GLP-1 guides for people actually on treatment.
Half-lives, dose ladders, pen click charts, injection sites, side-effect timing and food noise. Everything we had to work out to build Penwise, written down plainly, with the numbers shown rather than asserted.
By medication
What tracking looks like on each product, including the pen, the dose ladder and the things that catch people out.
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The Mounjaro tracker app that keeps your log on your phone
How to track Mounjaro (tirzepatide) properly: doses, the KwikPen, injection sites, side effects and where you actually are between shots.
Read the guide -
The Ozempic tracker that knows which pen you are holding
Tracking Ozempic (semaglutide) properly: four different pens, why the same dose is a different number of clicks on each, and where you are between shots.
Read the guide -
A Wegovy tracker built around the sixteen-week climb
Tracking Wegovy (semaglutide) for weight management: the five-step titration, both pen designs, and reading the weight trend against the dose you were actually on.
Read the guide -
A Zepbound tracker for the whole tirzepatide ladder
Tracking Zepbound (tirzepatide) for weight management: six strengths, two pen designs, the thirty-day clock, and reading weight against the dose you were on.
Read the guide -
A Saxenda and Victoza tracker built for a daily injection
Liraglutide is daily, not weekly, and a thirteen-hour half-life changes everything about reminders, site rotation and what a missed dose means.
Read the guide -
Tracking Rybelsus and the other oral semaglutide tablets
Oral semaglutide has no site, no pain and no clicks – but a strict fasting window, a daily cadence and three different dose ladders that are not interchangeable.
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Understanding your treatment
How long the medication lasts, how the two main drugs differ, when side effects tend to land, and what food noise really is.
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Mounjaro vs Ozempic: what actually differs
Two receptors versus one, five days of half-life versus seven, six fixed strengths versus a dial. A comparison of the things that change your week.
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Mounjaro vs Wegovy: two weekly injections, two different drugs
Both are weekly, both are for weight, and they are not the same molecule. The head-to-head trial, the dose ladders, the pens and what actually changes for you week to week.
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Zepbound vs Mounjaro: the same drug with two labels
Identical molecule, identical device, identical ladder. What actually differs is the licence on the box, and that turns out to matter for cost, supply and paperwork.
Read the guide -
How long does Mounjaro stay in your system?
Tirzepatide has a five-day half-life. Here is what that means week by week, why it takes a month to reach steady state, and where the trough you can feel comes from.
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How long does Ozempic stay in your system?
Semaglutide has a seven-day half-life, so it clears over about five weeks and doubles on itself before it settles. What that means week by week.
Read the guide -
The GLP-1 side effect timeline: what lands when
Nausea, fatigue, constipation and reflux do not arrive at random. Here is where they usually sit in the week, in the ladder and in the treatment.
Read the guide -
What food noise is, and why GLP-1 medication turns it down
The constant background chatter about food that most people never had a word for – what it is, why it goes quiet on a GLP-1, and why it comes back late in the week.
Read the guide -
The GLP-1 weight loss plateau: what it is and what it is not
Most reported plateaus are two weeks of noise on a trend that has not changed. Here is how to tell a real one from a scale reading, and what the log should show.
Read the guide -
What happens when you stop a GLP-1 medication
The drug leaves over weeks, not days, and appetite returns as the level falls. What the withdrawal trials actually found, and what to have written down before you stop.
Read the guide -
GLP-1 weight loss timeline: what happens month by month
Month one is titration, not results. What the trials actually recorded at each stage, why the first six weeks mislead everybody, and how to read your own curve.
Read the guide -
Muscle loss on a GLP-1, and what to do about it
Every kilogram lost contains some lean mass. What proportion, why it matters more in year two than year one, and the two things that change the ratio.
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Hair loss on a GLP-1: why it happens and when it stops
It is almost always telogen effluvium from rapid weight loss rather than a direct drug effect. Why it starts months after the trigger, how long it runs, and what actually influences it.
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Retatrutide: the triple agonist, and where it actually stands
Three receptors instead of two, the phase 2 numbers that got everyone talking, and the important part: it is investigational and not approved anywhere.
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Ozempic face: what it is and what actually causes it
Not a drug effect on the face. Fat loss reaches the face like everywhere else, and it shows more there because of how facial fat is built.
Read the guide -
GLP-1 medications and mood: what the reviews found
Regulators reviewed the suicidality signal and did not find a causal link. What that does and does not settle, and the mood changes people genuinely report.
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Day to day
Clicks, sites, discard windows, missed doses and titration. The mechanical detail that decides whether a week goes smoothly.
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GLP-1 medications and contraception: the interaction people miss
Tirzepatide carries a specific label warning about the pill that semaglutide does not. When it applies, how long for, and what to do about it.
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GLP-1 medications before surgery, endoscopy and anaesthesia
A stomach that empties slowly is a real anaesthetic problem. Why holding doses is now standard guidance, how far ahead, and why nobody should stop on their own.
Read the guide -
The GLP-1 pen click chart, and why one number never fits two pens
What a click is actually worth on every Ozempic, Mounjaro, Wegovy, Saxenda and Victoza pen, and the one rule that makes all of it make sense.
Read the guide -
How long does a GLP-1 pen last once you start it?
Every pen has two clocks: the doses left in it and the days it may still be used. The chart, and what happens when the second one wins.
Read the guide -
GLP-1 injection sites, and rotation that actually rotates
Abdomen, thigh or upper arm, and the question nobody can answer from memory: which one hurts least for you, and where did the last four shots go.
Read the guide -
Missed a GLP-1 dose? What it actually costs you
A day late on semaglutide is nothing. A day late on liraglutide is a real gap. Why the same question has a different answer for every product.
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GLP-1 dose schedules: every ladder, and why the steps are four weeks
The titration ladder for every GLP-1 product side by side, and the pharmacology that decides how long each step has to last.
Read the guide -
Storing a GLP-1 pen, and travelling with one
Fridge, room temperature, hand luggage and heat. The rules that hold for every pen, the ones that vary by product, and what to do when a pen has been somewhere it should not have been.
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Choosing your injection day, and changing it safely
Which day you inject changes which days your side effects land on. The 72-hour rule for moving it, and why the day before your next shot is the one that feels different.
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Nausea, constipation and sulphur burps: managing the gut effects
Why these drugs upset the gut, what actually helps for each effect, the symptoms that mean call someone today, and when it is a dose question rather than a coping question.
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Alcohol on a GLP-1: what changes and why
A lot of people find they simply want to drink less. Why that happens, what a slowed stomach does to how alcohol hits, and the situations that need real caution.
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Choosing a tracker
An honest look at the apps in this category, what they cost, and what happens to your medication history inside them.
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A Shotsy alternative, and how to bring your history with you
What Penwise does that Shotsy does not, what it costs instead, and the two-tap import that brings your shots, weights and side effects across.
Read the guide -
How to choose a GLP-1 tracker app
Twelve questions worth asking before you put a year of medication history into an app, and what the honest answers look like.
Read the guide -
Why a GLP-1 tracker should not have a server
Your medication history is one of the most sensitive records you will ever create. Here is what a cloud tracker actually holds, and what an on-device one cannot.
Read the guide
Occasional updates, nothing else.
New features, what we are working on, and the odd thing we learn about GLP-1 tracking. A few times a year at most.
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