How long does Saxenda take to work?

Knowing what to expect is important if you’ve recently started taking Saxenda (liraglutide) for weight loss. To determine if Saxenda is helping, you’ll want to know how long it takes to work and how much weight you can realistically lose. 

How long Saxenda takes to work and how much weight you can expect to lose within the first two months depends on factors like your starting BMI, individual medical history, and lifestyle factors like diet and exercise.

Keep reading for an in-depth look at some of Saxenda’s clinical trial data to learn what you might expect from Saxenda—and when. 

Saxenda (liraglutide) is a prescription medication that assists in weight loss and maintaining a healthy weight. Liraglutide belongs to a class of drugs called GLP-1 receptor agonists. Other drugs in this class, such as Wegovy and Ozempic, are used for weight loss or treating type 2 diabetes. 

Saxenda is a once-daily injection. It’s used to help people lose weight as part of a healthy lifestyle that includes increased physical activity and a reduced-calorie diet. Specifically, the Food and Drug Administration (FDA) has approved Saxenda for weight management in people who meet one of the following descriptions:

• Adults with a body mass index (BMI) of 30 or higher (obesity)

• Adults with a BMI of at least 27 (overweight) and have one or more weight-related medical conditions, such as high blood pressure, high cholesterol, or type 2 diabetes

• Kids ages 12 years and older who weigh more than 60 kilograms (~132 pounds) and are considered to have obesity based on their age, weight, and height

Saxenda is a once-daily injection. It begins to work after your first injection, but you’re not likely to see much change in your weight for a few weeks. This is because you’ll start with a low dose, and it takes several weeks to reach the dose of Saxenda that’s effective for weight loss. 

Generally, most people will notice some weight loss after 4-8 weeks. In one trial, people who combined Saxenda with a healthy diet and exercise lost up to 5% of their body weight by 8 weeks (more on that below). With any weight loss program, remember that the results can be affected by lifestyle factors, including diet and exercise. Since people have different fitness and activity levels, lifestyle factors can affect how and when you might see results.

That being said, data from clinical trials of Saxenda can help identify an average timeline and weight loss. Before the FDA approved Saxenda, trials were conducted to see if the drug could help people lose weight effectively and safely. In one trial, 3,731 adults were enrolled, all of whom were either obese or overweight and had at least one weight-related condition, such as high blood pressure. All participants were instructed to follow a reduced-calorie diet, eating about 500 fewer calories per day than usual. They were also encouraged to increase their physical activity, aiming for at least 150 minutes of exercise per week. 

After 4 weeks of treatment, Saxenda users saw an average weight loss of b 3-4% of their starting body weight. After 2 months of treatment, people lost an average of 5% of their body weight, when Saxenda was combined with a healthy diet and exercise. This table illustrates what a 5% decrease in body weight looks like for people starting Saxenda at different baseline weights.

Saxenda produces different weight management results depending on individual factors, commitment to lifestyle changes, and taking the medication as prescribed. In clinical trials, those who completed the trial and made lifestyle changes lost an average of 9% of their body weight after 56 weeks. 

But it doesn’t stop there. According to the clinical trials, approximately 15% of the participants on Saxenda lost up to 15% of their starting weight, and 1 out of 3 people taking Saxenda achieved significant weight loss of 10% or more. 

Talk to a healthcare provider about your specific weight loss goals while taking Saxenda, to determine a safe amount of weight to lose.

Saxenda will not result in immediate weight loss, especially in the first two weeks after starting treatment. Remember that clinical trial results are an average, with some individuals losing less weight than others despite taking the medication for 8 weeks or longer.

If Saxenda doesn’t seem to be working for you, consider improving your diet or increasing your physical activity. Keep in mind that Saxenda is meant to work in combination with a healthy diet and exercise regimens. Without implementing lifestyle changes, people taking Saxenda may not see the results they hoped for, if any.

In a clinical study, participants followed a strict diet and exercise plan while taking Saxenda. A follow-up investigation of the study found that both diet and exercise significantly improved weight loss outcomes, while a lack of diet and exercise reduced the effect of Saxenda. 

Consider increasing your physical activity over time to help reach your weight loss goal. When starting on Saxenda, 100 minutes of physical activity per week, such as walking, is a great start to support your weight loss goals. This exercise can be broken up into stretches of 10 minutes spread equally through 4 or 5 days of the week. Every 4 weeks, you can aim to increase the weekly target by 25 minutes, with an end goal of 250 minutes per week. 

Below is a detailed sample exercise plan to consider, as supported by clinical study evidence. Be sure to check with a healthcare professional before starting an intense fitness program.

In the clinical study discussed above, diet recommendations were shaped by the USDA guidelines with daily calorie goals ranging from 1,200 to 1,800 calories per day, depending on body weight. 

Participants followed a diet involving the following macronutrients: 15-20% of calories from protein, 20-35% from fat, and the remainder from carbohydrates. Here is a sample meal plan for a 266 lb individual consuming 1,600 calories while taking Saxenda, split into three meals throughout the day:

Developing a diet plan can be a daunting task. It’s okay to get professional help, especially if you’re not seeing results. Talk to a healthcare provider for advice, or schedule a consultation with a registered dietitian. 

Saxenda should be administered once daily as an injection into the skin of your abdomen, thigh, or upper arm. The timing of the dose does not impact the effectiveness of the medication, so any time of day is fine. However, taking the medication around the same time each day can help you get into a routine.

With Saxenda, taking the medication daily is essential to seeing positive weight management results. In studies, participants who consistently took Saxenda every day experienced an average weight reduction of 6.5% more than those who did not use the medication every day.

If you miss a dose of Saxenda, you should skip the missed dose and administer your next dose at the usual time the following day. You shouldn’t take multiple doses of Saxenda to make up for missed doses. This could result in worsened side effects, such as stomach upset. Contact your healthcare provider if you miss more than three days of Saxenda. They’ll instruct you to restart the medication at a lower dose, then slowly increase the dose each week until you’re back to your usual dosage.

If you struggle to remember to use Saxenda each day around the same time, several tips may help improve adherence:

• Work Saxenda into your daily routine. Try taking it immediately following your morning shower or after brushing your teeth in the evening. Pairing the dose with something you do daily makes it harder to forget.

• Set up reminders or set an alarm on your phone and ask someone to help remind you to take Saxenda every day. 

• Take Saxenda when you take your other medications. When starting the medication, talk to a healthcare provider or pharmacist about your other medications, and determine which medications are safe to take at the same time as you inject Saxenda each day.

This section describes side effects reported in clinical trials of Saxenda. Other side effects are possible. Common side effects of Saxenda include:

• Nausea

• Diarrhea

• Constipation

• Vomiting

• Indigestion

• Abdominal pain

• Acid reflux

• Flatulence

• Dry mouth

• Injection site pain or irritation

• Low blood sugar (hypoglycemia)

• Decreased appetite

• Headache

• Dizziness

• Fatigue

• Urinary tract infection

• Insomnia

• Anxiety

While uncommon, certain side effects from Saxenda can be serious, including:

• Pancreatitis (inflammation of the pancreas)

• Severe hypoglycemia (dangerously low blood sugar)

• Gallbladder disease

• Increased heart rate

• Kidney problems

• Allergic reaction

• Suicidal behavior and ideation (rare)

• Risk of thyroid tumors (boxed warning)

Saxenda has a boxed warning, which is a caution listed by the FDA when there is a rare but very serious concern with a medication. Saxenda’s boxed warning highlights the risk of thyroid C-cell tumors. During animal studies, the drug caused thyroid C-cell tumors in rats and mice. It isn’t known if Saxenda increases the risk of thyroid tumors in humans.

Out of caution, individuals with a personal or family history of medullary thyroid carcinoma (MTC), as well as those with multiple endocrine neoplasia syndrome type 2 (MEN2), should not take this medication. Also, people who experience throat pain, lumps, or hoarseness while taking Saxenda should notify their healthcare provider as these symptoms could be due to a thyroid tumor. 

It can take several weeks to months for Saxenda to help with weight loss. You can optimize your results by taking the medication every day as directed by your healthcare provider and following a diet and exercise plan.

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Current version

July 21, 2023

Written by

Patricia Weiser, PharmD

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.