Your Guide to GLP-1 & Weight Loss Injections

Ozempic®, Wegovy®, Rybelsus® are the Brand names for Semaglutide

Mounjaro® and Zepbound® the Brand names for Tirzepatide

About Your Medication

Semaglutide (Ozempic®, Wegovy®, Rybelsus®) and Tirzepatide (Mounjaro®, Zepbound®) are recommended in the UK for adults as a potential treatment option for weight loss and weight maintenance in conjunction with reduced caloric intake and increased physical activity.

Semaglutide is a Glucagon-like-peptide-1 (GLP-1) receptor agonist that has 94% structural similarity to human GLP.

Tirzepatide is a dual Glucose-dependent Insulinotropic Polypeptide (GIP) and Glucagon-like-peptide-1 (GLP-1) receptor agonist.

In simple words, they are a hormone that activates specific receptors in the body and consequently makes you feel fuller. It is primarily produced by the gut, pancreas and the brain.

 

How Does it Work?

The activation of GLP-1 receptors promotes insulin production by the pancreas, but only when glucose is present in the blood (e.g., after a meal). Insulin is a hormone that lowers blood sugar by helping cells take up glucose, whereas glucose itself is the main sugar found in the blood, not a hormone.

GLP-1 receptor activation also suppresses glucagon release (a hormone that raises blood sugar), slows stomach emptying, and reduces appetite by sending signals to the brain. Together, these effects improve blood sugar control and can contribute to weight loss.

The activation of GLP-1 and GIP receptors promotes enhanced insulin production by the pancreas, but only when glucose is present in the blood (e.g., after a meal).

The potential benefits and the risks associated with taking the medication have only been studied in people with increased weight and obesity, who present weight-related issues.

 

Treatment Plan

The treatment plan, including time spent on a specific dose and maximum dose reached, will vary on an individual basis.

Therefore, the following is just an overview of a standard dose escalation schedule, and your treatment plan will be determined with the prescribing Doctor through a continuous monitoring process.

Semaglutide dosing schedule

  • The starting dose of Semaglutide is 0.25 mg and is administered by subcutaneous injection once a week for 4 weeks.

  • The next dose, for 4 weeks, from week 5 through 8, will be 0.5 mg.

  • This is followed by 1 mg for 4 weeks, from week 9 through 12.

  • Weeks 13 through 16 may include 1.7 mg subcutaneous injection once a week for 4 weeks.

  • The final dose from week 17 and onwards may include 2.4 mg subcutaneous injection once a week until the target weight is eventually reached/maintained.

  • There are instructions as to how to use the pen in the box, but usually the pharmacist will talk you through the process.

Tirzepatide dosing schedule

  • The starting dose of Tirzepatide is 2.5 mg and is administered by subcutaneous injection once a week for 4 weeks.

  • The next dose up for 4 weeks, week 5 through 8, is going to be 5 mg.

  • This is followed by 7.5 mg for 4 weeks for week 9 through to 12.

  • Weeks 13 through 16 may include 10 mg subcutaneous injection once a week for 4 weeks.

  • Week 17 to 20 may include 12.5 mg subcutaneous injection once a week.

  • The final dose from week 21 onwards may be 15 mg until target weight is reached/maintained.

  • There are instructions as to how to use the pen in the box but usually the pharmacist will talk you through the process.

 

Treatment Plan Overview

  • Initial appointment for assessment
    Baseline bloods + lowest dose

  • Telephone review at end of month 1*
    Prescription for month 2

  • Telephone review at end of month 2*
    Prescription for month 3

  • Telephone review at end of month 3*
    Prescription plan for next 3 months

  • Telephone / in person review at 6 months*
    Prescriptions can now be ordered online

  • Annual bloods
    FBC, kidney, liver function, thyroid function +/- lipase

*Reviews can be added in at any time as needed

Administration

Prepare

  • Wash your hands

  • Check if the medication has a correct label with the name on it

  • Check if the liquid is clear and not cloudy

  • Push a new needle every time onto the pen and turn clockwise to tighten

  • If you use the pen for the first time, turn the dial to two dots and a line symbol

  • Press and hold the dose button until clear liquid appears at the tip of the needle

  • Turn the dose selector to the prescribed dose

subcutaneous tissue injection diagram for glp1 weight loss injections

Inject

  • Semaglutide / Tirzepatide should be injected into the fatty tissue of the stomach, thigh or upper arm, changing sites of injection each time

  • Insert the needle into the cleaned skin at a 45–90° angle into the subcutaneous tissue, and make sure the dose counter is visible

  • Press and hold down the dose button until the number shows 0, and carry on pressing for 6 seconds after this to ensure the whole dose has been delivered

 

Follow‑up Appointments

  • Your first follow-up appointment with the Doctor will be after your fourth injection.

  • This can be held over the phone (15 minutes) or in person, if this is your preference.

  • This is so we can assess your weight loss to date and if you are struggling with any side effects.

  • Based on this, we can assess whether we stick to the same dose or increase it.

  • Please be aware that pharmacies sometimes do not have certain doses in stock, and need to order them in. This may take 1–2 days for them, so please make sure you book your follow-up appointment with plenty of time to get your next pen before your next dose is due.

  • You will continue to have 4‑week interval follow‑ups for the first 3 months until we reach a stable dose.

  • Please note that this again may vary based on individual circumstances, and reaching a stable dose may be shorter or longer than 3 months.

 

Continuous Monitoring

  • Once you have reached a stable dose, you are welcome to submit prescription requests through our online portal and choose the “REGULAR Repeat Prescription” option.

  • Please add your most up‑to‑date weight in the box where you write your request, as the prescribing Doctor will be requesting to see your weight.

  • The next telephone or in‑person review will be held at 6 months.

  • You would need to come in or provide us with annual bloods, which include measures, such as blood sugar, thyroid, liver, etc.

 

Potential Side Effects

Every medicine has potential side effects to some degree.

When you first start taking the medication, or at any dose increase, you may experience such side effects.

Common side effects

  • diarrhoea or constipation

  • nausea

  • reflux

  • vomiting

These are generally not serious side effects and should resolve within days.

However, if the symptoms persist for several days, it may lead to more serious complications, such as dehydration so it is important to stay well‑hydrated by drinking plenty of fluids whilst you are on the medication.

Uncommon side effects

  • Hypoglycaemia – these medicines can rarely cause a low blood sugar in patients taking them, which can make you feel hungry, shaky and sweaty. Eating or drinking something sugary should stop this quite quickly, but if symptoms persist, medical assessment would be recommended.

  • Gall stones – again, uncommon but this can cause some right upper abdominal pain and nausea, and needs medical assessment.

  • Pancreatitis – a very rare side effect, so if there is any severe abdominal pain or upper back pain associated this needs prompt medical assessment.

 

Lifestyle Advice

GLP‑1 analogues and GLP‑1 and GIP analogues may influence your hunger levels and digestion; therefore, it is important to focus on the quality of your diet to avoid potential negative effects.

There are three main considerations when it comes to food intake whilst you are on the medication:

  • diversity

  • protein

  • dietary fibre

The weekly recommendation for physical activity is to reach at least:

  • 150 minutes of moderate intensity exercise (increased breathing but able to talk), such as brisk walking, swimming or cycling
    or

  • 75 minutes of vigorous intensity exercise (fast breathing and difficulty talking), such as running, playing sports or walking up the stairs

Additionally:

  • at least 2 days per week should be dedicated to resistance training, which also has a consequent effect on bone density and strength. Apart from weight training at the gym, this can also be achieved by carrying heavy bags or bodyweight training, including yoga.

Eating a diverse range of foods is essential to avoid potential nutrient deficiencies, especially whilst consuming fewer calories.

The focus should be on fruits, vegetables, wholegrains, nuts and seeds, dairy and lean proteins.

A lot of these foods are also high in dietary fibre, which may also help with constipation, which is one of the most common side effects of GLP‑1 and GIP analogues.

Sufficient protein intake helps prevent potential muscle loss.

 
Nutrition Dr Martin Private GPs

I’m Sandra, the Nutritionist at Dr Martin – Private General Practitioners


I am passionate about optimising my patients’ health for every stage of life.

Nutrition is a cornerstone of this journey, but to be truly effective, it must be sustainable.

I am dedicated to translating complex science into simple, actionable strategies that respect the importance of enjoying food.

Working closely with our wonderful team of general practitioners allows me to ensure that your nutritional goals are both clinically precise but also fit joyfully into your daily life.

You can read more about me and my approach here in my full bio.

Book your Nutrition Appointment in less than 60 seconds:

Any other questions?

Please do message us below and we will be in touch shortly

What Patients are saying…