Zepbound: What is it and how does it work for weight loss?

You may have noticed there's been a seismic shift in the health and wellness industry in recent years.

While those with chronic weight issues once found themselves stuck on a frustrating diet rollercoaster, weight loss medications have opened up a world of new possibilities.

These medications are highly effective at regulating appetite and metabolism, helping people lose weight sustainably without sacrificing the foods they love.

Alongside Saxenda, Wegovy and Mounjaro, one of the newer weight loss medications in the arena is Zepbound. Having been approved by the FDA in 2023, it's been making headlines for its promising early results.

But, how does Zepbound work, and is it as effective as the other alternatives on the market? Read on for everything you need to know about this new weight loss medication.

What is Zepbound?

Alongside Mounjaro, Zepbound is one of the current brand names for the active ingredient tirzepatide manufactured by US pharmaceutical company, Eli Lilly and Co.

It launched in the US in November 2023 and is slowly being rolled out internationally.

The injectable medication can be prescribed to people who are obese (body mass index over 30); or who are overweight (body mass index over 27) and have associated health issues such as type 2 diabetes, high blood pressure, heart disease, or obstructive sleep apnea [1].

Administered as a once-weekly injection, it's designed to be used in conjunction with a reduced-calorie diet and increased physical activity.

How does Zepbound work for weight loss?

Like all weight loss medications, Zepbound mimics naturally occurring hormones in the body to regulate insulin production.

This helps promote feelings of fullness after a meal, while also improving the flow of food through the gut. It can also help keep blood sugar levels under control, which is particularly important in patients with diabetes.

Zepbound works slightly differently from GLP-1 medications like Ozempic (which contains semaglutide) in that it's a dual GIP/GLP-1 receptor co-agonist.

This means it targets not one but two hormones — glucose-dependent insulinotropic polypeptide peptide-1, as well as glucagon-like peptide-1 [2].

These are sometimes referred to as 'twincretins' which work together in harmony to regulate glucose and, theoretically, achieve greater weight loss results [3].

How effective is Zepbound?

So far, the research points to positive results for Zepbound.

In a double-blind, randomised, controlled study, the highest dose of tirzepatide (15 milligrams) resulted in a 22.5% reduction in weight, or around 23 kilos, over the course of 72 weeks.

Those on lower doses of 5 or 10 milligrams also lost 15% of their body weight on average [4].

In another study, participants were given lifestyle intervention (diet and exercise) and either prescribed tirzepatide or a placebo.

The group taking tirzepatide lost 26.6% of their body weight, compared to just 3.8% in the placebo group. Interestingly, in this experiment, patients lost an additional 6.7% weight loss after an initial 36-week period, suggesting it's an effective solution for long-term weight loss [5].

The results of these studies went beyond weight loss, with other cardiovascular measures such as blood pressure also improving throughout the trials [6].

While these findings are encouraging, it's important to note that both of these studies were commissioned by Eli Lilly and Co, so may contain some bias.

However, the results align with those that have been found in Mounjaro.

How does Zepbound compare to other weight loss medications?

It's important to note that as Zepbound is still a relatively new medication, there are limited reviews and studies to compare it to other weight loss drugs.

However, here's what we know so far about how it stacks up against other medications:

Zepbound vs Mounjaro

For all intents and purposes, Mounjaro and Zepbound are the same medication (tirzepatide).

In other words, this is akin to comparing apples with apples.

The main difference is in how they are marketed, as Mounjaro was initially developed as a medication for type-2 diabetes (however, it can now be prescribed to patients without diabetes in the UK), while Zepbound was specifically created for chronic weight management.

As Mounjaro has been around for longer than Zepbound, there are more studies backing up its effectiveness.

For example, in one 78-week trial people with diabetes taking the highest dose of Mounjaro lost 15.7% of their body weight by the end of the study — with 1/3 of people reporting at least a 20% body weight reduction [7].

Zepbound vs Wegovy

Unlike Zepbound, the active ingredient in Wegovy is semaglutide.

One study found that Zepbound achieved a 22% reduction in body weight at 72 weeks, compared to 15% for Wegovy at 68 weeks [8].

However, it's worth noting that these timeframes are not directly comparable.

Still, the findings echo those wherein Mounjaro (another tirzepatide medication) achieved 20% weight loss compared to 15% for Wegovy in the same timeframe [9].

Set to conclude in 2025, an ongoing study will seek to confirm if these favourable results are specific only to people with diabetes [10].

Zepbound vs Saxenda

Like Wegovy, Saxenda is a semaglutide medication in the GLP-1 class.

It showed promising early results, with research showing an average of 5% weight loss in the first 8 weeks [12].

However, ultimately, it doesn't appear to be quite as effective as tirzepatide medications for weight loss over longer time periods.

What are the side effects of Zepbound?

Zepbound has been found to be overall safe and effective for weight loss. However, all medications are accompanied by potential side effects, and Zepbound is no exception.

The most common side effects (which typically do not require medication attention) include [13]:

• Stomach pain or discomfort
• Belching
• Constipation
• Diarrhoea

Other, less common side effects are:

• Bloating
• Anxiety
• Blurred vision
• Chest tightness
• Chills or cold sweats
• Hives anywhere on the body
• Shakiness
• Unusual tiredness
• Thoughts of harming oneself
• Hair loss
• Heartburn
• Stomach flu
• Runny nose
• Sore throat

Note, this is not an exhaustive list of Zepbound's side effects. So, if you notice any unusual symptoms, it's important to see a medical professional urgently.

Is Zepbound available in the UK?

Those wondering where you can buy Zepbound in the UK may be met with disappointment.

In the US, both Zepbound and Mounjaro can be prescribed to those who might meet the eligibility criteria — with the former being slightly more expensive.

However, in the UK, tirzepatide will only be prescribed under the brand name Mounjaro — at least for the time being.

Should you use tirzepatide for weight loss?

Like its fellow dual agonist medication Mounjaro, Zepbound appears to be a highly effective solution for treating excess weight and accompanying health issues.

However, at the end of the day, weight loss is not a one-size-fits-all solution. What works beautifully for one person, may not be effective for another.

It's important to look at the big picture (including side effects, eligibility, availability, cost, and your health background) to determine which weight loss drug is right for you.

For example, if you have a personal or family history of pancreatitis, medullary thyroid cancer, or thyroid c-cell tumours, tirzepatide likely won't be suitable for your needs [14].

Find your perfect weight loss solution with Juniper

Thankfully, you don't have to go through your weight loss journey alone.

At Juniper, we can prescribe Mounjaro or Wegovy, depending on your eligibility and overall needs.

This is combined with lifestyle coaching and nutrition support, for a holistic approach to weight loss. You also gain access to a community of like-minded women who can help you navigate challenges and cheer you on throughout your journey.

To learn more about whether our weight loss program can help you achieve your goals, start your consultation here.