What is a GLP-1 medicine and how does it work?
GLP-1 is a hormone your gut releases after you eat. It tells your brain you have had enough, slows down how fast your stomach empties, and helps your pancreas release insulin at the right time.
These medicines copy that hormone. The practical effect is that you feel full sooner, stay full longer, and the constant “food noise” in your head quietens down. Some newer medicines in this family act on two gut hormones instead of one, which increases the effect further.
They were first developed for type 2 diabetes. The significant weight loss was noticed along the way, and that is how the class ended up being studied and approved for weight management as well.
What results are realistic ?
In large trials lasting around 68 to 72 weeks, participants using these medicines alongside a reduced-calorie diet and increased physical activity lost, on average, somewhere in the region of 15% of their body weight with one agent and around 20% with the newer dual-hormone agent.
The numbers are just numbers, there are few more things matter more than the numbers:
- the trial participants also changed diet and activity. The injection was never tested on its own. It was tested as an adjunct to the lifestyle and dietary modification.
- the weight bounced back if we stop without a plan. In follow-up studies, people who stopeed the medication regained a large share of what they had lost. This is the part patients find hardest to accept.
Who might be considered for a weight loss injection?
Malaysia’s Clinical Practice Guidelines on the Management of Obesity (2023) are clear that medication is considered only alongside lifestyle change, not instead of it- and only above certain criteria.
BMI
In Malaysia, medications may be considered for adults with :
- a BMI of 30 and above, or
- a BMI of 27 or above plus a weight- related health condition- such as:
- type 2 diabetes
- high blood pressure
- high cholesterol
- fatty liver disease
- obstructive sleep apnea
- chronic kidney disease
- joint problems
Waist circumference
BMI alone misses a lot. Fat around the abdomen is the type most strongly linked to diabetes and heart disease. For Asian adults, a waist of 90cm or more in men, or 80cm or more in women, is the cut-off that raises concern — even if the BMI reading looks acceptable. Measure at the level of your belly button, standing, after breathing out normally. Not sucking in.
Who should not take these medicines
This is definitely not a complete list. Generally, these medicine are avoided or given very cautious if :
- A personal or family history of medullary thyroid cancer, or the genetic condition MEN2
- A history of pancreatitis
- Severe stomach or gut problems, including gastroparesis
- Active gallbladder disease
- Pregnancy, breastfeeding, or plans to conceive in the near future
- Certain eating disorders, past or present
- Advanced kidney disease
If you already take insulin or sulphonylurea for diabetes, doctors usually adjust the dose to avoid low blood sugar.
Side effects
common: nausea , vomiting, diarrhea, constipation,reflux and burping, . They are usually worst in the first few weeks and after each dose increase, and they settle for most people. Eating smaller portions, slowing down, and going easy on oily and very rich food helps considerably — which is, in fairness, half the point of the medicine.
Less common but more serious: gallstones (more likely with rapid weight loss), pancreatitis, and dehydration leading to kidney strain if vomiting or diarrhoea is severe. If you are unwell with vomiting for more than a day, contact your doctor rather than pushing on.
The one that gets least attention: muscle loss. When you lose weight quickly, some of what you lose is muscle. That matters enormously for older patients and for anyone who wants to keep the weight off, because muscle is where you burn energy
