Tirzepatide (Mounjaro): Effects, Side Effects, and Ideal Candidates, Explained by a Doctor
週1回の注射で食欲を抑えるマンジャロは、GLP-1とGIPという2つのホルモンに作用するお薬です。どのくらい体重が減るのか、どう打てばいいのか、副作用は大丈夫か——臨床試験のデータや増量のスケジュール、打ち忘れたときの対応、オゼンピックやゼップバウンドとの違いまでまとめました。
目次
June 22, 2026
Manjaro (Tirzepatide): Doctor Explains Effects, Side Effects, and Who It's Right For
Honest explanation of effects, side effects, and costs
"Is Manjaro really that effective for weight loss?" "GLP-1 injections scare me." "What's the difference between Manjaro and Rybelsus?" — While interest in Manjaro is rapidly growing, many questions also circulate.
Manjaro (generic name: tirzepatide) is a "dual agonist" that simultaneously acts on two hormone receptors, GLP-1 and GIP, making it one of the most effective medical weight loss medications currently available. Clinical trials have reported an average weight loss of approximately 15-20%.
In this article, a doctor from Mona Aoyama Clinic will explain in detail the effects, mechanism of action, side effects, differences from Rybelsus, and who Manjaro is suitable for.
- Manjaro (tirzepatide) available nationwide via online consultation
- Gradual prescription from 2.5mg to 15mg available
- Same-day prescription and shipping (for payments made by 4 PM)
What is Manjaro? – Basic Information
| Item | Content | ||
|---|---|---|---|
| Generic Name | Tirzepatide | ||
| Type of Drug | GLP-1 + GIP Receptor Dual Agonist (once-weekly injection) | ||
| Dosage | 2.5mg→5mg→7.5mg→10mg→12.5mg→15mg (gradual increase) | ||
| Administration Method | Once-weekly subcutaneous injection (abdomen, thigh, upper arm) | Weight Loss Effect | Average of approx. 20.9% in clinical trials (SURMOUNT-1) (max dose 15mg, 72 weeks) |
| Our Clinic Price | ¥12,000~ (depending on dosage and plan) |
Why is Manjaro so effective?
While conventional GLP-1 receptor agonists (such as Rybelsus and Ozempic) act only on GLP-1 receptors, Manjaro acts simultaneously on GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors.
- GLP-1 action: Appetite suppression, delayed gastric emptying, increased insulin secretion, prolonged satiety
- GIP action: Affects fat cells, improves energy metabolism, and also has an effect of reducing GLP-1 side effects (nausea)
- Synergistic effect of dual action: By acting on two receptors simultaneously, it exhibits a significantly greater weight loss effect than GLP-1 drugs alone.
Manjaro vs. Rybelsus – Which to choose?
| Comparison Item | Manjaro | Rybelsus |
|---|---|---|
| Administration Method | Once-weekly self-injection | Daily 1 tablet, oral |
| Weight Loss Effect | ◎ Approx. 15-20% | ○ Approx. 3-5% |
| Needle phobia | △ Injections (thin needle, minimal pain) | ◎ No needle required |
| Taking restrictions | ◎ Almost none | △ Immediately after waking, with 120ml water, wait 30 minutes |
| Cost | △ Slightly higher | ○ Relatively affordable |
| Who it's for | Those who want to maximize effect, have higher BMI, or found Rybelsus ineffective | Those who dislike needles, want to try it first, or prefer gradual effects |
Side Effects – What to Watch Out For with Manjaro
| Side Effect | Frequency | Management |
|---|---|---|
| Nausea/Vomiting | Common (early stages) | Start with 2.5mg and gradually increase. Avoid fatty foods. |
| Diarrhea/Constipation | Common | Hydration, fiber. Often improves within a few weeks. |
| Injection site reactions (redness, itching) | Rare | Rotate injection sites (abdomen → thigh → upper arm, etc.) |
| Hypoglycemia | Rare alone | Caution when used with other diabetes medications. Do not completely cut out carbohydrates. |
| Increased heart rate | Rare | Consult a doctor if palpitations or shortness of breath persist. |
✅ Due to the action of GIP, Manjaro tends to cause less nausea than GLP-1 monotherapy drugs. Even for those who found Rybelsus difficult to continue due to severe nausea, Manjaro has been reported to be relatively easier to continue.
How to Self-Inject – Why it's not scary
Manjaro is designed as an autoinjector, allowing you to inject without seeing the needle. The needle is extremely fine, 32G (gauge), and most people report "hardly feeling any pain."
- Confirm injection siteSubcutaneous fat areas on the abdomen, thigh, or upper arm. Shift the site by at least 2 cm each time to avoid repeated injections in the same spot.
- Disinfect with an alcohol swabClean the injection site.
- Press the autoinjector against the skin and push the buttonThe needle will automatically extend and retract. A click sound indicates completion.
- Hold in place for 10 secondsWait for the medication to be fully injected into the subcutaneous tissue.
Frequently Asked Questions
Clinical trials (SURMOUNT-1) showed an average weight loss of approximately 20.9% in the group that used the maximum dose of 15mg for 72 weeks. However, this is based on a combination with lifestyle improvements, and not everyone will lose 20% of their weight with the medication alone. There are individual differences.
If there are 4 or more days until your next scheduled dose, inject it as soon as you remember. If there are fewer than 4 days, skip that dose and inject as usual on your next scheduled day. Do not inject two doses at once.
The duration until you reach your target weight varies by individual, but clinical trials have continued for 72 weeks (approximately 1.5 years). There is a risk of weight regain if you stop, so continue until healthy eating and exercise habits are established, and discuss reduction or cessation with your doctor.
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Consultation Hours / Access (Online Consultation)
| Clinic Name | Mona Aoyama Clinic |
| Consultation Format | Online Consultation (nationwide) / In-person Consultation (Tokyo, Aoyama) |
| Location | D Building 3F, 1-10-3 Minami Aoyama, Minato-ku, Tokyo 107-0062 |
| Nearest Station | 5-minute walk from "Aoyama-itchome Station" on Tokyo Metro |
| Online Consultation | 24-hour reception / Same-day shipping available (for payments made by 4 PM) |
For Manjaro prescriptions, visit Mona Aoyama Clinic.
Online consultations available nationwide. Safely start from 2.5mg.
