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Weight loss injections/treatments

Discuss weight-loss injections and treatments, including personal experiences. Mumsnet hasn't checked the qualifications of anyone posting here. You may wish to speak to a medical professional before starting any treatments.

retatrutide new weight loss drug

55 replies

ElephantGrey101 · 19/04/2026 08:16

Most of my family are on GLPs. A couple of them are on a new drug called retatrutide. This is meant to be a better version of things like Monjouro and has fewer side effects and you retain more of your muscle etc.

However, it doesn’t seem to be available officially anywhere as it is still in clinical trials. They are buying it from someone at the gym.

Does anyone have any experience of this drug?

OP posts:
HeidiLite · 21/04/2026 09:54

I have seen those social media ads as well and am always marvel what kind of people are happy to actually inject themselves with totally random unknown substance bought from some dodgy website or guy at gym. It could literally be anything.

MeridaBrave · 21/04/2026 10:33

It’s not been approved anywhere in the world yet. I don’t get why anyone would take the risk with black market injectables. I’m taking a low dose of mounjaro from a licensed pharmacy. I also lost 12kg quite easily and keeping it off taking a microdose - BMI is around 23 now… microdosing also reduces the cost… so a 5mg pen costs £160 and lasts me 12 weeks - can someone explain why it’s worth the trade off of an unlicensed drug bought on the black market.

GiveMeWordGames · 21/04/2026 10:39

It's not just the peptides, it's the inactive ingredients which could be anything.
There's a lot in a mounjaro dose which isn't the GLP-1 itself but other things which stop it degrading, match salinity to the human body, prevent bacterial growth, maintain its stability, allow it to be taken only once a week and remain active in your system for that time. ALL of that stuff is just as expensive, if not more so, than the peptide. And those things are likely to be missing or have cheaper god-knows-what substitutions in this unknown garbage people are buying from gyms. The wilful stupidity of doing this astounds me.

WeAllHaveWings · 21/04/2026 14:04

OneThirdLess · 21/04/2026 09:28

This isn't a defence, but it's not illegal to take them. It also isn't illegal to sell them, because they're advertised as "for research purposes only and not for human consumption". Which is what makes them grey market, not black market.

I'd rather everyone had safe access! And I take mounjaro on a prescription, I'm way too risk averse to try anything else. But my understanding is that the peptides aren't all that difficult to make if you have the lab setup - which a lot of places in China (etc) do as they already make peptides legitimately for medicine companies.

So people taking grey market peptides are taking a risk - but it probably isn't as big a risk as we might think. Given how widespread they've become, there would be a lot more horror stories if they were all dodgy. In a way, that's more worrying - because they're becoming more popular so if a bad batch gets out, there could be a lot more harm done to more people, and there's no comeback on the manufacturer. For me that's a much bigger concern.

Because they are not regulated there is no way to tell if your mystery chemical in a bottle is tirzepatide or retatrutide or something completely different, what quality control has been used in it manufacture, accurately of dosing, transit and storage conditions etc.

It is no different to say ecstasy tablets, they are all risky, and not everyone who has a bad tab (either totally ineffective or more serious) shares their sob story in the Daily Fail.

CleanSkin · 21/04/2026 14:20

@GiveMeWordGames You’ve nailed it. I wish your words were mandatory for all the users who consider buying from dubious sources, be they TikTok, The Gym or anywhere else.

montysmaw · 21/04/2026 14:38

QuestionablePeptideChoices · 21/04/2026 07:59

It's about £5 a month at the dose I've been taking. I guess that's a lot cheaper than the officially licensed products. I wouldn't have been eligible for a Mounjaro prescription I don't think and unsure how much that would cost. I've been open with my Dr about what I'm doing and had blood tests - latest results were very good for my age and he told me to come back next year.

Its not retatrutide. for a fiver. Trust me.

whatifs1 · 21/04/2026 14:45

Heard loads of people are using it.

there are labs you can send your sample off too to be tested, they will ID it, test for endotoxins and also test for heavy metals but it comes at a price.

ElephantGrey101 · 21/04/2026 18:30

OneThirdLess · 21/04/2026 09:28

This isn't a defence, but it's not illegal to take them. It also isn't illegal to sell them, because they're advertised as "for research purposes only and not for human consumption". Which is what makes them grey market, not black market.

I'd rather everyone had safe access! And I take mounjaro on a prescription, I'm way too risk averse to try anything else. But my understanding is that the peptides aren't all that difficult to make if you have the lab setup - which a lot of places in China (etc) do as they already make peptides legitimately for medicine companies.

So people taking grey market peptides are taking a risk - but it probably isn't as big a risk as we might think. Given how widespread they've become, there would be a lot more horror stories if they were all dodgy. In a way, that's more worrying - because they're becoming more popular so if a bad batch gets out, there could be a lot more harm done to more people, and there's no comeback on the manufacturer. For me that's a much bigger concern.

I think that despite all the risks they do seem to have got a relatively decent source. It is like you describe where peptides are being bought for “research” purposes but then sold as weight loss drugs.

I wouldn’t take them but most of my family are on some kind of weight loss drug and everyone is very pro. One of them managed to get monjouro from a genuine online pharmacy despite being nowhere near the weight you need to be to be on it.

OP posts:
MeridaBrave · 21/04/2026 18:36

ElephantGrey101 · 21/04/2026 18:30

I think that despite all the risks they do seem to have got a relatively decent source. It is like you describe where peptides are being bought for “research” purposes but then sold as weight loss drugs.

I wouldn’t take them but most of my family are on some kind of weight loss drug and everyone is very pro. One of them managed to get monjouro from a genuine online pharmacy despite being nowhere near the weight you need to be to be on it.

It’s a totally different think taking mounjaro from a licensed pharmacy with a lower BMI than taking peptides bought over the internet. I mean I started taking MJ with a BMI of 27 and it’s now 22.5-23. How is that so different to someone taking it starting at a BMI of 24/25?

CleanSkin · Yesterday 17:18

What’s an “endotoxin” @whatifs1 ?
I’d not put an ounce of credibility on that result!

whatifs1 · Yesterday 17:28

CleanSkin · Yesterday 17:18

What’s an “endotoxin” @whatifs1 ?
I’d not put an ounce of credibility on that result!

That’s completely your choice. They are an accredited independent lab so I’m not sure what reason they’d have to lie. They are NOT manufactures of anything. you can also verify the tests with unique codes so you can check your COA hasn’t been altered/copied.

endotoxin testing detects toxins that are left over from bacterial contamination during the peptide manufacturing process.

Endotoxins are bacterial toxin fragments that remain after bacteria die during manufacturing - standard purity tests don't detect them though and to have your peptide product tested for this will cost extra.

this is all dependant on what an individuals risk tolerance is obviously. Some people wouldn’t touch it with a barge pole, others do.

QuestionablePeptideChoices · Today 07:13

whatifs1 · Yesterday 17:28

That’s completely your choice. They are an accredited independent lab so I’m not sure what reason they’d have to lie. They are NOT manufactures of anything. you can also verify the tests with unique codes so you can check your COA hasn’t been altered/copied.

endotoxin testing detects toxins that are left over from bacterial contamination during the peptide manufacturing process.

Endotoxins are bacterial toxin fragments that remain after bacteria die during manufacturing - standard purity tests don't detect them though and to have your peptide product tested for this will cost extra.

this is all dependant on what an individuals risk tolerance is obviously. Some people wouldn’t touch it with a barge pole, others do.

Yes, exactly. There was a recent scare with grey market tirzepatide from one distributor that had potentially significant endotoxin levels. So people are testing, and the market reacts - in this case by the distributor pulling that batch from sale and pausing shipping, other distributors doing more testing. It’s not for everyone, but people are assessing the risks for themselves, and the main risk of endotoxins at the levels they’re finding is allergic reactions, but not necessarily something that requires medical intervention.

Girlintheframe · Today 08:35

I’ve been seeing more and more about this peptide on SM and find it fascinating. People who are taking it absolutely raving about how good it is at not only controlling appetite but also helping with cravings, blood sugars etc. Some taking it have moved over from MJ due to costs, others taking it appear to be a healthy body weight but want to loose a few pounds and other like bodybuilders using it for prep.

MeridaBrave · Today 08:45

Girlintheframe · Today 08:35

I’ve been seeing more and more about this peptide on SM and find it fascinating. People who are taking it absolutely raving about how good it is at not only controlling appetite but also helping with cravings, blood sugars etc. Some taking it have moved over from MJ due to costs, others taking it appear to be a healthy body weight but want to loose a few pounds and other like bodybuilders using it for prep.

I also find it fascinating. But I’m very risk adverse and not short of money so will be sticking with MJ. Bodybuilders always been more willing to experiment so that doesn’t surprise me.

Girlintheframe · Today 09:57

@MeridaBravei think what I find so fascinating is that such a diverse group are using it. From what I’ve seen advice generally seems to be pretty sensible like advocating for very low dosing, only using for x amount of weeks, getting product tested etc. I’ve no ideas of pricing but am assuming it’s considerably lower than other GLP. There also seems to be lots of peptide stacking where people are using multiple peptides for different things. Like you I’m quite risk averse but SM has certainly opened my eyes to what’s available if you really want it!

Sunnyskiesa · Today 10:16

The crazy thing is that people here like the OP like to inject themselves with something clearly labelled as "for research only" or "not for human use" sold by a website in a "virtual office" (have a look to many of these peptide-selling addresses on Google map) just expecting to avoid the controls imposed by law.
But then maybe they were the ones saying "I will not get the covid jab as it is not tested".....

twilightcafe · Today 10:20

God Almighty! Buying backstreet shit from 'some bloke in the gym'?

What could possibly go wrong..!

Nanda66 · Today 10:23

QuestionablePeptideChoices · 21/04/2026 07:59

It's about £5 a month at the dose I've been taking. I guess that's a lot cheaper than the officially licensed products. I wouldn't have been eligible for a Mounjaro prescription I don't think and unsure how much that would cost. I've been open with my Dr about what I'm doing and had blood tests - latest results were very good for my age and he told me to come back next year.

Your doctor supports you injecting yourself with an unlicensed drug bought from an unlicensed provider for £5 a month?

whatifs1 · Today 10:26

Sunnyskiesa · Today 10:16

The crazy thing is that people here like the OP like to inject themselves with something clearly labelled as "for research only" or "not for human use" sold by a website in a "virtual office" (have a look to many of these peptide-selling addresses on Google map) just expecting to avoid the controls imposed by law.
But then maybe they were the ones saying "I will not get the covid jab as it is not tested".....

or they do both? 😆

QuestionablePeptideChoices · Today 10:41

Nanda66 · Today 10:23

Your doctor supports you injecting yourself with an unlicensed drug bought from an unlicensed provider for £5 a month?

‘Supports’ as in recommends? No. But since I was doing it anyway, he supported me by ordering the appropriate blood tests and interpreting the results, organising the follow up tests when I went back after two months, etc.

JMSA · Today 10:49

I’ve loved Mounjaro but would be very interested in an alternative that’s possibly more effective (and cheaper?). I still have to rely on willpower a lot as despite being on the highest dose, I could do with better appetite suppression.

MrsTravelBug · Today 11:07

People have bought illegal substances from gyms since the dawn of time, every gym I have been a member of has had a side hustle in steroids, they are just expanding their market. It’s hardly a new phenomenon.

whatifs1 · Today 11:20

MrsTravelBug · Today 11:07

People have bought illegal substances from gyms since the dawn of time, every gym I have been a member of has had a side hustle in steroids, they are just expanding their market. It’s hardly a new phenomenon.

This. It’s hardly front page news.

SomethingAboutNothing · Today 11:39

JMSA · Today 10:49

I’ve loved Mounjaro but would be very interested in an alternative that’s possibly more effective (and cheaper?). I still have to rely on willpower a lot as despite being on the highest dose, I could do with better appetite suppression.

But once it is approved and regulated it won't be any cheaper. It is being produced by the same pharmaceutical company so will potentially be more expensive if anything.

As for the OP, I certainly wouldn't inject something that comes from an unknown source. The risk is just not worth it.