GLP-1 Dose Conversion Chart for Semaglutide and Tirzepatide

There is no direct milligram-to-milligram conversion between GLP-1 drugs. They are different molecules with different potencies, different receptor targets, and different dose ranges. You can't simply swap 2.4 mg of semaglutide for 2.4 mg of tirzepatide. The numbers don't work that way.

What doctors use instead is clinical equivalence, matching approximate levels of appetite suppression, weight loss, and blood sugar control between drugs. A 2020 guidance paper in Clinical Diabetes by Almandoz and colleagues laid out rationale and practical approach for switching between GLP-1 receptor agonists. That paper, along with trial data from STEP, SURMOUNT, and SURPASS, forms basis for approximate conversion ranges used in clinical practice today.

Here is what those conversions look like and why they exist.

Why can't you convert GLP-1 doses by milligram?

Semaglutide and tirzepatide don't even target same receptors. Semaglutide activates only GLP-1 receptors. Tirzepatide activates both GLP-1 and GIP receptors. That dual mechanism is why tirzepatide produces more weight loss at doses that look numerically higher but are not "stronger per milligram."

The molecular weights are also different. Semaglutide has a molecular weight of about 4,114 daltons. Tirzepatide is about 4,813 daltons. Even within same receptor class, drugs like semaglutide and liraglutide have different binding affinities and different half-lives, which means same milligram number produces different clinical effects.

This is why every conversion chart comes with a disclaimer: these are approximations based on clinical outcomes, not pharmacological equivalents.

What are approximate dose equivalences?

Based on weight loss trial data and clinical practice patterns, here are approximate clinical equivalence ranges between most commonly used GLP-1 drugs.

Semaglutide 0.25 mg to 0.5 mg (Ozempic starter range) is roughly equivalent to tirzepatide 2.5 mg in terms of introductory level of GLP-1 activity. Both are starter doses designed for titration, not for maintenance.

Semaglutide 1.0 mg (standard Ozempic maintenance) maps approximately to tirzepatide 5 mg. At this level, both drugs produce meaningful appetite suppression and moderate weight loss.

Semaglutide 1.7 mg to 2.4 mg (Wegovy mid to full dose) maps to tirzepatide 10 mg to 15 mg. The range widens here because tirzepatide's GIP receptor activity adds weight loss effects that semaglutide doesn't have at any dose. Most clinicians consider semaglutide 2.4 mg roughly equivalent to tirzepatide 10 mg for clinical effect, with tirzepatide 15 mg exceeding anything semaglutide can do.

Liraglutide 1.8 mg (Victoza, diabetes dose) is roughly equivalent to semaglutide 0.5 mg to 1.0 mg in terms of GLP-1 activity. Liraglutide 3.0 mg (Saxenda, weight loss dose) maps to approximately semaglutide 1.0 mg to 1.7 mg. Liraglutide is less potent per milligram than semaglutide because it has a shorter half life (13 hours vs 7 days) and lower receptor binding affinity.

Dulaglutide 1.5 mg (standard Trulicity dose) is roughly equivalent to semaglutide 0.5 mg. Dulaglutide 4.5 mg (maximum Trulicity dose) maps to approximately semaglutide 1.0 mg.

These ranges come from comparing trial outcomes across STEP, SURMOUNT, SURPASS, SUSTAIN, SCALE, and AWARD programs. They're not exact, and individual responses vary.

How do doctors actually handle switching between drugs?

The official FDA prescribing information for tirzepatide says to start at 2.5 mg regardless of what GLP-1 drug you were on before. That's conservative approach, and it's what most insurance based prescriptions follow.

In practice, many obesity medicine specialists take a more nuanced approach. If a patient has been on semaglutide 2.4 mg for months and switches to tirzepatide, starting at 2.5 mg would be a massive step down in GLP-1 activity. The patient's appetite returns, they may regain weight during weeks it takes to titrate back up, and they go through side effects they already pushed through once.

So some doctors start new drug at a mid range dose that matches approximate equivalence of previous drug. For someone on semaglutide 2.4 mg, that might mean starting tirzepatide at 5 mg or even 10 mg, depending on how well they tolerated semaglutide. A 2025 study published in Endocrine Practice confirmed that patients switching from GLP-1 drugs directly to tirzepatide 5 mg showed improvements in blood sugar control within 12 weeks without unusual safety concerns.

If you're thinking about switching from Wegovy to Zepbound, that article walks through practical steps for most common switch scenario.

The timing of switch matters too. If you're on a weekly drug and switching to another weekly drug, wait at least seven days after your last dose of old drug before taking first dose of new one. This avoids stacking two GLP-1 drugs in same week, which would increase risk of severe nausea and vomiting.

What about converting between injectable and oral semaglutide?

Injectable semaglutide (Ozempic, Wegovy) and oral semaglutide (Rybelsus, oral Wegovy) contain same molecule, but oral bioavailability is very low. Only about 1% of oral dose actually gets absorbed. That's why oral doses are so much higher by number.

Oral semaglutide 14 mg daily produces roughly similar clinical effects to injectable semaglutide 1.0 mg weekly. Oral semaglutide 25 mg daily (new oral Wegovy dose) is approximately equivalent to injectable semaglutide 2.4 mg weekly.

If you're switching from oral to injectable or other way around, your doctor will match based on these clinical equivalence ranges and may adjust based on how you're responding.

What dose should you aim for on a new drug?

That depends on your goals. If you're switching because current drug stopped working or isn't producing enough weight loss, you'll likely want to land at a dose on new drug that matches or exceeds what you were on.

If you're switching because of side effects or cost, you might be fine at a lower equivalent dose on new drug. Some people tolerate one drug better than another even at similar potency levels.

What dose of Zepbound is most effective? In SURMOUNT trials, there's a clear dose-response relationship. More weight loss at 10 mg than 5 mg, and more at 15 mg than 10 mg. But jump from 10 mg to 15 mg adds about 3 percentage points of body weight loss while also increasing side effects. For many patients, 10 mg is sweet spot where results are strong and side effects are manageable.

What should you remember about these charts?

Three things. First, these are approximations. Your body may respond differently than trial average. A dose that seems equivalent on paper might feel stronger or weaker to you in practice.

Second, your doctor should guide switch. Conversion charts are a starting point for conversation, not a prescription. Your medical history, your current side effects, your weight trajectory, and your insurance coverage all factor into decision.

Third, every switch involves a transition period. Even when doses are matched well, your body needs one to two weeks to adjust to new molecule. Mild nausea or GI changes during this window are normal and usually resolve.