STEP / 01
Wear the patch.
Modular adhesive. You replace it like a sweat strip — peel, stick to your forearm, ride or run. No needles, no clinic, no setup window.
For endurance athletesLive · Seed · 2026
Train by lactate.
Not by guesswork.
A continuous sweat-based wearable that reads your metabolic state while you train — not three days later in a clinic. No finger pricks. No lab. No interruptions.
No blood No interruption No guesswork
Live · Tempo zone
Current zone
TempoZ3
Z2 · EnduranceZ4 · Threshold
Live
Zones on watch
0
Finger pricks
$150
One-time hardware
$25/mo
Sweat patches
Inside the app
The data your wearable can’t see.
Heart rate tells you intensity. Lactate tells you what your body is actually doing with that intensity — when you’re burning fat, when you’re burning carbs, and when you’re about to blow up. Lactyx resolves that signal into your personal training zones, live on your wrist.
Live lactate zone
Z3Tempo
Steady · climbing toward threshold
Last 30 minTracking
0:000:100:200:30
Your thresholds
LT1 · Aerobic
1.8mmol/LLT2 · Lactate
3.4mmol/LZ5 · VO₂
6.1mmol/LUpdated every workout. Yours, not a textbook’s.
Fuel
Cue30g carbs in the next 15 min.
Carb-burn rising. Stay ahead of the depletion curve.
Time in zone
Today · 1h 48m
Z2 Endurance1:08
Z3 Tempo0:26
Z4 Threshold0:12
Z5 VO₂0:02
Personal model
Confidence · 94%
28 sessions on file. Re-calibrates as you adapt.
Recovery readiness
82/ 100
Strong clearance
Below baseline at rest
Lactate clearance + HRV from your watch. Train hard today.
Built for the wrist
Glance down mid-interval. Read your body, not your guess.
Why Lactyx
Three things a lab test can’t do.
/ 01
No blood.
Continuous lactate, read from your sweat.
No needles, no finger pricks, no clinic visits. A modular adhesive patch reads sweat chemistry directly off your skin — and turns it into a live lactate signal you can read mid-workout.
/ 02
No interruption.
Train normally. The patch does the rest.
No calibration windows, no warmup protocol, no stopping mid-effort. You replace the patch like a sweat strip and keep training — outdoor climb, indoor track, hotel gym, dawn long-run.
/ 03
No guesswork.
Lactate threshold, live on your wrist.
Heart rate breaks down under race-day adrenaline. Lactate doesn't. The patch detects your threshold and training zones during every workout — on your watch and in your app, every time.
How it works
From skin to signal,
in three steps.
No needles. No lab. No tape on your finger. The patch wicks fresh sweat across a sensor and turns it into a real-time signal — paired with the watch you already wear.
STEP / 02
Train normally.
No interruptions. No calibration windows. The patch reads sweat chemistry continuously while you train — outdoor climb, indoor track, race day.
STEP / 03
See your zones live.
Lactate threshold and training zones surface on your watch and in your app — every workout, every time. The signal updates as you do.
Meet the patch
Engineered for the body, designed to disappear.
Two grams. Forearm. Two weeks. The patch is built to be forgotten — comfortable enough to sleep in, accurate enough to bet your race on.
- Form factorModular adhesive patch
- SensorContinuous sweat-chemistry electrode
- Wear modelReplace like a sweat strip
- Read-outTraining zones + lactate threshold, live
- SurfaceWatch + companion app, every workout
Sensor membrane
Flex circuit
Skin-safe adhesive
Live
Zones on watch
$150
Device
$25/mo
Patches
The science
What lactate is — and why it’s the most honest signal in your blood.
Heart rate lags. Pace lies in the wind. Lactate is the only metabolite that tells you, in real time, which fuel system is carrying your effort — and how close you are to falling off the edge of it.
Fat-burn ceiling
The intensity above which your body stops burning meaningful fat. Your aerobic ceiling. Your easy day.
Threshold (LT2)
The intensity you can hold for roughly an hour. The hinge between training that builds and training that breaks.
Clearance rate
How fast you flush lactate after an effort. The hidden number that tells you whether you’re recovered.
Lactate vs heart rate · same session
Heart rate flattens. Lactate keeps telling the truth.
Lactate (mmol/L)Heart rate (bpm)
The signal chain
/ 01
Sweat
Eccrine glands carry lactate to skin within seconds of effort.
/ 02
Enzyme electrode
A flex sensor wicks fresh sweat across a lactate-oxidase membrane.
/ 03
Personal model
Edge ML reconciles sweat → blood lactate, calibrated to you.
/ 04
Your wrist
Live zones, fueling cues, and a curve that updates every second.
Works with your watch
The watch you already wear, finally smart enough.
Lactyx doesn’t replace your ecosystem — it sharpens it. We fuse live sweat lactate with the heart rate, pace, and HRV streams from the wearable you already trust, then hand back zones that are actually yours.
WHOOP
Lactate fused with strain and recovery. Your zones, your sleep, one model.
Garmin
On-watch Connect IQ field. Live LT zones on your Fenix, Forerunner, or Edge.
Apple Watch
Workout complication shows live zone and threshold cues. HealthKit aware.
Coros
Coros sync pulls pace and HR; we hand back personalised zones each session.
WHOOPGARMINAPPLE WATCHCOROSPOLARSTRAVATRAININGPEAKSWAHOOWHOOPGARMINAPPLE WATCHCOROSPOLARSTRAVATRAININGPEAKSWAHOO
From the people we’re building this with
“
It would be a dream come true if I could look down at my wrist and see when I'm in the right zone — instead of guessing based on how my legs feel at mile 18.
Brady Murray
Ironman athlete
“
When you take a lactate draw it's one point — you don't know if it's climbing, stabilizing, or decreasing.
Pierre Niess
Head Nordic Ski Coach · U of Utah
Get involved
Three ways in.
Whether you want a stake, an early spot, or a place in the first study — here’s where you start.
Athlete collaborator
Are you an elite endurance athlete?
We’re offering an equity partnership — not a sponsorship — to the right collaborator who can help validate the product and open doors in the endurance community.
- A real ownership stake, not a free patch for a post
- Direct line to engineering and the roadmap
- Skin in the game — a partner, not a billboard
Email the founders
One spot. The right athlete. We read every email.
Be first
Hear it the moment it drops.
Drop your email to be first to know when Lactyx ships — and when the public waitlist opens. No spam, just the news that matters.
Utah · first study
Based in Utah? Join the first study.
We’re recruiting local endurance athletes for our first IRB-approved study in Salt Lake City. Help shape the product from the ground up and get hands-on with early hardware.
- Based in or near Salt Lake City, Utah
- Train seriously — run, ride, ski, or tri
- Up for early testing sessions with the team
Contact us
Built in Salt Lake City. Tested with local athletes.
Common questions
Everything you’d ask at the lab.
Still curious? Email the founders directly: s.kramer@utah.edu or krishnam.g@utah.edu.
Lactate appears in sweat seconds after it rises in blood. Our continuous sweat-chemistry electrode reads the signal directly off your skin and surfaces your lactate threshold and training zones live — no needles, no clinic, no waiting for results. It's the same metabolic signal coaches pay $100–200 per lab draw to read, except continuous instead of one point in time.