When it comes to regulating appetite, biology plays a powerful role. Research has shown that body weight is influenced by a complex interplay of factors, including genetics, environment, behavior and the body’s own signaling systems.
One of those systems involves the natural GLP-1 hormone that’s released from the gut after you eat, lasting only a few minutes before enzymes break it down.
GLP-1’s role in the body
One of GLP-1’s main jobs is to help coordinate how your brain and gastrointestinal organs respond to food by:
- Slowing down how quickly food leaves the stomach
- Stimulating insulin release when blood sugar rises
- Reducing the release of a hormone that raises blood sugar
Our bodies are designed to see weight loss as a sign of danger. Today’s high-calorie foods and less active lifestyles make it easier to gain weight, and our biology makes it harder to lose weight and keep it off.
How do GLP-1 medications work?
GLP-1 receptor agonist medications work by strengthening your body’s natural GLP-1 system and activating the same receptors that your natural GLP-1 hormone does. For some people, their normal signaling isn’t strong enough to manage hunger, help them feel full or keep blood sugar levels steady.
GLP-1 medications last longer in the body than naturally occurring GLP-1, which is broken down within minutes, and it can have a bigger effect on how the body uses and stores energy. They also reduce biological barriers, such as excess energy stores (body fat), that have made weight management difficult and contribute to type 2 diabetes and liver, kidney and cardiovascular health.
Working through multiple hormone pathways at once
GLP-1 medications affect different areas of the body simultaneously.
In the brain: GLP-1 medications help regulate appetite and reduce food cravings, leaving you feeling more satisfied with smaller portions and thinking less about food between meals.
In the stomach: They slow down digestion, so food stays there longer. This helps people feel full after eating.
In the pancreas: They help the body release more insulin when blood sugar rises and reduces another hormone that raises blood sugar.
In the liver: They help reduce glucose production and can decrease the amount of fat stored there.
Together, these effects help control blood sugar, reduce hunger and improve the way the body uses stored energy.
What are the different forms of GLP-1 drugs?
Your medical history, treatment goals and insurance coverage all help determine the best GLP-1 medication option for you.
Oral GLP-1 medications:
- Orforglipron (Foundayo)
- Semaglutide (Wegovy, Rybelsus)
GLP-1 injection medications:
- Tirzepatide (Mounjaro, Zepbound)
- Semaglutide (Ozempic)
- Liraglutide (Victoza, Saxenda)
- Dulaglutide (Trulicity)
Do GLP-1 medications cause hair loss or blindness?
Hair loss isn’t considered a direct medication side effect. When it occurs, it’s often related to rapid weight loss, nutritional changes or physiologic stress from significant weight loss.
Non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition that can cause sudden vision loss, has been reported in some studies of people taking GLP-1 medications. However, the condition remains uncommon, and researchers are still working to determine whether these medications directly increased risk.
Some patients with diabetes may experience temporary worsening of diabetic retinopathy if blood sugar levels improve very rapidly after starting treatment. This is primarily a concern for individuals who already have diabetic eye disease, and it’s one reason ongoing eye care and monitoring are important.
Do GLP-1s raise the risk of cancer or pancreatitis?
Human studies show GLP-1s aren’t linked to thyroid cancer in the general population. They carry a boxed warning about a rare type of thyroid cancer called medullary thyroid carcinoma (MTC) because thyroid tumors developed in rodents exposed to these medications. This is believed to have a species-specific effect, as rodent thyroid glands respond differently to GLP-1 stimulation than human thyroids do. People with a personal or family history of MTC or multiple endocrine neoplasia syndrome type 2 (MEN2) already have a higher risk of developing this cancer.
Even though cases of pancreatitis have been reported in some taking GLP-1 medications, the overall risk is low. A history of pancreatitis is usually considered a contraindication, so medication use should be a shared decision between patients and providers that consider current health risks and available treatment alternatives.
Are GLP-1s linked to depression?
While some people may notice changes in mood as their eating patterns, appetite and relationship with food change during treatment, current evidence doesn’t support GLP-1 medications as a cause of depression. In fact, many people experience improvement in mood related to weight loss, better sleep, increased mobility and improvements in overall health.
What are the common side effects of GLP-1 medications?
- Nausea, vomiting and diarrhea
- Constipation, bloating and abdominal discomfort
- Heartburn
These symptoms can improve over time and be minimized through dietary adjustments and gradual dose increases.
How to begin the GLP-1 conversation
A primary care provider, obesity medicine specialist, endocrinologist or other qualified health care provider can help determine whether GLP-1 therapy may be appropriate as part of a comprehensive care plan. Start by discussing:
- Your weight history and previous weight-loss attempts
- Medical conditions and current medications
- Your goals and expectations
- Your commitment to participating in evidence-based activities such as resistance training and monitoring protein intake to help preserve muscle mass during and after weight loss.
Will I have to be on GLP-1 medications forever?
Like hypertension or diabetes, obesity is a chronic disease, and almost everyone requires ongoing treatment to maintain benefits achieved with medication use. Studies show that when people stop taking these medications, their appetite regulation and energy balance signals return to the way they were before treatment. This can lead to weight gain and loss of health benefits, such as lower blood pressure or better blood sugar and cholesterol levels.
Some patients transition to other medical therapies or strategies, but the decision should be individualized based on their body’s response to treatment with close follow-up and a ready plan if they start to gain weight back.
Am I taking a shortcut if I use a GLP-1?
Calling GLP-1 medication a “shortcut” is like calling glasses a shortcut for seeing better. These medications are modern tools that help people manage health conditions that impact their daily lives.
Historically, most obesity medications produced weight loss in the range of 5% to 10%. When combined with optimal lifestyle habits, GLP-1 medications can help people lose about 15% to 25% of their starting body weight. This is clinically meaningful, as this amount of weight loss can improve or sometimes resolve obesity-related conditions such as type 2 diabetes, high blood pressure, fatty liver disease, kidney disease and cardiovascular risk factors.
At Ohio State, the foundation of comprehensive obesity care is a team-based approach that includes nutrition, physical activity and behavioral support as well as medical care. The goal is not just to lose weight. The goal is to help your body work so reaching better health is easier.
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