How fast does Zepbound work?

In this article:

• How Zepbound works
• Weight loss timeline
• Maximizing weight loss
• Alternatives

In this article

• How Zepbound works
• Weight loss timeline
• Maximizing weight loss
• Alternatives

Zepbound (tirzepatide) is a prescription drug approved for chronic weight management and, more recently, the treatment of obstructive sleep apnea (OSA). But as part of a class of drugs steadily growing in popularity, most people consider taking Zepbound to help them lose weight. 

Studies show that Zepbound is effective, with many people noticing weight loss about one to three months after they start the medication. Here’s what to expect if you’re taking Zepbound, how you’ll know it’s working, and what factors can slow down or speed up your progress.

Understanding the mechanics of Zepbound

Zepbound contains the active ingredient tirzepatide, which mimics the effects of two appetite-regulating hormones naturally produced by your body: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Tirzepatide was originally approved under the brand name Mounjaro to treat Type 2 diabetes because it helps to regulate blood sugar levels. Taking Zepbound makes you feel fuller faster, slows down your digestion, and decreases cravings, all of which help you eat fewer calories. Over time, a lower calorie intake causes weight loss.

Several studies confirm these effects. When the U.S. Food & Drug Administration (FDA) approved Zepbound for weight management, it cited two large clinical trials showing the drug was effective when combined with a reduced-calorie diet and regular exercise. These trials found that people taking Zepbound at any dose lost more weight over 72 weeks than people taking a placebo (inactive treatment).

You should know, however, that weight loss on Zepbound isn’t instantaneous. Not only does it take some time for the drug’s effects, like reduced appetite, to actually cause weight loss, it may be several weeks or months until you find the right dose for you.

“Most people begin to see measurable weight loss after the first month, once the dose has been gradually increased and their body reaches a steady level of the medication,” says Wiljon Beltre, MD, bariatric and metabolic surgeon and founder of Beltre Bariatrics in Florida. “The weight loss tends to build over time, [so] while the first few weeks may feel slow, the results often become much more noticeable after the two- to three-month mark.”

Typical Zepbound weight loss timeline

When you first start taking Zepbound, you’ll probably notice some effects right away,  although this probably won’t include weight loss just yet. In your first week on Zepbound, you might experience:

• Decreased appetite: One of the earliest effects of Zepbound is a decrease in appetite. “Zepbound works on the hormones that regulate hunger, so many people find themselves feeling satisfied with smaller portions or not thinking about food as much,” says Dr. Beltre. You might notice these changes within the first few days of taking your first dose.
• Nausea or vomiting: According to clinical trials, nausea and vomiting are two of the most common side effects of Zepbound. They usually hit the hardest soon after starting the medicine or increasing the dose, though they can get better once the body adjusts to a maintenance dose.
• Fewer cravings: Reduced appetite isn’t just about feeling fuller sooner. It’s also about having fewer food cravings, like wanting to eat favorite foods less often.

For the first few weeks, you will most likely have side effects without much noticeable weight loss, but clinical trials suggest this changes around the four-week mark.

Everyone will lose weight differently when taking Zepbound, but Dr. Beltre says the research we have gives us a good idea of what the typical weight loss journey looks like for someone taking the drug, although individual results can vary based on different factors such as the dose you take and lifestyle changes like diet and exercise:

• After 1 month: Weight loss of about 2% of your starting body weight.
• After 3 months: Weight loss of about 5%-10% of your starting body weight.
• After 6 months: Weight loss of about 15% of your starting body weight.
• After 12 months: Weight loss of up to 20% of your starting body weight.

Keep in mind that clinical trials usually include results across the full range of Zepbound dosing, including the minimum and maximum dosage, and higher amounts of weight loss are associated with higher doses. For example, in one study of tirzepatide’s effectiveness, 91% of people lost at least 5% of their body weight after 72 weeks on a 15 mg dose of the medication, but only 85% had the same results on a 5 mg dose.  

Your dose is just one piece of the puzzle, though, and it’s not recommended to begin with a high dose. Zepbound is a powerful drug with a lot of side effects, so healthcare providers usually start everyone on the lowest dose, which is 2.5 mg once a week. From there, they will help you slowly increase to the dose of Zepbound that’s right for you based on factors like your starting weight, how well you tolerate it, your general health, and any other chronic conditions you have. 

Maximizing weight loss with Zepbound

A few things affect how much weight you lose while taking Zepbound and when that weight loss occurs. 

1. Your dose: Zepbound is started at a low dose and then gradually increased as you work toward your weight loss goals. People typically lose more weight as they reach the higher maintenance doses, says Dr. Beltre. Your healthcare provider will work with you to determine the optimal dose for you. Some people stay on lower doses for longer, while others may need a dose increase every month to get to a higher maintenance dose.
2. Lifestyle changes: Zepbound is a tool in your weight loss toolbox, says Angela Baalmann, Pharm.D., assistant professor of clinical sciences at High Point University’s Fred Wilson School of Pharmacy. Like any other tool, it won’t work if you don’t use it as intended. If you don’t reduce your calorie intake and don’t exercise, you’ll lose less weight, she adds.  
3. Overall health: Individual factors like metabolism, starting weight, and any underlying health conditions can affect how much weight you lose and when, says Dr. Beltre.

Choosing to take Zepbound is a big step, so you should follow your provider’s medical advice when it comes to maintaining your health on the medication. Focusing on eating a balanced, nutritious diet and getting regular physical activity can help you maximize the weight loss benefits of Zepbound. You should also try to get enough sleep, manage your stress, and incorporate strength training into your exercise routine. Finally, many people using Zepbound and other GLP-1 drugs don’t consume enough protein, but Dr. Beltre says a high-protein diet can help you see better weight loss results and help prevent you from losing muscle.

You might also want to consider what happens after you stop taking Zepbound (after you meet your weight loss goals or discontinue treatment). Many people stay on Zepbound at least 18 to 24 months, but studies show many people regain the weight they lost once they stop taking these medications. It’s important for patients and their providers to think about more than just getting to a specific goal weight. It’s about getting healthier and staying that way.

One thing you don’t have to think hard about? The time of day you take your weekly dose. According to Dr. Baalmann, if Zepbound is going to work for you, it doesn’t matter when you take your weekly injection; you can choose morning or night. Just find a time that fits well into your routine, is easy to stick to consistently, and is accommodating of any side effects you might get from the drug. You’ll want to pick the best day of the week that works for you. 

“The ideal strategy would be to take Zepbound at a time when your nausea can be managed effectively and when it can help you stick to healthy diet behaviors, [like avoiding] indulging in food cravings,” says Dr. Baalmann.  

Zepbound vs. other weight loss medications

Remember when we mentioned that Zepbound mimics two appetite-regulating hormones, GLP-1 and GIP? That’s important because other similar injectable weight loss medications, like Wegovy (semaglutide), only mimic GLP-1. Tirzepatide’s dual action approach is generally considered to make it more effective and lead to higher levels of weight loss over time than other injectable GLP-1 medications. 

According to Zepbound’s manufacturer, Eli Lilly, the SURMOUNT-5 clinical trial found that people on Zepbound lost an average of 20.2% of their starting weight after 72 weeks versus an average of 13.7% on Wegovy. On top of that, more than 31% of people taking Zepbound lost at least 25% of their body weight, compared to 16% of people taking Wegovy. Another study confirms this difference between Zepbound and Wegovy, showing that people taking tirzepatide lost significantly more weight at the 3-, 6-, and 12-month marks than people taking semaglutide. 

There’s not a lot of difference in the typical weight loss timeline for either drug. However, most people on these medications start to see results about 1 to 3 months after starting, regardless of whether they’re taking Zepbound, Ozempic, Wegovy, or Mounjaro.

Cost Comparison of Zebound, Wegovy, Ozempic, Mounjaro

Medication	Retail price	Cost with SingleCare discount card
Zepbound	$1,540 per 4, 5 mg/0.5 ml pens	$950 per 4, 5 mg/0.5 ml pens
Wegovy	$1,852 per 4, 0.75 ml prefilled 2.4 mg/0.75 ml pens	$1,225 per 4, 0.75 ml prefilled 2.4 mg/0.75 ml pens
Ozempic	$1,387 per 1, 3 ml prefilled 2 mg/3 ml pen	$825 per 1, 3 ml prefilled 2mg/3ml pen
Mounjaro	$1,522 per 4, 5 mg/0.5 ml 0.5 ml pens	$875 per 4, 5 mg/0.5 ml 0.5 ml pens