RETATRUTIDE (Triple G)
By Mr Suhail Jamil
Retatrutide is an investigational medicine currently being studied as an upcoming weight-loss injection, from the US pharmaceutical company Eli Lilly. It is known as the “Triple G” drug, and is currently in clinical trials but not yet available in the UK.
With a half life of approximately six days, this once-weekly injection supports weight loss in three ways; by targeting three receptors —GLP-1, GIP, and glucagon— that help control hunger, metabolism, and energy use, with long-lasting effects.
This triple-action mechanism makes it a potential game-changer in the fight against obesity. In recent trials, people without diabetes with a BMI > 30, or a BMI > 27 plus one weight related condition were given retatrutide subcutaneously, as a once weekly injection for 48 weeks. A dose of 1mg, 4mg, 8mg, or 12mg were given and the trial was conducted from May 2021 - November 2022.
Percentage of total body weight loss on retatrutide
| 1 mg dose | 4 mg dose | 8 mg dose | 12 mg dose | |
| 24 weeks | 7.2% | 12.9% | 17.3% | 17.5% |
| 48 weeks | 8.7% | 17.1% | 22.8% | 24.2% |
While Retatrutide is still in research and doesn’t have a brand name, it could really shake up the weight-loss market, possibly outperforming treatments like Wegovy and Mounjaro.
It is also being tested for type 2 diabetes, where it has already shown great results in controlling blood sugar and aiding weight loss. The big question now is: when will it be available in the UK, and could the NHS make it an option for weight loss treatment?
In this post, we’ll look at how Retatrutide works, what it’s used for, possible side effects, when it might be available in the UK, and how it compares to other well-known treatments like Wegovy and Mounjaro.
"Clinical proof: In Lilly's Phase 2 trial published in The New England Journal of Medicine, Retatrutide achieved 17.5% mean weight loss at a 12mg dose at 24 weeks *- surpassing all competitors at that stage. By 48 weeks, this soared to* 24.2% (57.8 lbs/26.2 kg) as the triple-action mechanism continued working without plateauing."
What is Retatrutide (Triple G)?
Retatrutide is a novel medicine being researched for its effects on weight loss. It is gaining attention in the medical community by targeting more pathways than previous weight loss treatments such as Wegovy or Mounjaro. The triple hormone approach offers more promising results and is therefore being investigated for its potential benefits in several conditions including obesity, type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular health and knee osteoarthritis.
How Retatrutide Works: The Triple-G Mechanism
Retatrutide is a triple agonist, also called “Triple G,” because it targets three important hormone receptors at once: GLP-1, GIP, and glucagon. These hormones are naturally released by your body when you eat and play key roles in controlling hunger, blood sugar, and fat burning (how the body uses or stores energy).
Retatrutide Works On Three Receptors:
Retatrutide activates the GLP-1 receptor, which has an effect on the brain, pancreas, muscle and stomach/intestines.
- Brain: increases fullness and reduces cravings
- Stomach/ Intestine: slows digestion and appetite and controls blood sugars after meals
- Muscle: helps the muscles burn sugar for energy instead of storing it as fat
- Pancreas: helps secrete insulin to control blood sugar levels.
- GIP works in the pancreas and the muscles with their relative effects.
Glucagon works on the heart, liver and fatty tissue in the following ways:
- Heart: Glucagon boosts blood flow to the heart
- Liver: in the liver, glucagon helps reduce fat storage and helps break down fat.
- Fat tissue: glucagon helps the body burn stored fat for energy.
By activating all three key receptors together, retatrutide offers a more complete and effective approach to regulating hunger, improving metabolism, and supporting weight loss—compared to other incretin-based therapies like Wegovy (GLP-1 only) or Mounjaro (GLP-1 + GIP), which target only one or two of these receptors.
Mounjaro Weight Loss Injections
Rybelsus Tablets (Semaglutide)
Receive Tomorrow if you place order in next
What is Retatrutide Used For?
Retatrutide offers numerous health benefits and is used for:
OBESITY
Retatrutide has shown effective and promising results in weight management, with participants experiencing averages of weight losses of 17-24% of their initial body weight over 12 months. Although Retatrutide is a comprehensive solution for obesity management, an ongoing trial will confirm its effectiveness for weight loss. This trial is expected to wrap up in early 2026.
TYPE 2 DIABETES
Retatrutide not only suppresses your appetite but also improves metabolic health. Phase 2 clinical trials have shown that people with higher doses of Retatrutide experienced a remarkable drop in HbA1c compared to placebo. Participants also lost around 17% of their initial body weight, making this drug a stronger option for comprehensive metabolic management. Improvements were also seen in triglycerides, LDL-cholesterol, total cholesterol, fasting glucose and insulin at weeks 24 and 48.
72% of the participants at week 48, who had prediabetes at baseline in the retatrutide groups had reverted to normoglycemia (<39mmol/mol), as compared with 22% of the participants in the placebo group.
FATTY LIVER DISEASE
Recent findings in August 2025 also show retatrutide could become a “bottom up” therapy for at-risk patients of fatty liver disease, preventing it from advancing and possibly reversing it. metabolic dysfunction-associated steatotic liver disease (MASLD) is when fat accounts for more than 5% of the weight of the liver.
In the phase 3 trial, 93% of patients taking the higher dose of retatrutide (8 and 12mg) lost enough liver fat to fall below the 5% mark. This is quite significant, wiping out liver fat and erasing non-alcoholic fatty liver disease at its early stages.
Comparing Retatrutide with Other Weight Loss Medications
Although Semaglutide and Tirzepatide are effective weight loss medications, Retatrutide stands out due to its triple hormone action. Let’s compare these medications!
WEIGHT LOSS EFFICACY
Retatrutide: 24.2% weight loss over 48 weeks (PHASE 2 TRIALS).
Semaglutide: 15% weight loss over 68 weeks, with a higher dose (7.2mg) showing up to 18% of weight loss (STEP 1 TRIAL).
Tirzepatide: Up to 22% of weight loss over 72 weeks, with an average weight loss of 20.9% at 48 weeks (SURMOUNT-1 TRIAL).
Retatrutide dose schedule
Retatrutide is administered subcutaneously, once a week. Its dosage depends on your weight, health, medical history, metabolism, and desired goals. The standard Retatrutide dosing for weight loss is not confirmed since the drug is currently still in phase 3 trials. However, based on the current trials:
Initial dosing: 1-2mg.
Dose escalation: every 4 weeks
Maintenance dose: varies from 4-12mg.
Maximum dose: 12mg once weekly.
How to store Retatrutide?
The official guidance has not yet been released as the drug is not yet FDA approved, however storage instructions will likely be similar to other medicines of this type - a temperature between 2°C and 8°C to maintain its efficacy and stability.
RETATRUTIDE SIDE EFFECTS
Phase 2 trials showed the side effect profile of Retatrutide was similar to other incretin based therapies, with gastrointestinal symptoms being the most common.
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Abdominal pain
- Fatigue
These side effects were generally mild and subsided over time as the body adjusted to the new medication.
It is essential to note that Retatrutide is still in clinical trials and not yet approved for human use. The safety profile may evolve as more data becomes available in ongoing phase 3 clinical trials.
IS RETATRUTIDE AVAILABLE IN THE UK
The UK’s MHRA (Medicines and Healthcare products Regulatory Agency) has not yet approved Retatrutide for human use. It is expected to be available by 2026, after the final phase 3 trial results and regulatory approval.
Be cautious of counterfeit versions of Retatrutide being sold online, which may be sourced from unverified labs and can pose health risks.
Saxenda Weight Loss Pen
Wegovy Weight Loss Injections
Receive Tomorrow if you place order in next
FREQUENTLY ASKED QUESTIONS
How long does it take for Retatrutide to work?
Retatrutide shows noticeable weight loss within 4-8 weeks of starting treatment. However, the significant results may take several months of consistent use, particularly when combined with healthy lifestyle changes.
How safe is Retatrutide?
In clinical trials, Retatrutide has shown a favorable, safe profile. Sometimes it causes mild side effects such as nausea or gastrointestinal discomfort. The long-term safety will be evaluated in ongoing studies.
What happens when you stop taking Retatrutide?
Once you stop taking Retatrutide, the appetite suppression and metabolic benefits diminish. Blood sugar levels may also rise in people with type 2 diabetes. Regular follow-up and consistent lifestyle changes are crucial for sustaining results.
Is Retatrutide FDA-approved for weight loss?
Retatrutide is not FDA approved for weight loss. This medicine is still under phase 3 clinical trials and has not received FDA clearance for obesity treatment.
