The first month on Mounjaro or Wegovy can vary from person to person, but you’ll generally experience a similar trajectory of adaptation and weight loss. Understanding these phases can make your journey smoother—and knowing what to anticipate helps you plan your lifestyle changes accordingly.

Week 1: Getting Acquainted

• Mounjaro: You’ll likely start at a 2.5 mg dose. Subtle changes in appetite are common, though pronounced weight loss often isn’t immediate. Many people experience mild gastrointestinal issues—like nausea or constipation—as the body adjusts.
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• Wegovy: Initial dosage usually begins at 0.25 mg, focusing on acclimatizing your body to semaglutide. This is the week to establish a routine for administering injections. Weight loss may be minimal, but you’ll likely notice feeling full more quickly after meals.
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Tip: Keep a journal of any side effects, mood shifts, or appetite changes. This log can help your clinician adjust your dose if needed.

Week 2: Subtle Gains and Observations

• Mounjaro: Appetite suppression tends to strengthen, but weight changes are often minimal in the second week. The key is recognizing how your cravings shift—you may naturally eat smaller portions.
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• Wegovy: As your body becomes more accustomed to Wegovy weight loss mechanisms, expect a bit more consistency in reduced hunger. Some individuals see a small drop in weight (e.g., 1–2 pounds), though this varies widely.
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• Common Side Effects: Mild nausea, constipation, or diarrhea might persist. Keeping yourself hydrated and eating gentle, nutrient-rich foods can help mitigate discomfort.
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Week 3: Notable Changes Emerge

• Mounjaro: At this stage, many patients begin noticing the medication’s full potential. Appetite suppression becomes more pronounced, potentially leading to more visible weight loss—somewhere around 2% of your starting weight.
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• Wegovy: Many Wegovy users may observe a measurable drop—often 1–2% of body weight—by this week. With consistent use, decreased snacking and smaller meal portions help accelerate progress.
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• Lifestyle Matters: This is an ideal time to refine dietary habits and introduce moderate physical activity. For guidance on how to adjust your lifestyle, explore our Thinking of Starting? page for tips on meal planning and exercise routines.
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Week 4: Seeing the Bigger Picture

• Mounjaro: By the fourth week, it’s common to see a cumulative weight loss of around 4% (though it may be higher or lower depending on your starting point and personal biology). Your doctor might discuss increasing your weekly dose from 2.5 mg to 5 mg if well tolerated.
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• Wegovy: This marks a turning point for many Wegovy users, with weight loss totals often hitting 4–6 pounds. Appetite control feels more second nature by now. If well tolerated, your dose may increase to 0.5 mg or higher, depending on your healthcare provider’s plan.
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• Looking Ahead: The month-one milestone sets the stage for more significant progress in the months to come. Both Mounjaro and Wegovy require consistent use over several months to realize their full potential.
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If you’re curious about costs or different dosing schedules, check out our Medications and Pricing page for in-depth details on these and other weight loss injections.