GLP-1 injections explained: your weight loss shots guide (2026)

What is GLP-1 medication? How do GLP-1 injections work? These have become major questions in conversations about diabetes and weight management. If you’re trying to understand what GLP-1s are, how they work, and whether they’re right for you, this guide breaks down the basics in clear, practical terms.

GLP-1 injections are prescription weight loss and type 2 diabetes treatments that mimic a natural hormone involved in blood sugar control and appetite regulation.

GLP-1 stands for glucagon-like peptide-1. It helps manage how much insulin your pancreas releases, how much glucagon it holds back, how quickly food moves through your stomach, and how hungry you feel.

The synthetic version used in weight loss medications works like your natural GLP-1 but lasts much longer in your body. Your natural GLP-1 breaks down in just a few minutes, but GLP-1 medications can stay active for days or even a full week, depending on which one you use.

You can get GLP-1s as injections or tablets. Some are approved by the US Food and Drug Administration (FDA) just for weight loss, along with healthy lifestyle changes, including a reduced-calorie diet and increased physical activity. Others are approved for type 2 diabetes, but are often prescribed for weight loss too.

GLP-1 agonists and related medications are prescription drugs and must be prescribed and monitored by a licensed healthcare provider.

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GLP-1 is a natural hormone released mainly by cells in the lining of your small intestine when you eat. GLP-1 medications are designed to act like this hormone. They help regulate blood sugar by influencing insulin release and how quickly food moves through your stomach. GLP-1 drugs work in your body by:

• Stimulating insulin secretion from beta cells in the pancreas when blood sugar is high, which helps lower blood sugar levels.

• Slowing gastric emptying, meaning food moves more slowly from your stomach into your small intestine, which helps you feel full longer.

• Reducing the release of glucagon, a hormone that raises blood sugar..

Several FDA-approved GLP-1 injections for weight loss are available, including semaglutide, liraglutide, and tirzepatide medications. 

They all vary in dosing schedule and effectiveness, which is why the best GLP-1 for weight loss depends on your individual health profile and treatment goals.

Semaglutide-based injections

Semaglutide is a GLP-1 receptor agonist available in both injection and oral forms for weight loss.

Wegovy (semaglutide)

Wegovy was approved in June 2021 for chronic weight management. The drug is currently approved for other uses as well, including cardiovascular (CV) risk reduction and fatty liver disease (metabolic dysfunction-associated steatohepatitis, or MASH) in certain adults. Wegovy pill was approved in 2025,, and a higher-dose injection (Wegovy HD or 7.2 mg) was approved in March 2026.

How it’s taken: Wegovy comes as a once-weekly injection or as a once-daily tablet.

For the injection, treatment usually begins at 0.25 mg once a week. The dose is typically increased every four weeks to help your body adjust. Long-term doses for weight management are 1.7 mg, 2.4 mg, or 7.2 mg weekly.

What studies show: In a real-world study, researchers reviewed results from more than 8,000 adults with overweight or obesity who used semaglutide 2.4 mg and took part in a digital support program. Participants lost an average of 13.4% of their body weight at six months and 17.6% at 12 months.

Weight loss continued over time, reaching about 20% at 18 and 24 months. By one year, more than 40% of participants had lost at least 20% of their body weight.

Liraglutide-based injections

Like semaglutide, liraglutide works by stimulating insulin release, suppressing glucagon, and acting on appetite centers in the brain to reduce appetite and caloric intake. Unlike semaglutide, it requires a daily injection.

Saxenda (liraglutide)

Saxenda was approved by the FDA in 2014 for chronic weight management in adults.

How it’s taken: Saxenda is a once-daily injection. For weight loss, dosing starts at 0.6 mg daily and increases by 0.6 mg each week until reaching the target dose of 3 mg daily.

What studies show: In a 56-week clinical trial of adults with obesity or overweight, people taking liraglutide lost an average of about 18.5 pounds vs. 6.2 pounds with a placebo. That equals roughly 8% of body weight on average over one year. 

Tirzepatide-based injections (dual GIP/GLP-1)

Tirzepatide is a dual agonist that targets both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. It’s taken as a once-weekly injection and is approved for both type 2 diabetes and weight management.

Zepbound (tirzepatide)

Zepbound is approved for chronic weight management.

How it’s taken: Zepbound is available as a once-weekly injection in two forms: vials (administered with a syringe) and prefilled autoinjector pens, including single-dose pens and the multi-dose KwikPen. Both the vials and pens contain the same FDA-approved medication and are available in the same doses, with the same efficacy and potential side effects.

The starting dose is 2.5 mg weekly. Doses are often increased by 2.5 mg increments every four weeks, as needed, to a maximum of 15 mg. 

What studies show: In a 72-week trial of adults with obesity, once-weekly tirzepatide at 5 mg, 10 mg, and 15 mg led to average weight loss of 15.0%, 19.5%, and 20.9%, respectively, compared with 3.1% with a placebo.

Between 85% and 91% of participants lost at least 5% of their body weight, and more than half of those on the 10 mg and 15 mg doses lost 20% or more.

Some GLP-1 medications approved for type 2 diabetes are also commonly prescribed off-label for weight loss.

Off-label prescribing means a healthcare provider has determined that a medication may benefit you for a use beyond its FDA-approved indication. 

Ozempic (semaglutide)

Ozempic was first approved by the FDA in 2017 for treating type 2 diabetes. The drug is currently approved for additional uses, including reducing cardiovascular risks in people with type 2 diabetes and heart disease, and reducing the risk of kidney decline in people with type 2 diabetes and chronic kidney disease (CKD). It’s also prescribed off-label for weight loss.

How it’s taken: Ozempic is a once-weekly injection, in doses of 0.25 mg, 0.5 mg, 1 mg, or 2 mg.

What studies show: In the SELECT trial, people using semaglutide for type 2 diabetes experienced an average weight loss of 10.2% at 208 weeks, compared with 1.5% with a placebo. Weight loss was sustained over four years and was seen across different body sizes and demographic groups.

Mounjaro (tirzepatide)

Mounjaro was approved for the treatment of type 2 diabetes in 2022, and it’s also often prescribed off-label for weight loss.

How it’s taken: Mounjaro is a once-weekly injection, with a starting dose of 2.5 mg weekly. Doses are typically increased by 2.5 mg every four weeks, up to the 15 mg maximum dose.

What studies show: Clinical trials in people with type 2 diabetes showed that tirzepatide led to significant reductions in body weight, with average weight loss ranging from about 5%--14% across various studies.

The results also demonstrate meaningful improvements in blood sugar control.

Victoza (liraglutide)

Victoza was first approved by the FDA in 2010 as an add-on treatment to improve blood sugar control in people with type 2 diabetes. It also helps lower the risk of serious heart-related events like heart attack and stroke in adults with type 2 diabetes who already have heart disease.

How it’s taken: Victoza is a once-daily injection. For blood sugar control in adults, dosing starts at 0.6 mg daily for one week, then increases to 1.2 mg daily. The dose may be increased to 1.8 mg daily if additional glucose control is needed.

What studies show: In the SCALE Obesity and Prediabetes trial, people taking liraglutide 3.0 mg daily lost significantly more weight than those taking a placebo over 56 weeks: 8.0% vs. 2.6%.

A few other GLP-1 receptor agonists are sometimes prescribed off-label for weight loss, though they tend to be less effective than the options above.

Exenatide, a twice-daily injection FDA-approved for type 2 diabetes, is one example. The brand-name versions of this drug (Byetta and Bydureon BCise) were discontinued, but a generic version became available in late 2024. In clinical studies, exenatide led to about 10 lbs of weight loss over 12–24 weeks in adults without diabetes.

Trulicity (dulaglutide) is another example. It’s a once-weekly injection approved for type 2 diabetes and cardiovascular risk reduction, and has shown only slight weight loss in clinical trials, averaging around 2 lbs more than those taking a placebo.

For people seeking meaningful weight loss, tirzepatide, semaglutide, and liraglutide remain the more effective choices.

Weight loss results come from different studies with different groups of people and time frames. How much weight you may lose on a GLP-1 injection also depends on the dose and how long you stay on treatment. Your healthcare provider can help you pick the right option based on your health history, goals, side effects, and insurance coverage.

The medications showing the most weight loss in clinical trials are the tirzepatide-based options, Zepbound and Mounjaro. Next are semaglutide-based medications, Wegovy and Ozempic, then liraglutide-based options, Saxenda and Victoza.

But remember, "best" depends on you as an individual. Some people may do better with certain medications than others. You might have insurance that covers one option but not another. Or you might prefer a daily pill instead of weekly shots altogether.

A healthcare provider can help you figure out which medication fits your specific situation best.

You can give yourself most GLP-1 injections at home using a prefilled pen device. But for safety, you shouldn’t use your pen without proper training from your healthcare provider. They can show you the correct technique and help you feel confident before you inject on your own.

The steps below outline the general process for using the Zepbound KwikPen, a multi-dose single-patient-use prefilled pen. Other GLP-1 medications may have different instructions or devices, and Zepbound is also available as a single-dose prefilled pen and single-dose vial.

Always follow the detailed directions that come with your prescription.

1. Wash your hands and prepare your pen: After gathering all your supplies, wash your hands with soap and water. Pull the pen cap straight off. Check the label to confirm the medicine name and dose match your prescription, and that it hasn't expired. Make sure the liquid is colorless to slightly yellow, and that it’s not cloudy, frozen, or discolored. Wipe the red inner seal with an alcohol swab.

2. Attach a new needle: Always use a new needle for each injection. Pull off the paper tab from the outer needle shield, then push and twist the capped needle onto the KwikPen until tight. Pull off the outer needle shield and keep it, as you'll need to reuse it. Pull off the inner needle shield and throw it away.

3. Prime your pen: Before every injection, you need to remove air from the KwikPen and confirm it's working correctly. Turn the dose knob slowly until you hear two clicks and the prime symbol appears in the dose window. Hold the pen with the needle pointing up and tap the cartridge holder gently to collect air bubbles at the top. Push the dose knob in until it stops, then slowly count to five while holding it. A small drop of medicine at the needle tip means your pen is primed. If no drop appears, repeat the priming steps up to two more times.

4. Select your dose and choose an injection site: Turn the dose knob all the way until it stops, and the dose icon appears in the dose window. Choose an injection site, like your abdomen, at least 2 inches from the belly button, or thigh. If another person is giving you the injection, they can use the back of your upper arm. Rotate your injection site each week.

5. Give the injection: Push the dose knob into your skin until it stops, then slowly count to five while holding it. The dose icon must appear in the dose window before you remove the needle. Pull the needle out of your skin (a small drop of medicine at the needle tip is normal and won't affect your dose). If you see blood, press the area gently with gauze or a cotton ball. Do not rub.

6. After your injection: Replace the outer needle shield, then unscrew the needle and place it in a sharps container, or a sturdy, puncture-resistant, properly-labeled household container with a tight-fitting lid. Replace the pen cap. Never store the pen with a needle attached, as this can cause leaking, needle blockage, or air entering the pen.

Never share your pen with another person, even if the needle is changed. Sharing poses a risk of transmitting infections. Throw away your pen 30 days after first use or after four weekly doses, even if medicine remains.

GLP-1 dose escalation schedule

Most people start at a low GLP-1 dose and slowly go up over several weeks to months. This slow approach helps reduce side effects, especially gastric ones like nausea.

For example, Wegovy injection typically starts at 0.25 mg weekly. The dose goes up every four weeks until you reach the regular dose of 2.4 mg or 7.2 mg. Never increase your dose without your healthcare provider’s guidance.

Check for free

GLP-1 receptor agonists are generally considered to be safe, but like any prescription medication, they come with certain risks. Ongoing research continues to monitor long-term safety. Here’s what to know:

• The most common side effects are gastrointestinal, especially nausea. Vomiting, diarrhea, and constipation can also happen. Drinking enough fluids is important, since ongoing vomiting or diarrhea can lead to dehydration and kidney problems. Let your healthcare provider know if nausea, vomiting, or diarrhea don’t go away.

• Some people experience injection site reactions, headache, or cold-like symptoms. These side effects are usually mild and don’t often lead to stopping the medication.

• GLP-1 medications don’t typically cause low blood sugar when used with metformin or thiazolidinediones. However, if you’re taking one with insulin or sulfonylureas, your provider might lower your dose of those medications to reduce the risk of hypoglycemia.

• There have been reports, especially with exenatide, of sudden kidney problems. These cases were usually linked to severe nausea, vomiting, or diarrhea that led to dehydration and blood flow issues, which can strain the kidneys.

• Concerns have also been raised about possible effects on the pancreas and thyroid. GLP-1 medications carry an FDA boxed warning about a possible risk of thyroid C-cell tumors, based on findings in animal studies. It’s not known whether these drugs cause thyroid tumors, including medullary thyroid cancer (MTC), in humans. If you have a personal or family history of MTC or multiple endocrine neoplasia syndrome type 2 (MEN 2), these medications aren’t recommended.

GLP-1 receptor agonists are not appropriate for everyone. Certain medical conditions and safety concerns make these medications unsafe or not recommended for some people. You should not use GLP-1 injections if you:

• Have a known allergy to the medication

• Are pregnant

• Have severe gastrointestinal diseases such as gastroparesis

• Have a history of pancreatitis

• Have a personal or family history of MEN 2 or MTC

Because of these risks, GLP-1 injections should only be prescribed and monitored by a licensed healthcare professional.

Weight loss with GLP-1 medications develops over months, not days or weeks. Clinical studies show that meaningful changes typically become clear over the first year of treatment. With:

• Daily liraglutide, about one-third of people achieved 10% weight loss within one year, with weight loss sustained for more than a year.

• Weekly semaglutide, the 2.4 mg dose led to about 15% weight loss by 68 weeks, with maintenance for about two years. The higher 7.2 mg dose (Wegovy HD) led to about 18.7% weight loss at 72 weeks.

• Weekly tirzepatide, weight loss reached more than 22% at 72 weeks, and three-year follow-up showed average weight loss of about 20%.

Overall, the most significant results are seen over 1–2 years of consistent treatment, with continued benefits in longer-term follow-up.

You don’t necessarily need to stay on GLP-1 injections forever. But depending on your health and goals, you might choose to stay on them for a long time.

GLP-1 medications help reduce appetite and support weight loss, but obesity is a chronic condition. Research shows that stopping obesity medication can lead to weight regain.

For example, after stopping tirzepatide, about 82.5% of people regained at least 25% of the weight they had lost within one year. Along with the weight regain, improvements in blood pressure, blood sugar, and cholesterol often moved back toward pre-treatment levels.

This is one reason long-term planning is important before starting treatment.

A maintenance approach

Studies show that combining GLP-1 medications with lifestyle changes leads to greater weight loss than lifestyle changes alone.

In a large review of 33 clinical trials involving more than 12,000 adults, people using GLP-1 medications alongside diet and exercise lost an average of 7.1 kg (about 15.7 pounds) more than those using lifestyle changes alone.

Longer treatment duration and weekly medications like semaglutide or tirzepatide were linked to greater results. For many people, this supports thinking of treatment as ongoing rather than short-term.

Lifestyle changes and exercise matter for long-term results

Exercise plays an especially important role, even if you end up stopping medication. In one study, people who combined a GLP-1 medication with supervised exercise were more likely to maintain at least 10% weight loss one year after stopping treatment compared with those who used medication alone.

In contrast, stopping medication without ongoing exercise was linked to greater weight regain. Medication can help start the process, but long-term habits, especially regular physical activity, appear to make weight loss more sustainable.

The cost of GLP-1 injections varies widely depending on which medication you use, your insurance coverage, and what savings programs are available. Here's how list prices and cash-pay options compare:

*With manufacturer offer 

Insurance coverage

Insurance coverage for GLP-1 medications depends on why the drug is prescribed and what type of plan you have. Even when covered, plans may place these drugs on higher cost-sharing tiers, require prior authorization, or require you to try another medication first before it’s approved.

Some insurers require documentation confirming a diagnosis of type 2 diabetes or cardiovascular disease before providing coverage.

Under Medicare Part D, GLP-1 drugs that are FDA-approved for type 2 diabetes or cardiovascular disease may be covered.

Current law excludes drugs used specifically for weight loss from Medicare Part D coverage, even if the medication has FDA approval for obesity.

However, as of July 2026, the Medicare GLP-1 Bridge program allows eligible Medicare Part D beneficiaries to access certain GLP-1 drugs for $50 per month. Options include Wegovy pen or tablet, Foundayo, or Zepbound KwikPen.

Medicaid coverage of GLP-1 medications vary by state.

Prior authorization requirements

Insurance coverage for GLP-1 medications has expanded in recent years, especially for people using them to treat type 2 diabetes or reduce heart disease risk. But as coverage has grown, so have restrictions.

By late 2024, more than 80% of Medicare Part D plans required prior authorization for commonly prescribed GLP-1 diabetes medications like Ozempic, Mounjaro, and Rybelsus.

That means your provider may need to submit paperwork and get approval before your prescription is covered, which can sometimes delay access.

Manufacturer savings programs

Drug manufacturers may offer savings programs that lower your monthly cost, especially if you have commercial insurance.

For example, some programs advertise paying as little as $25 per month with insurance, or starting around $149 per month for self-pay options, depending on dose and eligibility.

Availability, rules, and pricing can change, so it’s important to check directly with the manufacturer for current details.

Starting GLP-1 injections on Ro begins with completing an online health questionnaire. A Ro-affiliated healthcare provider reviews your answers to determine whether treatment may be appropriate for you.

In some cases, you may be asked to complete a metabolic lab test before moving forward. If you’re eligible, your provider will discuss GLP-1 medication options and recommend a personalized treatment plan.

The Ro Body membership costs $39 for the first month, then  $74 per month with an annual plan paid upfront or $149 per month with a monthly plan. The membership covers your medical consultation, helps navigate insurance coverage, and offers ongoing provider support.

If you’re approved for treatment, medication costs are charged separately based on your insurance coverage or cash-pay option. If your insurance doesn’t cover the medication, you can choose a cash-pay option or cancel your membership at any time.

See if you qualify

GLP-1 injections are changing the way people approach weight loss. With several FDA-approved options available, more people now have access to medications that can deliver meaningful results. Here's what you need to know before getting started:

• GLP-1 injections work by mimicking a natural hormone known as GLP-1. In doing so, these medications can keep blood sugar in check, help you feel fuller longer, and ultimately eat less.

• There are several options when it comes to GLP-1 injections for weight loss. From once-daily injections like Saxenda to once-weekly options like Wegovy and Zepbound, each medication has different dosing schedules, approved uses, and average weight loss outcomes.

• Tirzepatide tends to lead to the highest weight loss results. GLP-1 injections like Zepbound (and Mounjaro, though not approved for weight loss) target two hormones (GLP-1 and GIP) instead of one. They have shown average weight loss of up to 21% in clinical trials, the highest among currently available options.

• Results on GLP-1 injections can take time. Most people see meaningful weight loss over 12–24 months of consistent treatment.

• Side effects are common, especially when starting treatment and increasing dosage, but are usually manageable. Nausea, vomiting, and diarrhea are the most frequently reported issues, especially when starting out. Beginning with a low dose and gradually increasing it can help your body adjust.

• Cost and insurance coverage vary widely. While list prices of GLP-1 injections can be over $1,000 per month, you may be able to save on certain medications if you use insurance, qualify for manufacturer savings programs, or pay with cash. On Ro, for example, you can get the Wegovy pen for $199–$399 per month, depending on dose, when you opt for self-pay (and are prescribed the medication). 

GLP-1 drugs can be a powerful tool for weight management. If you're considering them, the best first step is a conversation with a qualified healthcare provider who can help you figure out whether they're right for you.