yields 5 mg/mL, so a 0.1 mL draw contains 0.5 mg.
- Only four peptides in common research circulation have FDA-approved human dosing on a label: semaglutide, tirzepatide, tesamorelin, and bremelanotide. For every other compound on this site there is no established human quantity, only figures carried over from animal studies or from convention.
- Published preclinical quantities are usually given per kilogram of body weight in rodents, for example the 10 µg/kg intraperitoneal figure used across the BPC-157 rat literature. Converting a rodent per-kilogram figure to a human quantity by simple multiplication is not a validated method.
- Repeated freeze-thaw cycling is among the most common causes of unexplained potency loss; a working practice is to aliquot once and treat more than three cycles as a reason to re-verify the stock rather than trust it.
Every research peptide you order arrives the same way: a small glass vial holding a dry cake or a film of powder, sealed under a rubber stopper. It arrives that way for one reason. Peptides in solution degrade on a timescale of weeks; peptides in the solid state degrade on a timescale of years. Everything in this handbook follows from that single asymmetry, including the parts that look like fussy laboratory etiquette.
This is a handling document. It covers laboratory procedure for research compounds: what solvent does what, how to compute a concentration and convert it to a draw volume, what temperature preserves what, and which routine mistakes destroy material without any visible sign. It also reports the quantities that appear in approved labels and in the published preclinical literature, because those figures are what the arithmetic is usually pointed at. Reporting a published quantity is not recommending it. Nothing here is medical advice, these compounds are for laboratory research use only, and they are not for human or veterinary use.
What "lyophilized" actually means
Lyophilization is freeze-drying. The peptide is frozen, then held under vacuum so the ice sublimes directly to vapor without passing through a liquid phase. What remains is a dry, porous cake of peptide with almost no residual water. Water is the reagent that drives the three reactions that ruin peptides: hydrolysis of the backbone, oxidation of susceptible side chains, and aggregation of chains into insoluble clumps. Take the water away and all three slow dramatically.
The cake itself is not always obvious. Depending on the fill mass and the drying cycle, it may sit as a visible plug at the bottom, cling to the vial wall, or appear as a barely-there film that looks like an empty vial held up to the light. At low fill masses, a 2 mg or 5 mg vial in particular, near-invisibility is normal and is not evidence of a short fill. Vials are filled by mass, and the batch record on the Certificate of Analysis, not the appearance of the cake, is what documents content. If you want to read that document properly, see how to read a Certificate of Analysis.
Choosing a reconstitution solvent
Solvent choice is not a style preference. It determines whether the peptide dissolves at all, how long the resulting solution stays clean, and whether the vial can be entered more than once.
| Solvent | Typical use | Why |
|---|---|---|
| Bacteriostatic water (0.9% benzyl alcohol) | Multi-draw work over days or weeks | The benzyl alcohol suppresses microbial growth, so the vial tolerates repeated entry |
| Sterile water for injection | Single-session use | No preservative, so it should be used and discarded promptly once opened |
| Dilute acetic acid (typically 0.1%) | Poorly soluble or aggregation-prone sequences | Lowers pH to solubilize basic peptides that resist neutral aqueous solvents |
| Buffered saline (PBS) | Assay-matched work | Keeps the peptide in the same ionic and pH conditions as the downstream assay |
Adding solvent to the dry cake keeps the peptide at its most favourable dissolution conditions throughout the process. Doing it in reverse drops concentrated peptide into bulk liquid, where it can locally supersaturate and aggregate before it ever disperses. This ordering is one of the few genuinely universal rules in peptide handling.
The reconstitution procedure
- Let the vial reach room temperature before you open it. A cold vial opened into warm air pulls condensation onto and into the cake, adding an unmeasured quantity of water to a calculation that depends on knowing the volume exactly.
- Swab the stopper with 70% isopropyl alcohol and let it dry. Wet alcohol carried through on the needle is contamination of a different kind.
- Add the calculated volume slowly, aimed at the vial wall. Let the stream run down the glass rather than firing it into the cake.
- Stand the vial still for a few minutes. Most peptides dissolve on their own with no intervention at all. Patience does more work here than technique.
- If material remains, roll or swirl gently. Do not shake and do not vortex. Mechanical shear and the air-liquid interface created by foaming both denature peptides and drive aggregation.
- Inspect against the light. The finished solution should be clear and free of visible particulate. Cloudiness or floating material means incomplete dissolution, an unsuitable solvent for that sequence, or aggregation already underway.
Concentration arithmetic
There is exactly one formula, and it is the one you would guess: concentration (mg/mL) = peptide mass (mg) ÷ solvent volume (mL). A 10 mg vial reconstituted with 2 mL of bacteriostatic water gives 5 mg/mL, which means a 0.1 mL draw contains 0.5 mg of peptide. Nothing about a particular compound changes this; only the numbers change.
| Vial mass | Solvent added | Resulting concentration | Mass per 0.1 mL |
|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 0.5 mg |
| 5 mg | 2 mL | 2.5 mg/mL | 0.25 mg |
| 10 mg | 2 mL | 5 mg/mL | 0.5 mg |
| 10 mg | 5 mL | 2 mg/mL | 0.2 mg |
| 20 mg | 4 mL | 5 mg/mL | 0.5 mg |
One caveat sits underneath all of it. The mass printed on a vial refers to peptide content, but many peptides are supplied as salts, most often trifluoroacetate (TFA) or acetate. In salt form, the gross powder mass and the net peptide mass are not the same number, and the difference can be ten percent or more for a highly charged sequence. The Certificate of Analysis states which basis the figure is on. If it does not, you cannot compute a concentration you can defend, and the correct move is to ask the supplier rather than assume.
From a target quantity to a draw volume
The concentration formula run backwards is what you actually use at the bench: volume (mL) = target mass (mg) ÷ concentration (mg/mL). If a protocol calls for 0.25 mg and the stock is 5 mg/mL, the draw is 0.05 mL. That is the whole conversion.
In practice the graduations on the syringe are the thing that trips people up, because the small-volume syringes used for this work are marked in units rather than milliliters. A U-100 syringe divides 1 mL into 100 units, so 1 unit is 0.01 mL, 10 units is 0.1 mL, and 50 units is half a milliliter. Units are a volume marking on the barrel and carry no information about mass. The same 20-unit draw is 0.2 mL every time, but it is 1 mg from a 5 mg/mL stock and 0.4 mg from a 2 mg/mL stock. Every unit-based figure quoted anywhere is meaningless without the concentration it was computed from.
| Target mass | From 2 mg/mL | From 2.5 mg/mL | From 5 mg/mL |
|---|---|---|---|
| 0.1 mg | 0.05 mL (5 units) | 0.04 mL (4 units) | 0.02 mL (2 units) |
| 0.25 mg | 0.125 mL (12.5 units) | 0.1 mL (10 units) | 0.05 mL (5 units) |
| 0.5 mg | 0.25 mL (25 units) | 0.2 mL (20 units) | 0.1 mL (10 units) |
| 1 mg | 0.5 mL (50 units) | 0.4 mL (40 units) | 0.2 mL (20 units) |
| 2 mg | 1 mL (100 units) | 0.8 mL (80 units) | 0.4 mL (40 units) |
Reference quantities in the literature
The figures that follow are reported, not recommended. They are drawn from FDA-approved product labels and from published animal studies, and they are here so that the arithmetic above has something concrete to work on. This site does not issue dosing guidance, and none of these numbers is medical advice or a protocol for a person. These compounds are supplied for laboratory research use only and are not for human or veterinary use.
There is a hard line running through this material, and it is worth drawing before any numbers appear. A small number of peptides are approved drugs with dosing established by clinical trials and printed on a label reviewed by a regulator. Everything else is a research compound, where the only published quantities come from animal work, from small early-phase studies, or from convention that has propagated between vendors without ever having been tested.
For the approved compounds, the label figures are public and specific:
| Compound | Approved product | Label dosing | Indication |
|---|---|---|---|
| Semaglutide | Wegovy | 0.25 mg once weekly for 4 weeks, then escalating every 4 weeks through 0.5, 1.0 and 1.7 mg to a 2.4 mg weekly maintenance dose | Chronic weight management |
| Tirzepatide | Zepbound | 2.5 mg once weekly for 4 weeks, then 5 mg weekly, with further 2.5 mg increases no sooner than every 4 weeks; maintenance 5, 10 or 15 mg weekly, 15 mg maximum | Chronic weight management |
| Tesamorelin | Egrifta | 2 mg subcutaneously once daily in the original formulation; the reformulated products are 1.4 mg (Egrifta SV) and 1.28 mg (Egrifta WR) once daily | HIV-associated lipodystrophy |
| Bremelanotide | Vyleesi | 1.75 mg subcutaneously as needed, at least 45 minutes before anticipated activity; no more than one dose in 24 hours and no more than 8 doses per month | Hypoactive sexual desire disorder in premenopausal women |
For everything else, the honest answer is that no established human quantity exists. What does exist is preclinical data, and preclinical quantities are almost always expressed per kilogram of body weight in the study animal. BPC-157 is the best-documented example: the rat literature on tendon, ligament and muscle healing runs overwhelmingly at 10 µg/kg given intraperitoneally, once daily, and that single figure recurs across a decade of papers from the same research groups. It is a real, citable number. It is also a rat number, delivered by a route almost nobody outside a laboratory uses, in a species that is not a person.
This is why you will not find a table of protocols for ipamorelin, CJC-1295, or the rest of the research catalog anywhere on this site. Not because the figures are secret, they circulate freely, but because publishing a number implies a provenance the number does not have. A quantity repeated across a hundred forum posts and a dozen vendor pages has exactly as much evidence behind it as it did the first time someone guessed it.
Whose bodies these numbers came from
The approved figures are the strongest case, and even they need reading carefully. The obesity programs behind semaglutide and tirzepatide were majority female, deliberately so: enrollment in the SURMOUNT trials was capped at 70% women precisely because otherwise the proportion would have run higher. Bremelanotide was studied in premenopausal women and is approved only for them. That is genuinely good evidence, and it is why none of those labels carries a separate dose for women: the trials were large enough and mixed enough to have found a sex effect if one mattered at the studied doses.
The research compounds are the opposite case. The preclinical work those figures come from ran, in most instances, in male animals only, for the historical reasons covered in why almost every peptide study left women out. A 10 µg/kg figure derived from male Wistar rats is not a female figure that happens to be missing a caveat. It is a male figure, and the female version was never measured. This database records that absence as unstudied rather than filling it in, and a plausible-sounding conversion would be exactly the fabrication the whole project exists to avoid.
Storage
Storage requirements change the moment the powder becomes a solution, and the useful mental model is two separate regimes rather than one sliding scale.
| State | Temperature | Typical working stability |
|---|---|---|
| Lyophilized, unopened | −20 °C or below | Long term; years under stable conditions |
| Lyophilized, unopened | 2–8 °C | Months |
| Lyophilized, in transit | Ambient | Days; tolerates shipping without a cold chain |
| Reconstituted | 2–8 °C | Days to weeks, sequence-dependent |
| Reconstituted, aliquoted | −20 °C or below | Extended, provided freeze-thaw cycling is avoided |
Protect from light in both regimes. Sequences containing tryptophan, tyrosine, methionine, or cysteine are the ones most vulnerable to photo-oxidation, and for those an amber vial or a wrap of foil is worth the thirty seconds it costs. Copper-carrier peptides such as GHK-Cu also warrant the extra care, since the metal centre is part of what makes the molecule interesting and part of what makes it reactive.
Aliquoting and freeze-thaw
If a stock underperforms for no apparent reason, freeze-thaw cycling is the first thing to suspect. The mechanism is not exotic. As a solution freezes, ice forms first and pure water leaves the liquid phase, so everything dissolved in it, peptide, buffer salts, and any residual acid, gets concentrated into a shrinking volume at the ice interface. That transient spike in concentration, pH, and ionic strength is exactly the environment in which peptides aggregate. Each cycle repeats the insult, and the loss compounds invisibly: the vial still looks fine.
Divide the reconstituted stock into single-use aliquots right after it dissolves, then freeze them. Thaw only what a given session needs and never refreeze it. A practical rule of thumb: past three freeze-thaw cycles, treat the stock as unverified and re-check activity rather than assuming the label still describes the contents.
Common handling errors
- Vortexing to speed up dissolution. Shear and foaming denature peptide. Gentle rolling and five minutes of patience are faster than reordering the vial.
- Injecting solvent straight down onto the cake. A hard stream splashes powder up onto the stopper, where it stays. You lose mass you already counted, so every concentration downstream is wrong in the same direction.
- Opening a vial straight out of the freezer. Condensation adds water you did not measure and cannot subtract.
- Storing vials in the freezer door. It is the least temperature-stable spot in the appliance and it cycles every time the door opens. Use the back of a shelf.
- Treating gross powder mass as peptide mass. Salt form matters; the Certificate of Analysis settles which basis applies.
- Leaving reconstituted material at room temperature between sessions. Degradation in solution is cumulative and temperature-driven. An afternoon on the bench is not free, it is just not visible.
Why handling belongs in an evidence database
Degradation is not sex-specific, and nothing in this handbook changes because a study population is female. It earns a place here for a different reason. The female-evidence base for most of the compounds in this database is thin to begin with, often a handful of small studies, sometimes none at all. When the underlying signal is that faint, every avoidable source of variance matters more, not less, because a result produced from a half-degraded stock cannot be distinguished from a result that simply is not there.
Material handling is one of the very few variables in this field that is entirely within your control. The literature gap is not something any individual can close this week. A vial that was equilibrated, reconstituted gently, aliquoted once, and kept cold and dark is.