Weight loss medications: An endocrinologist’s perspective on science, safety and sustainability

Obesity has become one of the most pressing global health issues, driving a surge in interest in weight loss medications.

Monica Therese Cating-Cabral, MD·28 February 2025, 9:50 pm

A patient recently asked me if she could take a certain supplement, which was touted to help you burn fat while you sleep. We all wish such a thing existed!

Obesity has become one of the most pressing global health issues, driving a surge in interest in weight loss medications. As an endocrinologist, I often see patients seeking a “magic pill” to shed excess pounds. But is weight loss as simple as taking a drug? And how do these medications work from an endocrine standpoint?

The field of obesity medicine is rapidly evolving.
PHOTOGRAPHS COURTESY OF UNSPLASH

Understanding the science of weight regulation

Weight is not just about caloric math — calories in versus calories out. The human body tightly regulates weight through a complex interplay of hormones, appetite signals and metabolic processes. These hormones include leptin, ghrelin, insulin and glucagon-like peptide (GLP).

When weight loss occurs, the body often fights back by increasing hunger signals and slowing metabolism — a phenomenon known as adaptive thermogenesis. This is why losing weight and keeping it off is notoriously difficult.

Medications work best when combined with exercise.

The rise of weight loss medications

With our deeper understanding of weight regulation, pharmaceutical companies have developed medications that target specific hormonal pathways. Let’s break down the major categories of weight loss medications currently in use.

1. GLP-1 Receptor Agonists: The game changers

Originally designed to treat type 2 diabetes, GLP-1 receptor agonists have revolutionized weight loss therapy. Medications like liraglutide, semaglutide and tirzepatide (coming soon to the Philippines) mimic the GLP-1 hormone, leading to:

Reduced appetite by acting on the hypothalamus, the brain’s hunger center.

Slower stomach emptying, which prolongs feelings of fullness.

Improved insulin sensitivity, helping the body use glucose more effectively.

In clinical trials, patients on these medications have lost an average of 15-20 percent of their body weight — a breakthrough in obesity treatment. However, these medications are not without drawbacks: they can cause nausea, vomiting, diarrhea and some concerns remain about long-term safety and accessibility due to high costs.

2. Sympathomimetics: The old guard

Medications like phentermine have been around for decades and work by stimulating the release of norepinephrine, a neurotransmitter that suppresses appetite. However, their effects are short-lived, and they come with risks like increased heart rate and blood pressure. These are typically used for short-term weight loss under close medical supervision.

3. Lipase Inhibitors: The gut approach

The medication orlistat blocks fat absorption in the intestines, leading to modest weight loss. However, the side effects limit its appeal. Patients can have oily stools, frequent bowel movements, and leaking accidents.

Are weight loss medications the answer?

From an endocrine perspective, weight loss medications are tools, not cures. They help counteract the hormonal resistance to weight loss, but they do not replace the need for behavioral changes, diet modifications, and exercise.

Also make sure these medications are prescribed by a licensed physician who can determine which is the right one for you, and to explain possible side effects and any adverse reactions to watch out for. If you have diabetes your other medications may also need to be adjusted.

The biggest challenge? Sustainability. Many patients regain weight once they stop these medications, as their body’s natural hunger signals return. This has sparked debate on whether these medications should be taken for life, much like blood pressure or cholesterol medications.

The future of weight loss therapy

The field of obesity medicine is rapidly evolving. Newer medications, such as dual and triple hormone agonists, are showing even greater promise. Researchers are also exploring personalized weight loss treatments based on genetics, gut microbiome and metabolic profiling.

Additionally, cost remains a major barrier. These medications are expensive, and many insurance plans do not cover them. Addressing affordability and accessibility will be key in making these treatments widely available.

Final thoughts: A balanced approach

As an endocrinologist, I believe in a comprehensive approach to weight loss. Medications can be powerful allies, but they work best when combined with lifestyle interventions and a deeper understanding of one’s metabolism.

For patients considering weight loss medications, my advice is:

1. Know your why. Weight loss should be about health and feeling better, not just looking good.

2. Understand the science. These medications modify hormones, not willpower.

3. Manage expectations. Medications help, but they are not magic pills.

4. Plan for the long-term. Sustainable habits matter more than short-term results.

Even if weight loss medications are used to help get you started on your weight loss journey, a healthy lifestyle with proper diet and exercise are still part of the equation. Work with your doctor to figure out a plan that you can stick to and will lead to a healthier you.