> For the complete documentation index, see [llms.txt](https://peptara-labs.gitbook.io/peptaralabs-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://peptara-labs.gitbook.io/peptaralabs-docs/03-reconstitution-math.md). # 03 reconstitution math This page explains the arithmetic behind reconstitution. It is an educational reference on how concentration and syringe markings relate to each other. It does not recommend any dose, volume, or schedule. Peptides sold by [Peptara Labs](https://www.peptaralabs.io/) are research compounds, not approved medicines. For the full step-by-step walkthrough, see the [Peptara Labs reconstitution page](https://www.peptaralabs.io/reconstitution). ## What Lyophilized Powder Is Many research peptides ship as a lyophilized powder. Lyophilization is freeze-drying: the water is removed under vacuum, leaving a dry solid in the vial. The powder is stable in this form but is not a solution yet. The amount of peptide in the vial is stated in milligrams (mg) on the product label and the accompanying Certificate of Analysis. Reconstitution simply means adding a liquid back to the powder so it dissolves into a solution. The liquid commonly used is bacteriostatic water, a sterile water that contains a preservative. Adding the water does not change how many milligrams of peptide are in the vial. It only changes how that fixed amount is distributed through a volume of liquid. ## Concentration Is Milligrams Divided by Millilitres Once the powder is dissolved, the solution has a concentration. Concentration is the amount of peptide per unit of liquid, written as milligrams per millilitre (mg per mL). The formula is: **concentration (mg per mL) = milligrams of peptide in the vial / millilitres of water added** The milligrams come from the label and the Certificate of Analysis. The millilitres are however much bacteriostatic water you add. Add less water and the concentration is higher. Add more water and the concentration is lower. The total milligrams in the vial stay the same either way. ## How a U-100 Insulin Syringe Is Marked An insulin syringe is marked in units, not in millilitres. The most common type is labeled U-100, which means it is calibrated so that 100 units equals 1 millilitre. Units are a volume marking on this syringe, not a measure of peptide on their own. Because 100 units equals 1 mL on a U-100 syringe, you can convert between the two: **units = millilitres x 100** So 1 mL is 100 units, half a millilitre is 50 units, and one tenth of a millilitre is 10 units. This conversion is a property of the syringe markings and does not depend on what is inside the vial. To go from a volume of solution to the milligrams it contains, you multiply the volume by the concentration: **milligrams = millilitres x concentration (mg per mL)** Combining the two relationships lets you move between units on the syringe and milligrams in the solution, using only multiplication and division. ## One Illustrative Arithmetic Example The following is illustrative arithmetic only. It is included to show how the formulas work. It is not a dose, not a protocol, and not a recommendation. The numbers are chosen to be easy to follow, not to suggest any particular amount. Suppose a vial contains 10 mg of peptide and 2 mL of bacteriostatic water is added. * Concentration = 10 mg / 2 mL = **5 mg per mL** * On a U-100 syringe, 1 mL is 100 units, so the full 2 mL of solution is 200 units total. * Each 1 mL drawn (100 units on the syringe) contains 5 mg, because concentration is 5 mg per mL. * Each 0.1 mL drawn (10 units on the syringe) contains 0.5 mg, since 0.1 mL x 5 mg per mL = 0.5 mg. That is the whole of the math: divide milligrams by millilitres to get concentration, and multiply millilitres by 100 to read the volume in units. Changing the volume of water changes the concentration and therefore changes how many milligrams sit behind any given unit marking. ## What This Page Does Not Tell You This page does not tell you how much water to add, how many units to draw, or how often to do anything. Those decisions belong to your own research plan and are not covered here. Always work from the actual figures on the product label and the per-batch Certificate of Analysis for the specific vial in front of you, since the milligram amount is what drives every calculation above. For Peptara Labs reconstitution guidance and the full method, see the [reconstitution page](https://www.peptaralabs.io/reconstitution). To review what each compound ships with, including its third-party Certificate of Analysis, visit [peptaralabs.io](https://www.peptaralabs.io/). --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. 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