If you're staring at your vial and your prescription wondering "how many units do I actually draw?". Take a breath. You're asking the right question, and the math is simpler than it looks.

We built a tool that does the calculation for you. It works whether you're brand new, switching vials, stepping up your dose, or just want to double-check before you inject.

→ Open the Dosage Calculator

Use it any time you want a confident answer in under 60 seconds. It's especially helpful if:

There's no wrong reason to use it. The calculator is private, free, and saves nothing about you.

Before you open the calculator, have these three things in front of you:

That's it. About 60 seconds of your time and you'll have a clear answer.

The calculator asks one question per screen, so it never feels overwhelming. Here's the flow:

The first question is "Have you been on this medication before, with a different vial or provider?"

You'll see a grid of every product we offer. Tap the one that matches your prescription.

Look at your vial label. Enter the total mg and the total mL. The calculator will show you the concentration automatically.

→ Quick tip: Most labels look like "5mg/2mL" or "Total: 10mg in 2mL." Both numbers are right there.

You'll choose one of three options:

Tap whichever applies. If you're titrating, you'll see your product's standard ladder. Just tap your current step.

The final screen shows:

You can screenshot it, save it, or come back any time.

If you've ever felt like the math on your prescription is in another language, this section is for you.

Your vial label tells you two things:

So 5mg/2mL means there are 5 milligrams of medication mixed into 2 milliliters of liquid.

Concentration tells you how much medication is in each milliliter. You get it by dividing:

5 mg ÷ 2 mL = 2.5 mg per mL

That's why two vials of the same medication can look completely different. A 5mg/2mL vial and a 10mg/2mL vial are both Semaglutide. But the second one is twice as concentrated. Same medication, different math.

This is the part that confuses almost everyone, and it's worth understanding.

The dose is how much medication you're taking (measured in mg). That's set by your provider and doesn't change just because you got a new vial.

The units are just where the line is on your syringe. That changes based on the vial's concentration, because a stronger vial means you need less liquid to get the same dose.

Same dose. Different vial. Different line on the syringe. That's normal.

Let's walk through the most common scenario.

Your dose didn't change at all (still 0.625 mg). But because your new vial is twice as concentrated, you only need half as many units to get the same medication. Draw to the 12.5 unit line instead of 25.

The calculator does all of this automatically. You just enter the numbers.

Compounded GLP-1s and peptides are extremely concentrated medications. A typical Semaglutide dose is between 5 and 100 units on an insulin syringe. Which looks like a tiny amount of liquid. That's normal and intended.

If the calculator tells you to draw more than a full syringe, that means your dose has to be split into two injections. Your provider will tell you how to split it. Message them through your Patient Portal if you're not sure.

Always follow your prescription label. The calculator is here to help you understand the math. Not to override your provider's instructions. If something doesn't match, message your provider through your Patient Portal at my.goodguyrx.com before injecting.

Yes. The math is the same regardless of who prescribed your medication. As long as you know the total mg, total mL, and your prescribed dose, the calculator works.

Titration is the process of slowly increasing your dose over time so your body has a chance to adjust comfortably. Most providers titrate GLP-1 doses over 12 to 16 weeks. There's no rush. Going slowly is the goal.

No. The calculator runs entirely in your browser. Nothing about your dose, vial, or prescription is stored or sent anywhere.

The calculator does the arithmetic. Your provider sets your dose.

If anything looks off. The number seems too high, too low, or doesn't match what you remember. Pause, message your provider, and don't inject until you're confident.

→ Message your provider in your Patient Portal

Compounded medications are prepared by independent, state-licensed pharmacies and are not FDA-approved.

→ Open the Dosage Calculator

Stay with the protocol.

— The Good Guy Rx Team