When Switching from Wegovy to Mounjaro, Is It Okay to Change Immediately? Including Dosage Change Guidelines

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Hello,

I am Seong Hyeon-ju, director of Cheongdam OK Clinic.

▶ Full Member of the Korean Academy of Aesthetic Plastic Surgery (KACS)
▶ Full Member of the Korean Society for the Study of Obesity (KSSO)
▶ Full Member of the Korean Academy of Aesthetic Medicine and Obesity (KAAM)
▶ Full Member of the Korean Society of Liposuction (KSSL)
▶ Full Member of the Korean Society for Aesthetic Surgery (KSAS)

Among those who have started weight-loss treatment,

some consider switching from Wegovy

to Mounjaro,

while others

switch from Mounjaro

to Wegovy.

However, even though both are injections for obesity treatment,

it may not be appropriate to switch at any time

or continue using the same dosage without adjustment.

In this post,

we will discuss the timing of the switch

when considering switching between Wegovy and Mounjaro,

as well as useful dosage adjustment guidelines

and points to keep in mind.

Table of Contents
1. What is the difference between Wegovy and Mounjaro? 2. When switching between Wegovy and Mounjaro, is it okay to change immediately? 3. How should the dosage be started? 4. Key points to check when switching

1. What is the difference between Wegovy and Mounjaro?

Wegovy

contains semaglutide,

and acts on GLP-1 receptors

to reduce appetite

and increase feelings of fullness.

Mounjaro, on the other hand,

contains tirzepatide,

and has a dual mechanism of action,

acting on not only GLP-1

but also GIP receptors.

Both medications

are injections used once a week,

but because their ingredients and mechanisms of action differ,

their dosages cannot simply be compared

or continued at the same level.

2. When switching between Wegovy and Mounjaro, is it okay to change immediately?

Many people ask,

“Do I need to wait a few days before taking the next injection?”

In general,

without a separate extended washout period,

the new medication is often started

on the next scheduled injection date

after the final injection.

For example,

if you took Wegovy on a Monday,

you would start Mounjaro

the following Monday.

Conversely,

when switching from Mounjaro to Wegovy,

the new medication is also usually started

on the next scheduled injection date.

However, the plan may vary depending on

your individual health status,

medications you are taking,

previous dosage,

whether you experienced side effects,

and other factors,

so the judgment of a medical professional is important.

3. How should the dosage be started?

Even if you have used Wegovy

up to a high dosage,

that does not mean you should

start Mounjaro

at a high dosage right away.

In general,

Mounjaro is

started at 2.5 mg

and is often gradually increased

at approximately four-week intervals.

Conversely,

when switching

from Mounjaro

to Wegovy,

it is generally recommended to

increase the dosage gradually

rather than starting at the maximum dosage

from the beginning.

This is also intended

to reduce gastrointestinal side effects

such as

nausea,

vomiting,

abdominal discomfort,

and constipation.

4. Key points to check when switching

When changing medications,

it is important to consider

your current physical condition

rather than focusing only on effectiveness.

Recent weight changes,

amount of food consumed,

blood glucose status,

existing side effects,

coexisting conditions,

and medications you are taking

should all be considered together.

In addition,

using Wegovy and Mounjaro

together during the same week

is not recommended.

Calculating the dosage on your own

or starting at a high dosage

with the expectation of rapid weight loss

may also increase the risk of side effects.

The appropriate strategy may also differ

depending on whether the reason for changing medications is

weight-loss effectiveness,

side effects,

or supply issues.

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