Mary R.
Great for double check or find your dosing
Great for double check or find your dosing
Response from Fat ScientistMar 15, 2026
Thanks Mary! Glad Fat Scientist has been a useful double-check for you.

Fat Scientist is a free online resource built for people using GLP-1 medications like tirzepatide (Mounjaro, Zepbound) and semaglutide (Ozempic, Wegovy). We specialize in tools and educational content for users of compounded versions of these medications, which come in multi-dose vials and require precise dosage calculations. Our suite of calculators helps users convert prescribed milligram doses into exact syringe units based on their specific vial concentration, calculate split doses for improved tolerability, estimate medication costs, and plan their treatment timelines. Every calculator is free, requires no account, and works on any device. We built Fat Scientist because compounded GLP-1 medications present a unique challenge. Unlike brand-name auto-injectors with pre-measured doses, compounded vials require users to do math that directly impacts their safety. A wrong calculation means injecting too much or too little medication. We believe nobody should have to guess when it comes to their health, and the tools to get it right should be accessible to everyone. Beyond calculators, Fat Scientist provides guides on topics like reading vial labels, understanding concentration values, proper injection technique, and navigating the differences between brand-name and compounded medications. Our FAQ library addresses the most common questions we see in GLP-1 communities, written in plain language without medical jargon. Fat Scientist is operated by Productist LLC. We are not a pharmacy, we do not sell medications, and we are not a substitute for medical advice. Our mission is purely informational — giving GLP-1 users the tools and knowledge to use their medications safely and confidently. We are funded by voluntary donations from our users, not advertising or affiliate deals, so our recommendations are never influenced by commercial interests. Whether you are just starting your GLP-1 journey or adjusting an existing regimen, Fat Scientist is here to help you get the nu
Fat Scientist (fatscientist.com) has 129 customer reviews on Five Star Index, with an average rating of 5.0 out of 5.
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Mary R.
Great for double check or find your dosing
Response from Fat ScientistMar 15, 2026
Thanks Mary! Glad Fat Scientist has been a useful double-check for you.
SS
I’m in maintenance now but still use fat scientist website to double check my dose every week! Wonderful site. Love the split dose calculator as well.
Response from Fat ScientistMar 15, 2026
Congrats on maintenance! So glad Fat Scientist is still a useful part of your weekly check-in, and that the split dose calculator has come in handy too.
Laura H.
This is such a helpful website to verify dosage, especially when changing vials with a different concentration or increasing dose on the same vial. I have also used it when changing my shot day with the split dose calculator to keep the weekly level similar.
Response from Fat ScientistMar 15, 2026
Thanks Laura! Those are two of the trickier scenarios to navigate — concentration changes and mid-week shot day adjustments — so really glad the calculators have been able to help with both!
Candice
This calculator is FANTASTIC. Super user friendly.
Response from Fat ScientistMar 15, 2026
Thanks Candice! We aim for clarity, simplicity, accuracy, and ease-of-use. So glad to be of help!
Sheri B.
Extremely helpful tool with accurate dosing calculations. Highly recommend!
Response from Fat ScientistMar 15, 2026
Thank you, Sheri!
Fritter A.
Fat Scientist is an absolutely must to safely calculate your Glp dose! And as a beginner, there are many helpful guides to get you started on your weight loss journey.
Response from Fat ScientistMar 15, 2026
Thanks Fritter! Very glad to hear that the guides and educational material were useful to you.
Tori
I love having this tool to have confidence in how many units to use based on the concentration of the vial and what my dose is!
Response from Fat ScientistMar 15, 2026
Thank you Tori, so glad Fat Scientist has been a help to you!
Stanley P.
Great product
Response from Fat ScientistMar 15, 2026
Thanks Stanley!