Wegovy (Semaglutide) Complete Guide: Effects, Side Effects, Korea Launch, and Who Can Be Prescribed It

A Clear Overview of GLP-1 Obesity Medications

Names like “Wegovy” and “Mounjaro” have recently come up often in conversations about weight loss. These are obesity treatments that use a hormone called GLP-1, and contrary to what some people believe, they are not diet supplements you can easily buy at a pharmacy. They are prescription medicines that require a doctor’s prescription. This article is general information that neutrally explains what these medicines are, how they work, and what precautions to keep in mind.

What Is Wegovy?

Wegovy is an obesity treatment from Novo Nordisk. Its active ingredient is semaglutide. It is given as a once-weekly subcutaneous injection using a self-injection pen and is indicated for obesity treatment. It was launched in Korea in 2024. Ozempic, a diabetes treatment with semaglutide from the same Novo Nordisk group, and Saxenda, a once-daily injectable obesity medicine with liraglutide, also belong to the same GLP-1 drug class.

How Weight Loss Happens: Mechanism of Action

GLP-1 is a hormone our bodies naturally secrete after meals, and it is involved in satiety and blood sugar regulation. Medicines such as Wegovy act similarly to this hormone and reduce food intake in two ways. Specifically, they act on the appetite center in the brain to suppress appetite and delay gastric emptying, meaning the speed at which food leaves the stomach, so that fullness lasts longer. As a result, people naturally eat less, which leads to weight loss.

How Is Mounjaro (Tirzepatide) Different?

Mounjaro is a medicine from Eli Lilly. Its active ingredient is tirzepatide. Unlike Wegovy, which acts only on GLP-1, it is a “dual-action” medicine that works on both GIP and GLP-1 hormone receptors at the same time, and it is injected once weekly. In Korea, Mounjaro was launched for diabetes as its indication, with release in 2024-2025. In the United States, the same ingredient is approved for obesity under a separate brand name, Zepbound. It is worth remembering that even the same ingredient can differ by country, brand, and approved indication.

When Will Oral GLP-1 Obesity Medicines Arrive?

For people who find injections burdensome, oral GLP-1 obesity medicines are being developed. A leading example is Eli Lilly’s orforglipron, which is known to have completed phase 3 clinical trials and to be in the approval process, including development and review. However, it has not yet been released for general use, and the exact launch date, price, and domestic brand name have not been finalized and may change. Specific product names or launch timing circulating online may be inaccurate, so if you are interested, check official announcements and the latest news.

Who Can Be Prescribed These Medicines: Indications and Candidates

These medicines are not for anyone to use for cosmetic purposes. They are prescribed at a doctor’s discretion to patients with obesity or overweight who meet certain medical criteria. In general, candidates include people whose body mass index (BMI) is above a certain threshold or those who are overweight and have related conditions such as hypertension, diabetes, or dyslipidemia. The specific criteria vary by medicine, country, and approved labeling, so you should confirm whether you are eligible through medical consultation whenever possible.

Main Side Effects and Contraindications

• The most common side effects are gastrointestinal problems, including nausea, vomiting, diarrhea, and constipation, especially during the early period when the dose is being increased.
• Rarely, side effects requiring closer attention, such as pancreatitis and gallstones or gallbladder disease, have been reported.
• A boxed warning, the strongest level of warning, is included because thyroid C-cell tumors were observed in animal studies involving rodents.
• Use is contraindicated in people with a personal or family history of medullary thyroid carcinoma, or in people with multiple endocrine neoplasia syndrome type 2 (MEN2).
• If unusual symptoms appear, do not simply endure them on your own. Consult the prescribing doctor or pharmacist immediately.

Practical Precautions to Know

1. These are not diet supplements. Whenever possible, they should be used after medical consultation and prescription when the indication criteria are met.
2. Misuse for cosmetic purposes and arbitrary purchase or use through overseas direct buying or secondhand transactions are risky in terms of both safety and authenticity.
3. When treatment is stopped, appetite may return and “weight rebound,” or weight regain, may occur. Medication should go together with lifestyle management such as diet and exercise.
4. If prescribed without insurance coverage, the cost can be quite high. Coverage status and price vary by timing and product, so direct confirmation is necessary.

In Summary

GLP-1 class medicines such as Wegovy and Mounjaro are obesity treatments that reduce intake by suppressing appetite and delaying gastric emptying. As much as clear effects have been reported, they also come with practical limitations such as gastrointestinal side effects, contraindications, cost, and weight regain after stopping. The key point is that these medicines are not “miracle diet pills,” but prescription medicines used under medical criteria and doctor supervision.

Disclaimer (Please Read)

This article is for general medical information only and does not replace recommendation of a specific product, diagnosis, or prescription. Decisions about whether to treat obesity, which medicine to choose, and whether to start, stop, or change an oral or injectable medicine should be made in consultation with a doctor or pharmacist whenever possible. Launch status, price, insurance coverage, and approval status of medicines can change, so check the latest official information.