PLEASE NOTE THIS WIKI IS NO LONGER UP TO DATE. SOME INFORMATION WILL STILL BE ACCURATE BUT SINCE SUMMER 2025 THERE HAVE BEEN A LOT OF CHANGES.
This wiki is to support users in the UK with the prescription-only weight loss drugs, Wegovy and Mounjaro. Please do not post on the thread if you've lied about your BMI to obtain these prescription medications. This is not the thread for you
Referral codes are banned on Tattle.
(Note - Ozempic is the US brand name for semaglutide. In the UK it is marketed as Wegovy. In the UK, Ozempic is prescribed for diabetes).
Which has published a useful guide to weight-loss injections.
About Wegovy and Mounjaro
Wegovy and Mounjaro are both approved weight loss treatments for adults with a BMI of 30 or above, or 27 and above with a weight-related condition. It is currently (at July 2024) very difficult to obtain an NHS prescription from your GP. The vast majority of users on Tattle are buying from private online prescribers.
Both medications are weekly injections. They work by:
Suppressing your appetite
Making you feel fuller for longer
Slowing down the rate that food leaves your stomach
Although they work in similar ways, they are not the same drug. The key differences are mentioned below.
Active ingredients
The active ingredient in Mounjaro is called tirzepatide. This ingredient activates two hormonal receptors (GIP and GLP-1). When these hormones are mimicked, your appetite is suppressed, blood sugar is better regulated, and the rate of food leaving the stomach is slowed down. All of these actions result in weight loss.
The active ingredient in Wegovy is called semaglutide. This works by mimicking the hormonal receptor GLP-1, resulting in the same actions mentioned above. However, Wegovy does not mimic GIP.
Dosages
As well as the active ingredients, the dosages are different. On Wegovy, you can expect to start on a dosage of 0.25mg. It then goes up in increments until a maintenance dose of 2.4mg is reached.
When taking Mounjaro, your starting dose is 2.5mg. This then goes up in 2.5mg increments until a dose of 15mg is reached – this is called the maintenance dose.
Important note on starting doses
Some users report weight loss and appetite reduction from Day 1, while others take weeks. There is no need to be disheartened if you do not feel any effects right away. This is completely normal. The official guidance as to whether these medications ‘work’ for you is that you should have lost 5% of your starting weight in the first 12 weeks of treatment. It is recommended that you discontinue use if this is not the case.
Which drug is better?
Mounjaro is more effective than Wegovy. A clinical trial over a 72-week period showed that 96% of the participants taking Mounjaro (on the highest dose) lost 5% or more of their starting body weight. In a similar trial, 84% of people taking Wegovy on the highest dose lost at least 5% of their body weight.
There is also anecdotal evidence from our users that Wegovy can lower mood, and both can suppress appetite for alcohol.
Serious side effects include
low blood sugar
pancreatitis
gallbladder problems, including gallstones or swelling of the gallbladder
increased heart rate
severe nausea, vomiting, or diarrhoea which may lead to dehydration and related kidney problems
low blood pressure
appendicitis
increased risk of fractures
boxed warning: risk of thyroid cancer
Buying weight loss pens
There are many online pharmacies whose doctors may prescribe weight loss injections if you meet the criteria.
They compete in price, so it is worth checking all suppliers for current prices and discount codes. It is relatively easy to switch providers dose by dose if you want to, just be prepared to answer all of the questions and submit the supporting evidence (photos, videos, ID, proof of previous dose) each month to your new chosen supplier as you switch.
Weekly Price Comparison
There is currently an up-to-date price comparison chart on the Reddit sub UKMounjaro. It's always pinned to the top of the sub and is updated regularly. www.reddit.com/r/UKMounjaro
There is also a website you can check for the lowest price by dosage at www.monj.co.uk
There have been news reports that "fake" semaglutide pens are in circulation. If the price seems too good to be true on a Facebook advert, it probably is!
Also please be aware that it is illegal to sell on prescription medications you don't want to use anymore.
Tips for newbies to Mounjaro
Please bear in mind that thread members can offer anecdotal advice and their own experiences of these drugs, but you should ask your GP or private prescriber for medical advice.
Unlike the Wegovy pens, for the first Mounjaro dose, you need to twist the pen a LOT to get to 1! When injecting, hold down the button until the number goes back to 0. Once at 0, keep holding down the button and count to 6 with the needle still in.
Some people find that they don't need to go up a pen dose each month if the current pen dosage is working well for them. If you are unsure when to go up, speak to your prescriber.
If you are having bad side effects after titrating up or you are struggling to eat your calories each day, your dose may be too high so should consider lowering your dose. Speak to your prescriber if unsure.
An unused pen must be kept in the fridge. Once you take your first dose you can keep your pen in the fridge (if you are 'hiding' it, a tomato puree box is a good place) or somewhere else. It does not need to be refrigerated once opened. It can be more comfortable to inject it at room temperature, so take it out of the fridge a few hours before injecting, if that's where you are keeping it.
Do not reuse any needles as this could risk infection. If you damage a needle or one isn't working, you can buy a pack of spare needles, or some prescribers will send you a few extras if you contact them. If you want to buy spares, the Mounjaro KwikPen is compatible with ISO 11608-2 compliant pen needles from brands such as BD, Novo Nordisk, and Terumo, in any length and gauge combination:
Lengths: 4 mm, 5 mm, 6 mm, 8 mm, 12.7 mm
Gauges: 29G, 31G, 32G, 33G, 34G.1
You might find supplements helpful. Multivitamins are a good idea. Some people use magnesium (for sleep and constipation), collagen (skin elasticity), aloe vera (for constipation), and psyllium husks (fibre for constipation).
Drink LOTS of water. Water helps with the weight loss. Try and drink at least 2 litres a day. Electrolytes are really helpful too if you're suffering from diarrhoea, as you'll get dehydrated easily. Dehydration can cause real issues with your kidneys.
If you are unsure how many doses you have left in a pen, this image is helpful.
Counting clicks
This should only be done if you want to take a smaller dose than recommended. It's not necessary and you'll need to be reasonably good at maths to use the whole pen this way, proceed with caution! Informative video here:
The "extra dose"
A slightly controversial issue. Technically there is no extra dose, but you will likely see a fair amount of medication remaining in the pen after your fourth injection. Additional liquid is included to prime the pen.
For Wegovy simply use a new needle and inject.
For Mounjaro, you used to be able to twist the pen really hard and break it, but the pen design has changed and this doesn't seem to work anymore. It is easy to extract the remaining dose, and some users prefer this method as you can more accurately see how much medication you are injecting. Just purchase some human grade, sterile 1ml insulin needles, and extract the remaining liquid. (Be aware most of the needles sold on Amazon are not human grade, sterile needles, you'll probably want to order from a medical supplies website, there are lots to choose from, one example is https://ukmedi.co.uk/products/fms-micro-syringe-32g-8mm-1ml-fms-fms-32g-10ml-ukmedi-co-uk). This way you can also see exactly how much you are injecting. If you are interested in this, see this video guide
What to do with used pens and needles
Used Wegovy pens can be recycled at Boots. Currently, Mounjaro pens can not be recycled and should be disposed of in household waste. Always make sure you have removed needles and placed those in your supplied sharps bin. Full sharps bins can be taken to a pharmacy for safe disposal. Some councils offer a sharps bin collection service, you can see if yours does here.
We and our partners set cookies and collect data from your browser in order to improve the user experience, keep you logged in if you register, personalize content, analyze data traffic and customize advertisements.
By continuing to use this site, you are consenting to our use of essential cookies.
