GLP-1 Drugs for Weight Loss: What You Need to Know

GLP-1 drugs are revolutionizing the weight loss industry. Maintaining a healthy weight can be difficult for some people, but GLP-1s hold great promise, particularly for those with conditions that make it harder to lose weight — for instance, those with diabetes. This article explains what GLP-1s are, how they work for weight loss, potential concerns about the drug, and tips on optimizing their use for weight loss.

GLP-1 Drugs for Weight Loss: What You Need to Know
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The weight loss market in 2023

More than 70% of adults in the U.S. aged 20 or older are either overweight or obese, according to the CDC. In parallel, there has been a huge upturn in cases of type 2 diabetes globally. In 2022 the American Diabetes Association highlighted levels of type 2 diabetes among young people may surge in the coming years without interventions. This has led to a much greater demand for weight loss products and services with the U.S. weight loss now expected to reach more than $159 billion by the end of 2023.
GLP-1s and their potentially game-changing ability to help manage type 2 diabetes and support meaningful weight loss for people with obesity have given real hope to many. Recent news stories about high-profile individuals, such as Elon Musk and Michael Rubin, sharing their positive experiences with GLP-1 drugs have also triggered a new surge of interest in them.
The market is definitely shifting, and companies in the space are looking to adapt their strategies to incorporate a more medical approach. But it’s important to remember that these drugs are still quite new. Measurement of vital signs to monitor any secondary effects is critical, as is continuing to provide comprehensive care plans that support long-term behavior change.

What are GLP-1 drugs?

GLP-1 is a peptide hormone released in the small intestine when nutrients are ingested. It activates receptors in the pancreas for blood sugar management by regulating insulin and inhibiting glucagon release. Insulin release helps the body’s cells take up sugar in the blood, thus lowering blood sugar levels. These glucoregulatory effects are impaired in people with type 2 diabetes, so GLP-1 drugs help them by mimicking GLP-1 in the body.
GLP-1s also activate receptors in the hypothalamus area of the brain (the control center for hunger and thirst) to curb appetite. And in the gut, they reduce the speed at which the stomach empties after eating, known as 'gastric emptying' ,slowing the absorption of glucose into the blood and creating the feeling of being full last longer.

How do GLP-1s lead to weight loss?

Naturally occuring GLP-1 lasts only a few minutes in the body, but the drug form can last up to 14 hours, meaning that effects on appetite also last. So taking a GLP-1 agonist can control a person’s cravings and make them feel fuller and less hungry for longer. It can also raise your resting metabolism.

Which GLP-1s are better for weight loss?

Although GLP-1s were first licensed by the FDA in 2005 to treat people with type 2 diabetes, they are increasingly being  prescribed off-label to treat obesity.

There are 8 types of GLP-1s, each administered either as oral or injectable medications:

  • Semaglutide once-daily pill: Rybelsus (Novo Nordisk)
  • Semaglutide once-weekly injection: Ozempic (Novo Nordisk)
  • Semaglutide once-weekly injection: Wegovy (Novo Nordisk)
  • Dulaglutide once-weekly injection: Trulicity (Eli Lilly)
  • Lixisenatide once-daily injection: Lyxumia (Sanofi)
  • Liraglutide once-daily injection: Victoza (Novo Nordisk)
  • Exenatide twice-daily injection: Byetta (AstraZeneca)
  • Exenatide extended-release once-weekly injection: Bydureon (AstraZeneca)
To date,FDA approval has only been granted to Novo Nordisk’s semaglutide Ozempic, marketed as Wegovy, as a weight loss drug, after patients reported weight loss as a side effect.

How much weight can you lose with GLP-1s?

The rate of weight loss varies depending on the type of GLP-1 medication and the dosage. In a clinical trial, people using liraglutide and making other lifestyle changes lost more than 5% of their body weight over 56 weeks, while those on semaglutide lost almost 15% over 68 weeks. By comparison, people making the same lifestyle changes but taking a placebo lost about 3% of their body weight. So average weight loss can vary between 5-15% of a persons body weight over a period of 50-70 weeks. We recommend speaking to a healthcare professional to more accurately assess predicted weight loss results.

What are side effects of GLP-1 drugs?

There are a number of gastrointestinal side effects from use of GLP-1 medications.

Possible side effects:

  • Nausea
  • Diarrhea
  • Constipation
  • Vomiting
  • Heartburn
  • GERD (gastroesophageal reflux disease)
These side effects can improve over time, and starting a GLP-1 medication at a low dosage may lessen their severity.

Additional potential benefits of GLP-1s

One of the contributing factors in the development of Alzheimer’s disease is the accumulation of amyloid protein in the hippocampus, a complex structure in the brain's temporal lobe. Recent evidence suggests that GLP-1 drugs can help reduce this accumulation.
Better control of blood glucose levels through GLP-1 treatment has been shown to improve cardiovascular outcomes and limit small blood vessel damage that can lead to health complications such as diabetic retinopathy.

Concerns about the use of GLP-1s

Heighten cancer risk

There is some research that shows a potential link between GLP-1s and thyroid cancer, so their use is not recommended for people who have a history of medullary thyroid carcinoma (cancer) or multiple endocrine neoplasia syndrome.

Muscle Mass Loss

There is also evidence that GLP-1 drugs like Ozepmic result in decreased muscle mass, reduced bone density, a lower resting metabolic rate and can the onset of sarcopenia - the gradual loss of muscle mass strength and function. Scaropenia is typically associated with ageing and more commonly known as ‘skinny fat’. A study from 2021 where participants underwent a DEXA (dual-energy X-ray absorptiometry) scan measuring bone mineral density, highlighted that of the total mass loss of participants, 60% was fat loss and 38% was lean muscle loss. This is often the case where weight loss occurs very quickly and given GLP-1s lead to rapid weight loss users of the drug must take extra care in their nutritional intake, increasing the intake of protein-rich foods.
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Sky-high costs

The average monthly cost of Ozepmic per patient is approximately $1000 without insurance, putting them out of reach for many patients. Additionally, many Insurers are hesitant to cover GLP-1s due to their steep price tag and the unknown long-term effects. An analysis by the Annals of Internal Medicine published in October 2022 found that the price of GLP-1s would need to drop by 90% to be considered reasonable for use as a first-line therapy for diabetic patients. Additionally, many of the most commonly prescribed GLP-1 medications are currently affected by supply issues due to an increase in demand, and it’s estimated that this will continue into 2024, contributing to price increases.

Tips for effective weight loss with GLP-1s

GLP-1s show great promise for helping people who want to lose weight. However, it’s recommended that, for best results, these sorts of clinical interventions always be made as part of a comprehensive program that addresses nutrition, lifestyle, and behaviors.
Some key players in the weight loss industry are making GLP-1s a part of their offerings:


Noom aims to help you understand and manage the way you think about your food intake, so that while you lose weight, you’re developing sustainable lifestyle changes. They have recently introduced Noom Med, a personalized clinical support program built on top of their existing psychology-based program.


WeightWatchers, the long-established weight loss program focused on food intake tracking, has recently acquired the telehealth platform Sequence, marking an expansion into medication-based weight-management programs.

Using GLP-1s for weight loss

Ultimately, GLP-1s work best for weight management, when they are combined with a nutritious diet, appropriate levels of exercise, healthy amounts of sleep, and stress management. Without these supporting behaviours, a patient will likely regain weight when they reduce dosage or stop taking the drug altogether.
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But how do companies in the weight loss industry ensure that their users adhere to healthier lifestyle changes?
Leading weight management and diabetes companies have used Vital’s Wearables API to ensure adherence and monitor progress. For example, Vital’s MyFitnessPal integration has helped users track their meal and nutrition data. With greater visibility into key biomarkers like sleep, activity, heart rate, users are better able to measure their advancement toward their goals. Being able to visualize progress in this way helps to reinforce positive behaviour changes.
Fastic, an intermittent fasting app that offers personalized weight loss support, found that users leveraging their wearables, via Vital’sWearables API, achieved their weight loss goals 24% faster than those who didn't. The additional longitudinal data also gave their clinicians more data, so they could better tailor fasting plans — ultimately leading to higher user success rates and better adherence to the program. In other cases, Vital’s Lab Testing API, which allows patients to perform blood tests at home, was valuable in helping users uncover underlying hormone imbalances that were contributing to weight gain. GLP-1s are a promising innovation for the weight loss industry, but we’re still at an early stage of their use as a tool for effective weight loss over time.
If you’re a company in the weight management space looking to incorporate GLP-1s into your program, wearables data could be powerful in helping your users improve their weight loss results.
Sign up for a demo to discover how Vital’s Wearables API can help you leverage Wearables data to personalize programs at scale and reduce engineering costs.

Written by

Simba Deu
Simba Deu

Growth @Vital