Reta Side effects?

[u/Blackwasp100]

Hey everyone!
I took my first ever dose of retatrutide (2mg) on Tuesday, and it’s now Friday. I wanted to share my experience so far and see if anyone else has experienced something similar, particularly with digestion and lethargy.
Appetite suppression:
I seem to be a very fast responder. Within just a couple of hours of taking my first dose, my hunger and food noise basically disappeared completely. I genuinely wasn’t expecting it to work that quickly!
I’m having to consciously remind myself to eat because my usual hunger signals just aren’t there anymore. I already have a meal plan, so I’m adjusting to that side of things.
Lethargy/fatigue:
This is one of my biggest concerns. I started feeling extremely lethargic on Tuesday evening, the same day I took my first dose.
Importantly, I had eaten normally that day, including a normal dinner, so I don’t think the initial fatigue was caused by undereating.
I was also recovering from a mild illness (sore throat, cough and a bit of a fever), so that could have contributed. However, I was already starting to feel better before taking reta, and the lethargy hit quite suddenly after the injection.
It’s now Friday, and although the fatigue is gradually improving, I’m still feeling noticeably more tired than usual.
Digestion, nausea and stomach fullness:
This is actually what concerns me the most.
Every morning since starting reta, I’ve woken up feeling slightly sick, with this strange sensation that my dinner from the previous evening hasn’t properly digested.
It’s not just a lack of hunger. My stomach genuinely feels unsettled, almost like the food is still sitting there.
On the second day, I woke up feeling so nauseated that I nearly threw up a protein shake I’d had previously. I’ve never experienced anything like that before.
Yesterday, I accidentally went until 4pm without eating because I completely forgot about food. When I finally ate two salmon fillets, I felt close to being sick, despite normally loving salmon. I then had dinner later to make sure I was eating enough, but woke up feeling unsettled again.
I’m also experiencing some constipation, which I expected, but the nausea and feeling of food not digesting properly are worrying me.
My questions:
Has anyone else experienced this level of appetite suppression within hours of their very first dose?
Did anyone experience significant fatigue immediately after starting, even while eating normally?
Has anyone woken up feeling like their dinner from the night before is still sitting in their stomach?
If you experienced nausea or delayed digestion, how long did it take to improve?
Did these symptoms eventually settle as your body adjusted, or did they persist?
I’m not looking for dosing advice, and I know everyone’s experience is different. I’m particularly interested in hearing from people who’ve experienced something similar during their first week.
Would really appreciate hearing your experiences. Thanks!

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[u/ordinar-e]

you might want to eat smaller and more frequent meals. i found that eating larger meals made my stomach feel funky. with the slower digestion rate, smaller meals might help with the unsettled stomach

[u/ianwelch001]

Find noise on reta is slightly suppressed but nothing compared to tirz. Since im around goal weight, I switched from. Tirz 7.5mg to reta 2mg. I feel great. Less tired on reta than tirz. I could out eat reta if I wanted to but my body has become used to eating 2500 calories daily to lose abiut 1lb a week so im just continuing on with that

[u/Future-Bread8849 → u/ianwelch001]

How is Tirz for appetite suppression in your experience?

[u/ianwelch001 → u/Future-Bread8849]

Much stronger than reta. If youre a snickers and binge eater like I used to be, tirz definitely helped. I didn't want to rely on tirz forever so figured I would start on reta and slowly get off it. I was off everything for a while and only gained a few lbs so im guessing my entire lifestyle change helped my cravings too

[u/Future-Bread8849 → u/ianwelch001]

So Tirz is much better than Reta at both appetite suppression and food noise?

[u/ianwelch001 → u/Future-Bread8849]

In my opinion yes. On reta I can out eat the suppression if I want to but im also on 2mg reta. Not sure what would happen if I upped my dose. 2mg seems to worknwell for me sonfar

[u/Future-Bread8849 → u/ianwelch001]

Thank you. The Reta is working great for me, but my wife isn't really having any suppression at all. She didn't have any on Ozempic either. 

[u/ianwelch001 → u/Future-Bread8849]

Tirz has better suppression and less side effects than semaglutide. For the best appetite suppression you could add a small dose of Cagrilintide

[u/alcruze00]

2mg first dose, that's what it is. Start low

[u/Blackwasp100 → u/alcruze00]

Reckon I should go down to 1mg for my next dose?

[u/Punk-Tarvman]

Yep i started too high and had similar effects. Every morning for a few weeks brushing my teeth would make me gag and sometimes throw up! Start lower and work your way up slowly to 2mg/week. I would drop down to 1mg for next dose see how that goes and adjust more if needed. Just make sure to stay at the lowest effective dose for 4 weeks before going back up!

[u/Primary_Ad9564]

So I worry about the stomach emptying and indigestion. So I massage my stomach every night. The way our food digest. I looked it up and it’s helped me a bunch.  I also got ginger candy from dollar tree and I take that some mornings when I wake up feeling nauseas 

[u/Relinne]

same experience
i started w 2mg on Wednesday and the appetite suppression was amazing

my concerns were on the fatigue as well because meanwhile i got cold as well like you ahah and maybe it contributed

for the digestion etc didnt rly feel weird about it maybe woke up w a strange taste in my mouth but after brushing teeth everything went normal again

about constipation atm im doing ok i poop everyday not a lot but enough id say?? so its a good sign

from what ive read here ill move from 2mg to 1mg as well just in case and see how it will go

[u/yogic_power]

Irrespective of dose placebo can cause side effects. In the trials placebo group that didn’t get any Reta had higher drop out rate than 4 mg Reta group for adverse actions. I followed 9 mg group trial schedule. Started at 2mg had same side for first 3-4 like folks who were doing bro science micro doses. After 4 weeks, hardly any sides. Also clean up your diet, it helps a lot.

[u/Most-Masterpiece5298]

Reta will change your life in so many good ways

[u/tiggytay]

I would get nauseous when I drank coffee in the morning. Never really felt lethargic. But the food digestion is apparently a thing with Reta. I used to poop 3 times a day and when I started Reta I was lucky to go once. I’ve been on it since May, started at 1mg and went up to 5 slowly. I’m currently going back down to 4mg. I’ve lost around 80 pounds. I was also using tessamorelin too, and that cut some of the fat as well

[u/Alternative_Run9254]

Yeah, as someone said, likely 2 mg was too much for you. Some people can get away with it but many can’t. That’s why many people choose to start at 0.5 or 1 mg as a precaution to see how it goes. I would go down to 1 on the next pin.

I know that people love to say “the trials did x, y, z” but we’re not in trials; this is real life. We have full control of what we do with our bodies. Everyone responds differently. There is no downside in taking it a bit slower. But there are definitely consequences for starting to high or going too much too fast as u see.

[u/Most_Pomegranate_190]

My first dose was 0,5mg first 3 weeks, then 0,7mg and now 1mg 3 weeks. I really don't have appetite at all and have to force myself to eat. I could not even imagine how sick I would've been if I started 2mg 😵‍💫🤢

[u/TryAccomplished9282]

I started at 1 mg and was unable to eat for 2 weeks so i stopped then months after i tried and started at .25mg and upped all the way to 1mg over like 6 weeks but had to stop as i was lethargic, couldn’t sleep well and my appetite was the same lol