Comparison

TFI Trainer vs Hormetic

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

Head to head
About

TFI Trainer

Features
Read full description

TFI is an easy platform built for connecting our trainers to their clients. Clients receive an elevated training experience: • Personalized workouts delivered to their phones • Access to all training data on the go • Stay accountable with workout and task reminders • Sync with Apple Health app to update your metrics instantly

About

Hormetic

This app tracks your body's response to heat exposure using heart rate and manually entered temperature. It provides detailed session data, a heat-dose score, and a history of your thermal-dose sessions. Your data remains private on your device.

Highlights
  • Heart-rate tracking during sessions
  • Three-zone classification with color-coded badges
  • Estimated heat-dose score calculation
  • Per-session detail and full history
  • Algorithm versioning for transparency
  • Private data architecture, no account needed
Features
Read full description

Hormetic tracks how your body responds to heat and cold exposure, using heart rate and the temperature involved, with honest math and full transparency. WHAT YOU GET - Heart-rate tracking during a session, recorded as a standard HealthKit workout - Heat: three color-coded zones (Zone 1, Zone 2, Zone 3) and an estimated heat-dose score from your heart rate, the temperature you enter, and session duration - Cold: cold-plunge tracking with three calm zones — Entering, Moderate, Significant — and an estimated cold dose from your time in the water and the water temperature - Spa (new): hot tubs and hot baths, with their own zones and an estimated soak dose from your time immersed and the water temperature. A separate algorithm from heat — a 40 °C soak is not a 90 °C sauna, and one score cannot honestly describe both - Contrast: follow a sauna or a soak with a plunge and Hormetic notes the pattern with honest, recovery-framed context — never a combined-benefit claim - Per-session detail: peak heart rate, time in each zone, calories, algorithm version - Adapt: your weekly consistency, with estimated heat, cold, and soak dose as separate trends - Full session history HONEST BY DESIGN - Every value the algorithm derives is labeled "Estimated" - Heat, cold, and spa use separate, independently versioned algorithms; each session records the version that produced its values - In cold and spa, heart rate is shown for context but never scored — water changes it in ways a wrist reading can't fairly judge - The soak estimate stops growing past 40 °C and past 20 minutes, because that is where the published evidence stops. More time is not more dose - Historical sessions are never silently recomputed - Grounded in published research, with tappable source citations; water safety and its risks are covered prominently in the app PRIVATE BY ARCHITECTURE Your data never leaves your device. No account. No analytics. No telemetry. No third-party SDKs. We do not sell personal information. IMPORTANT — YOUR DEVICES Hormetic never asks you to put a device anywhere Apple's own guidelines say it should not go. For heat, Hormetic does not require you to place your Apple Watch or iPhone in any hot room — the temperature is a value you enter manually, and Apple Watch simply contributes heart rate from your wrist. Cold plunges, hot tubs, and hot baths are shallow-water immersion, which Apple Watch's water resistance supports. Hormetic's own in-app guidance caps a soak at 40 °C (104 °F), well under the 55 °C (130 °F) figure Apple publishes for Apple Watch Ultra in a hot environment. As Apple recommends, rinse your Watch with fresh water after a treated pool or tub. On Apple Watch Ultra, submersion and water temperature are read by the watch's built-in sensor; on other models you enter the water temperature. Keep your devices within Apple's published guidelines — water resistance is not permanent, and depth limits apply. IMPORTANT — YOUR HEALTH Cold-water immersion carries real risk. The cold-shock response can cause gasping and raise heart rate and blood pressure — enter gradually, never breath-hold beforehand, and don't plunge alone. Hot water is a real cardiovascular load. Stand up slowly, hydrate, skip alcohol, and don't soak alone. Get out at the first sign of dizziness, nausea, or headache. Hormetic is not a medical device and does not diagnose, treat, or prevent any condition. Consult a healthcare professional before starting heat or cold exposure, especially with a heart condition, high blood pressure, or pregnancy. REQUIREMENTS iPhone running iOS 18.6 or later, and Apple Watch running watchOS 11.6 or later, which records your sessions and heart rate. Apple Watch Ultra adds automatic submersion detection and water-temperature sensing for cold plunges and soaks.

Screenshots

TFI Trainer4 screens
Hormetic4 screens

Verdict

The call

The clearest difference is price: TFI Trainer at Free against Hormetic's $2.99. TFI Trainer also leads on iOS requirement (11.0 vs 18.6). Hormetic's advantage is chart position (#196 vs unranked). On update cadence, 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

TFI Trainer is free to download; Hormetic costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

TFI Trainer ships an update every 10 days, Hormetic every 5 days. The most recent releases landed on October 14, 2026 and October 16, 2026 respectively.

Scorecard3 real differences · 8 level
TFI Trainer versus Hormetic: the parameters behind the verdict, then further details
ParameterTFI TrainerHormetic
PriceFree — better$2.99
Rating—5.0 (2 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—2 — better
Update frequencyEvery 10 daysEvery 5 days — better
AdsNoNo
In-app purchasesNoNo
Monetization—Paid
Best chart rank—#196 — better
DevicesiPhone, iPad, iPod — betteriPhone, Apple Watch
Requires iOS11.0 — better18.6
Further details — not scored
Size255 MB10 MB
Age rating4+17+
DeveloperThe FIT Institute PCAvesta Forge LLC

In-app purchases

None

TFI Trainer

No in-app purchases

None

Hormetic

No in-app purchases

Questions

Is TFI Trainer free?
TFI Trainer is free to download, with no in-app purchases.
Is Hormetic free?
Hormetic costs $2.99, with no in-app purchases.
Do TFI Trainer or Hormetic have ads?
Neither TFI Trainer nor Hormetic shows ads.
Which is updated more often, TFI Trainer or Hormetic?
TFI Trainer ships an update every 10 days, and Hormetic every 5 days. Most recently, TFI Trainer was updated on October 14, 2026 and Hormetic on October 16, 2026.

Other comparisons