Under­stand­ing pop­u­lar weight-loss drugs

 

The class of drugs known as GLP-1 receptor agon­ists have become renowned for their effects in help­ing weight loss.

MALAYSIA is the most obese and over­weight nation in Asean.

Over­weight adults form 32.6% of the pop­u­la­tion, while obese adults form another 21.8%, adding up to 54.4% of the pop­u­la­tion.

Not only that, about 29.8% of chil­dren are obese or over­weight.

In addi­tion, about 21% of Malay­si­ans are dia­betic, of which 80% are obese or over­weight.

The Health Min­istry (MOH) is intro­du­cing glu­ca­gon-like pep­tide 1 (GLP-1) medi­cines for “vul­ner­able groups” this year.

Who the vul­ner­able groups are is unclear.

However, it behoves every­one to ensure that patient safety is not com­prom­ised by the use of GLP-1 medi­cines.

How they work

GLP-1 medi­cines are receptor agon­ists that mimic the GLP-1 hor­mone that is nat­ur­ally released in the gastrointest­inal tract in response to eat­ing.

When a per­son eats, the digest­ive sys­tem breaks down car­bo­hydrates into simple sug­ars that enter the blood­stream.

GLP-1 stim­u­lates the release of insulin from the pan­creas.

Insulin, a pan­cre­atic hor­mone, helps get gluc­ose out of the blood­stream into the body’s cells, where it is used for nour­ish­ment and energy.

In dia­betes, the body’s cells are res­ist­ant to insulin, do not pro­duce suf­fi­cient insulin, or both. GLP-I medi­cines stim­u­late the pan­creas to release insulin and reduce the release of glu­ca­gon.

Both insulin and glu­ca­gon con­trol the blood gluc­ose levels in humans, includ­ing type II dia­bet­ics.

GLP-1 medi­cines also act on the brain to reduce hun­ger and delay empty­ing of the stom­ach.

These drugs are used in the man­age­ment of type II dia­betes, and in some instances, obesity in non-dia­bet­ics.

They reduce food crav­ings, increase full­ness (sati­ety), slow diges­tion and can help con­trol blood gluc­ose.

GLP-1 medi­cines were licensed for dia­betes man­age­ment in Malay­sia in 2007, and was approved for obesity man­age­ment in 2019.

As of 2025, there are more than 30 GLP-1 medi­cines registered.

There are dif­fer­ent types of GLP-1 medi­cines.

Some are injec­tions and oth­ers

are tab­lets. Some are licensed for dia­betes, and oth­ers are licensed for weight-loss man­age­ment, or to treat the over­weight with weight-related health prob­lems.

Side effects

Like all medi­cines, GLP-1 agon­ists have side effects.

The com­mon ones are gastrointest­inal, i.e. nausea, vomit­ing and diarrhoea, which are usu­ally mild to mod­er­ate, and of short dur­a­tion.

Some­times, these side effects can be ser­i­ous, lead­ing to severe dehyd­ra­tion that requires hos­pit­al­isa­tion.

A ser­i­ous, but uncom­mon, side effect is pan­cre­at­itis.

Any­one on GLP-1 medi­cine with severe abdom­inal pain that radi­ates to the back should seek imme­di­ate med­ical atten­tion.

Other ser­i­ous, but uncom­mon, side effects include: > Gast­ro­paresis – where move­ment of food out of the stom­ach is slowed or stopped > Bowel obstruc­tion – a block­age that keeps food from passing through the intest­ines > Gall­stone attacks, and

> Bile duct block­age.

Rapid weight loss can cause facial changes that include a hol­lowed look, wrinkles, sunken eyes, sag­ging jowls around the jaws and neck, and changes in the size of the lips, cheek and chin.

This is com­monly called the “Ozempic” face, after the brand name of one of the more wellknown GLP-1 med­ic­a­tions.

If the weight loss is less rapid, the facial changes would not be so obvi­ous.

Sig­ni­fic­ant facial changes can be treated by plastic sur­gery.

The sexual side effects of GLP-1 medi­cines involve both poten­tial improve­ments (through weight loss and hor­monal optim­isa­tion), and declines in libido or arousal, which is vari­able across sex and indi­vidual pro­files.

A full list of the known side effects is found in the product inform­a­tion of the indi­vidual GLP-1 medi­cine.

A recent review repor­ted that

GLP-1 medi­cines may have little or no effect on obesity-related can­cers, i.e. thyroid, breast, pan­cre­atic or kid­ney.

They may also have little or no effect on colorectal, oeso­pha­geal, liver, gall­blad­der, ovarian or endo­metrial can­cer; mul­tiple myel­oma; or men­in­gioma (low cer­tainty).

The effect on gast­ric can­cer was very uncer­tain.

Cur­rent data does not sup­port a causal asso­ci­ation between GLP-1 medi­cines and depres­sion, sui­cidal ideation and sui­cide.

Pre­cau­tions

GLP-1 medi­cines should not be taken in preg­nancy, by those who are try­ing to get preg­nant or by those who are breast­feed­ing, because there is insuf­fi­cient data on the drugs’ safety in such situ­ations.

In the case of those try­ing to get preg­nant, the num­ber of months the GLP-1 medi­cine should be stopped prior to attempt­ing con­cep­tion var­ies, depend­ing on the indi­vidual medi­cine.

Oral con­tra­cept­ive users should use bar­rier con­tra­cep­tion, e.g. con­doms, for four weeks after start­ing GLP-1 medi­cines, and for four weeks after any increase in dose.

The reason is that the GLP-1 medi­cines may reduce the effect­ive­ness of oral con­tra­cept­ives in the over­weight or obese.

Altern­at­ively, a non-oral form of con­tra­cep­tion, e.g. an intrauter­ine con­tra­cept­ive device (IUCD) or implant, which are not as affected by GLP-1 medi­cines, can be used.

Prior to a sur­gical pro­ced­ure, the patient should inform their attend­ing doc­tors and nurses if they are tak­ing GLP-1 medi­cines.

This is because these drugs slow the empty­ing of the stom­ach, thereby increas­ing the like­li­hood of stom­ach con­tents enter­ing the air­ways and lungs dur­ing the sur­gical pro­ced­ure while under gen­eral anaes­thesia or sed­a­tion.

This means that modi­fic­a­tion of the pre-pro­ced­ure instruc­tion and anaes­thetic tech­nique may be required.

The attend­ing doc­tor(s) will also advise on the tak­ing of pre­scribed medi­cine(s).

Be aware

It is vital to remem­ber that GLP-1 medi­cines are Group B pois­ons, i.e. they require a doc­tor’s pre­scrip­tion.

It is illegal to pur­chase them over the counter or through unli­censed online sellers.

Self-med­ic­a­tion is poten­tially dan­ger­ous – a mes­sage that applies not only to GLP-1 medi­cines, but also many pre­scrip­tion medi­cines.

Reports of mis­use of GLP-1 medi­cines for cos­metic weightloss pur­poses are of con­cern.

The global demand for GLP-1 medi­cines has led to the spread of false and sub­stand­ard products, with severe risks to patient safety, eco­nomic impacts and erosion of pub­lic trust.

These coun­ter­feit medi­cines often con­tain incor­rect dosages, harm­ful ingredi­ents or lack the act­ive GLP-1 entirely, lead­ing to inef­fect­ive treat­ment and poten­tially life-threat­en­ing com­plic­a­tions such as hyper/hypoglycaemia and car­di­ovas­cu­lar (heart) issues.

The eco­nomic impacts are con­sid­er­able, with sub­stan­tial costs incurred in man­aging com­plic­a­tions that include hos­pit­al­isa­tion and increased mon­it­or­ing efforts.

Guidelines for doc­tors The frame­work for GLP-1 use in Malay­sia is found in the

Clin­ical Prac­tice Guidelines for the Man­age­ment of Obesity.

GLP-1 medi­cines are recom­men­ded for adults with a body mass index (BMI) more than 30kg/m2 or a BMI more than 27kg/m2 with one weight-related con­cur­rent ill­ness, e.g. hyper­ten­sion (high blood pres­sure), type II dia­betes or dys­lip­id­aemia (abnor­mal fat levels).

The World Health Organ­iz­a­tion (WHO) launched its guideline on the use of GLP-1 ther­apies for the treat­ment of obesity in adults on Dec 1, 2025.

The good prac­tice state­ments in the guideline are:

> “Obesity is a chronic com­plex dis­ease that requires lifelong care begin­ning with clin­ical assess­ment and early dia­gnosis.

“Once dia­gnosed, indi­vidu­als should have access to com­pre­hens­ive chronic care pro­grammes offer­ing sus­tained beha­vi­oural and life­style inter­ven­tions.

“When appro­pri­ate, phar­ma­co­lo­gical, sur­gical or other thera­peutic options may be used to sup­port effect­ive dis­ease man­age­ment.

“In par­al­lel, care should address the pre­ven­tion and treat­ment of obesity-related com­plic­a­tions and comor­bid­it­ies.”

> “In adults liv­ing with obesity, GLP-1 receptor agon­ists or GIP/ GLP-1 dual agon­ists may be used as long-term treat­ment for obesity.”

> “People liv­ing with obesity should receive con­text-appro­pri­ate coun­selling on beha­vi­oural and life­style changes – includ­ing, but not lim­ited to, phys­ical activ­ity and healthy diet­ary prac­tices – as an ini­tial step toward more struc­tured beha­vi­oural inter­ven­tions.

“For indi­vidu­als who are pre­scribed GLP-1 receptor agon­ists or GIP/GLP-1 dual agon­ists, coun­selling on beha­vi­oural and life­style changes should be provided as a first step to intens­ive beha­vi­oural ther­apy to amp­lify and sup­port optimal health out­comes.

> “In adults liv­ing with obesity who are pre­scribed GLP-1 receptor agon­ists or GIP/GLP-1 dual agon­ists, intens­ive beha­vi­oural ther­apy may be provided as a co-inter­ven­tion within a com­pre­hens­ive mul­timodal clin­ical algorithm.”

The jury is out on whether the WHO good prac­tice state­ments will be imple­men­ted in toto or par­tially in MOH facil­it­ies.

Part of a strategy

Recog­nising that medi­cines by them­selves would not by them­selves address the global obesity chal­lenge, the WHO recom­men­ded a com­pre­hens­ive strategy based on:

> “Cre­at­ing health­ier envir­on­ments through robust pop­u­la­tion-level policies to pro­mote health and pre­vent obesity. > “Pro­tect­ing indi­vidu­als at high risk of devel­op­ing obesity and related comor­bid­it­ies through tar­geted screen­ing and struc­tured early inter­ven­tions. > “Ensur­ing access to lifelong per­son-centred care.”

The safe use of GLP-1 medi­cines requires reg­u­lated dis­tri­bu­tion and pre­scrip­tion by doc­tors, strong over­sight, patient edu­ca­tion and stake­hold­ers’ cooper­a­tion to ensure that pub­lic health is pro­tec­ted.

Dr Milton Lum is a past pres­id­ent of the Fed­er­a­tion of Private Med­ical Prac­ti­tion­ers Asso­ci­ations and the Malay­sian Med­ical Asso­ci­ation. For more inform­a­tion, email star­health@the­star.com.my. The views expressed do not rep­res­ent that of organ­isa­tions that the writer is asso­ci­ated with. The inform­a­tion provided is for edu­ca­tional and com­mu­nic­a­tion pur­poses only, and it should not be con­strued as per­sonal med­ical advice. Inform­a­tion pub­lished in this art­icle is not inten­ded to replace, sup­plant or aug­ment a con­sulta­tion with a health pro­fes­sional regard­ing the reader’s own med­ical care. The Star dis­claims all respons­ib­il­ity for any losses, dam­age to prop­erty or per­sonal injury suffered dir­ectly or indir­ectly from reli­ance on such inform­a­tion.

The doc­tor says by DR MILTON LUM 18 Jan 2026