CommunityInjection Technique

No RegreReta.

26 replies11 peopleMay 11, 2026☆ Follow
Summary

How does starting retatrutide at very low doses affect weight loss progress, side effects, and vial longevity for someone combining it with exercise?

One user began at 0.5 mg and titrated slowly to 2.5 mg over weeks while tracking modest weekly losses of 0.2-1.5 kg alongside running and lifting. Several others supported starting low to test tolerance and avoid sudden side effects, while a few argued it delays results without preventing issues later. Experiences varied from minimal appetite change at 1 mg to noticeable fatigue and nausea at 2-2.5 mg. Questions about reconstituted vial safety beyond one month and possible under-dosed batches remained open.

What this discussion establishesWhere people disagree

Whether beginning at 0.5 mg is sensible caution or simply too low to produce meaningful effects compared with starting at 2 mg.

Still open

How long a reconstituted vial remains fully potent and whether the user's specific batch delivered the intended dose.

Nothing here is advice.

26 replies · 11 people
GreenQuill54archiveopening postMay 11

Peptides arrived about 24 days after I ordered them. I used to run 30-50 km a week but struggled with diet. Evening snacking has been hard to control and after a holiday and Christmas my weight rose from 94 kg to 104 kg. I have planned a 24-week mix of running and weights and am hoping the medication will help keep food choices in check. Today is day one. Age 45, starting weight 104.9 kg, first dose 0.5 mg. Goal is around 85 kg at 6 ft 3 in.

QuietPebble47archiveMay 11

85 kg sits in the healthy BMI range for your height and would be about a 19 percent loss. Some trial participants lost up to 28 percent. The 0.5 mg starting amount is mainly to check tolerance; you can move up fairly quickly to 2 mg if all feels fine.

LevelSignal24archiveMay 11

You could try another 0.5 mg shot four days later if there are no side effects and appetite has not changed yet.

PlainAlder11archiveMay 11

0.5 mg is too small an amount. Begin at 2 mg for four weeks and then reassess. How are you even measuring 0.5 mg without a tiny syringe?

GreenQuill54archiveMay 11

I chose 0.5 mg to see how my body handles it first. Results matter, but I want the smallest effective amount with the fewest issues. This is my first time with any peptide, so I am being careful. Several threads here suggested the same approach.

SlowLantern29archiveMay 12
↳ replying to @GreenQuill54

A few of us prefer to stay cautious with the dose increases.

WrySignal84archiveMay 12

I am on week two at 0.5 mg and like the idea of the lowest effective amount. I may move to 1 mg in week four.

PatientAlder89archiveMay 12
↳ replying to @GreenQuill54

Starting low makes sense for caution. Some people respond well at lower amounts and stay there longer. My husband lost weight on 0.5 mg and stayed at 1 mg for a while with good results. He is only now increasing a little. By the way, I like your username.

GreenQuill54archiveMay 12
↳ replying to @WrySignal84

I will probably follow the same plan. It seems the medication needs time to build up, and I am using a tracking app recommended here. No rush. I have never given myself an injection before yesterday. I am using an injection pen with 4 mm needles.

CopperSignal27archiveMay 12

Starting at 0.5 mg seems pointless; 1 mg at least matches half the usual trial starting dose. Very low doses do not stop side effects from appearing later when you reach the amount that triggers them. It may only delay when they show up. For nearly 20 percent body-weight loss you will probably need higher amounts, though some lighter people do well on 2-4 mg.

CopperLedger65archiveMay 12
↳ replying to @SlowLantern29

I agree with staying cautious. I began at 0.25 mg twice weekly and had side effects for three weeks. Now at 0.75 mg twice weekly I forget to eat. Responses differ a lot between people.

PatientAlder89archiveMay 12
↳ replying to @GreenQuill54

Icing the area beforehand helps a lot if the shot still feels uncomfortable.

LevelSignal24archiveMay 12

After reading about someone ending up with bad nausea and vomiting on a low dose of a similar medication and considering the ER, I see little downside to starting slow except losing a bit of time.

GreenQuill54archiveMay 18

First week: started at 104.9 kg, now 103.6 kg, down 1.3 kg. I have added some running and gym time. The loss is probably water and glycogen at this stage. No real effects or side effects from the shot yet, though I am choosing better foods. Dose increased to 1 mg today. Question: how long can a reconstituted 20 mg vial stay usable in the fridge inside the pen?

CopperSignal27archiveMay 18

Official guidance says no more than four weeks refrigerated. Longer storage raises the chance of contamination even with careful technique. Most people here do not report problems up to two or three months, but there is always a small infection risk.

GreenQuill54archiveMay 25

Second week: 103.6 kg to 103.4 kg, only 0.2 kg down. I was traveling and ate some convenience food while missing a couple of workouts. Still no strong appetite changes or side effects beyond slight fatigue on dosing day. Increased to 2 mg this week.

QuietPebble47archiveMay 25
↳ replying to @GreenQuill54

Even with some off-plan eating you are still moving in the right direction. The 2 mg dose should help more, and you can always increase further since you are still at the lower end of trial doses.

GreenQuill54archiveMay 27

Another thread mentioned a batch that may have been labeled double the actual strength. My batch number matches. Some tests on the same batch look okay, others do not. I am unsure whether I am actually taking 2 mg or only 1 mg, which might explain the mild response so far.

BlueCinder96archiveMay 27
↳ replying to @GreenQuill54

A testing service noted that potency may start dropping after about two months post-reconstitution. With 20 mg vials and low doses I expect to use one for more than a month, so I am watching for any cloudiness and accepting a possible small loss in strength toward the end of month two or three.

GreenQuill54archiveMay 27
↳ replying to @GreenQuill54

I contacted my contact and they said the suspect vials were all from February orders. Mine arrived in late April so they claim it is fine.

GreenQuill54archiveJun 1

Last week started at 103.4 kg, now 101.9 kg, down 1.5 kg. I took 2.5 mg today because effects seemed to be fading. Planning to stay here for a few weeks if loss continues. Felt the usual half-day fatigue and brief nausea while eating. Exercise is improving with 11 km running this week.

GreenQuill54archiveJun 8

This week: 101.9 kg to 100.7 kg, down 1.2 kg even after starting creatine again. Ran another 11 km and spent 3.5 hours lifting. Side effects included more fatigue, low mood, and noticeable nausea for the first couple of days. Still sticking with 2.5 mg for now.

RustBramble70archiveJun 8

I also began low: 0.5 mg week one, 1 mg week two, then 1 mg twice weekly by week four. Appetite dropped quickly and I had to remind myself to eat protein. Now at 2-2.5 mg twice weekly. Weight has come off steadily with occasional small rebounds. Main side effects have been skin sensitivity, feeling cold in the evenings, and facial changes from fat loss. I started another supplement a few weeks ago to help with skin appearance.

GreenQuill54archiveJun 8
↳ replying to @RustBramble70

Thanks for sharing. Congratulations on the loss and good luck with the knee and the supplement. Keep us updated.

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