Retatrutide Dosing Schedule: Complete Week-by-Week Titration Plan
Follow the standard retatrutide dosing schedule from week 1 through maintenance. Learn exactly what dose to take each week and what to expect at each stage.
The Standard Retatrutide Dosing Protocol
The Phase 2 retatrutide trial used a standardized 12-week escalation schedule followed by long-term maintenance dosing. This schedule balances rapid efficacy with tolerability, allowing participants\' bodies to adapt while achieving clinically significant weight loss. The entire schedule spans weeks 1 through indefinite maintenance, with the critical escalation period completing by week 13.
All escalations are step-wise (not gradual), meaning you go directly from your current dose to the next tier each week. For example, at the end of week 4, you stop 1mg and immediately begin 4mg in week 5—there\'s no intermediate dosing.
The Four Dosing Phases
- Phase 1 (Weeks 1-4): 1mg weekly—tolerability and adaptation
- Phase 2 (Weeks 5-8): 4mg weekly—appetite suppression optimization
- Phase 3 (Weeks 9-12): 8mg weekly—accelerated weight loss
- Phase 4 (Week 13+): 12mg weekly—long-term maintenance and maximum efficacy
Week-by-Week Dosing Schedule Breakdown
Here\'s exactly what to inject and when during the standard 12-week escalation protocol. Most providers recommend consistent timing (e.g., every Monday morning) to maintain stable blood levels.
Weeks 1-4: The 1mg Starting Phase
| Week | Injection Day | Dose | Key Changes & Expectations |
|---|---|---|---|
| 1 | Day 1 (e.g., Monday) | 1mg | First dose; expect mild nausea 2-4 hours post-injection, lasting 4-6 hours. Subtle appetite decrease. Begin food diary. |
| 2 | Day 8 | 1mg | Second dose; nausea likely repeats but may be milder. Appetite suppression becomes noticeable. Slight energy dip possible. |
| 3 | Day 15 | 1mg | Third dose; nausea typically diminishes. Appetite suppression extends full week. Small amounts of food feel satisfying. |
| 4 | Day 22 | 1mg | Fourth dose; body largely adapted. Nausea minimal in most cases. Clear appetite suppression throughout week. Baseline weight loss 1-3 lbs total. |
Weeks 5-8: The 4mg Escalation Phase
| Week | Injection Day | Dose | Key Changes & Expectations |
|---|---|---|---|
| 5 | Day 29 | 4mg | ESCALATION DAY: 4x dose increase. Expect return of nausea (typically 1-2 days). Appetite suppression dramatically increases. Food aversion possible for 2-3 days. |
| 6 | Day 36 | 4mg | Nausea typically subsiding. Very strong appetite suppression (most report smallest appetite of entire trial). GI changes possible (constipation or diarrhea). |
| 7 | Day 43 | 4mg | Body adapting to 4mg. Nausea minimal. Consistent appetite suppression throughout week. Weight loss accelerating (0.5-1.5 lbs per week typical). |
| 8 | Day 50 | 4mg | Full tolerance to 4mg established. Appetite suppression consistent. Total weight loss from baseline 6-12 lbs typical. Ready for escalation to 8mg. |
Weeks 9-12: The 8mg Acceleration Phase
| Week | Injection Day | Dose | Key Changes & Expectations |
|---|---|---|---|
| 9 | Day 57 | 8mg | ESCALATION DAY: 2x dose increase. Expect nausea recurrence (1-2 days typical). Appetite suppression intensifies dramatically. Food avoidance common. |
| 10 | Day 64 | 8mg | Nausea resolving. Maximum appetite suppression reached. Food feels optional; eating becomes task. GI side effects may peak. Weight loss accelerating significantly. |
| 11 | Day 71 | 8mg | Tolerance improving. Appetite suppression consistent. GI symptoms typically improving. Weight loss 1-2 lbs per week common. Total weight loss from baseline 15-25 lbs typical. |
| 12 | Day 78 | 8mg | Full tolerance at 8mg. Appetite suppression predictable. Side effects minimal in most cases. Ready to escalate to final 12mg maintenance dose. |
Week 13+: The 12mg Maintenance Phase
| Week | Injection Day | Dose | Key Changes & Expectations |
|---|---|---|---|
| 13 | Day 85 | 12mg | FINAL ESCALATION: 1.5x dose increase. Nausea return possible (1-3 days typical). Maximum appetite suppression reached. Most potent anorectic effect. |
| 14-16 | Weekly | 12mg | Body adapting to maximum dose. Appetite suppression becomes baseline. Most side effects resolve. Weight loss velocity high (1.5-2.5 lbs per week typical). |
| 17-24 | Weekly | 12mg | Full tolerance established. Steady weight loss continues. Metabolic benefits accumulating (improved A1c, blood pressure, lipids). This is long-term maintenance. |
| 25-48 | Weekly | 12mg | Year-long maintenance phase. Cumulative weight loss 24.2% typical (as per Phase 2 trial results). Body composition improves. Sustained appetite suppression with minimal side effects for most. |
What to Expect at Each Dose Level
Understanding the expected timeline and symptoms at each dose prevents confusion and helps you distinguish expected adaptation from true adverse events requiring provider contact.
1mg Phase (Weeks 1-4): Tolerability & Adaptation
Primary Experience: Gentle introduction to the triple agonist mechanism. Nausea is the hallmark early symptom, typically resolving by day 2-3 post-injection.
- Nausea: 2-6 hours post-injection in most users; typically mild
- Appetite: Noticeable reduction by day 2; full week of mild appetite suppression
- Weight loss: 1-3 lbs total over 4 weeks
- Energy: Slight fatigue in first week; resolves by week 2
- Mood: Stable; some report mood improvement from appetite reduction
4mg Phase (Weeks 5-8): Appetite Suppression Optimization
Primary Experience: Dramatic appetite reduction becomes the dominant effect. The escalation week (week 5) is typically the most challenging due to returning nausea.
- Nausea: Returns for 1-2 days post-injection at week 5; returns briefly at week 6 in some users; minimal by week 7
- Appetite: Very strong suppression; some report smallest appetite of entire protocol
- Food aversion: Some foods may become unappealing; chicken and red meat common aversions
- Weight loss: 5-12 lbs total (week 4-8 combined)
- GI effects: Constipation or diarrhea possible; more common than at 1mg
- Energy: Stable in most; some report fatigue if not eating enough protein
8mg Phase (Weeks 9-12): Accelerated Weight Loss
Primary Experience: Weight loss accelerates significantly. Triple agonist reaches powerful dose. Nausea escalation week, then sustained appetite suppression.
- Nausea: Brief return at week 9 (escalation); minimal by week 10
- Appetite: Maximum suppression; eating becomes challenging for some
- Food intake: Many report difficulty meeting 1,200 calorie minimum; protein becomes critical focus
- Weight loss: 8-20 lbs additional (weeks 8-12 combined); total loss 20-30 lbs from baseline typical
- GI effects: Usually stabilizing; constipation often improving
- Metabolic changes: Blood sugar stabilization becomes noticeable; energy more stable despite lower food intake
12mg Phase (Week 13+): Maintenance & Maximum Efficacy
Primary Experience: Plateau at maximal appetite suppression. Side effects minimal for most. This is the long-term maintenance phase used in Phase 2 trials for 48+ weeks.
- Nausea: Brief return at escalation day (week 13); minimal thereafter
- Appetite: Consistent maximum suppression throughout week
- Weight loss: Continues at 1-2.5 lbs per week sustained
- Total efficacy: 24.2% body weight loss achievable over 48 weeks
- Side effects: Most users report minimal side effects by week 16+; GI mostly stable
- Quality of life: Returns to near-baseline for most; appetite suppression becomes new normal
When to Hold or Delay Your Dose Escalation
The standard schedule works for most users, but individual tolerance varies. Your provider may recommend holding at a lower dose before escalating. This is not failure; it\'s optimization.
Reasons to Delay Escalation
- Severe nausea: If nausea extends beyond 2-3 days or interferes with nutrition, delay 1-2 weeks
- Vomiting: Any vomiting warrants provider contact and possible delay before escalation
- Constipation: Severe constipation may require stool softeners and delayed escalation
- Rapid heart rate: If heart rate elevation occurs, pause and contact provider before escalating
- Inability to meet caloric minimum: If appetite suppression is preventing adequate nutrition, hold at current dose longer
- Pancreatitis-related pain: Any concerning abdominal pain warrants immediate provider evaluation
How to Request a Delay
Contact your provider directly: "I\'m experiencing [symptom] at 4mg. Would it be safe to stay at 4mg for 2 additional weeks before escalating to 8mg?" Most providers will support this adjustment. Document your symptoms and share them during your request.
Injection Day Timing & Consistency
Maintaining consistent injection timing optimizes the medications\' effects and helps your provider track side effects relative to dosing.
Best Practices for Injection Day
- Pick a day: Choose a specific day each week (e.g., Monday) and maintain it
- Pick a time: Inject at the same time each day (e.g., 8am). Morning injections before food may maximize appetite suppression.
- Allow prep time: Remove vials from refrigerator 15 minutes before injection to bring to room temperature
- Rotate sites: Alternate between abdomen, thighs, and upper arms to prevent lipohypertrophy and ensure consistent absorption
- Use sterile technique: Always use new sterile syringe and needle for each injection
- Track symptoms: Document post-injection nausea, appetite changes, and any side effects; note weight weekly
Long-Term Maintenance Beyond Week 13
Once you reach the 12mg maintenance dose, the schedule becomes indefinite weekly injections. Phase 2 trial data followed participants for 48 weeks at 12mg, demonstrating sustained weight loss and metabolic improvements. Your provider will monitor your progress periodically and may adjust dosing or discontinuation timing based on your goals and response.
For more detailed information on retatrutide dosing mechanics, see our guide on retatrutide dosage calculations. For expectations on weight loss outcomes, review retatrutide before and after results. If considering alternatives, compare with retatrutide versus tirzepatide or retatrutide versus semaglutide.
Frequently Asked Questions
The standard starting dose is 1mg injected once weekly. This dose is used during weeks 1-4 to allow your body to adapt to the triple agonist and establish tolerability. Most users experience mild nausea and early appetite suppression at this dose.
You escalate to 4mg in week 5, after completing 4 weekly injections of 1mg (weeks 1-4). The escalation happens in a single step: your 5th injection is 4mg, not a gradual increase. Remain at 4mg for weeks 5-8 (four more weekly injections) before considering the next escalation.
At 4mg, you'll experience significantly increased appetite suppression compared to 1mg. Most users report nausea for 1-2 days post-injection, strong satiety that lasts 5-7 days, reduced food cravings, and early weight loss (0.5-1 lb per week average). Some users report fatigue or constipation at this dose.
Contact your provider to discuss extending your time at the current dose. You might stay at 1mg for 6-8 weeks instead of 4, or hold at 4mg for 6-8 weeks. This approach allows better tolerance adjustment before escalation. Never escalate if experiencing severe side effects; delaying is safer.
The 12mg dose is the maximum studied in Phase 2 trials and the standard maintenance dose. Higher doses are not recommended outside research settings. If you achieve your weight loss goals before reaching 12mg, discuss maintenance at a lower dose with your provider.
Most users notice reduced appetite in the first 2 weeks at 1mg. Measurable weight loss typically begins by week 4-5 as you establish a caloric deficit. By week 8 (transition to 8mg), weight loss usually becomes obvious. Maximum weight loss velocity occurs at the 12mg maintenance dose.
Yes. You can pause at any dose level and either maintain that dose or discontinue entirely. If you pause, coordinate with your provider about continuing weekly injections at your current dose, skipping injections for a period, or tapering. Discontinuing abruptly is safe (retatrutide has no rebound safety concerns), but gradual dose reduction may ease symptom transition.