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Comparison

Tirzepatide vs Semaglutide

Which is more effective for weight loss, Tirzepatide (Mounjaro / Zepbound) or Semaglutide (Ozempic / Wegovy)? Side-by-side on dose, mechanism, side effects, FDA status.

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Tirzepatide
Fat LossEvidence: Strong

Tirzepatide is the prescription weight-loss drug sold as Mounjaro (diabetes) or Zepbound (weight loss). It hits two appetite-control receptors at once. Most users lose 15-20% of body weight over several months. One injection per week.

Onset
80
Documentation
95
Side intensity
100
Popularity
95
009
Semaglutide
Fat LossEvidence: Strong

Semaglutide is the first wave of modern weight-loss drugs — sold as Ozempic and Wegovy. Single-receptor version of Tirzepatide. Slightly less effective and slightly rougher side effects, but well-studied and widely available.

Onset
80
Documentation
95
Side intensity
82
Popularity
92
Side-by-side
Field
Left
Right
Category
Fat Loss
Fat Loss
Half-life
~5 days
~7 days
Route
Subcutaneous
Subcutaneous
Schedule
Once weekly
Once weekly
Cycle length
Open-ended, titrate over months
Open-ended, titrate over months
Dose
Start 2.5mg weekly. Titrate by 2.5mg every 4 weeks. Common max 10-15mg.
Start 0.25mg weekly. Titrate every 4 weeks. Common max 2.4mg.
FDA
Approved as Mounjaro (2022, type 2 diabetes) and Zepbound (2023, obesity).
Approved as Ozempic (2017, type 2 diabetes), Rybelsus (2019, oral), and Wegovy (2021, obesity).
WADA
Not listed
Not listed
Natty?
Not natty
Not natty
Prescribed
Yes — widely prescribed by primary care, endocrinologists, and obesity-medicine specialists.
Yes — extremely widely prescribed. Insurance coverage variable for weight-loss indication.
Top side effects
Nausea; Constipation; Reflux
Nausea (often more than tirzepatide); Constipation; Fatigue

Which one should you pick?

Pick Tirzepatide if users who couldn't tolerate semaglutide or metabolic-syndrome adults under provider guidance.

Pick Semaglutide if beginners to glp-class peptides or users with insurance coverage on wegovy / ozempic.