Retatrutide: My Experience and Side Effects

I did not try retatrutide because I could not lose weight without it. Quite the opposite. I know how to track calories, maintain a deficit, and keep a diet under control. I saw Ozempic and other GLP-1 receptor agonist medications as more of an unnecessary luxury. But I did not want to dismiss them just because I can diet without them.

I wanted to find out firsthand what taking a substance like this actually feels like. Mostly, I expected to feel less hungry. The biggest surprise came from somewhere else: after a large, high-fat meal, I felt uncomfortably full for hours.

My experience at a glance

• At a low dose, I was not sure I felt anything at all during the first two weeks.
• My hunger did not disappear completely. It simply felt less urgent, and a smaller portion was enough.
• At a higher dose, large or high-fat meals left me feeling uncomfortably full, with abdominal pressure and nausea.
• My day-to-day life and performance in the gym did not change much.
• My cigarette cravings stayed the same.
• The experiment was not worth it just to finish the diet. Its main value was the experience itself: I now understand better how substances like this can change a person's relationship with food and why they can help someone who deals with constant hunger.

Where I started: finishing a cut, not treating obesity

I am 188 centimeters tall and weighed about 85 kilograms at the start, with an estimated body fat level of 12%. I lift regularly, do not usually struggle with hunger, and maintain my weight without much difficulty. I only added retatrutide during a harder stage of the diet, when I was trying to get down to around 10% body fat.

That is exactly why I was fairly skeptical of substances like this. My thinking was simple: if a calorie deficit works, why inject something just to lose weight? Only later did I see the flaw in that argument. I had automatically assumed that other people experience hunger the same way I do.

Why did I choose retatrutide specifically? It interested me as a new investigational substance; I wanted to see what it would do during a cut, and it was available as a research chemical. I was not obese and was not looking for treatment. I simply wanted to see how it would affect the final stage of my diet.

Retatrutide activates the GLP-1, GIP, and glucagon receptors. There is no reason to explain all of the pharmacology again here. What matters for my story is that gastrointestinal adverse effects were the most common in trials, and their incidence was dose-related.⁴

Timeline: four weeks and a rushed titration

The table shows what I did at the time; it is not a recommended schedule. I split the total weekly dose between Monday and Thursday, while the clinical trials used once-weekly dosing.

I accelerated the titration because the diet was ending and I did not want to use retatrutide for long. In hindsight, it was too fast. Retatrutide has a biological half-life of about six days, and I increased the dose each time before the drug level could approach steady state.⁵ That meant I could not distinguish the effect of a specific dose from retatrutide gradually accumulating in my body.

I explain why I split the dose and the reasoning behind it separately in my article on retatrutide during a diet and split dosing. Here, I will stick to my own experience.

Hunger did not disappear. Food started to “punish” me

I expected a simple effect: less hunger, less food. For me, it was more subtle. I still got hungry, perhaps a little less so. The main difference was how I felt after eating.

A smaller portion, a salad, or a normal meal of a few hundred calories was fine. But if I had a large burger, a loaded burrito, pizza, or another big, high-fat meal, my stomach made its objection very clear. I did not feel sick for no apparent reason. The discomfort mainly showed up after I ate too much in one sitting.

It really clicked before one workout. I would normally eat a meal of around 900 calories about 90 minutes before training, with plenty of carbs, fat, and protein. This time I went to the gym with pressure in my abdomen and mild nausea. I did not vomit or feel as though I was about to, but for several hours I could tell that I had overdone the portion.

From then on, I thought about food differently. If someone suggested getting pizza, just imagining how I would feel afterward was enough. It was not only about satiety. I quickly began to associate a large portion with several uncomfortable hours. Choosing smaller, lighter meals then became almost automatic.

This is my observation, not a rule that applies to everyone. One personal experience cannot show that retatrutide changes everyone's appetite or that every person will feel sick after a high-fat meal.

Day-to-day life and performance in the gym

Retatrutide did not interfere much with my normal life. A regular lunch at a restaurant was not a problem. At a party, I could still eat; I would probably just skip a course or avoid grazing at the buffet. Chips, tapas, and other small bites throughout the evening simply appealed to me less than usual.

I did not notice a direct drop in gym performance or any unusual fatigue. As long as I made sure I got enough carbs and did not eat an absurdly large meal before training, I functioned normally. My strength stayed the same or declined slightly, which I consider normal near the end of a diet. I did not do any sprints or long endurance sessions during this period, so I do not know how retatrutide would have affected those.

I was also curious whether my cigarette cravings would change. They did not. I smoked the same amount as before, and the only effect I noticed involved food.

I also used kratom on some days, which makes the experience harder to interpret. On those days in particular, I felt more abdominal tightness and experienced constipation. But I cannot tell whether that came from the combination of substances, retatrutide itself, kratom, hydration, or what I ate. It would be dishonest to present it as a proven interaction.

How much weight did I lose on retatrutide?

I am deliberately not giving a weight-loss figure. I was tracking calories and maintaining a deficit at the same time, and I would have completed the diet without retatrutide. I therefore cannot attribute the change in my weight to a single substance.

All I can say is this: if I had not been tracking calories, I probably would have eaten less. Smaller portions were enough, and large, high-fat meals did not appeal to me. But that is an inference based on my own behavior, not a measured outcome.

What happened after I stopped retatrutide

By the time I reached 2 mg, the diet was nearly over and I was getting below 10% body fat. On some days, hitting maintenance calories was difficult unless I made a conscious effort. Further appetite suppression no longer made sense, so I stopped taking retatrutide.

The effects did not disappear overnight, which was no surprise given the approximately six-day biological half-life.⁵ I returned to normal gradually. One of the first signs was the return of my sweet cravings, which had virtually disappeared during the experiment.

How retatrutide changed my view of obesity treatment

Before the experiment, my view was simple: download an app, track your calories, and lose weight. Energy balance still determines weight loss. But it was only during the experiment that I realized how much harder controlling food intake can be for some people than for others.

I probably do not experience hunger as intensely as many other people. I cannot apply my own dieting experience to someone who thinks about food all day and finds every deficit miserable. If an approved treatment with a favorable benefit-risk profile exists for that person's specific condition, I do not see using it as a lack of discipline.

That does not mean I recommend what I did to anyone else. Medically supervised obesity treatment is different from my short experiment at the end of a diet.

Was it worth it?

In purely practical terms, no. I would have finished the diet without retatrutide. The fast titration also created a problem I did not have before: eating enough to support training and maintain my weight became a chore on some days.

As an experience, however, yes. I no longer have to imagine how a substance like this can change someone's perception of hunger, portion sizes, and food in general. I felt it firsthand. I also learned that adverse effects are not proof that a substance is “finally working.” Once the lower dose was achieving its intended purpose, there was no sensible reason to push it higher just to feel a stronger effect.

Looking at how I ran the experiment, the biggest mistake was the pace. I spent too little time at each dose and tried to fit everything in before the end of the diet. Even the most careful table cannot turn that into a controlled experiment.

Frequently asked questions

How did retatrutide affect my hunger?

My hunger did not disappear completely, but it felt less urgent, and I was satisfied with a smaller portion. The bigger difference was that I no longer wanted large, heavy meals because of how uncomfortable they made me feel afterward.

What side effects did I experience?

Abdominal pressure and fullness, mild nausea after large portions, and occasional constipation. I did not vomit; the nausea only appeared after eating.

Did retatrutide affect my performance in the gym?

Not directly, in my case. I had to adjust the size and timing of my pre-workout meal. I attributed the slight decline in strength to the calorie deficit, not retatrutide.

Would I take it again?

Not for a similar diet. The experience itself and the change in perspective were more valuable to me than the outcome on the scale.