# Undercurrent: Symptom Log — Food, Headache & Pattern Diary

> Food, Headache & Pattern Diary (iPhone/iPad app by Lloyd Rowat.)

- Source: https://appshunter.io/ios/app/undercurrent-symptom-log/id6759209174 (this page in markdown: same URL + `.md`)
- Developer: [Lloyd Rowat](https://appshunter.io/developer/1166734628)
- Category: Health & Fitness, Medical
- Price: Free with in-app purchases
- Age rating: 12+
- Requires: iOS 16.4 · 73 MB
- Languages: American English
- Released: 2026-04-06
- Data updated: 2026-10-24

## What is Undercurrent?

You know something is off, but what?

Headaches that seem random. Energy that crashes for no reason. You suspect a pattern, but every time the doctor asks "have you noticed any patterns?" you draw a blank.

Undercurrent is a private symptom log and food diary for the small things, and the patterns hiding inside them. Use it as a headache log, a food symptom diary, or a flare journal for a chronic illness.

LOG IN FOUR TAPS OR FEWER
Symptoms, food, medications, activities, and observations. Quick chips for what you log most. Voice if you'd rather. Or just tell the on-device AI assistant in plain language: "headache after lunch" and it handles the rest.

WHAT WE'VE NOTICED
Once you've logged enough events, the Insights page surfaces co-occurrences in your own data, phrased in soft language. None of it claims to cause anything. You decide if it's signal or noise.
• Pre-window pattern: what tends to show up in the hours before symptoms
• Time-of-day cluster: when symptoms tend to gather
• Day-of-week peak: which days run hottest
• Recurring sequence: a familiar arc, repeated
• Co-occurrence: tags that appear alongside symptoms
• Seasonality: a year, at a glance (Pro)
• Environment: weather, barometric pressure, humidity, air quality, for migraine weather and pressure patterns (Pro)
• Long-term cycles and intervention effectiveness (Pro)

A REPORT YOU CAN HAND TO YOUR CLINICIAN
One tap exports an editorial PDF: auto-numbered observations, frequency tables, time-of-day distributions, and an event log. Black-and-white printable, sized for a five-minute appointment. No portal login on the other end.

READINGS: GLUCOSE, HEART RATE, BLOOD PRESSURE, WEIGHT
Your numbers sit on the same timeline as everything you log. Log a reading by hand in a couple of taps, or import from Apple Health with Pro, including a CGM's glucose every five minutes.

ON YOUR WRIST
Log what you log most with one tap on Apple Watch. Set severity with the Digital Crown, mark a symptom improved later, or start from its watch face complication.

MEDICINE CABINET AND PILL BOX
Set a dose schedule once and the medications you take regularly log themselves. A daily pill box shows what's taken and what's still due.

APPLE HEALTH INTEGRATION
Pull in workouts, mindful sessions, and readings automatically (Pro).

TRACK MULTIPLE PEOPLE (PRO)
Separate threads for yourself, your kids, or anyone you care for.

100% PRIVATE BY DEFAULT
• No account required, start logging immediately
• All data stored locally on your device
• AI runs on-device using Apple Intelligence; nothing is sent to a server to be analysed
• Optional iCloud backup, protected by Apple's encryption
• No analytics, no tracking, no ads

BUILT ON PUBLISHED RESEARCH
Across 85 clinical studies, self-monitoring was the most effective technique in digital health interventions for chronic conditions.

FREE FOREVER
• Unlimited logging, medicine cabinet, and manual readings
• Today, Timeline, and Calendar views
• AI chat assistant for plain-language logging
• Basic Insights: pre-window, time-of-day, day-of-week, sequences, co-occurrences

UNDERCURRENT PRO · ONE-TIME PURCHASE · $19.99
Pay once, keep everything forever. No subscription, no recurring charges.
• Weather, pressure, and humidity correlations
• Long-term cycles, seasonality, intervention effectiveness
• Full clinician PDF report
• Multiple people
• Apple Health sync, including CGM glucose
• iCloud backup

Whether it's what shows up before your migraines or which foods leave you uncomfortable, Undercurrent gives you a quiet place to write it down.

NOT A MEDICAL DEVICE
Undercurrent describes statistical co-occurrences in your self-logged data. It is not intended to diagnose, treat, cure, or prevent any disease. Observations are informational only, not medical advice. Always consult a qualified healthcare professional about symptoms, medications, or treatment decisions. In an emergency, call your local emergency number.

Notice what's quietly shaping how you feel.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Undercurrent Health: Pro | $19.99 | one-time |


## Is Undercurrent safe?

Not enough ratings yet to assess Undercurrent.

## Is Undercurrent legit?

Undercurrent: Symptom Log appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Undercurrent is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 2.1.0 — 2026-10-22

Undercurrent is now on Apple Watch and iPad.

On Apple Watch:
• Log the entries you use most with one tap from your wrist
• Set a symptom's severity with the Digital Crown
• Mark a symptom improved, up to a day after you logged it
• Add the Log complication to your watch face
• Tapped the wrong one? Undo within a few seconds
If your iPhone is out of range, logs wait on the watch and arrive when it's back.

On iPad:
• Tabs down the side, with your day in a calm, readable column
• Log, edit an entry, or chat with the assistant in a pane beside your day
• Works in any orientation

### 2.0.1 — 2026-10-15

Now on iPhone Duo. Open your phone and Undercurrent opens with it: logging, event details, and chat sit beside your day instead of on top of it.

### 2.0.0 — 2026-10-09

Undercurrent 2.0: readings

• Log blood glucose, heart rate, blood pressure, and weight alongside everything else. Choose Measurement when you log, or type it in chat: "glucose 142 after lunch", "bp 128/84".
• Charted with your day. Each day charts its readings with your meals, activities, and symptoms marked on the same axis and the healthy range shaded. Tap a reading on Home to see the last 1, 7, 30, or 90 days.
• Apple Health import (Pro). Bring in glucose from a CGM, heart rate, blood pressure, and weight automatically. Readings stay on your device.
• Insights for readings (Pro). See how readings respond to different meals and activities, what they look like before symptoms, and whether out-of-range days line up with symptom days.
• Clinician report (Pro). A short measurements summary with averages, ranges, trends, and CGM time in range.
• Smoother logging, plus fixes throughout.

### 1.1.1 — 2026-10-06

Bug fixes and improvements to user experience

### 1.1.0 — 2026-10-05

New in 1.1

• Medicine cabinet. Every medication you've logged, in one place, with its usual dose, your notes, and when you last took it. Find it in Settings › Medications.
• Schedules. Set when you take a medication: every day, every other day, specific days, or monthly, at one or more times a day. Scheduled doses are logged for you as their time passes; delete any you skipped.
• Pill box. Today's doses sorted into morning, afternoon, evening, and night. Tap a dose to mark it taken. It's at the top of the medicine cabinet, with a summary on Home.
• Quick Log medication chips now show how long ago you last took each one.
• Already over? Log a symptom with its end time in one step.
• Send feedback straight from Settings.
• Updated for the latest iOS, plus bug fixes.

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## More apps by Lloyd Rowat

- [Lumen's Lab: Light Puzzles](https://appshunter.io/ios/app/lumens-lab-light-puzzles/id6760675666)
- [Homebound: Lost Creatures](https://appshunter.io/ios/app/homebound-lost-creatures/id6761587494)
- [Songtrail: Bird Discovery](https://appshunter.io/ios/app/songtrail-bird-discovery/id6781903536)

All apps by Lloyd Rowat: https://appshunter.io/developer/1166734628

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-24.*