The GLP-1 Starter Guide

Starting GLP-1

The biggest misconception is that these medications are fat burners. They are not. They primarily suppress appetite, help regulate blood sugar, and slow stomach emptying, making it easier to maintain a calorie deficit. The weight change comes from eating less; what you eat and how you train decides what you lose.

Step 1 — Eliminate food noise

Food noise is the constant urge to think about or eat food. When the medicine is working, that background noise should suppress. If it returns later, reassess intake, training and stress before asking about a dose increase.

Step 2 — Master nutrition

Track calories accurately every day. Know your maintenance calories and aim for roughly 500 below. Do not count exercise calories back into your intake — they are overestimated. Cardio is good for the heart, but conserve energy for lifting and walking. Aim to lose no more than about 2 lb per week to protect muscle.

Step 3 — Protect your muscle

Without resistance training, as much as 40% of weight lost can come from muscle. Lift at least 2–3 times per week covering the whole body. Eat protein close to your goal body weight in grams per day. Use a smart scale to track muscle and skeletal muscle percentage.

Step 4 — Progressive overload

Keep challenging your muscles. If you can do 10 bicep curls with 20 lb, either increase weight so you are near failure around 8 reps, or keep the weight and add reps. Track every session so progress is visible, not guessed.

Step 5 — Before increasing your dose

Ask: has food noise returned? Are you truly hungry, or just bored? Have you tracked calories honestly? Are you still in a deficit? Have you increased training or steps? Many stalls happen because your body now needs fewer calories — adjust the deficit or output before raising dosage.

Step 6 — Monitor your health

Get baseline blood work before starting and repeat at 6–12 weeks: A1c, fasting glucose/insulin, lipids, liver enzymes, creatinine, CBC, vitamin D, B12, electrolytes and thyroid. Discuss supplements such as omega-3, D3+K2, magnesium glycinate, creatine, psyllium, electrolytes and a multivitamin with your clinician.

When you hit a plateau

Plateaus are often adaptive thermogenesis: as body weight falls, resting metabolic rate slows and the body becomes more efficient. Two ways to fix it: lower calories, or increase output through more muscle, cardio or daily steps. Make one change, wait 3–4 weeks, and judge from the trend — not a single week. A short maintenance phase is a legitimate strategy, not a defeat.

Peptides explained for beginners

Peptides are short chains of amino acids that act as signalling molecules. Incretin-based therapies mimic hormones involved in appetite, blood-sugar regulation, digestion and energy balance. They can reduce appetite and cravings, increase fullness, slow gastric emptying and improve glucose regulation. They change the biological environment for weight management — they do not magically remove body fat.

Retatrutide — the triple-receptor approach

Retatrutide is an investigational once-weekly peptide from Eli Lilly. It is not FDA-approved and not available by prescription. It activates three receptors:

• GLP-1 — decreases hunger, increases fullness, slows digestion and improves glucose regulation.
• GIP — supports glucose-dependent insulin signalling.
• Glucagon — adds a pathway associated with energy expenditure.

This is why retatrutide is called a GIP/GLP-1/glucagon triple agonist. The term “GLP-3” is not scientifically accurate. In the published Phase 2 trial, 12 mg produced about -24.2% mean weight change at 48 weeks versus -2.1% with placebo, and the curve had not clearly plateaued. Phase 3 TRIUMPH-1 topline results reported in 2026 are company-reported and have not been peer reviewed.

Tirzepatide — the dual-receptor approach

Tirzepatide is an FDA-approved once-weekly medicine that activates GIP and GLP-1 receptors. It is sold as Zepbound for chronic weight management and as Mounjaro for type 2 diabetes; the products have different approved uses and require clinical supervision.

• GLP-1 — reduces appetite, increases fullness, slows gastric emptying and supports glucose-dependent insulin release.
• GIP — works alongside GLP-1 in glucose-dependent insulin signalling and may contribute to appetite and metabolic effects.

In the peer-reviewed SURMOUNT-1 trial, average weight change at 72 weeks was -15.0%, -19.5% and -20.9% in the 5 mg, 10 mg and 15 mg groups, versus -3.1% with placebo. In SURMOUNT-4, people switched to placebo regained substantial weight, while continued treatment maintained and extended weight loss. Common effects are gastrointestinal. Labelled warnings include thyroid C-cell tumours in rodents, pancreatitis, gallbladder disease, kidney injury from dehydration and hypoglycaemia when combined with insulin or sulfonylureas.

Semaglutide — the GLP-1 approach

Semaglutide is an FDA-approved once-weekly GLP-1 receptor agonist. It is sold as Wegovy for chronic weight management and as Ozempic for type 2 diabetes; the products have different approved uses and require clinical supervision. GLP-1 signalling reduces appetite and food intake, increases fullness, slows gastric emptying and supports glucose-dependent insulin release.

In the peer-reviewed STEP 1 trial, average weight change at 68 weeks was -14.9% with semaglutide 2.4 mg versus -2.4% with placebo. In the STEP 1 extension, participants regained roughly two-thirds of their prior weight loss during the year after treatment and lifestyle support stopped. Common effects are gastrointestinal. Labelled warnings include thyroid C-cell tumours in rodents, pancreatitis, gallbladder disease, kidney injury from dehydration and hypoglycaemia when combined with insulin or sulfonylureas.

What the research shows