Retatrutide-Peptide.bizDosing
Overview of Retatrutide Dosing and Titration
Common retatrutide dosing approaches — starting dose, weekly increments, and a weekly milligram chart, with measurements given in both mg and syringe units.
Written by Eric J. Topol, MD
Reviewed by Ania M. Jastreboff, MD, PhD
To grasp retatrutide dosage, begin here: it is an investigational compounded peptide, and the right amount for any person is determined by a licensed prescriber, not a chart. Retatrutide has not been approved by the FDA. This page describes how retatrutide dosing is typically structured in clinical studies and by telehealth services, why the stepwise increase matters, and how a milligram prescription converts to the 'units' you measure on a syringe. Treat this as educational content, not personalized medical advice. Your clinician determines your starting dose, how fast it escalates, and the maximum amount.
Essential points on retatrutide dosing
- Given as a subcutaneous injection once per week on the same day.
- Studies generally started at a low dose (often around 2 mg weekly) and escalated on a monthly schedule.
- Research protocols studied maintenance doses up to approximately 8 mg and 12 mg per week.
- The milligram amount is set by your doctor; syringe 'units' depend on how the compound was formulated.
- Retatrutide is investigational and compounded, and it requires a prescription.
Starting retatrutide dose and why titration is gradual
A cautious starting amount is mainly because of the gastrointestinal system. Retatrutide acts on GLP-1, GIP, and glucagon receptors, and the GLP-1 component is particularly associated with nausea, reflux, and other digestive side effects when the body is exposed to a new dose too quickly. A gradual increase lets the digestive tract adjust, often making these side effects milder and easier to manage.
In clinical trials, participants frequently started at about 2 mg weekly and remained at that level for four weeks before any increase. Some telehealth plans begin even lower. The goal of a slow schedule is not to rush to high amounts; it is to find the smallest effective dose that is also well tolerated. Not everyone needs the highest studied dose.
An example retatrutide dose escalation table
The following retatrutide dosage plan is a representative schedule based on how trials and many compounding-pharmacy protocols carry out a gradual monthly increase. This is only an example and not a prescription; it does not indicate what you should take. Your clinician will create your personalized retatrutide dosing plan based on your responses, tolerance, and goals.
| Weeks | Dose (mg/week) | Notes |
|---|---|---|
| 1–4 | 2 mg | Initial phase when the body adjusts to the peptide. |
| 5–8 | 4 mg | First increase if the starting dose is well tolerated. |
| 9–12 | 6 mg | Some people reach their effective maintenance amount at this level. |
| 13–16 | 8 mg | Higher maintenance dosage range evaluated in studies. |
| 17+ | up to 12 mg | Maximum research dosage range; considered only if your clinician deems it necessary. |
What amount of retatrutide is right for me?
No single dose works for everybody. Put simply, the amount you take is whatever your prescriber decides after reviewing your medical background, the other medicines you use, and how you respond in the first several weeks. Two people at a similar body weight can end up on quite different maintenance doses. To view one possible titration pattern, our retatrutide dosage calculator You may sketch out a possible plan to discuss with your clinician—this does not substitute for their professional judgment.
Measuring retatrutide: units compared with milligrams
This is the point where confusion most often happens. Your provider writes the dose in milligrams, while an insulin-type syringe is marked in units. Those units measure volumevolume, not the quantity of drug: with a standard U-100 syringe, 100 units equal 1 mL. Therefore a 4 mg dose may convert to a very different number of units depending on the strength of your vial, which is determined by reconstitution.
Before these figures are relevant, the freeze-dried powder must be mixed. See our tutorial on reconstituting your vial with bacteriostatic water for the exact steps—the amount of water you add sets the concentration, and therefore the retatrutide dose in mL and units.
Example dose conversion table
The chart below illustrates how a given vial strength translates into units at different water volumes. These are only examples to demonstrate the math, not instructions for your own vial.
| Vial | BAC water added | Concentration | 2 mg dose | 4 mg dose |
|---|---|---|---|---|
| 10 mg | 1 mL | 10 mg/mL | 0.20 mL = 20 units | 0.40 mL = 40 units |
| 10 mg | 2 mL | 5 mg/mL | 0.40 mL = 40 units | 0.80 mL = 80 units |
| 30 mg | 3 mL | 10 mg/mL | 0.20 mL = 20 units | 0.40 mL = 40 units |
Guidelines for using retatrutide safely
Once mixed, the medicine is injected under the skin in the abdomen, thigh, or upper arm. For correct technique—rotating sites, clearing bubbles, needle placement—see our guide on how to inject retatrutideNever share pens, needles, or vials, and store the vial as your pharmacist advises.
Dosing frequency, missed doses, and long-term use
Why retatrutide is dosed once weekly
Retatrutide has a long half-life, roughly six days based on early research. A once-weekly dose keeps levels reasonably steady between injections without the need for daily shots, which is why most retatrutide schedules use one fixed day each week.
Pick a consistent day
Choose a single day of the week and keep to it. A steady interval helps sustain stable levels and makes a missed dose easier to spot.
Managing a missed dose correctly
Several plans state that if you notice within roughly 1–2 days, you can take it and then resume your regular schedule; if the next dose is close, skip it and carry on. Never take a double dose. Follow what your clinician recommended.
Stay at a maintenance dose
If you discover a dose that works well and produces only mild side effects, you can remain at that level rather than moving up to the highest one. The aim is to use the smallest amount that still works.
Maintenance vs maximum dose
Maintenance and maximum are not the same thing. The maximum studied weekly retatrutide dose hit the top of the chart above, yet once weight and appetite are steady, most people are managed at a lower maintenance amount. Chasing the highest dose seldom delivers better results and frequently causes more side effects.
Unsure about the correct starting point for a safe, medically supervised plan? Complete the intake questions, and a licensed clinician will review whether you qualify.
Get startedWhen your clinician changes your dose
A retatrutide dosing schedule is not set in stone. Doctors often reduce, pause, or hold off on increasing a dose when nausea or other side effects are hard to tolerate, when weight loss is occurring so fast that it needs monitoring, or when other health problems arise. They may keep you at one step for an extra month rather than increasing as planned. They may also stop raising the dose early if you are responding well. Always attend check-ins, be honest about side effects, and never change your own dose to make up for missed ones. To see what a realistic response looks like in the first months, refer to our weight-loss timeline.
Retatrutide dosage FAQ
What is a common starting dose for retatrutide?
Many studies and treatment plans start at about 2 mg once a week, held for around four weeks before any increase. Some telehealth programs begin with a lower amount. Your doctor determines your actual initial dose.
How can I change my retatrutide dose from milligrams to units?
Units measure volume, which depends on the concentration. To find mL, divide your dose in milligrams by the concentration in mg/mL. Then multiply that result by 100 to get the number of units on a U-100 syringe. Verify with your pharmacy.
What is the highest weekly dose of retatrutide?
In research, maintenance targets rose to around 8 mg and 12 mg per week, but most people are kept on a lower dose for maintenance. The maximum is not a target to aim for.
What should I do if I forget a weekly dose?
As a general rule, you may take the missed dose if it is within about 1–2 days and then continue your normal schedule. If the next dose is soon, you might skip the missed one. Never take two doses at once, and always follow the specific instructions from your doctor.
Is there an official dosing chart for retatrutide?
No. Since retatrutide is still being studied and is not approved by the FDA, there is no official chart included in the label. Any chart, including the one on this page, is only an example to discuss with a licensed prescriber.
Can I use a dosing chart I found on the internet?
No. Charts differ depending on the bottle strength and how the peptide is mixed, and self-dosing is dangerous. Use only the dose and concentration that your clinician and pharmacy have confirmed for your specific vial.
Sources & references
Claims of fact on this page are checked against the primary literature and regulators below. See our editorial standards.
- Jastreboff AM et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine 2023;389:514–526. View source
- ClinicalTrials.gov — TRIUMPH-1 (NCT05929066), a phase 3 retatrutide trial in obesity or overweight. View source
- Eli Lilly investor announcement detailing phase 3 TRIUMPH-1 preliminary weight-loss outcomes. View source
- United States Food and Drug Administration regulations on human drug compounding, covering sections 503A and 503B. View source