GLP-1 and urological health: separating signal from hype

What did @socalurologyinstitute actually say?

A urologist at SoCal Urology Institute posted a reply to a viewer question about mixing compounded GLP-1 medications at home. He walked through the basic arithmetic of diluting a lyophilized peptide vial with bacteriostatic water, using two examples: a 30 mg tirzepatide vial and a 2 mg semaglutide vial. His core claim was simple: "if you put in a CC of bacteriostatic water, each 0.1 will be 3 milligrams" for the 30 mg vial. He was trying to explain the 1:10 ratio that emerges when you add 1 mL of diluent to a powder and draw doses in 0.1 mL increments. The video is clearly a response to real patients who are self-injecting compounded peptides purchased online without professional guidance.

This is a real public health situation. Compounded semaglutide and tirzepatide have exploded in use since FDA shortage designations opened the door for 503A and 503B compounders. People are absolutely out there with vials and syringes, guessing at math.

Does the science back this up?

The dilution math itself is correct in principle, but the framing strips out everything that actually matters. Yes, adding 1 mL of bacteriostatic water to a dry powder and drawing 0.1 mL increments divides the total mass by 10. That is basic pharmaceutical arithmetic, not a controversial claim.

The problem is that this framing assumes the powder dissolved completely and uniformly, that the vial actually contains what the label says, and that the person at home has the sterile technique and equipment to execute this safely. None of those assumptions are safe to make. A 2023 analysis published by the U.S. Pharmacopeia found significant variability in peptide content among compounded GLP-1 preparations tested from online sources. Separately, the FDA issued multiple warnings in 2023 and 2024 about dosing errors with compounded semaglutide, specifically because patients were confusing mg and mL, or miscalculating after non-standard reconstitution volumes. The math he presents only works cleanly if you add exactly 1 mL. Change that volume and everything shifts.

What did they get wrong (or right)?

He got the core ratio right. If you add 1 mL to 30 mg, each 0.1 mL is 3 mg. That arithmetic holds. Credit where it is due.

But here is where it breaks down. He says "bacteria static water" twice, which is a minor verbal slip, but more importantly he presents one reconstitution volume as if it is the only one. Many compounders and prescribers use 2 mL, 3 mL, or other volumes depending on the peptide concentration and the dosing protocol. A patient who watches this video, then reconstitutes with 2 mL instead of 1 mL, and follows his math, will inject twice the dose they intended. That is not a hypothetical. The FDA's MedWatch database contains reports of exactly this error pattern. He also does not mention that compounded tirzepatide base (not salt form) has different stability and absorption characteristics than the brand-name formulation. Calling it "30 milligrams of tirzepatide" as if it is a uniform product glosses over real quality variation between compounders.

• The 1 mL reconstitution assumption is not universal and he does not say so.
• He gives no guidance on sterile technique, needle gauge, or injection site.
• He does not distinguish between compounded and FDA-approved formulations.

What should you actually know?

If you are reconstituting a compounded GLP-1 at home, the single most important thing is not the ratio. It is knowing exactly how much diluent you are adding and matching your dose calculation to that specific volume. Every calculation resets with every reconstitution volume change.

The FDA issued a safety communication in May 2024 specifically about compounded semaglutide dosing errors, noting that some products were labeled in units that patients misread as milligrams. Tirzepatide compounding had its own back-and-forth: the FDA removed tirzepatide from the shortage list in late 2024, which raised questions about the legality of continued compounding. If you are using compounded versions, ask your prescriber for written reconstitution instructions tied to the exact vial and diluent volume you have, not a general ratio from a TikTok video. A telehealth provider or pharmacist can walk through this with you for your specific product. General math tutorials, even accurate ones, are not a substitute for product-specific guidance.