Losing weight is not always as simple as eating less and exercising more. For some people, obesity continues despite genuine efforts to improve their diet, activity levels and lifestyle. This is where prescription weight-loss medicines may have a role.
Weight-loss injections such as semaglutide and tirzepatide have received considerable attention because they can reduce appetite, increase feelings of fullness and support clinically meaningful weight loss. But their popularity has also created confusion. People sometimes assume that anyone wanting to lose a few kilograms can take these medicines.
That is not how they should be used.
Weight-loss injections are prescription medicines, not cosmetic treatments. Whether someone is a suitable candidate depends on factors such as BMI, obesity-related diseases, medical history, current medicines, pregnancy plans and potential contraindications.
The World Health Organization now recognises GLP-1-based medicines, including semaglutide and tirzepatide, as an option for long-term obesity treatment in adults, but recommends using them as part of comprehensive care rather than as a replacement for healthy eating, physical activity and professional support.
If you are considering obesity treatment in Delhi, understanding both the benefits and limitations of these medicines is an important first step.
What Are Weight-Loss Injections?
Weight-loss injections are prescription medicines that influence hormones involved in appetite, blood sugar regulation and digestion.
Some commonly discussed medicines include:
- Semaglutide, a GLP-1 receptor agonist
- Tirzepatide, a medicine that acts on both GIP and GLP-1 pathways
- Liraglutide, another GLP-1 receptor agonist
These medicines are not identical, and their approved uses, doses and eligibility criteria can differ.
GLP-1-based medicines work partly by increasing feelings of fullness, reducing appetite and slowing stomach emptying. Tirzepatide acts on both GIP and GLP-1 receptors and also affects appetite and metabolic regulation.
This can make it easier for some patients to reduce food intake and maintain a calorie deficit.
However, a prescription should never be based simply on the fact that a medicine is popular or that someone you know has lost weight with it.
Who May Be a Candidate for Weight-Loss Injections?
There is no single BMI number that automatically means a person should receive an injection.
Doctors consider the complete clinical picture.
In general, prescription obesity medicines may be considered for adults with obesity, particularly when lifestyle measures alone have not produced adequate improvement or when excess weight is contributing to other health problems.
The WHO’s current guidance states that GLP-1 therapies may be used as a long-term treatment option for adults with obesity, defined as a BMI of 30 kg/m² or higher, with the important exception that its recommendation does not cover pregnant women.
Eligibility criteria can differ between medicines and healthcare systems. For example, NICE guidance uses BMI together with weight-related health conditions when determining eligibility for medicines such as semaglutide and tirzepatide. It also notes that lower BMI thresholds may apply to people from certain ethnic backgrounds, including South Asian populations, because metabolic risk can occur at lower BMI levels.
This is particularly relevant for Indian patients.
People With Obesity and Related Health Conditions
A doctor may consider medication when obesity is accompanied by conditions such as:
- Type 2 diabetes
- High blood pressure
- Obstructive sleep apnoea
- Abnormal cholesterol levels
- Fatty liver disease
- Cardiovascular risk
- Other obesity-related complications
The goal is not simply to reduce the number on the weighing scale. Reducing excess weight may also help improve several obesity-related health problems.
People Who Have Struggled With Lifestyle Measures Alone
Some patients have followed structured diets, increased physical activity and made sustained lifestyle changes but continue to struggle with obesity.
That does not mean they have failed.
Obesity is a complex, chronic condition influenced by metabolic, genetic, behavioural and environmental factors. Medication can sometimes become one component of a broader treatment plan.
WHO specifically recommends combining GLP-1 therapy with structured behavioural interventions that include healthy eating and physical activity.
Who Should Avoid Weight-Loss Injections?
This is one of the most important questions to discuss with a doctor.
A person may need to avoid a particular weight-loss injection because of a contraindication, or the medicine may require additional caution and monitoring because of another medical condition.
Pregnancy
Weight-loss injections should not be used as a routine treatment for weight reduction during pregnancy.
For example, prescribing information for semaglutide and tirzepatide warns about use during pregnancy. NICE also advises that semaglutide, liraglutide and tirzepatide are not recommended during pregnancy.
Women who are planning pregnancy should tell their doctor before starting treatment.
For semaglutide, current prescribing information advises stopping treatment at least two months before a planned pregnancy.
Personal or Family History of Medullary Thyroid Carcinoma
Semaglutide and tirzepatide products such as Wegovy and Zepbound carry a contraindication for people with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
This does not mean that every person with a thyroid problem must avoid these medicines.
A history of common thyroid conditions is not the same thing as MTC or MEN 2. The specific diagnosis matters, so patients should provide their doctor with an accurate medical and family history.
Previous Serious Allergic Reaction
People who have experienced a serious hypersensitivity reaction to the active medicine or its ingredients should not receive the relevant medication.
For example, serious hypersensitivity is listed as a contraindication for both semaglutide and tirzepatide products.
Conditions That May Require Extra Caution
Not every situation is an absolute “no.” Sometimes the doctor needs to assess the risks carefully before deciding whether a medicine is appropriate.
Pancreatitis
Patients with a history of pancreatic problems should discuss this with their doctor before starting treatment.
Severe, persistent abdominal pain, particularly pain that may radiate to the back and occurs with or without nausea or vomiting, requires prompt medical assessment because pancreatitis is a recognised safety concern with these medicines.
Gallbladder Problems
Gallstones and gallbladder inflammation can occur during treatment.
Rapid or substantial weight loss itself can increase the risk of gallstones, while prescribing information for semaglutide also reports an increased occurrence of gallbladder disease.
A patient who develops persistent pain in the upper abdomen, fever or yellowing of the eyes or skin should seek medical attention.
Severe Gastrointestinal Problems
Nausea, vomiting, diarrhoea and constipation are among the common side effects associated with these medicines. More serious gastrointestinal reactions can also occur.
Because these medicines slow stomach emptying, patients with certain gastrointestinal conditions may require careful evaluation.
Diabetes and Diabetic Retinopathy
Patients with diabetes should not independently start or change a weight-loss injection.
Diabetes medicines, particularly insulin and some other glucose-lowering medicines, may need adjustment to reduce the risk of low blood sugar. Patients with diabetic retinopathy may also require additional monitoring.
Planned Surgery or Anaesthesia
Patients taking GLP-1-based medicines should tell their surgeon and anaesthesia team.
These medicines delay gastric emptying, and aspiration during general anaesthesia or deep sedation has been reported.
The medical team can decide how the medication should be managed around a planned procedure.
What Symptoms Can Occur With Weight-Loss Injections?
Side effects vary between medicines and between patients.
The commonly reported symptoms include:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Abdominal discomfort or pain
- Indigestion
- Reduced appetite
- Fatigue
- Injection-site reactions
These symptoms are often more noticeable when treatment is started or when the dose is increased. WHO notes nausea, vomiting, constipation and diarrhoea among common side effects of GLP-1 therapies.
For some people, symptoms improve as the body adjusts. For others, the medication may not be well tolerated.
That is one reason gradual dose adjustment and follow-up matter.
How Does a Doctor Decide Whether You Need a Weight-Loss Injection?
A responsible assessment goes beyond checking your weight.
During an obesity consultation, the doctor may consider:
BMI and Weight History
BMI provides one useful starting point, but it does not tell the entire story.
Your previous weight-loss attempts, weight changes over time and pattern of weight regain can provide important information.
Obesity-Related Diseases
The doctor may assess whether excess weight is contributing to diabetes, hypertension, sleep apnoea, fatty liver disease, joint problems or other conditions.
Current Medicines
Some medicines can influence body weight or interact with weight-management treatment.
Your doctor should review your prescription medicines, over-the-counter products and supplements before starting therapy.
Eating Patterns and Lifestyle
Medication does not replace nutritional and behavioural support.
A realistic treatment plan considers eating habits, physical activity, sleep, stress, work routine and other factors that may influence weight.
Pregnancy Plans
Pregnancy status and future pregnancy plans are particularly important when discussing weight-loss medication.
Previous Surgery or Medical Conditions
A history of abdominal surgery, pancreatic disease, gallbladder disease, gastrointestinal problems or other significant conditions can affect treatment decisions.
Are Weight-Loss Injections a Replacement for Diet and Exercise?
No.
This is one of the most common misconceptions surrounding these medicines.
Weight-loss injections can help regulate appetite and support weight reduction, but they do not replace balanced nutrition, adequate protein intake, physical activity, sleep or long-term behavioural changes.
WHO recommends GLP-1 treatment as part of comprehensive obesity care and specifically states that these medicines should not replace healthy diet and regular physical activity.
A patient who stops paying attention to nutrition and physical activity may find it difficult to maintain progress over the long term.
What Happens After Stopping Weight-Loss Injections?
Another important point is that obesity is a chronic condition.
Stopping medication does not necessarily mean that the body will automatically maintain the weight that was lost.
The long-term role of treatment needs to be discussed with a doctor. WHO describes GLP-1 therapies as generally long-term treatments and notes that questions around long-term effectiveness, safety and discontinuation continue to be monitored.
This is why the treatment plan should focus on sustainable habits and ongoing medical follow-up rather than a short-term target.
Why You Should Not Buy Weight-Loss Injections Without a Prescription
The growing popularity of medicines such as semaglutide and tirzepatide has also led to unsafe use outside medical settings.
WHO warned in 2026 about people obtaining GLP-1 medicines outside approved indications and healthcare settings, including through online and informal channels. It also highlighted concerns about falsified and substandard products.
Buying an injection from an unverified source creates several problems.
You may not know whether the product is genuine, whether it has been stored correctly, whether the dose is appropriate, or whether it is safe with your existing medical conditions and medicines.
A prescription from a qualified doctor provides an opportunity to assess whether treatment is appropriate before you take the first dose.
When Should You See a Doctor?
Consider speaking with an obesity or bariatric specialist if:
- You have obesity and have repeatedly struggled to lose weight.
- Your weight is affecting your blood sugar or blood pressure.
- You have symptoms of sleep apnoea.
- You have obesity-related joint or mobility problems.
- You are considering semaglutide, tirzepatide or another weight-loss injection.
- You have regained significant weight after previous weight-loss treatment.
- You are unsure whether your BMI or health conditions make medication appropriate.
You should seek urgent medical care for severe or persistent abdominal pain, repeated vomiting, symptoms of a serious allergic reaction, or other sudden severe symptoms during treatment.
How to Use Weight-Loss Injections Safely
If your doctor decides that medication is appropriate, a few principles can make treatment safer.
Take Only the Prescribed Dose
Do not increase the dose because you want faster weight loss.
Higher doses can increase side effects and are not necessarily appropriate for every patient.
Keep Follow-Up Appointments
Your doctor may need to monitor your weight, blood pressure, blood glucose, side effects and other health parameters.
Maintain Adequate Nutrition
Reduced appetite can sometimes make it difficult to consume enough protein and other nutrients.
A dietitian or doctor can help create a suitable eating plan.
Stay Hydrated
Vomiting or diarrhoea can contribute to dehydration, particularly during dose adjustments.
Tell Your Doctor About All Medicines
This is particularly important if you take medicines for diabetes or medicines that may be affected by delayed stomach emptying.
Do Not Share Injections
Prescription weight-loss medicines should never be shared with another person, even if they have a similar weight or health problem.
Weight-Loss Injections vs Bariatric Surgery
Weight-loss medication and bariatric surgery are not interchangeable treatments.
For some patients, medication may be appropriate. For others, particularly those with severe obesity or significant obesity-related complications, a surgical option may need to be discussed.
The choice depends on factors such as BMI, medical conditions, previous treatment attempts, expected health benefits, surgical suitability and patient preferences.
A bariatric consultation can help determine whether medication, surgery, lifestyle treatment or a combination of approaches is appropriate.
Conclusion
Weight-loss injections have changed the way doctors can approach obesity treatment, but they are not suitable for everyone.
The right question is not simply, “Which injection will help me lose weight?”
A more useful question is, “Is this medicine safe and appropriate for my health situation?”
A proper assessment considers your BMI, weight history, obesity-related diseases, medications, pregnancy plans, gastrointestinal and pancreatic health, and other risk factors.
For people considering obesity treatment in Delhi, a consultation with an experienced obesity or bariatric specialist can help clarify whether medication is appropriate and what other treatment options may be available.
The goal should not be rapid weight loss at any cost. It should be safer, sustainable improvement in health, mobility and quality of life.
Medical disclaimer: This article is for general educational purposes and does not replace an individual medical consultation. Weight-loss medicines should be used only under the supervision of a qualified healthcare professional.
5. FAQs
1. Who should take weight-loss injections?
Weight-loss injections may be considered for selected adults with obesity, particularly when lifestyle measures alone have not achieved sufficient improvement or when obesity is associated with health complications. Eligibility depends on the specific medicine and the patient’s medical assessment.
2. Who should avoid weight-loss injections?
People with certain contraindications should avoid specific medicines. For semaglutide and tirzepatide, this includes people with a personal or family history of medullary thyroid carcinoma or MEN 2, as well as those with a previous serious hypersensitivity reaction to the medicine or its ingredients. Pregnancy also requires avoidance of these medicines for weight management.
3. Can I take weight-loss injections if I have diabetes?
Some GLP-1-based medicines and tirzepatide are also used in people with type 2 diabetes, but treatment must be individualised. Diabetes medicines may need adjustment, particularly when there is a risk of hypoglycaemia.
4. Are weight-loss injections safe?
They can be appropriate for selected patients when prescribed and monitored correctly. However, they can cause side effects and have important contraindications and precautions. Medical assessment is necessary before starting treatment.
5. Can I use semaglutide or tirzepatide without a prescription?
These medicines should not be self-prescribed or purchased from unverified sources. WHO has specifically raised concerns about obtaining GLP-1 medicines outside approved indications and healthcare settings.
6. Can weight-loss injections replace exercise?
No. Medication should be part of a broader weight-management programme that includes appropriate nutrition, physical activity and behavioural support.
7. How long do people need to take weight-loss injections?
Treatment duration varies. GLP-1 therapies are generally considered long-term treatments, and stopping treatment should be discussed with the prescribing doctor rather than done independently.
8. Can someone with a BMI below 30 take weight-loss injections?
BMI alone does not determine whether medication is appropriate. Different medicines have different approved indications and eligibility criteria. A doctor should assess the person’s overall health, weight-related risks and treatment goals before prescribing.
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