Comparison

zZz vs Marrow

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

zZz

Easily log your sleep with a single tap using home or lock screen widgets. Track time in bed, awake time, and actual sleep duration, syncing data with Apple Health for insightful analysis.

Highlights
  • One-tap sleep logging
  • Home and lock screen widgets
  • Tracks time in bed, awake, and sleep
  • Syncs with Apple Health
  • Siri and Shortcuts integration
Read full description

One Tap and your sleep schedule is tracked. Add a small widget to your home or lock screen, tap it before going to bed and after waking up and your sleep is tracked. It doesn't get any easier than this. Widgets: • Go to bed • I just woke up • Used to track your sleep as easy as possible Shortcuts & Siri: • Go to bed • I just woke up • Used to track your sleep as easy as possible via Siri, Shortcuts or Automations • Activate in the zZz settings Your time in bed, time awake (the duration before you fall asleep) and your actual sleeping time is saved to Apple Health. The same data is also read from Apple Health to give you great insights into your sleeping schedules.

About

Marrow

Features
Read full description

Most people fall short of the 1,000 mg daily calcium goal without realizing it. Marrow makes it effortless to close that gap — log what you eat, track sun exposure for vitamin D, and see your progress at a glance. — KEY FEATURES — • Daily calcium progress bar — live mg counter tracks your intake toward the 1,000 mg goal, turning green the moment you hit it • Sun exposure log — tap +/- to record minutes of sun each day to support natural vitamin D synthesis • 30 curated calcium-rich foods — dairy, leafy greens, fish, nuts, seeds, and plant-based options, each with exact mg per serving • Category filters and search — quickly find any food by category (Dairy, Leafy Greens, Fish, Nuts, Plant-Based) or by name • Foods sorted by calcium content — highest-impact choices always surface first • Log and remove meals — add a food in two taps; remove it just as easily if you log by mistake • 14-day history chart — color-coded bar chart shows daily totals at a glance, with a goal reference line • Summary stats — see your average daily calcium and how many of the last 14 days you hit the goal • Per-day breakdown — tap into any past day to see every food logged and sun minutes recorded • Fully offline and private — no account, no data leaves your device Whether you are preventing osteoporosis, recovering bone density, or simply building better eating habits, Marrow gives you an accurate, distraction-free way to take control of your bone health. This app is for informational and tracking purposes only and is not a substitute for medical advice. Consult a qualified healthcare professional before changing your diet or health plan. — Marrow Bone Health PREMIUM — Premium unlocks unlimited food and sun logging, the full 14-day history chart with goal trends, a personalized daily calcium target, and an ad-free experience — everything stored 100% offline on your device. Subscription options: • Weekly — $9.99 / week • Yearly — $49.99 / year (includes a 3-day free trial) Payment is charged to your Apple Account at confirmation of purchase. Subscriptions renew automatically unless turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the period. Manage or cancel anytime in your Apple Account settings. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://pnkl26.web.app/privacy-policy

Screenshots

zZz4 screens
Marrow3 screens

Verdict

The call

The clearest difference is update cadence: zZz at every 4 days against Marrow's every 8 days. On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. zZz sells 1 one-off in-app purchase and Marrow sells 2 in-app purchases, starting at $9.99 per 7 days. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

zZz ships an update every 4 days, Marrow every 8 days. The most recent releases landed on October 24, 2026 and October 13, 2026 respectively.

Scorecard1 real difference · 9 level
zZz versus Marrow: the parameters behind the verdict, then further details
ParameterzZzMarrow
PriceFreeFree
Rating2.9 (11 ratings) — better—
Positive reviews0.0% of reviews—
Number of ratings11 — better—
Update frequencyEvery 4 days — betterEvery 8 days
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad — betteriPhone
Requires iOS16.0 — better17.0
Further details — not scored
Size6 MB1 MB
Age rating4+4+
DeveloperFlorian SchweizerLinh Phan Nhat Khanh

In-app purchases

1 purchases

zZz

One-time1
  • Pro Tier$0.99
2 purchases

Marrow

Subscriptions2
  • Marrow Bone Health Weekly$9.997 Days
  • Marrow Bone Health Yearly3 Days trial$49.991 Year

Questions

Is zZz free?
zZz is free to download, with in-app purchases available.
Is Marrow free?
Marrow is free to download, with in-app purchases available.
Do zZz or Marrow have ads?
Neither zZz nor Marrow shows ads.
Which is updated more often, zZz or Marrow?
zZz ships an update every 4 days, and Marrow every 8 days. Most recently, zZz was updated on October 24, 2026 and Marrow on October 13, 2026.

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