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GLP-1 Weight Loss Medications: Uses and Side Effects?

GLP-1 Weight Loss Medications: Uses and Side Effects?
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 5 min read

Prescription weight loss medications are becoming increasingly popular due to their innate ability to help those with obesity and/or weight-related medical conditions eliminate fat. One of the recent additions to the prescription weight loss market is GLP-1 receptor agonists. These treatments are known for their strong link to regulating blood sugar levels but have recently been found to help with weight loss. With FDA approval and evidence confirming their efficacy and safety, we take a better look at their uses and possible side effects below:

What are GLP-1 Medications and their Uses?

GLP-1 Medications belong to a class of medicines called Glucagon-like peptide-1 receptor agonists, more commonly known as GLP-1RAs or GLP-1As. They were specifically created to manage/treat type 2 diabetes. These non-insulin medications are often used when standard measures—oral treatments such as metformin or sulfonylureas have failed to control blood sugar levels. 

GLP-1 medications are considered incretin mimetic/agonists because they mimic the function of a naturally occurring hormone called GLP. GLP-1 deals with two primary hormones affecting blood sugar levels: insulin and glucagon. It essentially enhances insulin secretion and stops glucagon release to regulate blood sugar levels. Insulin decreases blood sugar levels while glucagon increases them. Because GLP-1 medications copy the effects of the GLP-1 hormone, it effectively brings balance to blood sugar levels. 

While regulating blood sugar levels is one of its primary uses, research has found that this class of medication can also be useful for weight loss in certain individuals. Those who suffer from weight-related medical conditions or obesity often have fluctuating sugar levels due to insufficient insulin production or excessive glucagon release. The regulatory effect on blood sugar levels provided by GLP-1  medications works in favor of weight loss in these cases.

A Deeper Look into How GLP-1 Medications Work for Weight Loss?

The transition of GLP-1  medications from diabetes treatment to weight loss aid has been seamless due to the extensive research backing its new use. Drugs that fall into this class have been confirmed to be effective weight loss aids for those with chronic obesity and other health conditions that fuel weight gain. GLP-1 medications are preferred over amphetamine-based weight loss treatments because amphetamine use typically comes with side effects that outweigh their benefits.  

GLP-1 treatments work with GLP-1 receptors in the body to trigger weight loss and enhance metabolic function. They encourage the pancreas to produce/release insulin after meals to lower blood sugar levels and bind to brain receptors to suppress appetites. Although the body naturally produces this hormone, it doesn't last long in the GI tract, so the body cannot fuel weight loss through these processes on its own. 

This is one of the reasons why GLP-1 medications are used in cases of obesity. It provides a non-invasive and safe approach to weight loss with effects that do the following to accelerate fat burning:

  • Slows stomach emptying, which results in users feeling satisfied with smaller amounts of food. This helps users eat less and create a calorie deficit which leads to weight loss.

  • Manipulates the brain into thinking there is food in the stomach. This helps decrease appetites, unnecessary, unhealthy eating.

  • Lowers the secretion of glucagon and encourages insulin release after meals. Together this stabilizes blood sugar levels and reduces cravings for sugary food or foods high in carbohydrates, leading to weight loss.

Studies show that using GLP-1 weight loss medication also reduces the risks of heart failure/disease, stroke, and kidney disease, which are common consequences of obesity/excessive weight. Blood pressure and cholesterol levels are also subsequently improved following the use of GPL-1 medication. However, the jury is still out on whether this is due to the effects of these treatments alone or a combined effort from the treatment and weight loss. 

Efficacy and Safety of GLP-1 Medication for Weight Loss 

Medication efficacy and safety are among the most important aspects users tend to look at before commencing a treatment plan. This is especially the case regarding weight loss drugs such as GLP-1 treatments. Clinical trials have focused on the efficacy and safety of GLP-1 medication for weight loss and found that these treatments safely and efficiently eliminate fat from the body. 

Recommended use provides users with substantial weight loss, which makes a difference to the condition being dealt with. According to a PubMed study, even a modest  5–10% weight loss can significantly impact glucose control, medication use, and overall body and mind functionality in overweight individuals. 

Below we look at the clinical evidence presented from several trials dealing with the efficacy and safety of GLP-1 medication for weight loss:

  • GLP-1 receptor agonists (GLP-1 medications) use proved to be effective in eliminating fat stores. Results showed a mean weight loss ranging from 0.4kg to 5.1kg in an average of 6 months. This weight loss was achieved with standard doses once weekly. No serious side effects were reported with use except for mild nausea, which was short-lived. 

  • Higher doses administered in another trial resulted in a mean weight loss of 8.4kg (8% body weight) in 56 weeks. However, higher dosing was associated with intense side effects that were predominantly GI-related. 

These results prove that GLP-1 medications have an excellent safety and efficacy profile when used according to dosage and usage recommendations. 

Types of GLP-1 Medications

GLP-1 medications can be either short- or long-acting, depending on how long their effects last. There are currently 7 GLP-1 receptor agonists on the market, all of which are approved to manage/treat type 2 diabetes mellitus. Below we list the different types of GLP-1 medications:

GLP-1 Medications

Active ingredient

Administration Method

Frequency of Administration 



subcutaneous injection

taken once weekly



subcutaneous injection

taken once weekly



subcutaneous injection

taken once weekly



subcutaneous injection

taken once weekly



subcutaneous injection

taken once weekly



subcutaneous injections

taken once weekly



oral taken by mouth

once daily

The FDA has approved certain of the GLP-1 medications above for treating obesity, except Rybelsus (oral semaglutide). The approved GLP-1 medications can be used in patients with a BMI of 27+ with comorbidities or patients with a BMI of 30+. Unlike Rybelsus, which has a short-acting formula that requires frequent administration, the other GLP-1 medications on the list have long-acting formulas which only require once-a-week administration. 

This means that the active ingredient in these formulas is released over several days. The delivery method (subcutaneous injections) used to administer the approved options is quite apt for patients with obesity and other weight-related conditions. It works more effectively, ensuring the active ingredient enters the bloodstream faster. This means that the beneficial effects of the drugs are seen much faster than short-acting drugs.

Side Effects of GLP-1 Medications Use?

Side effects are one of those unavoidable possibilities that come with any treatment or supplement use. The side effects linked to GLP-1 medication use are quite common and often seen with the use of most medicines that affect hormone function or production. As mentioned earlier, GLP-1 drugs used for weight loss work by slowing digestion, increasing insulin release and stopping the release of glucose from storage which triggers the natural elimination of fat. 

This natural method of eliminating fat means the possibility of side effects when using these medications is extremely rare. Over 95% of individuals who take them do not experience side effects. On the rare occasion that they do occur, users have noted the following common side effects:

  • Diarrhea or constipation 

  • Abdominal pain or flatulence

  • Headache, dizziness, or fatigue

  • Mild nausea, vomiting, or indigestion

These side effects often have a mild disposition and typically occur because the body is trying to get familiar with the new compound in the body and the changes it causes. They have a relatively short life and resolve within the first month without hindering the possibility of successful outcomes. 

In a mediation analysis found in BMJ Journal, professionals investigated the effect of common side effects above within the GLP-1RA class. The analysis found that the side effects contributed minimally to the significantly greater body weight reductions.

Other side effects include:

  • Dyspepsia, eructation

  • Abdominal distension

  • Hypoglycemia in patients with type 2 diabetes

  • Gastroenteritis or gastroesophageal reflux disease

If side effects become increasingly more intense or become unbearably uncomfortable, professional advice must be sought to ensure the body is not suffering from an allergic reaction.

Contraindications and Interactions 

Contraindications and interactions are not common as they are solely triggered by health conditions or other drugs that are incompatible with the treatment being administered. Because GLP-1 medications are quite potent, they can rarely be taken with a large number of medicines or by individuals with several underlying conditions.

GLP-1 medications should not be consumed with other treatments used to treat type 2 diabetes, such as Metformin or insulin. Combining these drugs with GLP-1 agonists can put users at increased risk of developing low blood sugar (hypoglycemia). Pregnant women, those with pancreatitis, a history of medullary thyroid cancer, or multiple endocrine neoplasia type 2 (MEN2) should also avoid the use of GLP-1 medicines.

If users are using/consuming any of the treatments above or have any health conditions mentioned, they should avoid GLP-1 medication use. Using GLP-1 treatments in conjunction with the above can cause serious adverse effects that can be potentially harmful to one's health. 

The Bottom Line

Apart from being an excellent second-line therapy for type 2 diabetes, GLP-1 medications are becoming more recognized for their role in weight loss. Various trials and studies prove its effectiveness and safety in reducing fat ratios in obese patients and those with conditions that fuel uncontrollable weight gain. GLP-1 medications are a viable option for those who meet the criteria for use. In conjunction with a controlled diet and increased activity/exercise, GLP-1 medications can produce noticeable, permanent weight loss outcomes. 


6 Sources

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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.