The A lyophilized vial is a vial of medication that has been freeze-dried into a powder and is reconstituted with a liquid before use. Lyophilization is the pharmaceutical word for freeze-drying. BrightSide's compounded NAD+ and glutathione injections come as a liquid in a vial, not as a lyophilized powder.
What is lyophilization?
Lyophilization is freeze-drying. FDA's inspection guide for lyophilized injectable drugs defines it as a process in which water is removed from a product after it is frozen and placed under a vacuum, so the ice changes directly from solid to vapor without passing through a liquid phase. The guide describes three stages: freezing, primary drying and secondary drying. The drug is first dissolved, sterilized by filtration and filled into sterile vials, and the vials are then frozen and dried with their stoppers partly in place. FDA lists the advantages as enhanced stability of a dry powder, removal of water without excessive heating of the product, and rapid and easy dissolution when the product is reconstituted. It lists the need for a sterile diluent at reconstitution among the disadvantages. The guide says products are made in lyophilized form because of their instability when in solution.
How does a lyophilized vial apply to compounded GLP-1 treatment?
A lyophilized vial matters when a medication is supplied as a powder, and the FDA-approved GLP-1 injections are not. The Zepbound label describes a clear, colorless to slightly yellow solution in pens and vials. The Wegovy label describes a clear, colorless solution. Compounded medications vary by pharmacy and by drug, so the form is something to confirm for each prescription. A vial that holds a dry cake or powder is lyophilized and has to be mixed with a liquid before it can be injected. A vial that holds a liquid is drawn up as supplied. BrightSide's NAD+ injection and glutathione injection both come as a liquid in a vial. For any prescription, the pharmacy label and instructions say what is in the vial and how to use it. Our pharmacy network page covers how we choose pharmacies.
What does a lyophilized vial look like on an FDA-approved label?
On a label, a lyophilized vial is described as a powder for reconstitution, with the liquid and the steps named. For a powdered medication you mix with bacteriostatic water before injecting, the label describes the powder and the vial, names bacteriostatic water as the diluent, and gives the mixing steps and how long the mixed solution keeps. FDA's list of dosage form names for drug labels has separate entries for an injection supplied as a solution and for an injection supplied as a lyophilized powder for solution. Those steps and times belong to each product. A different lyophilized drug has its own liquid, its own volume and its own storage time.
| Lyophilized vial | Solution vial | |
|---|---|---|
| What is in the vial | A freeze-dried powder | A liquid |
| Before injecting | Reconstituted with a sterile diluent | Drawn up as supplied |
| FDA dosage form name | Injection, powder, lyophilized, for solution | Injection, solution |
| Label example | A powdered medication you mix with bacteriostatic water before injecting | Zepbound vial: clear, colorless to slightly yellow solution |
| Why it is made this way | FDA: products are lyophilized because of their instability in solution | Supplied ready to use |
Common questions
Why are some medications freeze-dried?
For stability. FDA's inspection guide says products are manufactured in lyophilized form because of their instability when in solution, and it lists enhanced stability of a dry powder among the advantages. The trade-off FDA names is the need for a sterile diluent when the product is reconstituted, along with added handling and processing time.
Do you shake a lyophilized vial after adding the liquid?
Follow the label for that product. The label for a powdered medication you mix with bacteriostatic water before injecting says how to mix it, including whether to swirl the vial or shake it. For a compounded prescription, the instructions come from the pharmacy, and your provider can answer questions in your patient portal.
Related terms
- Bacteriostatic water and reconstitution: the liquid often used to mix a lyophilized powder, and the mixing step.
- Subcutaneous injection: how the mixed medication is given.
- Beyond use date (BUD): the date after which a compounded vial must not be used.
- Compounded medication: a drug a pharmacy makes for one patient.
Sources
- FDA, Inspection guide: Lyophilization of parenterals (7/93), content current as of November 11, 2014: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/inspection-guides/lyophilization-parenteral-793
- FDA, Structured product labeling resources: dosage forms, content current as of February 3, 2022: https://www.fda.gov/industry/structured-product-labeling-resources/dosage-forms
- Zepbound (tirzepatide) prescribing information, Eli Lilly, revised 8/2026, on DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b
Compounded medications are not FDA approved. They are prescribed by a licensed clinician and filled by a licensed 503A pharmacy.
