Worn, not scheduled
Continuous, at home. Nothing to book, nothing to send away.
Reads flow, not a guess
Optical sensing against your own baseline — not a single snapshot compared to an average.
Responds automatically
Not just a number on a screen. A capped, low-current nudge, only when it's warranted.
Checked against sham
Some sessions carry no current at all — so a good week is measured, not assumed.
Your brain doesn't work in snapshots.
Marrow continuously tracks subtle physiological signals to understand how your state changes throughout the day.
01
Live, not a snapshot
Oxygenation, pulse and breathing update as you go, against your own baseline.
02
Weak spots shown too
One Core Score, with sub-scores underneath — including the low ones.
03
Every session logged
Before and after, with real and sham sessions kept apart.
ILLUSTRATIVE DATA
What did that session actually change?
A closed-loop headband — that shows its working.
The app
Your Core Score, at a glance.
One number, with the sub-scores underneath — including the weak ones.
Home
Core Score
72
Focus78
Recovery84
Load42
Sleep readiness48
↑ 4 from your baseline
Live
Monitoring
Load↑
Recovery↓
Head motionFiltered
State changing
Session
Before
61
After
74
Logged
Counted against your sham sessions before it's called a response.
Hardware
Built to sense.
Built to respond.
OPTICAL
One chip, two LEDs, two photodiodes. Oxygenation, pulse and breathing come from the same signal.
MOTION
An accelerometer flags head movement before it can be mistaken for a physiological reading.
STIMULATION
Low-current tDCS, capped under 2mA by a hard resistor — regardless of any software fault.
ISOLATED
Separate batteries, no shared ground. Only a pulse of light crosses between the two sides.
SENSING DOMAIN
Always on. Reads you.
Optical sensor, accelerometer, main battery.
OPTOISOLATOR
light only
light only
STIMULATION DOMAIN
Only when warranted. Adjusts you.
Its own battery, constant-current source, two electrodes.
Two systems. One headband.
Honest about depth
Marrow reads your prefrontal cortex — not your feelings.
Light reaches about 1–2cm into tissue. That's the outer surface of the prefrontal cortex: focus, decisions, load. Deeper structures like the amygdala sit around 7.5cm away, out of reach of any light-based sensor.
What it reads
Prefrontal oxygenation (HbO2 / HbR)
Heart rate and HRV
Breathing rate
Head motion, to filter noise
Chip temperature, for calibration only
What it doesn't
Emotions or fear, directly
Deep brain structures
A diagnosis of any condition
Anything from a single snapshot
Validation
We want to know if it works.
YOUR BASELINE
Sessions are compared with your own history, not a generic population average.
CALIBRATION
A breath-hold test forces a predictable oxygenation change, confirming the sensor works on you before it's trusted.
SHAM
Some sessions deliver zero current, indistinguishable from real ones — standard practice in clinical tDCS research.
Marrow is a wellness product currently being developed and validated. It is not FDA or CDSCO cleared.
Exploring
What we're exploring.
Focus &
fatigue
fatigue
Cognitive load
Sustained attention
Fatigue onset
Working memory load
Task-switching cost
Vigilance decline
Recovery windows
Stress &
load
load
HRV shift detection
Stimulation response
Baseline drift
Strain spikes
Recovery half-life
Real vs. sham sessions
Session comparison
Post-exertion
recovery
recovery
Oxygenation return
Time to baseline
Load tolerance
Recovery consistency
Exertion-to-rest ratio
Overtraining signals
Session-to-session trend
Evening
wind-down
wind-down
Pre-sleep breathing
Pulse deceleration
Stimulation windows
Evening HRV shift
Sleep-onset readiness
Nightly baseline reset
Areas we're investigating, not promises. Availability depends on validation holding up.