€2.99/mo
Welcome to Peakly. I built it to help me see what my GLP-1 is doing in my body.
Hi, I'm Ylfa. I'm a pharmacist, and I use a GLP-1 too. I wanted to know how much medicine was still active in my body between doses, not just how much I took that week. Peakly reads the doses I log, estimates my current level, and shows how that level changes over time. I built it with Freek so I could use it myself.
Founding offer: 60-day free trial for the first 100 to start tracking, then €2.99/mo · no card required
Ylfa — Why I built Peakly
As a pharmacist, I read up on how these medicines are dosed before I started my own. I wanted to raise my dose slowly, in small steps, and settle at the dose that suited me. To choose a dose with any confidence, I needed to follow my own level from week to week, and Peakly turns my dose history into a current level and a projection I can bring to my prescriber.
Pharmacist and GLP-1 userWhat I built
Here is Peakly on sample data.
Tap a number to see what each part shows.
01The level chart
The line estimates the active amount of your GLP-1 day by day. It rises after each dose and eases off as your body clears it before the next one.
02Your level right now
The number under the chart estimates how much of your GLP-1 is active in your body today, based on the doses you've logged.
03Your target level
Set the level you want to explore. The stepper moves in fifty small steps, and Peakly shows the dose that reaches it. You and your prescriber decide.
04Days between doses
Set the number of days between doses. The chart and the dose update to match, so you can see what a wider or tighter gap does to your level.
Noor — I want to know if a smaller dose is enough
I have been steady for months and I feel fine. I keep wondering whether a smaller dose would hold me where I am, and I want more than a guess before I bring it up. Peakly shows me the level each smaller dose would hold, including the steps between the standard doses, so I can take a concrete picture to my prescriber.
Composite example, not a real person
Marcus — I want a messy month to still make sense
Between shifts and family, my routine is uneven. I take some doses a day or two late, and I sometimes catch up on my logging days after the fact. Peakly works my level out from the dates I actually logged, so late doses and late logging still add up to a picture I can read.
Composite example, not a real person
Dev — I want to read the scale next to my level
The scale gives me one number, and that number moves around for reasons besides the medicine. I want to see my weight next to my level, so a good or bad week makes sense in context. Peakly keeps my weight trend and my level history on one screen, and I read the scale alongside the dose.
Composite example, not a real person
Pricing
I keep the plan simple.
billed monthlyTry Peakly freeFounding offer: 60-day free trial for the first 100 to start tracking · no card required
€19.99/year
≈ €1.67/moQuestions I get about Peakly
Which GLP-1 medicines does Peakly track?
- Mounjaro and Zepbound (tirzepatide)
- Ozempic and Wegovy (semaglutide)
- Retatrutide (experimental)
Each one absorbs and clears differently; the projection uses the right curve for your GLP-1 medication.
What makes Peakly different?
Most GLP-1 plans move in a handful of fixed doses, with a big jump between each step. Peakly works in 50 target levels instead — pick the level you want, and Peakly shows the dose that lands on it.
That means you can start low, move up one step at a time, and adjust as your body changes.
What does "current level" actually mean?
Get to know your level: the active amount of medication in your body, tracked day by day, the way a glucose app tracks glucose.
Each shot takes time to absorb, then clears slowly (half-life ~5–7 days), so your active level rises after a dose, peaks, then declines until your next one. Doses from weeks ago are still contributing today.
The number you see is the model's estimate of what's active right now, based on every dose you've logged plus published data on how your medication is absorbed and clears. It's not a blood test reading — it's a way to see a level that's normally invisible.
Why did the same dose feel different from week to week?
Because a GLP-1 builds up. It has a long half-life, so when you take your next shot the last one hasn't cleared. The amount active in your body climbs over the first several weeks, even though the number on the pen never changes.
Peakly tracks that level from the shots you log, so the change stops being invisible. You can see where you are, and the dose that reaches it.
What's the science behind this?
Peakly's approach is built on the MyLevel frameworkby Ian J. Ellis, MD — a clinical methodology arguing that day-to-day GLP-1 experience depends primarily on cumulative active level (not the milligrams in this week's shot), and that dosing should be guided by a target level rather than a fixed escalation ladder.
Peakly adapts that idea into a self-tracking app, with implementation differences. Peakly is not affiliated with MyLevel Inc. and the MyLevel name and methodology remain the property of their owners.
What pharmacology is the projection built on?
Every GLP-1 medication follows the same arc: after a shot it's absorbed into your body, rises to a peak, then clears slowly over days. A few standard pharmacokinetic values describe that arc, and Peakly uses them to model your level:
- Half-life:how long the amount in your body takes to fall by half. Semaglutide and tirzepatide sit around 5–7 days, which is why one weekly shot can hold a fairly steady level.
- Bioavailability: how much of each dose actually reaches your bloodstream, rather than being lost on the way.
- Tmax: how long after a shot the level reaches its peak.
- Medication-specific curves: each GLP-1 medication absorbs and clears at its own rate, so Peakly uses the curve that fits yours: tirzepatide, semaglutide, or retatrutide.
Feed in the doses you've logged plus published absorption and clearance rates, and the model estimates what's active in your body right now and where it's heading.
Is this medical advice?
No. Peakly is information — it shows the projection of your GLP-1 level based on doses you've logged. You decide what to do with that information. Always consult your prescriber.
Does the projection match my body exactly?
Peakly's projection uses published averages, and your body's response varies (composition, metabolism, GI absorption). It gives you a starting projection; over time you'll see how your own experience lines up with it — that's the point of tracking.
Do I need a prescription to use Peakly?
No. Peakly is information about doses you already take. It doesn't prescribe or sell medication; it works with whatever your prescriber has put you on.
What devices and platforms work?
Any modern browser — phone, tablet, or laptop. You can install Peakly to your home screen on iOS or Android. There's no separate app-store version, and there's no plan for one.
Can I import dose history from another app?
Not from another tracker automatically — no other GLP-1 app exposes its data in a way that's safe to import. For your own records, Peakly has a bulk-entry screen and a CSV import for past doses, so a few months of weekly shots takes a couple of minutes to back-fill.
What if my GLP-1 isn't listed?
Today Peakly models tirzepatide, semaglutide, and retatrutide. If a new GLP-1 medication gets approved and there's real demand, it'll get added — see the contact link in the footer.
What happens after the 30-day trial?
Subscribe to keep the interpretation — current level, projection, the dose for your target level, and logging for Food noise and Side effects. If you don't subscribe, the interpretation locks but your logged data stays yours (dose log, weight chart, history, export).
What if I stop subscribing later?
Your data stays yours — every dose, every weight, every event, the full history, the export. Forever. Only the interpretation stops. Pick the subscription back up anytime and the projection is right where you left it.
Can I cancel anytime?
Yes. Cancel from settings; your subscription runs through the period you've paid for.
Is my data safe?
Yes — your data is yours, stored in an EU-region database, never sold or shared. See the Privacy page for the full details.
About us
Freek and I live in Leusden, a small town in the Netherlands, where we're raising our two toddlers. We both use a GLP-1, and Peakly is the tool we wanted for ourselves: I work out the pharmacokinetic math, Freek builds the app. Tell us what you think, or what you'd like to see next.
— Ylfa & Freek