GLP-1 side effects and tips: what TikTok gets right and wrong

What did @erin.e.arnold actually say?

The creator walked through a specific reconstitution calculation for what she called "tricep attack" (clearly tirzepatide) at a 5 mg weekly dose. She said to take a "20 mg violin" (vial), add "2 ml or 200 units of backwater" (bacteriostatic water), then pull "50 units per shot" to hit a 5 mg dose. Her conclusion: one vial gives you four doses.

That's the whole video. No disclaimers, no mention of a prescribing provider, no acknowledgment that this is a compounded peptide rather than an FDA-approved branded product. Just math, delivered casually, to 34,000 viewers who are presumably trying to inject themselves with a compounded GLP-1 at home.

The math itself is worth examining carefully. So is the context around it, which is where things get genuinely problematic.

Does the science back this up?

The reconstitution math is internally consistent, but the framing erases critical variables that make it unreliable for real-world use.

Tirzepatide, the active ingredient in FDA-approved Mounjaro and Zepbound, is a dual GIP/GLP-1 receptor agonist. The branded injectable comes in pre-filled, pre-dosed pens. Compounded tirzepatide, which is what this video describes, is a lyophilized powder or liquid that requires reconstitution before injection. The FDA has repeatedly warned that compounded versions are not the same as FDA-approved drugs and have not been evaluated for safety, efficacy, or sterility (FDA Drug Safety Communication, 2024).

Here is where the math gets slippery. Adding 2 mL of bacteriostatic water to a 20 mg vial gives you a concentration of 10 mg/mL. If you pull 50 units on a U-100 insulin syringe, you are pulling 0.5 mL, which at 10 mg/mL equals 5 mg. The arithmetic works. But "units" on an insulin syringe is not a standardized measure for peptides. It is a volume proxy specific to U-100 insulin syringes, and using that language without explanation creates real room for dosing error if someone uses a different syringe type.

What did they get wrong (or right)?

The math is right, assuming a U-100 syringe and exact vial labeling. Credit where it is due.

But several things are wrong or missing. First, the language is dangerously sloppy. "Units" means something specific in pharmacology and something different when used as a volume shortcut for insulin syringes. A viewer with a U-40 syringe or a 0.5 mL syringe with different gradations would miscalculate their dose using this guidance.

Second, there is no mention that compounded tirzepatide concentration can vary by pharmacy. A vial labeled "20 mg" from a 503A compounding pharmacy may not contain exactly 20 mg. Potency verification is not guaranteed the way it is with branded drugs (Gudeman et al., 2013, Drug Safety).

Third, and most seriously, this video presents a specific dose, "5 mg per week," as a default starting point without any clinical framing. The FDA-approved tirzepatide titration schedule for Zepbound starts at 2.5 mg weekly for four weeks before escalating. Starting at 5 mg increases the likelihood of gastrointestinal adverse events (Jastreboff et al., 2022, New England Journal of Medicine).

Telling 34,000 viewers to pull 50 units and start at 5 mg, with no provider in the frame, is not just incomplete. It is the kind of content that leads to preventable harms.

What should you actually know?

Reconstitution math for compounded peptides is not inherently dangerous to discuss, but it requires precision and clinical context that this video skips entirely.

If you are using a compounded GLP-1 under the care of a licensed provider, your provider or pharmacist should be walking you through reconstitution, not TikTok. The calculation the creator describes, dividing total mg by volume to get concentration and then calculating volume per dose, is real pharmacokinetic arithmetic. But the inputs have to be verified: confirmed vial potency, correct syringe type, and a dose that has been prescribed by someone who knows your medical history.

The FDA placed compounded semaglutide and tirzepatide on its shortage list for a period, which created legal pathways for compounding pharmacies to produce them. That window has been closing. In 2025, the FDA removed tirzepatide from its shortage list, which has significant implications for the legal status of compounded versions going forward.

No online video, regardless of how accurate the math is, replaces a prescribing relationship. If a telehealth platform is involved, your provider should be available to answer exactly the questions this video is trying to answer.