Pen Pal
How it works
1
Tap the lid
Take the lid off your case and tap your phone to the inside of it. No app to dig for, no form to fill out, no remembering to write it down.
2
It fills in the rest
Date, medication, dose, and injection spot are logged in a second, and Pen Pal shows you where the next one goes.
3
It reminds you
A nudge on shot day, so "was that Tuesday or Wednesday?" stops being a question you have to answer.
What you get
Never guess which side was last
A body map tracks every injection spot and shows you where to go next, so rotating stops being a memory test.
Your whole history in one place
Every shot, every dose change, every week, laid out in a timeline you can scroll back through or show your prescriber.
Your titration plan, mapped out
Enter the schedule your prescriber gave you, and Pen Pal shows what's coming and when.
Track what you want. Skip what you don't.
Weight, measurements, and side effects are there if you want them and gone if you don't. Nothing is required, and nothing nags.
Private by design
Your log is never sold, never used for ads, and never shared unless you choose to share it. It's encrypted, stored in the US, and yours to export or delete anytime.
Pen Pals Coming this winter
Share small wins with a few friends: "hit my protein today," "made it to the gym." They never see your weight, and there's never a leaderboard.
Take it with you
Phone, tablet, or laptop, it's the same log, always up to date.
Free, or a little more
Pen Pal
Free with every case
Everything above, for as long as you have the app.
MC Membership
$39 a year, or $4.99 a month
- Everything in Pen Pal
- 15% off every Massive Customs order, for as long as you're a member
- A 15% code every month for a friend, and a free month for you when they use it
- A heads-up before you run low, so the next box shows up before the last pen does
- Early access to limited-release colors and new designs
Coming this winter
- A printable report for your prescriber, so appointments go faster
- Protein, food, movement, labs, and a journal, all in one place
- Every account comes with two signups. We don't punish your household for sharing.
Every new case comes with a free trial of MC Membership: one month with a 4-shot case, three months with a 12-shot case.
No case? You can still use Pen Pal for $6.99 a month, which includes everything in MC Membership. With a case, Pen Pal is free and Membership is $4.99.
Get in early
Your rent went up. Your groceries went up. Your Pen Pal price never will.
Patron: $1,000 Opening soon
10 spots
Lifetime MC Membership. A free custom case every year. Your name in the app's credits. A direct line to me and a vote on what gets built next. A numbered Patron badge. Beta access in November.
Backer: $500 Opening soon
25 spots
Lifetime MC Membership. A free custom case at launch. Your name in the credits. A numbered Backer badge. Beta access in November.
Founder: $29 a year
100 spots. Opens to the waitlist January 1.
MC Membership locked at $29 a year (normally $39) for as long as you stay. A Founder badge. New colors, designs, and features two weeks before anyone else.
Patron and Backer open soon, and the waitlist hears first. Both are fully refundable if Pen Pal doesn't launch.
What's happening when
25 people from the waitlist get Pen Pal early and try to break it.
Pen Pal launches, and Founder spots open to the waitlist first.
Questions
Does my case have the tag?
Cases shipped from December on have it built into the lid. Smart lids are available as an upgrade for your existing case. If you bought a case from October 1 on, we'll gladly mail you a tag to retrofit it, free of charge.
Does it tell me what dose to take?
No. Pen Pal is a logbook. It records what you enter and never suggests or changes a dose. That's your prescriber's job.
What if I don't have a case yet?
You can still use Pen Pal for $6.99 a month, which includes everything in MC Membership. With a case, Pen Pal is free, and Membership is $4.99 a month after your free trial. Shop cases
What happens after I join the waitlist?
A handful of short emails: a chance to join the beta in November, a heads-up before launch, and one on January 1 when Founder spots open. Unsubscribe anytime.
Which phones does it work on?
iPhone and Android, plus a web version for your laptop. Tapping the lid needs a phone with NFC, which almost every recent phone has. The QR code on the tag works with any phone camera.
Pen Pal is a logbook and doesn't give medical advice. Massive Customs isn't affiliated with any medication maker.
Patron and Backer purchases are fully refundable if Pen Pal does not launch. "Launch" means Pen Pal is available to download on the App Store and Google Play. The dates on this page are targets, not guarantees. A later launch is not grounds for a refund, as long as Pen Pal launches by June 30, 2027. If it hasn't launched by then, you can request a full refund at any time.