Why this guide exists

If you live in India and you've been diagnosed with type 2 diabetes, you've probably been on metformin for years. You may also be on a sulfonylurea, perhaps a DPP-4 inhibitor, possibly insulin. And you've almost certainly been told to "lose some weight" — usually without much practical help on how to actually do it.

This page is about the class of medicines that has, more than any other development in the last two decades, changed what is possible in T2D: GLP-1 receptor agonists (semaglutide, tirzepatide). They are not a miracle. They are not a replacement for diet, sleep, or movement. But the published evidence — from large, well-conducted randomised trials in major medical journals — shows benefits that older oral drugs simply do not produce: meaningful weight loss, fewer heart attacks and strokes, slower progression of kidney disease, and HbA1c reductions of 1.5 to 2.5 percentage points.

This guide is written for an educated Indian patient who wants to understand what these drugs actually do, why South Asian diabetes is different, and where they fit in your treatment plan.

Why Indian (South Asian) diabetes is its own disease

T2D in India is not the same disease American textbooks describe. Three differences matter clinically.

First, we get diabetes at lower BMIs. The ICMR-INDIAB study, the largest epidemiological survey of diabetes ever conducted in India, has repeatedly shown Indians developing T2D at BMIs of 23–25 — weights that would be considered "normal" by Western cut-offs. The Indian Council of Medical Research and the Indian Diabetes Federation have therefore recommended lower BMI thresholds (≥23 for overweight, ≥25 for obesity) for South Asians.

Second, we have the so-called "thin-fat" phenotype — first described in Indian cohorts by Yajnik and colleagues. At any given BMI, Indians carry more visceral (abdominal) fat and less lean muscle than Europeans. This visceral fat is metabolically toxic: it drives insulin resistance, inflammation, and dyslipidaemia even when the bathroom scale looks reassuring.

Third, our beta cells fail earlier. South Asian beta-cell reserve declines faster than in white European populations, which is why many Indian patients move from metformin to insulin in 8–10 years even when "doing everything right."

The practical implication: a drug class that simultaneously addresses insulin resistance, visceral adiposity, beta-cell stress, and weight is not a luxury for Indian patients — it is, increasingly, a logical first-line addition.

How GLP-1 medicines actually work

GLP-1 (glucagon-like peptide-1) is a hormone your small intestine releases after every meal. It does four useful things at once:

Semaglutide is a once-weekly synthetic analogue of GLP-1. Tirzepatide is a dual agonist — it activates both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors, which appears to add improvements in insulin sensitivity and energy expenditure on top of the GLP-1 effects. For a deeper dive on either molecule, see our semaglutide guide and tirzepatide guide.

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What the trials actually show

SUSTAIN-6 — the cardiovascular trial that changed semaglutide's identity

SUSTAIN-6 (Marso et al., New England Journal of Medicine, 2016) randomised 3,297 patients with T2D and high cardiovascular risk to subcutaneous semaglutide or placebo. Over roughly two years, major adverse cardiovascular events — cardiovascular death, non-fatal MI, non-fatal stroke — occurred in 6.6% of semaglutide patients versus 8.9% on placebo. That's a hazard ratio of 0.74, a 26% relative risk reduction. This is the trial that elevated semaglutide from "another diabetes drug" to "a drug that prevents heart attacks."

SURPASS-2 — the tirzepatide vs semaglutide head-to-head

SURPASS-2 (Frías et al., NEJM, 2021) is the trial every patient asks about. 1,879 adults with T2D on metformin were randomised to tirzepatide (5, 10, or 15 mg) or semaglutide 1 mg. At 40 weeks, tirzepatide 15 mg reduced HbA1c by 2.30 percentage points versus 1.86 for semaglutide; weight loss was 11.2 kg versus 5.7 kg. All three tirzepatide doses beat semaglutide on both measures.

STEP-2 — semaglutide for T2D + obesity together

STEP-2 (Davies et al., Lancet, 2021) tested semaglutide 2.4 mg specifically in patients with T2D and overweight or obesity. After 68 weeks, mean weight loss was 9.6% on semaglutide 2.4 mg versus 3.4% on placebo — meaningful, though notably less than the 14.9% achieved in non-diabetic patients in STEP-1. HbA1c dropped by about 1.6 percentage points.

SELECT — cardiovascular protection beyond diabetes

SELECT (Lincoff et al., NEJM, 2023) proved GLP-1 cardiovascular benefit extends beyond diabetes: in 17,604 patients with established cardiovascular disease and obesity but no diabetes, semaglutide 2.4 mg cut major adverse cardiovascular events by 20% (HR 0.80) over a mean follow-up of 39.8 months.

FLOW — the trial that changed kidney medicine

FLOW (Perkovic et al., NEJM, 2024) studied patients with T2D and chronic kidney disease. Semaglutide 1 mg reduced the composite of major kidney events, cardiovascular death, and all-cause mortality by 24%. The trial was stopped early for efficacy — the benefit was that clear.

Where GLP-1s fit alongside metformin, SGLT2 inhibitors, and insulin

Metformin remains foundational. It is cheap, well-tolerated, has decades of safety data, and modestly reduces cardiovascular risk. GLP-1s work alongside metformin, not instead of it.

For a typical Indian patient who is overweight, has visceral adiposity, and is not at target HbA1c on metformin, a GLP-1 (or tirzepatide) is now the preferred next step in most international guidelines — ahead of sulfonylureas and well ahead of starting insulin.

SGLT2 inhibitors (empagliflozin, dapagliflozin) are complementary, not competitive: they are particularly strong in heart failure and CKD and can be combined with GLP-1s. Insulin is still essential for patients with significant beta-cell failure, but a key benefit of getting on a GLP-1 early is delaying or avoiding insulin altogether.

Treating diabetes and obesity as one disease

For a patient with HbA1c 8.2 and BMI 32, treating "the diabetes" with sulfonylureas while the obesity goes unaddressed is incomplete medicine. Weight loss of 10–15% in someone with T2D reverses many of the metabolic abnormalities driving the disease; published series show meaningful T2D remission in a subset of patients who achieve this. GLP-1s and tirzepatide are the first medications to deliver this kind of weight loss without surgery.

Side effects and how they're managed

The most common side effects are gastrointestinal: nausea, mild diarrhoea or constipation, occasional vomiting, reflux. They cluster in the first few weeks after each dose increase and almost always settle. Eating smaller meals, avoiding very oily or spicy food during titration, and staying well hydrated (which matters more in the Indian summer) reduces them substantially.

Gallstones and pancreatitis are rare but real risks. Thyroid C-cell tumours have been seen in rodents but not convincingly in humans — the contraindication for personal or family history of medullary thyroid carcinoma remains precautionary. For details on thyroid considerations specifically, see our thyroid & weight guide.

Long-term outcomes

The 3-year follow-up of SURMOUNT-1 (NEJM, 2024) showed sustained weight loss and a markedly lower rate of progression from prediabetes to T2D with tirzepatide. SELECT and FLOW both showed accruing cardiovascular and renal benefit over years, not weeks. The honest caveat: when patients stop these medicines without continued lifestyle changes, weight tends to return. These are chronic-disease treatments, not cures.

What to expect when starting

You'll begin at a low dose (0.25 mg for semaglutide, 2.5 mg for tirzepatide) and increase every four weeks. The first month is mostly about tolerability. Most patients see initial weight changes by week 4–8, meaningful HbA1c improvement by week 12, and the bulk of benefit between months 4 and 12. Your Kaivo doctor — trained at AIIMS and at hospitals in the AIIMS network — will check your HbA1c, kidney function, and lipid panel before starting and at regular intervals. For the full baseline and monitoring panel — and why B12 monitoring matters if you're on metformin — see which blood tests you need before and during a GLP-1.

  1. Marso SP, Bain SC, Consoli A, et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). N Engl J Med. 2016;375(19):1834–1844.
  2. Frías JP, Davies MJ, Rosenstock J, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2). N Engl J Med. 2021;385(6):503–515.
  3. Davies M, Færch L, Jeppesen OK, et al. Semaglutide 2.4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP-2). Lancet. 2021;397(10278):971–984.
  4. Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT). N Engl J Med. 2023;389(24):2221–2232.
  5. Perkovic V, Tuttle KR, Rossing P, et al. Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes (FLOW). N Engl J Med. 2024;391(2):109–121.