• Common: nausea, diarrhea, vomiting, constipation, decreased appetite (dose-titration-dependent).

• Notable: gallbladder events; pancreatitis (rare); rodent thyroid C-cell tumor signal → boxed warning; contraindicated with personal/family history of medullary thyroid carcinoma or MEN2.

• Body composition: meaningful lean-mass loss accompanies fat loss — same resistance-exercise/protein consideration as semaglutide.

• Off-label-specific: dosing errors from self-titration off multi-dose vials.

Sourcing red flags - Same principle as every Tier-A incretin: the molecule isn't the risk, the supply is.

• Mislabeling is documented in unapproved peptide/incretin supply — a vial labeled one incretin may contain another, or an unverified dose.

• "99% purity" ≠ correct dose — purity is contaminants, potency is active-drug amount.

• Safest supply is a Health-Canada-approved product dispensed by a licensed pharmacy on a prescription.

• The flat-feeling signal (emerging — low evidence tier). A growing number of people report emotional blunting on GLP-1 drugs — reduced libido, feeling numb, loss of interest in relationships. The mechanism is plausible: GLP-1 receptor activity dampens dopamine signalling in the brain's reward circuitry, which is why it quiets "food noise" and alcohol craving — but that dampening doesn't necessarily stop at food. The evidence is patient reports, case reports, and mechanism — not randomized trials; no RCT has measured it with a validated instrument. The honest nuance: the same reward-dampening that helps someone with a dysregulated reward system can flatten someone whose reward system was healthy, and you often can't tell from the inside which is happening. If the people around you notice you've gone flat, take that as seriously as any physical side effect. → See the full discussion on Reward, motivation, and the flat feeling.