Pup's Guides

GLP-2 - Tirzepatide

CAS ID: 2023788-19-2

About Tirzepatide

Tirzepatide is a FDA approved, once-weekly injectable “dual hormone receptor agonist” being developed by Eli Lilly and Company. It’s a single molecule designed to activate two metabolic hormone receptors GLP-1 and GIP. It is currently commercially available as compounded medication, Zepbound, and Mounjaro.

GLP-1 mainly helps you feel full and eat less, and it also improves blood sugar by boosting insulin release when glucose is high, lowering glucagon, and slowing stomach emptying.
GIP also increases glucose-dependent insulin secretion and may support healthier energy balance and fat tissue signaling; in the brain, GIP receptors appear to influence “reward eating” mostly indirectly, in part by dampening nausea/aversion signals through brainstem circuits (AP/NTS), which can change how reinforcing food feels and improve tolerability of incretin therapy.

In addition to appetite suppression, tirzepatide improves insulin sensitivity, alters nutrient partitioning, and may reduce food reward signaling, making its effects both behavioral (reduced intake) and metabolic (improved glucose handling and energy utilization).

Reconstitution

Common Vial Sizes	BAC Water Amount for 10 mg/mL	BAC Water Amount for 20 mg/mL
10	1 mL	0.5 mL
20	2 mL	1 mL
30	3 mL	1.5 mL
40	4 mL (will need bigger vial)	2 mL
50	5 mL (will need bigger vial)	2.5 mL
60	6 mL (will need bigger vial)	3 mL

BEFORE DOING ANYTHING MAKE SURE TO WIPE EVERYTHING DOWN WITH AN ALCOHOL WIPE. Use a fresh, sterile needle and syringe (do not reuse needles). Many people use one needle to draw and a fresh one to inject later (if applicable). When reconstituting peptides, remove the vacuum by taking a needle, pulling the plunger out, and piercing the stopper to equalize pressure. Pull the desired amount of water and make sure to angle it to the side of the vial—do not spray the peptide directly. Once all the water is added, swirl or roll the vial (do not shake) until the solution is clear. You can also let it sit for about 20 minutes to fully dissolve. After it’s dissolved, inspect the solution for any cloudiness, particles, discoloration, or anything “stringy.” Once reconstituted, store the peptide in the fridge and don’t freeze it.

Dosage

Common Dosage	10mg/mL	20mg/mL
2.5 mg	25 units (0.25 mL)	12.5 units (0.125 mL)
5 mg	50 units (0.50 mL)	25 units (0.25 mL)
7.5 mg	75 units (0.75 mL)	37.5 units (0.375 mL)
10 mg	100 units (1.0 mL)	50 units (0.5 mL)
12.5 mg	125 units (1.25 mL))	62.5 units (0.625 mL)
15 mg	150 units (1.50 mL)	75 units (0.75 mL)

Common dosing schedule

The currently approved dosing schedule is to increase the dose by 2.5 mg every 4 weeks until adequate appetite control is achieved or the maximum dose is reached. The dose is then maintained until appetite control declines or weight loss goals are met. Afterward, the dose can be gradually reduced to a maintenance level or discontinued entirely.

Month	Dose/Week
1	2.5 mg
2	5 mg
3	7.5 mg
4	10 mg
5	12.5 mg
6	15 mg
7	15 mg

Dosing principles (clinical context)

• Dose escalation is primarily for tolerability, not just effectiveness. Slower titration helps reduce gastrointestinal side effects such as nausea and fullness.
• The effective dose is individualized. Some individuals achieve sufficient appetite control at lower doses (e.g., 5 mg), while others require higher doses (10–15 mg).
• The goal is to use the lowest dose that maintains appetite control and progress, rather than automatically reaching the maximum dose.

Plateau and adjustment guidance

• Weight loss may slow over time even if appetite remains controlled—this is expected and not necessarily a sign to increase dose.
• Before increasing dose, evaluate:
• calorie intake drift
• protein intake
• activity level
• Dose increases should be driven by loss of appetite control, not just slower weight loss.

Maintenance and discontinuation

• After reaching goal weight, many individuals can maintain results on a lower maintenance dose rather than stopping completely.
• Gradual dose reduction may help:
• reduce rebound hunger
• maintain metabolic benefits
• Discontinuation often leads to return of appetite signaling, so long-term or maintenance use is common.

Administration notes

• Administer once weekly, on the same day each week
• Can be taken with or without food
• If a dose is missed, it can typically be taken within ~4 days; otherwise skip and resume the regular schedule

Body composition considerations

• Tirzepatide supports fat loss, but lean mass preservation depends on lifestyle:
• adequate protein intake
• resistance training
• Weight loss should be evaluated beyond scale weight alone

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