Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician, Doctor Samui.
Last reviewed: October 2026
Mounjaro (tirzepatide) is available on Koh Samui by prescription through Doctor Samui’s walk-in clinic in Chaweng and via 24/7 hotel and villa visits across the island. A short consultation is required before your first dose. Both new starters and patients continuing treatment from home can be seen. Costs in Thailand are significantly lower than UK or US equivalents.
You have been on Mounjaro for three months at home, you are making real progress, and your next dose falls mid-holiday on Koh Samui. Or you have been reading about tirzepatide for a while and you finally want to start somewhere with proper clinic access. Either way, you need a doctor who actually handles this on the island, not a Bangkok page that lists Samui in the URL and leaves it there.
Mounjaro is a once-weekly injection used for medical weight management and blood sugar control in type 2 diabetes. It is legal in Thailand, prescription-only, and available here. This article covers what you need to know: how to access it, what it costs, how to store it safely in Koh Samui’s heat, and who should not be on it at all.

Is Mounjaro Legal in Thailand — What You Need to Know First
Yes, tirzepatide is legally approved in Thailand. It is classified as a prescription-only medication under Thai FDA regulations. You cannot walk into a pharmacy and buy it off the shelf. A doctor’s prescription is required, and the consultation that comes with it is not a formality. It protects you.
Mounjaro is distributed in Thailand through Zuellig Pharma, the regional distributor for Eli Lilly products. Supply on Koh Samui is not as simple as in Bangkok, but it is available. For a full picture of how GLP-1 medications sit within Thai law, our guide to GLP-1 therapy in Thailand covers the regulatory framework in detail.
Who Is a Candidate for Mounjaro on Koh Samui
The right candidate is an adult with obesity, or an adult who is overweight with at least one weight-related health condition such as type 2 diabetes, high blood pressure, or high cholesterol. Tirzepatide is not a quick fix for someone who wants to lose five kilograms before a beach holiday. It is a medical weight management tool used under clinical supervision.
Long-stay expats managing type 2 diabetes and visitors already enrolled in a weight management programme at home are the patients seen most often for this at the Chaweng clinic. If you are unsure whether you qualify, a consultation will tell you clearly within the first appointment.
Safety Screening Before Your First Mounjaro Injection
This is the part most online articles skip, and it matters. Before prescribing tirzepatide, the doctor needs to know your thyroid history. Tirzepatide carries a warning for patients with a personal or family history of medullary thyroid carcinoma, or a condition called MEN2 syndrome. It is not prescribed for these patients.
A history of pancreatitis also rules it out. Your cardiovascular history, kidney function, and any current medications all factor into the decision. A baseline blood panel is standard before starting. This is what responsible prescribing looks like, not bureaucracy.
Mounjaro vs Ozempic on Koh Samui — Which One Is Right for You
Both are available here on prescription. Ozempic (semaglutide) targets the GLP-1 receptor only. Mounjaro targets both GIP and GLP-1. Clinical trial data shows greater average weight loss with tirzepatide, particularly at higher dose tiers. For patients whose primary goal is weight loss with no prior experience of either medication, tirzepatide is now often the first recommendation.
If you are already on Ozempic and thinking about switching while you are on Koh Samui, that transition can be managed at Doctor Samui. The timing and starting dose need to be discussed individually. Do not switch without speaking to a doctor first.
Mounjaro Dosing — Step-Up Schedule and What to Expect
Tirzepatide starts at 2.5 mg once weekly for four weeks. This low starting dose gives your body time to adjust before stepping up. Most patients move through 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and up to 15 mg over several months, staying at each level until it is well tolerated and clinically appropriate to increase.
| Dose | Typical Duration at This Dose |
|---|---|
| 2.5 mg | 4 weeks (starting dose) |
| 5 mg | At least 4 weeks |
| 7.5 mg | At least 4 weeks |
| 10 mg | At least 4 weeks |
| 12.5 mg | At least 4 weeks |
| 15 mg | Maintenance (maximum dose) |
If you miss a dose and your next scheduled day is more than four days away, take it as soon as you remember. If your next scheduled dose is within four days, skip the missed one and continue your regular schedule. Never double dose.
Rotate your injection site each week between your abdomen, upper thigh, and upper arm. This reduces localised skin reactions over time.
Storing Your Mounjaro Pen in Koh Samui’s Heat
This is the section that matters most when you are actually on this island.
Mounjaro pens must be stored at 2 to 8 degrees Celsius in the fridge. Once removed from the fridge, the pen can be kept at room temperature up to 30 degrees Celsius for a maximum of 21 days. Koh Samui’s ambient temperature regularly exceeds 30 degrees outdoors, in parked vehicles, and in beach bags. Inside a car or bag in direct sun, temperatures can exceed 50 degrees.
Keep your pen in your hotel minibar or villa fridge at all times. Use an insulated medical cooler for any trip away from air conditioning. Never leave it in a vehicle, a beach bag, or on a balcony. A pen that has been frozen is damaged and must be discarded. If you think your pen was exposed to excessive heat, contact Doctor Samui before injecting. A compromised dose is not worth the risk.
Arriving Already on Mounjaro — Continuity of Care on Koh Samui
Most articles on this topic are written for people starting fresh. But a large number of patients seen at the Chaweng clinic are already mid-programme. They are on a prescribed dose at home, they are on holiday, and they need their next pen.
Doctor Samui can review your existing prescription and clinical history, confirm your current dose, and issue a bridging prescription to keep your treatment on track. Bring your prescription details or medication history. Hotel and villa visits are available if you cannot easily reach the clinic. The island-wide service covers Chaweng, Lamai, Bophut, Maenam, Choeng Mon, and the rest of Koh Samui, around the clock.
If you are arriving with your own supply from home, Thailand allows a 30-day personal-use import allowance for prescription medications. Carry your prescription or a letter from your prescribing doctor as supporting documentation.
Mounjaro Prices on Koh Samui — What to Budget
Tirzepatide in Thailand costs significantly less than in the UK or US. Exact costs vary by dose strength and shift with supply. Lower dose pens cost less, and prices increase at higher tiers. The 15 mg pen is the most expensive.
At Doctor Samui, pricing includes the pen and the required consultation. Contact the clinic directly for current pricing at your specific dose. Live prices are not published here because supply costs change, and an accurate number is more useful than a figure that has drifted since this page was written.
Doctor Samui prescribes Mounjaro (tirzepatide) from our walk-in clinic in Chaweng and via 24/7 hotel and villa visits across Koh Samui. Whether you are starting for the first time or need a refill to continue your programme from home, we can see you the same day. Bring your prescription details if you have them. Contact Doctor Samui to book your consultation or request an island-wide visit.
Frequently Asked Questions
Dr. Ponlawat Pitsuwan
Physician, Doctor Samui
a walk-in clinic based in Chaweng, Koh Samui, with 24/7 hotel and villa visits across the island. He sees tourists, families, and long-stay expats for medical weight management, [GLP-1 and GIP receptor agonist therapy](https://doctorsamui.com/glp-1/), and ongoing chronic disease care. His approach is straightforward and evidence-based, delivered in plain language.


