How to Calculate Research Peptide Dosage (With Examples)

Calculating a research peptide dose sounds deceptively simple: weigh the powder, add solvent, inject. In practice, four compounding sources of error, nominal vs. net peptide mass, counter-ion contribution to molecular weight, purity variability across lots, and reconstitution volume inaccuracy, can combine to produce a working concentration that differs from the intended value by 20-40% or more. 1 That magnitude of systematic error is large enough to shift a dose-response curve by a full log unit, rendering mechanistic conclusions unreliable and cross-laboratory comparisons essentially meaningless.

This protocol provides a rigorous, step-by-step framework for calculating peptide dosage in research contexts. It is grounded in published analytical and formulation methodology for synthetic peptides 2 and cross-referenced against the pharmacological literature on the specific compounds most commonly used in contemporary preclinical research, including GLP-1 receptor agonists, BPC-157, and growth hormone secretagogues. 3 Each step includes the underlying rationale, failure modes, and recovery procedures. Worked numerical examples at the end translate the abstract framework into concrete laboratory arithmetic.

Quick Summary

The protocol has five core arithmetic operations, performed in sequence:

1. Determine net peptide mass, apply the purity percentage and, where relevant, the moisture/counter-ion correction.
2. Convert mass to moles, divide net mass by molecular weight.
3. Calculate target molar concentration, decide whether the experiment requires a mass-per-volume (mg/mL) or molar (µM / nM) concentration, then derive the required stock solution.
4. Compute reconstitution volume, rearrange the concentration equation to find the solvent volume needed.
5. Apply body-weight scaling for in vivo work, convert literature-reported animal-equivalent doses to the specific subject mass used in the study.

Each operation is developed in full in the step-by-step protocol section. Worked numerical examples for BPC-157 10 mg, GLP-1 analogue 5 mg, and CJC-1295/Ipamorelin follow in the dedicated examples section.

Why This Protocol Matters

The reproducibility crisis in peptide research

Reproducibility in biomedical research is a well-documented systemic problem, and peptide studies are not immune. 4 A recurring source of non-reproducibility is imprecise reagent preparation: when two laboratories use the same nominal dose but different effective concentrations, their results diverge not because of genuine biological differences but because of arithmetic and procedural inconsistency. 1

Peptides introduce several additional variables absent from small-molecule work. Commercial synthetic peptides are typically supplied as lyophilized powders with purity values ranging from roughly 85% to greater than 99% by HPLC. 2 The remainder is mostly counter-ions from the purification process (commonly trifluoroacetate, or TFA, from reversed-phase HPLC), water of hydration, and synthesis-related impurities such as deletion sequences and oxidized side-chains. 5 If a researcher weighs 1 mg of an 87%-pure peptide and treats it as 1 mg of pure compound, every downstream concentration and dose calculation is systematically high by approximately 15%.

Pharmacodynamic consequences of dose errors

The relationship between peptide dose and biological effect is rarely linear across the full concentration range relevant to research. Most receptor systems exhibit sigmoidal dose-response behavior governed by the Hill equation, meaning that small concentration errors in the steep region of the curve (EC10-EC90) translate into large apparent potency differences. 6 For immunomodulatory peptides studied in autoimmune models, the dose window separating protection from pathological priming can be narrow enough that a 20% concentration error shifts an experiment from a protective to a disease-exacerbating condition. 7

For GLP-1 receptor agonist research specifically, histological endpoints in steatohepatitis models correlate with specific exposure profiles shaped by peptide stability, hepatic uptake, and receptor kinetics, not simply with the mass injected. 8 Accurate dose calculation is therefore a prerequisite not just for good data but for correct mechanistic interpretation.

Regulatory and translational implications

Researchers who anticipate moving peptide candidates toward IND-enabling studies need accurate early-stage dosing records. Regulatory guidance on peptide APIs requires that purity, potency, and counter-ion content be documented and used in dose calculations from the earliest preclinical stages. 9 Retroactively correcting a dataset for systematic dose errors is rarely straightforward, and institutions subject to GLP (Good Laboratory Practice) audit requirements may reject retrospectively corrected data. Starting with correct arithmetic is significantly less expensive than repeating experiments.

Materials and Equipment

Step-by-Step Protocol

Step 1, Retrieve and verify the Certificate of Analysis

Before touching the vial, download the lot-specific CoA from the supplier. Verify that the lot number on the physical vial matches the CoA exactly. Record the following values: HPLC purity (%), molecular weight (g/mol) as stated on the CoA, counter-ion identity and mass fraction if reported, and moisture content from Karl Fischer analysis if available. 2

Rationale. Two vials of the same peptide from different lots may differ in purity by 5-15 percentage points. Using an outdated or catalog-level purity figure introduces a systematic error that compounds with every subsequent dilution. Published guidelines on peptide reference standards recommend lot-specific documentation as a minimum standard for quantitative analytical work. 10

Failure mode. Researchers frequently accept the label claim ("≥95% purity") without checking the actual lot value. If the true lot purity is 91%, and the label claim is ≥95%, the researcher is working with a 4.2% systematic overestimate before any other errors are introduced.

Step 2, Calculate net peptide mass (purity-corrected)

The nominal mass weighed on the analytical balance includes impurities. To obtain the net mass of the active peptide, apply the purity correction:

Net peptide mass (mg) = Weighed mass (mg) × [Purity (%) ÷ 100]

If a Karl Fischer moisture value (W%) and a counter-ion mass fraction (CI%) are also available, the fully corrected formula is:

Net peptide mass (mg) = Weighed mass (mg) × [(Purity%) ÷ 100] × [1 − (W% + CI%) ÷ 100]

Rationale. TFA counter-ions are the dominant non-peptide component in HPLC-purified synthetic peptides. A study comparing gravimetric and quantitative NMR methods for peptide reference standards found that TFA content accounted for 3-18% of lyophilized mass across a panel of 12 representative peptides, with larger, more basic sequences (containing multiple Arg, Lys, or His residues) incorporating more TFA per molecule. 5 Ignoring TFA content systematically overestimates effective peptide mass, which translates directly into overstated concentrations.

Failure mode. Researchers who skip this step and work from nominal weighed mass will consistently overestimate their working concentration. The error is reproducible within a lot (so within-study precision is maintained) but biases all absolute potency and EC50 estimates high.

Step 3, Determine the molecular weight to use

The CoA molecular weight (MW) is the mass of the free-acid or free-base form of the peptide as synthesized. If the peptide is supplied as a salt (e.g., trifluoroacetate salt or acetate salt), the MW on the CoA may reflect the salt form, not the free peptide. Clarify this with the supplier if the CoA is ambiguous. 2

For molar concentration calculations, use the MW of the peptide backbone (free acid form) unless you are specifically interested in the salt form for stability modeling. The free-acid MW is the value most commonly reported in primary literature and used in pharmacological databases.

Worked check. BPC-157 free acid: MW = 1419.56 g/mol. If the CoA lists MW = 1419.56 and specifies "trifluoroacetate salt," the actual MW in solution is approximately 1419.56 + (114.02 × number of TFA counter-ions). For a peptide with two basic residues, add ~228 g/mol to get the salt MW. Use the free-acid MW (1419.56) for molar dose calculations referenced against the pharmacological literature.

Step 4, Convert mass to moles

Moles = Net peptide mass (g) ÷ MW (g/mol)

Because research quantities are typically in the milligram range and concentrations in the micromolar to nanomolar range, it is convenient to work in micromoles and µg:

Micromoles (µmol) = Net peptide mass (µg) ÷ MW (g/mol)

Rationale. Molar units are essential for receptor binding studies, enzyme kinetics, and any experiment that will be compared to a published Ki, Kd, or EC50 value, all of which are expressed in molar terms. 6 Mass-per-volume units (mg/mL) are sufficient for in vivo dosing when the literature protocol you are replicating also uses mass-per-volume, but they cannot be directly compared across peptides of different MW.

Step 5, Define the target concentration and working volume

Decide, before touching any solvent, what concentration you need and in what total volume:

• Stock solution concentration (typically 1-10 mg/mL or 1-10 mM for in vitro; 0.1-1 mg/mL for in vivo vehicle)
• Working solution concentration (the concentration delivered to the assay or animal)
• Total volume needed (accounts for dead volume in syringes, aliquot overage, stability replicates)

Write these values down explicitly. Stock solutions are prepared at higher concentration than working solutions to allow dilution into the appropriate vehicle. For in vivo work, ensure the injection volume per animal body weight is within physiologically acceptable limits, typically ≤10 mL/kg for subcutaneous routes and ≤5 mL/kg for intravenous routes in rodents. 11

Step 6, Calculate the reconstitution volume

Rearrange the basic concentration equation:

Volume (mL) = Net peptide mass (mg) ÷ Target stock concentration (mg/mL)

Or in molar terms:

Volume (mL) = Net moles (µmol) ÷ Target stock concentration (µM) × 1000

Add solvent in two portions: approximately 80% of the target volume first, mix gently (do not vortex, see reconstitution guide at /guides/how-to-reconstitute-peptides), then bring to final volume with the remaining 20%. This technique minimizes concentration error from incomplete dissolution before final volume adjustment. 2

Failure mode. Adding the full target volume at once, then discovering incomplete dissolution and adding more solvent to force it, results in an unknown final volume and therefore an unknown concentration. Always confirm complete dissolution before adjusting to final volume.

Step 7, Calculate the working dilution

Stock-to-working dilutions follow the standard dilution equation:

C₁ × V₁ = C₂ × V₂

Where C₁ = stock concentration, V₁ = volume of stock to take, C₂ = target working concentration, V₂ = final working solution volume.

Rearrange to find V₁:

V₁ = (C₂ × V₂) ÷ C₁

For serial dilutions (commonly used to generate dose-response curves), calculate each step independently and verify that the dilution factor at each step is within the accurate transfer range of your pipettes (typically ≥1:10 for single-channel mechanical pipettes; go to ≥1:5 if using manual delivery for viscous solutions).

Step 8, Apply body-weight scaling for in vivo experiments

In vivo research doses reported in the literature are expressed as mass per unit body weight (e.g., µg/kg or mg/kg). To calculate the dose for a specific animal:

Dose volume (mL) = [Dose (µg/kg) × Animal body weight (kg)] ÷ Stock concentration (µg/mL)

Verify that the resulting dose volume is within the acceptable range for the chosen route of administration and species. If it is not, adjust the stock concentration, not the dose, to bring the injection volume into range. 11

Allometric scaling note. Direct mg/kg extrapolation from rodent to larger species is not biologically equivalent due to differences in metabolic rate and clearance. Human equivalent dose estimates from animal data use the body surface area normalization method (multiply animal mg/kg dose by the animal-to-human Km ratio), but this is beyond the scope of a dosage calculation protocol and should follow published FDA guidance on allometric scaling. 12

Step 9, Document everything

Record in your lab notebook (or electronic equivalent): lot number, CoA purity, MW used, weighed mass, calculated net mass, solvent identity, total volume, calculated concentration, date, and operator initials. This documentation forms the audit trail required for GLP compliance and is essential for troubleshooting if unexpected results arise. 9

Common Mistakes to Avoid

1. Using nominal mass instead of purity-corrected net mass. This is the single most common arithmetic error. A peptide at 88% purity weighed at 1.000 mg provides only 0.880 mg of active compound. Using 1.000 mg in the concentration formula overstates concentration by 13.6%.

2. Using catalog MW instead of lot-specific MW. Synthetic peptides are sometimes modified post-synthesis (e.g., oxidation of methionine, deamidation of asparagine) in ways that alter MW slightly. Lot-specific CoA values capture these differences; catalog values do not.

3. Vortexing the peptide solution. Vigorous vortex mixing introduces air-liquid interfaces that promote peptide aggregation and oxidation, particularly for cysteine-containing and amphipathic sequences. 2 Use gentle swirling or end-over-end rotation.

4. Ignoring adsorption to tube surfaces. Hydrophobic and amphipathic peptides adsorb to polypropylene surfaces, particularly at low concentrations (sub-µM range). Use siliconized or low-binding tubes, and add carrier protein (0.1% BSA) if working below ~100 nM. 13

5. Neglecting dead volume. A 1 mL syringe retains approximately 50-100 µL of dead volume. If you prepare exactly 1.00 mL of working solution and fill a 1 mL syringe, the delivered volume may be 0.90-0.95 mL. Always prepare 10-20% more than the minimum needed.

6. Confusing mg/mL with µg/µL. These are numerically identical (1 mg/mL = 1 µg/µL), but mixing mass-per-volume units with molar units in the same calculation without explicit conversion is a frequent source of off-by-1000 errors. Use SI prefixes consistently throughout a calculation and convert only at the final step.

7. Storing stock solutions in large aliquots. Repeated freeze-thaw cycles degrade many peptides, particularly those with disulfide bonds or oxidation-susceptible residues. Prepare stock aliquots sized for single-use and store in cryogenic conditions (-20°C or -80°C depending on peptide stability). 2

8. Assuming all solvents are equivalent. The choice of reconstitution solvent affects both solubility and long-term stability. Bacteriostatic water is appropriate for most aqueous-soluble peptides intended for in vivo research. Acetic acid (0.1-1%) improves solubility for hydrophobic and cationic peptides. DMSO is effective for lipophilic sequences but is cytotoxic above ~0.5% in cell assays and is not suitable for in vivo vehicle without careful formulation. 14

Advanced Considerations

Peptide purity and counter-ion correction in detail

The TFA counter-ion issue deserves expanded discussion because it affects dosage calculation in a non-obvious way. Synthetic peptides purified by reversed-phase HPLC with TFA-containing mobile phases retain TFA as an ion pair with basic residues. 5 The number of TFA molecules per peptide molecule is not constant, it depends on the number and accessibility of basic residues (Arg, Lys, His, N-terminus) and on the lyophilization conditions used to prepare the final product.

For a peptide with three basic residues, TFA content can contribute 5-15% of total lyophilized mass, depending on these factors. If you weigh 10 mg of such a peptide and apply only the HPLC purity correction, you may still overestimate net peptide mass by several percent because the purity assay by HPLC (UV at 214 or 220 nm) measures peptide bond absorbance and does not directly measure TFA content.

A more rigorous approach uses quantitative NMR (qNMR) with an external reference standard, which can simultaneously quantify peptide content and counter-ion content in a single measurement. 10 For laboratory contexts where qNMR is not available, requesting a Karl Fischer moisture value and an ion chromatography counter-ion measurement from the supplier provides sufficient data to apply the full correction described in Step 2.

Molar concentration vs. mass concentration: when each is appropriate

Mass-per-volume concentrations (mg/mL, µg/mL) are appropriate when: (a) you are replicating a published in vivo protocol that used the same peptide and the same MW, (b) you are performing pharmacokinetic studies where plasma concentrations are measured by LC-MS/MS using stable isotope-labeled peptide internal standards calibrated in mass units, or (c) the biological assay endpoint is calibrated against a mass-based standard curve.

Molar concentrations (µM, nM) are appropriate when: (a) comparing potency across peptides of different MW, (b) receptor binding or competition assays where affinities are expressed as Ki or Kd in molar units, (c) enzyme kinetics experiments where Km and Vmax are in molar terms, or (d) in silico pharmacological modeling using published molar parameters. 6

The conversion is straightforward but must be performed explicitly:

Concentration (µM) = Concentration (mg/mL) × 1000 ÷ MW (g/mol)

For example, a 1 mg/mL solution of BPC-157 (MW = 1419.56 g/mol) is: 1000 ÷ 1419.56 = 0.705 µM = 705 nM.

Extinction coefficient-based concentration verification

For peptides containing tyrosine (Tyr), tryptophan (Trp), or disulfide-bonded cysteine (Cys-Cys), UV absorbance at 280 nm can provide an independent check on concentration after reconstitution. The molar extinction coefficient (ε₂₈₀) can be calculated from sequence using the Pace formula: 15

ε₂₈₀ (M⁻¹ cm⁻¹) = (n_Trp × 5500) + (n_Tyr × 1490) + (n_Cys-Cys × 125)

Measure absorbance at 280 nm and apply Beer-Lambert:

Concentration (M) = A₂₈₀ ÷ (ε₂₈₀ × path length in cm)

This method is useful but has limitations: peptides lacking aromatic residues cannot be quantified this way, and TFA and other co-solutes absorb at shorter wavelengths (205-220 nm) where peptide bond absorbance is measured, complicating low-wavelength UV quantification. For critical quantitative work, amino acid analysis (AAA) remains the gold standard for peptide content determination. 10

Stability and shelf-life considerations affecting effective dose

A peptide solution prepared at the correct concentration today may not deliver the same effective dose in 72 hours if stored incorrectly. Stability studies on synthetic peptides show that degradation rates depend on peptide sequence, solvent, pH, temperature, and oxygen exposure. 16 For GLP-1 analogues, dipeptidyl peptidase-4 (DPP-4) cleavage at the His-Ala N-terminal dipeptide is the principal degradation pathway in solution 3, which is why research formulations of GLP-1(7-36)NH₂ are typically stored at -80°C in single-use aliquots and never thawed more than once.

BPC-157 (pentadecapeptide GEPPPGKPADDAGLV) is relatively resistant to proteolysis under physiological conditions, but undergoes oxidative degradation when exposed to light or atmospheric oxygen over extended periods. 17 Storage at -20°C in light-proof, argon-purged vials extends shelf life. When calculating doses from stock solutions that have been stored for more than 2-4 weeks, running a parallel HPLC or LC-MS purity check provides assurance that the assumed concentration still reflects actual peptide content.

Working with peptide mixtures: CJC-1295 / Ipamorelin combination

Some research protocols use co-administration of two peptides, most commonly CJC-1295 (a GHRH analogue) with Ipamorelin (a selective GHS-R agonist) to study synergistic growth hormone secretagogue effects. 18 When two peptides are combined in a single vehicle, the dosage calculation must be performed independently for each compound, then combined into the final injection volume.

The calculation sequence:

1. Calculate net mass and molar amount for each peptide separately.
2. Prepare individual stock solutions.
3. Combine the appropriate volumes of each stock to achieve the target dose ratio in the final injection volume.
4. Verify that the combined solution's pH and solubility are compatible (mixing acidic and basic stock solutions can cause precipitation).

Do not co-lyophilize two research peptides and dissolve as a mixture without first verifying that their reconstitution solvent requirements are identical and that the two compounds do not interact chemically.

Troubleshooting

After the Protocol, Documentation and Storage

Laboratory documentation requirements

Every peptide dosage preparation should be documented with sufficient detail that an independent researcher could reproduce the preparation exactly. At minimum, record:

• Peptide name, catalog number, lot number
• CoA purity (%), MW (g/mol), counter-ion (if stated), moisture (if measured)
• Weighed mass (mg), analytical balance ID, calibration date
• Net calculated mass (mg), showing the purity correction arithmetic
• Solvent identity, lot, and volume added
• Final calculated concentration (both mg/mL and µM)
• Date and time of preparation, preparer initials
• Storage conditions and planned use-by date

For GLP-compliant studies, documentation must be contemporaneous (written at the time of the action), signed, and stored in a retrievable format per institutional SOP. 9

Storage conditions by peptide class

Different peptide classes require different storage conditions, and selecting the wrong condition can result in a significant reduction in effective concentration over time. The guidance below reflects published stability data: 16

Lyophilized peptide (undissolved): Store at -20°C, desiccated, light-protected. Most research peptides are stable for 24 months under these conditions. Some oxidation-sensitive sequences (Met, Cys) require -80°C.

Aqueous stock solutions (≥1 mg/mL): Store at -20°C in single-use aliquots. Limit freeze-thaw cycles to ≤2 for most sequences. GLP-1 analogues and GHRH analogues: -80°C preferred.

Working dilutions (<100 µg/mL): Prepare fresh from stock immediately before use. Peptide adsorption to tube surfaces and microbial contamination risk increase significantly at low concentrations, and long-term stability at working concentrations is rarely established. 2

DMSO solutions: Store at -20°C, sealed with Parafilm to prevent moisture absorption. DMSO freezes at 18°C, so frozen DMSO stocks must be thawed completely and mixed before use.

Linking dosage records to experimental outcomes

A dosage record that is not linked to the experimental outcome file has limited utility. Use a consistent file naming convention or electronic lab notebook (ELN) linking that connects each preparation record to the raw data from the experiment that consumed it. If a result is unexpected, the first question should always be: was the dose what we calculated it to be? Having the preparation record linked to the result file makes this check immediate rather than requiring a retrospective search.

For information on cycle design and dosing frequency for in vivo peptide studies, see our guide at /guides/how-to-cycle-peptides.

Worked Examples

Example 1, BPC-157 10 mg vial, 500 µg/mL stock, rodent in vivo

Given:

• Vial contains: 10 mg nominal BPC-157
• CoA purity: 98.2%
• MW (free acid): 1419.56 g/mol
• Counter-ion: TFA; moisture not reported
• Target stock concentration: 500 µg/mL (0.500 mg/mL)
• Reconstitution solvent: bacteriostatic water

Step 1, Net mass: Net mass = 10.000 mg × (98.2 ÷ 100) = 9.820 mg

Step 2, Molar amount: Moles = 9.820 mg ÷ 1419.56 g/mol = 0.006918 mmol = 6.918 µmol

Step 3, Reconstitution volume for 500 µg/mL stock: Volume = 9.820 mg ÷ 0.500 mg/mL = 19.64 mL

This volume is large for a typical bench prep. In practice, if only a fraction of the vial is being used, reconstitute proportionally. For example, to use 1 mg of the 10 mg vial:

Net mass of 1 mg weighed portion = 1.000 × 0.982 = 0.982 mg Volume = 0.982 mg ÷ 0.500 mg/mL = 1.964 mL → round to 1.96 mL

Step 4, Molar concentration of this stock: Molar conc = 0.500 mg/mL × 1000 ÷ 1419.56 g/mol = 0.352 µM = 352 nM

Step 5, Dose calculation for a 250 g rat at a literature-reported research dose of 10 µg/kg: Dose per animal = 10 µg/kg × 0.250 kg = 2.5 µg Volume from 500 µg/mL stock = 2.5 µg ÷ 500 µg/mL = 0.005 mL = 5 µL

A 5 µL injection volume is below the practical accuracy limit of most pipettes without a Hamilton syringe. Adjust stock concentration down to 50 µg/mL to achieve a more practical 50 µL injection volume:

Dilution: C₁ × V₁ = C₂ × V₂ → V₁ = (50 µg/mL × 1.0 mL) ÷ 500 µg/mL = 0.100 mL (100 µL) of stock into 900 µL saline.

See our BPC-157 10 mg product review for details on lot-specific purity values from this catalog product.

Example 2, GLP-1 analogue 5 mg vial, in vitro receptor assay at 100 nM

Given:

• Vial contains: 5 mg nominal GLP-1(7-36)NH₂ analogue
• CoA purity: 96.4%
• MW: 3298.7 g/mol (free acid)
• Target working concentration: 100 nM in cell culture medium
• Final assay volume: 10 mL
• Reconstitution solvent: sterile PBS pH 7.4

Step 1, Net mass: Net mass = 5.000 mg × 0.964 = 4.820 mg

Step 2, Molar amount: µmol = (4.820 mg × 1000 µg/mg) ÷ 3298.7 g/mol = 4820 µg ÷ 3298.7 = 1.461 µmol

Step 3, Stock concentration (aim for 100 µM to allow 1:1000 dilution to 100 nM): Volume for 100 µM stock = 1.461 µmol ÷ 100 µmol/mL = 0.01461 mL

That is only 14.6 µL, too small for accurate measurement. Lower stock concentration to 1 µM: Volume = 1.461 µmol ÷ 1 µmol/mL = 1.461 mL

Step 4, Achieve 100 nM working solution via serial dilution: First dilution: 1 µM → 10 nM (1:100 in medium, intermediate stock) V₁ = (10 nM × 10 mL) ÷ 1000 nM = 0.100 mL (100 µL) into 9.900 mL medium

Wait, this gives 10 nM, not 100 nM. Correct the target dilution: 1 µM → 100 nM requires 1:10 dilution: V₁ = (100 nM × 10 mL) ÷ 1000 nM = 1.00 mL into 9.00 mL medium ✓

Step 5, Verify mass-equivalent: 100 nM × 3298.7 g/mol = 329.87 µg/L = 0.330 µg/mL = 0.330 ng/µL

This confirms the working solution contains approximately 330 ng/mL, consistent with published in vitro GLP-1 receptor assay concentrations in the literature. 3

For details on this compound see our GLP-1S 5 mg product review.

Example 3, CJC-1295 / Ipamorelin combination, separate stocks, combined injection

Given:

• CJC-1295: 2 mg vial, purity 97.1%, MW = 3367.9 g/mol
• Ipamorelin: 2 mg vial, purity 98.8%, MW = 711.9 g/mol
• Literature research protocol dose: CJC-1295 at 1 µg/kg + Ipamorelin at 1 µg/kg (rodent model)
• Animal body weight: 300 g rat
• Target injection volume: 200 µL subcutaneous
• Reconstitution solvent: bacteriostatic water for both

Step 1, Net masses: CJC-1295 net = 2.000 × 0.971 = 1.942 mg Ipamorelin net = 2.000 × 0.988 = 1.976 mg

Step 2, Per-animal doses: Both peptides dosed at 1 µg/kg × 0.300 kg = 0.300 µg per animal

Step 3, Combined injection volume = 200 µL = 0.200 mL. Each peptide contributes 100 µL of its stock: Required stock concentration for each: Concentration = 0.300 µg ÷ 0.100 mL = 3.0 µg/mL = 0.003 mg/mL

Step 4, Reconstitution volume for each stock at 0.003 mg/mL: CJC-1295: 1.942 mg ÷ 0.003 mg/mL = 647 mL, this is far too large for bench use.

Instead, prepare a concentrated intermediate stock and dilute: CJC-1295 concentrated stock: dissolve 1.942 mg in 2.0 mL → 0.971 mg/mL Dilution to 0.003 mg/mL: V₁ = (0.003 × 10 mL) ÷ 0.971 = 0.0309 mL (30.9 µL) into 9.969 mL saline

Similarly for Ipamorelin: Concentrated stock: 1.976 mg in 2.0 mL → 0.988 mg/mL Dilution to 0.003 mg/mL: V₁ = (0.003 × 10 mL) ÷ 0.988 = 30.4 µL into 9.970 mL saline

Step 5, Prepare combined injection: Draw 100 µL of CJC-1295 working solution (0.003 mg/mL) + 100 µL of Ipamorelin working solution (0.003 mg/mL) into the same syringe immediately before injection. Verify pH compatibility (both solutions in buffered saline at pH ~7.0-7.4; no precipitation expected).

Molar check: CJC-1295: 0.300 µg ÷ 3367.9 g/mol = 0.0891 nmol = 89.1 pM per animal Ipamorelin: 0.300 µg ÷ 711.9 g/mol = 0.4214 nmol = 421 pM per animal

The molar ratio CJC-1295:Ipamorelin is approximately 1:4.7 despite equal mass dosing, because Ipamorelin is ~4.7× smaller by MW. Researchers replicating molar-dose protocols from the literature should adjust mass accordingly.

See our related CJC-1295/Ipamorelin product page and GLP-2T 15 mg review for lot-specific MW data.

FAQ