Starting Mounjaro: What to Expect in Your First Month
⚡ Quick Summary - What You Need to Know
- Week 1 (2.5mg): Medication reaches peak levels within 8-72 hours. Many patients notice reduced appetite within days. Common side effects like nausea and fatigue may begin within 24-72 hours but are usually mild
- Week 2-3 (2.5mg): Side effects typically peak then improve as your body adjusts. You'll feel fuller for longer and fatty foods become less appealing
- Week 4 (2.5mg): Average weight loss is less than 4% of starting body weight. Side effects usually mild or resolved
- G-1 Nutrition provides same-day dispatch, 24-hour repeat prescriptions, free delivery with no hidden dispensing costs, and responsive clinical support throughout your first month and beyond
📋 Quick Navigation
Them pharmacist hands you the Mounjaro pen and instruction leaflet. Your heart races slightly as you realise you'll be injecting this yourself at home. You've read about people losing over 20% body weight on Mounjaro, but right now you're just hoping you can do the injection correctly and that side effects won't be unbearable.
You're not alone in feeling nervous. Thousands of UK patients start Mounjaro every month, most with similar anxieties about self-injection, side effects, and whether the medication will actually work for them. The first month represents a significant transition as your body adjusts to the medication whilst you learn new habits and routines.
Understanding what to expect during your first four weeks makes the experience less daunting. Knowing which side effects are normal, when to seek guidance, and how to maximise results whilst minimising discomfort helps you approach treatment confidently.
The first month isn't about dramatic weight loss. You're on the lowest dose (2.5mg) specifically to help your body adjust gradually. This titration period builds tolerance, establishes new eating patterns, and prepares you for higher doses where significant weight loss occurs.
At G-1 Nutrition, we guide patients through their first month with clear instructions, responsive support, and realistic expectations. Our clinical team helps you manage side effects, answers questions promptly, and ensures you feel confident throughout the initial adjustment period. Complete our online consultation to start your Mounjaro journey with expert support.
Unhappy with your current provider's support? Learn how to swap Mounjaro providers here.
Before Your First Injection: Essential Preparation
Understanding Your Prescription
Your first Mounjaro pen contains four doses at 2.5mg strength. One pen lasts exactly four weeks with weekly injections. The starting dose intentionally stays low to minimise side effects whilst your body adjusts to the medication.
Verify you received the correct strength. The dose should be clearly marked on both the box and pen. Check the expiry date and inspect the solution through the viewing window. The liquid should be clear to slightly yellow with no particles or cloudiness.
Storage Requirements
Store unused pens in the refrigerator at 2-8°C until first use. Don't freeze the medication. Once you've started using a pen, you can keep it at room temperature (up to 30°C) for the remainder of that month. Many patients find injections more comfortable when the medication isn't cold.
Gathering Supplies
- Mounjaro pen (removed from fridge 30 minutes prior)
- New pen needle (provided separately or with pen)
- Alcohol wipes for cleaning injection site
- Sharps container for safe needle disposal
- Clean, flat surface to work on
- Good lighting to see instructions clearly
Why Choose G-1 Nutrition:
Unlike providers who hand you a pen with minimal guidance, G-1 Nutrition ensures you understand every step before your first injection. Our clinical team provides detailed instructions, answers all your questions, and remains available if you encounter problems. Phone consultations for concerns include same-day support because your confidence matters for treatment success.
Week 1: Your First Injection and Initial Adjustment
Days 1-2: First Injection and Immediate Effects
Mounjaro reaches peak levels in your system within 8-72 hours of injection. Many patients notice reduced appetite within the first 24-48 hours, though some take several days to feel obvious changes.
Your first injection might feel more intimidating than subsequent doses. Choose an injection site—abdomen, upper thigh, or upper arm. The abdomen typically provides the most comfortable injection experience.
First Injection Checklist:
- Remove pen from fridge 30 minutes before injection
- Wash hands thoroughly with soap and water
- Attach new pen needle securely
- Clean injection site with alcohol wipe
- Wait for alcohol to dry completely
- Inject at 90-degree angle, hold for 10 seconds
- Dispose of needle in sharps container immediately
Days 3-4: Early Side Effects May Begin
Common side effects typically emerge within 24-72 hours of your first injection. Clinical trials show approximately 22% of patients experience nausea at therapeutic doses.
Managing Early Side Effects:
Nausea: Eat smaller, more frequent meals rather than three large meals. Bland foods like crackers, toast, or rice often settle better.
Fatigue: Ensure adequate hydration (2-3 litres daily). Gentle walks boost energy without overwhelming your system.
Constipation: Increase fibre intake gradually through vegetables, fruits, and whole grains. Stay well-hydrated.
Days 5-7: Establishing New Eating Patterns
By the end of your first week, you've likely noticed significant changes in your relationship with food. Portions that previously satisfied you now feel overwhelming.
Pay attention to your body's new hunger and fullness signals. Stop eating when you feel comfortably satisfied rather than pushing to finish everything on your plate.
Why Choose G-1 Nutrition
Unlike providers who leave patients struggling alone through side effects, G-1 Nutrition offers responsive support during your adjustment period. Our clinical team answers questions promptly, provides practical management strategies, and helps you distinguish between normal adjustment symptoms and issues requiring medical attention.
Complete Our Online ConsultationWeek 2: Establishing New Patterns
Second Injection and Side Effect Management
Your second injection continues building medication levels in your system. Remember to rotate injection sites from last week. Site rotation prevents irritation and ensures consistent absorption.
Side effects often peak during week 2 before improving. This pattern is completely normal and doesn't indicate problems with treatment.
Developing Sustainable Eating Habits
Week 2 represents an opportunity to establish eating patterns you'll maintain throughout treatment. Focus on protein at every meal. Adequate protein preserves muscle mass during weight loss.
Week 2 Meal Suggestions:
- Breakfast: Scrambled eggs with spinach and tomatoes; Greek yoghurt with berries
- Lunch: Chicken salad with mixed greens; turkey and avocado wrap
- Dinner: Grilled fish with roasted vegetables; chicken stir-fry
- Snacks: Handful of almonds; apple with peanut butter
Exercise and Activity Levels
You might feel less energetic during week 2 as your body adjusts to reduced calorie intake. Gentle movement like walking, swimming, or yoga benefits both physical and mental health without overwhelming your system.
Week 3: Building Momentum
Third Injection and Symptom Improvement
By week 3, most patients notice significant improvement in side effects. Nausea typically decreases substantially or resolves completely as your body adapts to Mounjaro's effects. Energy levels often improve as you establish better eating patterns.
Continue rotating injection sites weekly. Consistent site rotation prevents lipohypertrophy (lumps or thickening under the skin) and ensures reliable medication absorption.
Noticing Physical and Behavioural Changes
Weight loss during the first month at 2.5mg typically ranges from 2-4 kg (4-9 pounds) depending on starting weight and individual factors. Clinical trials show average weight loss of less than 4% of starting body weight by the end of month one.
Beyond scales, you might notice clothes fitting differently, reduced bloating, or decreased water retention. Some patients report improved sleep, reduced joint pain, or better mood.
Week 3 Progress Indicators:
- Reduced appetite lasting between doses
- Feeling full sooner during meals
- Decreased interest in snacking
- Less difficulty adhering to healthy eating
- Clothes feeling looser around waist or hips
- Reduced bloating or water retention
- Improved energy compared to week 1-2
- Better sleep quality
Preparing for Dose Increase
Your provider will assess whether you're ready to increase from 2.5mg to 5mg after completing four weeks at the starting dose. This decision depends on how well you tolerated 2.5mg and whether side effects have resolved or remain manageable.
Week 4: Completing Your First Month
Fourth Injection and Reflecting on Progress
Your fourth injection completes the first month at 2.5mg. This represents a significant milestone—you've successfully navigated the initial adjustment period, managed side effects, and established new eating patterns.
Take time to reflect on changes beyond the scales. Consider how your appetite has changed, whether eating feels easier or more enjoyable, if energy levels have improved, and how clothes fit differently.
Many patients feel frustrated with relatively modest weight loss during the first month. Remember that 2.5mg is intentionally a low titration dose designed for adjustment rather than maximum efficacy.
Assessment for Dose Increase
Your provider will evaluate several factors when determining whether to increase your dose:
- Tolerability: Have side effects resolved or become manageable?
- Appetite Control: Is 2.5mg still effectively suppressing hunger?
- Adherence: Have you injected consistently each week?
- Progress: Are you making satisfactory progress toward goals?
What to Expect at 5mg:
The increase to 5mg typically enhances appetite suppression without dramatically worsening side effects. Some patients experience mild nausea recurrence for 3-5 days after the first 5mg dose, but symptoms are usually less severe than initial adjustment at 2.5mg.
Continuing Your Treatment Journey
Completing your first month represents just the beginning of your Mounjaro journey. Most patients remain on treatment for 12-18 months or longer, gradually titrating to optimal doses where significant weight loss occurs.
At G-1 Nutrition, we support patients throughout their entire treatment journey, not just during the initial month. Our 24-hour repeat prescription service, phone consultations for dose adjustments, and responsive clinical support ensure you receive guidance whenever needed. Complete our online consultation to experience ongoing support that prioritises your success.
Common First Month Mistakes and How to Avoid Them
Expecting Dramatic Immediate Weight Loss
The most common disappointment during month one stems from unrealistic expectations about weight loss at 2.5mg. Social media showcases dramatic transformation photos, but these results occur over many months at higher doses, not during the initial titration period.
The 2.5mg starting dose serves a specific purpose: helping your body adjust to Mounjaro gradually whilst minimising side effects. Average weight loss of 2-4% body weight during month one represents appropriate progress.
Not Eating Enough
Mounjaro's appetite suppression is powerful. Some patients find eating feels like a chore rather than an enjoyment. However, consuming inadequate nutrition undermines weight loss success and potentially causes health problems.
Your body needs adequate protein to preserve muscle mass during weight loss. Aim for at least 60-80 grams daily even if portions feel small.
Minimum daily calorie intake should generally stay above 1,200 calories for women and 1,500 for men unless specifically guided otherwise by your provider.
Red Flags That You're Not Eating Enough:
- Extreme fatigue that doesn't improve with rest
- Hair thinning or increased shedding
- Dizziness or lightheadedness when standing
- Difficulty concentrating or "brain fog"
- Feeling cold all the time
- Irregular or stopped menstrual periods
- Muscle weakness or loss
Contact your provider if you experience these symptoms. Adjusting your eating strategy or temporarily reducing your dose might be necessary.
Dehydration
Inadequate hydration worsens nearly every Mounjaro side effect whilst creating new problems. Constipation, fatigue, headaches, and dizziness all intensify when you're dehydrated.
Aim for at least 2 litres daily, more if you're exercising or experiencing diarrhoea. Carry a water bottle throughout the day and sip consistently.
Comparing Your Progress to Others
Social media and online forums showcase patients losing dramatic amounts rapidly. These comparisons create unrealistic expectations and unnecessary disappointment when your progress feels slower.
Focus on your own journey. Are you making progress? Do you feel better? Are you establishing sustainable habits? These matter infinitely more than whether you're losing weight as quickly as strangers on the internet.
How G-1 Nutrition Supports Your First Month
Comprehensive Initial Consultation
Unlike providers who process prescriptions with minimal patient interaction, G-1 Nutrition conducts thorough consultations to ensure Mounjaro suits your specific situation. Our GPhC-registered pharmacist reviews your medical history, discusses realistic expectations, and provides detailed guidance about starting treatment.
We explain exactly what to expect during your first month, including typical side effects, their timeline, and management strategies. You'll receive clear injection instructions, dietary guidance, and information about when to seek additional support.
Our online consultation takes 10-15 minutes to complete and is included in your medication price. Clinical review happens within 24 hours, with immediate or next-day consultations available when you need to start treatment quickly.
Fast Prescription and Delivery Service
We understand that once you've decided to start Mounjaro, waiting weeks for treatment feels frustrating. G-1 Nutrition offers same-day dispatch for orders placed before 2pm, with next-day delivery to your address. Free delivery is included with no additional charges or hidden dispensing costs.
For consultations completed after 2pm, we dispatch the following day with next-day delivery, ensuring you receive medication within 48 hours of completing your consultation. All delivery costs are included with no extra fees.
Responsive Clinical Support During Adjustment
Your first month requires more guidance than subsequent months as you navigate initial side effects and establish new patterns. G-1 Nutrition provides accessible clinical support when you need it:
- Phone Consultations: Speak directly with clinical team members for guidance about side effects or concerns
- Email Support: Ask questions via email with prompt responses from qualified staff
- Dose Adjustment Guidance: Phone consultations for dose increases are included in your treatment cost
We don't leave patients struggling alone through difficult adjustment periods. Our team helps you manage symptoms effectively and makes treatment modifications when necessary to improve tolerability.
24-Hour Repeat Prescriptions
Established patients benefit from our 24-hour repeat prescription service, ensuring you never run out of medication. Simply request your next prescription through our online system, and receive same-day dispatch (for orders before 2pm).
Transparent Pricing Without Hidden Fees
Our advertised Mounjaro prices represent your complete monthly cost with everything included. Unlike some providers who advertise low medication prices then add consultation fees, delivery charges, and dispensing costs, G-1 Nutrition maintains straightforward pricing:
- 2.5mg: £149.50 monthly
- 5mg: £165.00 monthly
- 7.5mg: £220.00 monthly
- 10mg: £245.00 monthly
- 12.5mg: £260.00 monthly
- 15mg: £280.00 monthly
Your medication cost includes consultations, free delivery, clinical support, and all the services you need throughout treatment with no hidden dispensing costs. What you see is what you pay.
Why Patients Choose G-1 Nutrition:
- Responsive Support: Clinical team available when you need guidance
- Fast Service: Same-day dispatch and next-day delivery
- Transparent Pricing: Clear costs with free delivery and no hidden dispensing fees
- GPhC-Registered Pharmacist: Qualified professionals who understand weight loss treatment
- Patient-Focused: We prioritise your success and wellbeing
Complete our online consultation to experience the difference that genuine clinical support makes during your first month and beyond.
Ready to Start Your Mounjaro Journey?
G-1 Nutrition supports you through every step of your first month with responsive clinical care, transparent pricing, free delivery, and fast prescription service. Our GPhC-registered pharmacist ensures you feel confident, informed, and well-supported as you begin treatment.
Complete Online Consultation