Tirzepatide

Structure: Dual-acting peptide — agonist at both GIP (Glucose-dependent Insulinotropic Polypeptide) and GLP-1 receptors. The dual mechanism provides more potent metabolic effects than GLP-1 alone.

Dosage:

• Weight loss (titrate up): 2.5mg/week x4 weeks → 5mg/week x4 weeks → 7.5mg/week → 10mg/week → 12.5mg/week → 15mg/week
• Bodybuilding cut: 5-10mg/week (titrate based on appetite suppression and tolerability)

Administration:

• SubQ injection once weekly, abdomen/thigh/upper arm
• Titrate slowly — at least 4 weeks at each dose level to minimise GI sides

Key Notes:

• Clinical trials show greater weight loss than Semaglutide at maximal doses
• Same GI side effect profile as Semaglutide but can be more pronounced during titration
• Dual GIP/GLP-1 mechanism may better preserve muscle mass compared to GLP-1-only agonists (emerging data)
• Extremely potent appetite suppression — some users struggle to eat enough protein
• Maintain resistance training and high protein intake (>2g/kg) to preserve muscle
• Monitor: fasting glucose, HbA1c, lipid panel, amylase/lipase, liver enzymes
• Same pancreatitis risk considerations as Semaglutide

The monitoring panel for dual agonists, including the pancreatic and thyroid questions: GLP-1 bloodwork: what to test on semaglutide.