Weight Loss Injections: Are They Safe?

Craig Primack MD

Reviewed by Craig Primack, MD, FACP, FAAP, FOMA

Written by Sian Ferguson

Published 11/08/2023

Weight loss injections have become incredibly popular in the last year or so. In fact, these medications are so widely used that there have been worldwide shortages of semaglutide, also known by the brand names Ozempic® or Wegovy®.

If you’re unhappy with the size of your waistline or the number on the scale, you might be considering using weight loss shots to shed a few pounds. 

And that’s understandable. Losing weight can be a difficult and long process.

There’s a reason about 42 percent of the U.S. population has obesity, and roughly 74 percent are overweight. It’s because weight loss can be tough, even for those who eat healthily and go to the gym religiously.

It’s easy to romanticize the idea of weight loss injections: You take an injection, and boom, you shed the stubborn pounds you thought you’d never drop on the treadmill. 

Unfortunately, it’s a bit more complicated than that.

These medications can be pretty effective, and they could help you avoid more invasive weight management therapies like bariatric surgery. But they come with a range of potential side effects and risks — not to mention the hefty price tag.

Here’s what you need to consider before using weight loss injections.

Injections for weight loss include semaglutide (Ozempic and Wegovy), liraglutide (Saxenda® and Victoza®) and tirzepatide (Mounjaro®). These injections are taken either once a week or once a day and are usually self-administered by the patient (meaning you give yourself the shots at home).

Most of these medications are primarily used for type 2 diabetes, but they’re also used off-label for weight loss.

When a drug is used off-label, it means the drug itself is approved by the FDA for a particular use, but the healthcare provider is prescribing the drug for a different use. This is a legal — and common — practice for many medications.

You’ll find that most weight loss injections are made by one pharmaceutical company: Novo Nordisk. Novo Nordisk also funded some of the studies on these weight loss drugs.

Although these medications are proven to cause weight loss, it’s important to remember they’re not a silver bullet. They’re not a replacement for eating well and exercising — you’re meant to use weight loss injections alongside healthy lifestyle changes, which can include a nutritious, lower-calorie diet and exercise. Read our article on walking to lose weight for more details.

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These weight loss injections are generally considered safe to use. But that doesn’t mean there aren’t risks or side effects.

Since these drugs are so new, there’s a lack of long-term clinical trials looking at the safety of weight loss injections, so right now, we can only go by the available data.

On the other hand, carrying extra weight also has a number of health risks, including heart disease, stroke, type 2 diabetes, high blood pressure and certain types of cancer. These conditions are among the leading causes of preventable death.

Having extra weight is not great for your health, but for some people, weight loss injections may be riskier. 

It’s important to discuss the potential risks with a healthcare professional to determine whether using weight loss injections will be worth a try, or whether an alternative medication might be a better option for someone with your health history.

Another note: It’s possible to regain the weight you lost once you stop taking these medications, which can be pretty demotivating.

The most common side effects of weight loss injections are gastrointestinal, particularly nausea and diarrhea. You may also experience vomiting and constipation.

Over five percent of people experience nausea and diarrhea on semaglutide and liraglutide. These adverse reactions also affect up to 10 percent of people who use tirzepatide.

Other side effects include:

  • Dizziness

  • Fatigue 

  • Headaches

  • Hypoglycemia (very low blood sugar)

  • Indigestion 

  • Mild tachycardia (fast heartbeat)

  • Itching or redness at the site of the injection

It may be a good idea to keep some supplies on hand in case you experience gastrointestinal issues or other side effects. For example, you could get over-the-counter medication for nausea, diarrhea and headaches. Home remedies like ginger tea might also help you feel better.

There’s a risk that weight loss injections can cause serious health problems. Although these issues are rare, they’re possible.  

These risks include:

  • Allergic reaction to the drug

  • Complications with diabetic retinopathy (an eye condition occurring in people with diabetes)

  • Dehydration 

  • Gallbladder disease  

  • Kidney issues

  • Pancreatitis

  • Tachycardia (fast heartbeat)

  • Thyroid cancer

Weight loss injections also have certain contraindications, meaning some people shouldn’t use them.

You can’t use weight loss injections if you have any of the following:

  • Type 1 diabetes

  • Diabetic retinopathy

  • Family or personal history of thyroid tumors, especially medullary thyroid carcinoma (MTC)

  • A history of pancreatitis

  • Gallstones or other gallbladder diseases

  • Kidney disease

There isn’t much research on how safe weight loss injections are during pregnancy or breastfeeding.

In some cases, a healthcare provider will determine a medication is worth prescribing when the benefits outweigh the potential risks (treating diabetes, for example). But this is definitely something you’ll want to discuss with your provider rather than Googling whether it’s okay.

Also, since weight loss injections delay gastric emptying, they can affect how your body processes medications — including contraceptive pills. It’s important to discuss your current medications with a healthcare professional, as it might be necessary to use a different type of contraceptive while using weight loss injections.

Possible Weight Gain After Stopping Weight Loss Injections

Another thing to keep in mind is that, like other methods of weight loss, you can regain the weight after using weight loss injections.

In the 2022 study mentioned above, researchers found that people gained most of their weight back after stopping semaglutide for a year. These participants regained an average of two‐thirds of their prior weight loss, highlighting the importance of ongoing treatment.

If you’ve done your research, spoken with a provider, considered all the risks and side effects, and decided that you’d like to consider weight loss injections, you’ll have some choices to make. 

According to much of the research we currently have, tirzepatide appears to have the edge over its competitors when it comes to the effectiveness of injections for weight loss. But the story is slightly different when it comes to side effects and safety. 

For instance, one 2022 trial compared the weight loss effects of semaglutide with liraglutide. This trial looked at 338 non-diabetic adults who had obesity or were overweight. Participants received counseling for diet and physical activity as well as either semaglutide or liraglutide injections.

The study found that once-weekly semaglutide injections were more effective for weight loss than once-daily liraglutide. On average, participants lost 15.8 percent of their body weight with semaglutide and 6.4 percent of their body weight with liraglutide over 68 weeks.

A 40-week trial looked at the effects of tirzepatide versus semaglutide in people with type 2 diabetes. Although the goal of the trial wasn’t to measure weight loss, researchers noted that participants who used tirzepatide lost more weight than those who used semaglutide.

But if you’re concerned about safety and side effects, the story is slightly different. 

The same study also found that five to seven percent of patients who used tirzepatide experienced serious side effects, as opposed to only three percent of those who received semaglutide.

Still, further research needs to be done before there’s an official consensus on which weight loss injection is more effective, and which is more safe. 

And when considering the best weight loss injection, it’s also crucial to consider the cost of the medication.

Typically, a one-month supply of brand-name weight loss injections costs as follows:  

  • Ozempic (1.5 milliliters): $995

  • Wegovy (2 milliliters): $1,430  

  • Mounjaro (2 milliliters): $1,087  

  • Victoza (6 milliliters): $794

  • Saxenda (15 milliliters): $1,430  

Of course, the price will vary depending on the pharmacy you visit and the dosage you’re prescribed. But there are a few things to keep in mind when considering cost.

First, weight loss medications are meant to be taken continuously. It’s not safe to stop using the medication when you run out of cash and restart when you can afford it. So, the cost of the medication can impact the safety of your experience if it means you won’t be able to continue to use it as prescribed. 

Second, health insurance policies seldom cover weight loss injections. Most insurance companies don’t cover newer weight loss medications, including treatments like semaglutide, liraglutide and tirzepatide.

Since weight loss injections cost quite a lot, they’re not accessible to most people.

Let’s be real — few of us have an extra $1,000 to $1,500 to spend every month. But if you do have the cash and are struggling to get rid of excess weight, it might be worth talking to a provider. 

Weight loss injections come with quite a few side effects, and many people might not feel that it’s safe to take. If you’re concerned about the safety of weight loss injections, or if the side effects have been too intense for you, you might want to consider some alternatives.

Alternatives to weight loss injections include:

  • MetforminMetformin is used for treating diabetes 2, polycystic ovary syndrome (PCOS) and obesity. While safe, up to 30 percent of people who take metformin experience gastrointestinal side effects like nausea, vomiting and diarrhea.  

  • Naltrexone-bupropion. An FDA-approved weight loss medication, naltrexone-bupropion is generally considered effective and safe to use. You may, however, experience side effects like dizziness, mood changes, trouble sleeping and headaches.  

  • Phentermine-topiramate. This is a combination of an appetite suppressant called phentermine and an anticonvulsant called topiramate. Topiramate is used to treat seizures and migraines. Phentermine-topiramate is effective for weight loss and seems to reduce blood pressure in people with hypertension.  

It’s important to remember, though, that what is safe for one person might not be safe for the next person. All medications have potential side effects, and you might tolerate some of the above drugs better than others. A healthcare professional can help determine which weight loss medications will be safest for you.

Weight loss is a multi-pronged system that requires balance, discipline and — when necessary — medication. While weight loss medications can speed up weight loss, they don’t replace healthy habits. In fact, they’re usually prescribed alongside a healthy diet and frequent exercise.

The safest alternative to weight loss medications is a healthy lifestyle. While frequent exercising and eating a balanced diet doesn’t automatically lead to weight loss for everyone, they are still necessary components of self-care. These habits aren’t just good for losing weight, but for your overall health and well-being.

Given the media hype around medications like Ozempic and Wegovy, you’d be forgiven for thinking weight loss injections are an instant cure-all. 

Though weight loss injections can help you slim down significantly, there are a few drawbacks to consider before taking that prescription to the pharmacy. 

  • Weight loss injections don’t replace healthy eating and exercise. If you’re considering weight loss injections, you’re probably already tired of dieting and exercising. But it’s still important to eat a balanced diet and work out while using this type of medication, not only for your waistline but for your overall well-being.

  • The side effects of weight loss injections are real. Nausea and diarrhea are common with weight loss injections. There’s also a risk of dizziness, fatigue and headaches. Rarer (but more serious) health risks include kidney issues, pancreatitis and dehydration.

  • Weight loss injections cost a pretty penny. Between $1,000 and $1,500 a month, to be exact. And since it’s possible to regain the weight you lost, it’s vital to ensure you have enough cash to stay on the medication for the long haul.

Losing weight can be a tedious and complicated process, especially if you have a health condition that affects your metabolism.

If you need extra support, we can connect you with a healthcare provider to chat about potential solutions. Want to learn more about effective and convenient weight loss treatments? We can help you there, too.

24 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

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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 doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.