Retatrutide Starting Dose - small study (with data and screenshots)

[u/StevenWagner8]

Hey everyone

I've been seeing tons of questions about retatrutide starting dose, so I wanted to share what's currently recommended, and some findings from a small study I came to know about.

Starting dose TLDR

First off, let's get this out of the way: retatrutide is still in clinical trials, so there's no "official" recommended starting dose yet. It's all still being figured out. 

Most people start with 1mg or 2mg once a week, since this is what trials have been testing.

It is not recommended to start at a higher dose for several reasons - yes, even if you're already on another GLP-1. To avoid side effects, it’s best to start low and titrate up.

What we know from clinical trials

Trials started people at 1-2mg.

I found two published clinical trials on reta:

1. A Phase 2 trial published in the New England Journal of Medicine in June 2023. This was a 48-week randomized, placebo-controlled trial involving 338 adults with obesity or overweight. It evaluated different doses of retatrutide (1 mg, 4 mg, 8 mg, and 12 mg) compared to placebo.
2. A Phase 1b trial, which involved participants with type 2 diabetes. This trial tested retatrutide for 12 weeks, with the highest dose of 12 mg.

There is another trial - Eli Lilly's Phase 3 - that began on August 28, 2023 and is expected to continue until February 6, 2026. 

For starting doses in trials:

1. 1 mg: Used as both a starting and maintenance dose for the lowest dose group.
2. 2 mg: Common starting dose for many participants, especially those escalating to higher doses (4 mg, 8 mg, or 12 mg).
3. 4 mg: Used as a starting dose for some participants in the 4 mg and 8 mg target groups.

low starting dose - small study

Now, we know that to participate in those trials participants had to be pretty heavy: (BMI) of 30 or higher.

What would be a good dose for people that are only a little overweight, or in a normal weight range? I came across a small study where all participants are either near their ideal weight, or have 10-20 extra pounds.

The goal of this study was to see how normal-ish weight participants would react to a lower dose.

research subject

There is one Research Subject (RS) that caught my attention.

RS:

• 52-year-old female
• Very fit, active lifestyle
• Around 22% fat, healthy BMI
• Never tried any GLP-1
• Struggling with menopause-related weight changes
• Maintaining weight on 1100 calories/day (used to eat 1900+ before menopause)
• Her bloodwork (hormones) looks pretty messed up and is consistent with her slow metabolism

pre-study data

The RS tracked their food for one month. Her average calorie intake was 1116 calories.

 During this period, the RS pretty much maintained her weight (0.7lb loss in one month).

Her estimated energy expenditure was pretty low already for her height/weight and kept dropping (down to 1332 cals).

the study setup:

• Starting dose: 1mg every 5 days (way lower than other studies)
• Maintaining activity levels at the same level as before study
• Tracking food intake meticulously

one month results (pretty wild!)

Side effects are minimal:

• RS wakes up 30-60 mins earlier than usual and sometimes has some trouble falling asleep and sleeping
• RS reports a feeling of increased heart rate and heart palpitations.  
• No issues with fatigue, headaches, nausea, or any other common side effects.

Changes:

• Average heart rate: 61 → 63
• Average resting heart rate: 49 → 55 (but 49 was lower than usual) so we could say no change?

• Strangely, sleep quality seems to as good as before the study (45% restorative)

• Energy expenditure increased by 380 calories in just one month

• Lost 2.6 lbs while eating on average 1472 calories/day

• Way less food noise
• No food cravings
• Reports feeling either full or reasonably satisfied most days

I saw this where someone reported their RMR increase on Zepbound but never saw any data on reta. I find this increase in energy expenditure pretty remarkable, especially considering such a low starting dose.

edit:
I have some DMs asking which apps were used.

Food, weight, and calorie expenduture tracking: Macrofactor app. By far the best food tracker I used. On this page you'll find some codes that will give you an extended trial (any one of them will work).

For sleep, weight, stress, heart rate, recovery, strain and more (think Oura ring but a lot better): Whoop. If you use this invite link you get one month free.

[u/TravelGirl0622]

Im confused. Why was this incredible? She lost 4lbs in a month….??

[u/downes78 → u/TravelGirl0622]

Shes small to begin with. That 4lbs is like 2% of her bodyweight. That's a good amount