For decades, adequate treatment for type 2 diabetes (T2D) has been in focus for nutritional therapy and weight management [1]. Concerning diet therapy, former calorie restriction (CR) has been transitioned into low carbohydrate diet (LCD) [2]. Authors have developed actually useful LCD methods that are super-LCD, standard-LCD and petite-LCD through Japan LCD promotion association (JLCDPA) [3]. In addition, several novel oral hypoglycemic agents (OHAs) have been introduced to clinical practice in the primary care setting, which include glucagon-like peptide-1 receptor agonists (GLP-1RA) [4].

From practical medical point of view, tirzepatide is a once-weekly long-acting glucose-dependent insulinotropic polypeptide (GIP) /glucagon-like peptide-1 (GLP-1) receptor agonist (GIP/GLP-1 RA) developed by Eli Lilly and Company [5]. In Japan, it is sold as T2D treatment drug “Mounjaro®," and in the United States (US) and other countries. It is also used as an obesity treatment drug that is an injectable medication for diabetes and weight loss. In US, Zepbound™ is also used for an obesity treatment agent. The characteristic aspect of this agent includes appetite control, increased satiety, once-weekly administration, and subcutaneous injection.

Regarding the mechanism of action of drugs, tirzepatide has been a GIP/GLP-1 RA. For clinical effectiveness of GIP/GLP-1 RA, many cases with T2D and metabolic dysfunction-associated steatotic liver disease (MASLD) were investigated in various studies [6]. Significant reductions in body weight, HbA1c, FIB-4 index, fatty liver index, and hsCRP values were observed.

Several clinical studies for GLP-1RA were reported. A systematic review and meta-analysis of RCTs were conducted for PubMed. Among 21 papers, 15 placebo comparative test showed the predominance of GLP-1RA compared with placebo for higher percentage of successful weight reduction [7]. The pooled odds ratio (OR) was 11.37 (p<0.0001), where tirzepatide and semaglutide showed the greatest relative efficacy. For both tirzepatide and semaglutide, comparative study was conducted for 12 meta-analysis [8]. Tirzepatide showed significantly greater percentage body weight reduction, where OR was 1.52, 2.33, 2.82, for >5%, >10%, and >15%, respectively.

Authors’ clinical group have been involved in various treatments for T2D, Metabolic syndrome (MetS) and arteriosclerosis. We recently treated an impressive young male who suffered from T2D and obesity, who had remarkable effect for tirzepatide. General clinical progress and related perspectives are described in this article.

History & Physicals

The patient is a 33-year-old male. His medical history includes diagnosis with type 2 diabetes (T2D) during a health checkup at age 26 and referral to the diabetic department of our hospital. Subsequently, at age 27, he was also diagnosed with hyperuricemia, dyslipidemia and fatty liver (metabolic dysfunction-associated steatotic liver disease, MASLD). He has been receiving outpatient treatment since then. A physical examination in March 2023 showed normal speech and consciousness, with vital signs of blood pressure 136/76 mmHg, pulse 76, and SpO2 99%. Examination of the head, lungs, heart, abdomen, and nervous system revealed no significant changes. His stature showed height 183 cm, weight 127.6 kg, and BMI 38.1 kg/m².

Several Exams

Several exams were conducted in March 2023. The progress in blood chemistry from 2023-2026 is summarized in Figure 1. A chest X-ray was negative, and an electrocardiogram (ECG) showed ordinary sinus rhythm (OSR) without ST-T changes. Pulse wave velocity (PWV) revealed ankle-brachial index (ABI) of 1.26/1.14 on right/left (standard range: 0.91–1.40) [9] (Figure 2). The brachial ankle PWV (baPWV) value was 1185/1181 on right/left (standard: 1400–1800). Thus, ABI and baPWV showed within normal range. Abdominal CT scan revealed severe fatty liver, significant fat deposition in the pancreas, and visceral and subcutaneous fat deposition (Figure 3).

Figure 1: Changes in Blood Chemistry and Treatment.

Figure 2: Result of Pulse Wave Velocity (PWV).

Figure 3: Image of Abdominal CT scan.

His overall medication regimen has consisted of Metformin, Canagliflozin, Rosuvastatin, and Febuxostat for years, where this treatment was continued until spring 2025. From July 2025, novel treatment regimen was started. It was tirzepatide (Mounjaro) 2.5 mg once a week which has been recently introduced to clinical medicine (Figure 4). The dosage was increased to 5.0 mg in August and to 7.5 mg in October, 2025. As a result, HbA1c decreased significantly from 6.8% to 5.9% in 8 months. His body weight also decreased from 134 kg to 125 kg for the same period. Furthermore, improvements were observed in blood tests for AST, ALT, GGT, ChE, and LDL levels (Figure 1).

Figure 4: Clinical Progress of the Case.

Ethical Standards

Current case was complied with the guideline in Declaration of Helsinki [10]. In addition, certain comment exists for personal information for ethical principle rule. Necessary guideline was shown from Ministry of Education, Culture, Sports, Science Technology and Ministry of Health, Labor and Welfare. The authors have set up ethical committee in Kanaiso hospital, including director, physician, nurse, pharmacist, nutritionist and legal professional. We discussed the protocol, and obtained informed consent of the case.

This case showed several characteristic aspects as follows: #1 T2D with HbA1c 6.8%, #2 obesity with BMI more than 35 kg/m², #3 hyperuricemia, #4 dyslipidemia, #5 clinical beneficial effect of tirzepatide, #6 fatty liver (MASLD), #7 remarkable decrease of HbA1c and weight, #8 simultaneous improvement of glucose control, liver function, LDL-cholesterol, and #9 unremarkable gastro-intestinal adverse effect (GI-AE).

In the light of pharmaco-physiologic mechanism, tirzepatide stimulates the function and mobilization of endothelial progenitor cells that facilitates vascular repair and also mitigates hyperglycemia-related damage [11]. Tirzepatide can enhance the activity of endothelial nitric oxide synthase, reduce the activity of endothelial activation molecules including intercellular adhesion molecule 1 and also vascular cell adhesion molecule 1, promote dilatation of blood vessels, and reduce peripheral vascular resistance. Moreover, this agent inhibits inflammatory process by suppressing the expression of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin-1β, and interleukin-6.

As clinical beneficial points, tirzepatide would improve lipid profiles by decreasing LDL-C and triglycerides, while increasing HDL-C [11]. By reducing inflammation, improving endothelial function, and lowering body weight, tirzepatide can lower both systolic and diastolic BP. From these, tirzepatide has possessed useful mechanisms underlying the anti-atherosclerotic and vasoprotective effects.

From previous comparative studies, tirzepatide shows efficacy on cardiovascular (CV) parameters and major adverse cardiovascular events (MACE) in clinical trials. Real-world observational studies involving individuals with T2D receiving tirzepatide were studied [12]. They included 8 retrospective cohort studies with 118,252 cases. In comparison with control group, tirzepatide decreased risks of acute coronary syndrome (ACS) as HR 0.74, HF as HR 0.65, stroke as HR 0.71, MACE as HR 0.72, and all-cause mortality as HR 0.49 (p < 0,0001). The risk for composite outcomes of all-cause mortality and CV outcomes was calculated for lower with tirzepatide as HR 0.65 (p<0.0001).

This case showed the improvement of liver function test as AST 58 to 32 IU/L and ALT 99 U/L to 45 U/L after the administration of tirzepatide. The single-arm, prospective, and observational pilot study was conducted for 16 cases with T2D and MASLD [13]. For the protocol, tirzepatide was administered for 48 weeks, and liver function was analyzed. As a result, significant improvements were observed in HbA1c, liver enzymes, body weight for 12-week with sustained to 48-week. Weight reduction showed correlation with reduction of ALT levels (p<0.05). Several biomarkers showed significant decrease from 0 to 48 weeks, such as fibrosis-4 index (Fib-4), type IV collagen 7s, liver stiffness, and Wisteria floribunda agglutinin-positive Mac-2-binding protein. Consequently, tirzepatide improved liver steatosis, body weight, diabetes situation, and liver fibrosis markers.

Certain limitation may be present in current article. The application of irzepatide contributed medical benefit for the decrease in HbA1c and body weight. No remarkable GI-AEs were found during the clinical progress [14,15]. This case is in the young generation, and arterial stiffness has been not apparently detected yet. His future medical course will be carefully followed.

In summary, 33-year-old diabetic male has shown obesity and T2D and tirzepatide was treated. No apparent problems of arterial stiffness were not found. Current report will be hopefully useful reference for clinical studies in the diabetic research and practice.

Conflict of Interest

The authors declare no conflict of interest.

Funding

There was no funding received for this paper.

1. American Diabetes Association Professional Practice Committee for Diabetes*; 8. Obesity and Weight Management for the Prevention and Treatment of Diabetes: Standards of Care in Diabetes-2026. Diabetes Care. 2026; 49: S166-S182.
2. Kusayev J, Weininger D, Frishman WH, Aronow WS. Low-Carbohydrate/Ketogenic Diet and Coronary Artery Disease: A Brief Review of the Limited Evidence between Them. Cardiol Rev. 2026; 34: 53-56.
3. Bando H, Ebe K. Beneficial and Convenient Method of Low Carbohydrate Diet (LCD) as Petite, Standard and Super LCD. Asp Biomed Clin Case Rep. 2023; 7: 1-4.
4. American Diabetes Association Professional Practice Committee for Diabetes*. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes-2026. Diabetes Care. 2026; 49: S183-S215.
5. Drugs-supplements. Mayo clinic.
6. Okuma H. Effects of Tirzepatide on Patients with Type 2 Diabetes and Metabolic Dysfunction-Associated Steatotic Liver Disease: A Retrospective Cohort Study. Cureus. 2025; 17: e83712.
7. Ahmad N, Alruwayyes A, Alarjani A, Tawhari A, Aldosri A, Alahmari A, et al. GLP-1 receptor agonists for weight loss: A systematic review and meta-analysis of randomized controlled trials. Medicine (Baltimore). 2026; 105: e47994.
8. Zufry H, Hariyanto TI. Head-to-head comparison of tirzepatide and semaglutide for weight loss: A systematic review and meta-analysis. Obes Res Clin Pract. 2026; 20: 92-102.
9. Dong T, Fan F, Chen H, Dong Z, Yang L, Luo Y, et al. Comparison between vascular age based on brachial-ankle pulse wave velocity or carotid-femoral pulse wave velocity. Hypertens Res. 2025; 48: 2315-2325.
10. General Assembly of the World Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. J Am Coll Dent. 2014; 81: 14-18.
11. Rzepinski L, Tywoniuk A, Jaraczewska J, Al-Shaer A, Wicinski M. Beyond Diabetes: The Vasculoprotective Effects and Anti-Atherosclerotic Potential of Tirzepatide. Int J Mol Sci. 2025; 26:12028.
12. Kamrul-Hasan ABM, Chatterjee S, Ashraf H, Nagendra L, Dutta D, Pappachan JM. Cardiovascular Outcomes in Adults With Type 2 Diabetes Treated With Tirzepatide: A Systematic Review and Meta-Analysis of Real-World Studies. Endocr Pract. 2026; 32: 369-379.
13. Arai T, Atsukawa M, Nagao C, Yamada Z, Rokugo T, Suzuki K, et al. Effect of Tirzepatide Treatment on Hepatic Biomarkers in Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease and Type 2 Diabetes Mellitus. Hepatol Res. 2025; 55:1346-1352.
14. Chan ZH, Omar AS, Gill K, Volucke G, Azhar MM, Haleem SM, et al. Incretin-Based Dual and Triple Agonists in Overweight or Obese Individuals: A Systematic Review and Meta-Analysis. Cardiol Rev. 2026.
15. Bando H. Current Situation and Problems for Weight Reduction Using GLP-1 Receptor Agonists. J Med Clin Stud 2025; 8: 224.