The hormone operating app built on YOU.
The hormone operating app built on YOU.
Just you. 100% private.
Just you. 100% private.
Your logs build every piece of the system: the predictions, the phase patterns, the cycle insights. No two people share the same system. HLI learns your body alone.
Your logs build every piece of the system: the predictions, the phase patterns, the cycle insights. No two people share the same system;
HLI learns your body alone.
Invitation-only. Annual membership.
Invitation-only. Annual membership.
WE KNOW.
WE KNOW.
You're tired of being confused.
You're tired of being confused.
Prediction.
Prediction.
The tracker told you your period was two days late.
The app synced your cycle to the moon and suggested you journal.
The wearable collected your heart rate, sleep, temperature… and well, that's it.
The tracker told you your period was late.
THE TRUTH IS
THE TRUTH IS
Everything you've been given was built for the average woman.
Everything you've been given was built for the average woman.
…there is no average woman.
…there is no average woman.
DESIGNED FOR YOU, SPECIFICALLY.
DESIGNED FOR YOU, SPECIFICALLY.
Experience Real Cycle Clarity
Experience Real Cycle Clarity
Understand exactly why your cycle is longer or shorter at times.
Understand exactly why your cycle is longer or shorter at times.
Get real predictions built by YOUR hormone signals.
Get real predictions built by YOUR hormone signals.
Implement a lifestyle that aligns with your body’s phases.
Implement a lifestyle that aligns with your body’s phases.
It takes a minimum of three complete cycles to activate your Hormonal Fingerprint.
It takes a minimum of three cycles to activate your Hormonal Fingerprint.
MEET YOUR FINGERPRINT
MEET YOUR FINGERPRINT
HLI Doesn't Just Track Your Period.
It Learns Your Hormonal Fingerprint.
HLI Doesn't Just Track Your Period.
It Learns Your Hormonal Fingerprint.
YOUR SIGNALS
YOUR SIGNALS
How Your Body Speaks.
How Your Body Speaks.
Every woman experiences a different cycle. HLI captures the shifts in energy, mood, skin, digestion, and pain that show up for you.
Every woman experiences a different cycle. HLI captures the shifts in energy, mood, skin, digestion, and pain that show up for you.
YOUR STRESSORS
YOUR STRESSORS
How Your Life Affects Your Cycle.
How Your Life Affects Your Cycle.
Stress, nutrition, sleep… all shift your hormonal timing. HLI identifies how your cycle patterns respond to each one.
Stress, nutrition, sleep… all shift your hormonal timing. HLI identifies how your cycle patterns respond to each one.
YOUR CLARITY
YOUR CLARITY
What You Can Do.
What You Can Do.
Understanding your body is only half of it. HLI gives you something to do about it with a library of proven research-cited practices.
Understanding your body is only half of it. HLI gives you something to do about it with a library of proven research-cited practices.
WILL YOU MAKE THE SHIFT?
WILL YOU MAKE THE SHIFT?
This is a Hormone Revolution.
This is a Hormone Revolution.
HLI's system unlocks a new age of bodily autonomy for women that has never been widely accessible. For once, you hold the reins to your body. What will you do with this power?
Better yet, what can't you do?
HLI's system unlocks a new age of bodily autonomy for women that has never been widely accessible. For once, you hold the reins to your body.
HLI's Founding Membership Is Now Open.
500 Seats. Your call.
500 Seats. Your call.
$96 / year — Founding Member Lifetime Pricing.
$96 / year — Founding Member Lifetime Pricing.
7 day trial.
7 day trial.
One question.
One question.
When the 500 seats are filled, founding pricing closes.
When the 500 seats are filled, founding pricing closes.
OUR FOUNDATION
OUR FOUNDATION
HLI Is Built On Established Science.
HLI Is Built On Established Science.
Drawn from peer-reviewed research in women's endocrinology, exercise physiology, and hormonal cycle science.
Drawn from peer-reviewed research in women's endocrinology, exercise physiology, and hormonal cycle science.
Barron & Fehring, Journal of Obstetric, Gynecologic & Neonatal Nursing, 2005
Cervical Mucus, BBT, & Ovulation Detection
Oosthuyse & Bosch, Sports Medicine, 2010
Hormonal Fluctuation & Exercise Performance
Liu et al., Journal of Clinical Endocrinology & Metabolism, 2019
Lifestyle Variables & Cycle Length Variation
YOUR DATA, YOURS ONLY
YOUR DATA, YOURS ONLY
Most apps have a privacy policy.
Most apps have a privacy policy.
HLI has a privacy architecture.
HLI has a privacy architecture.
Your data never leaves your device.
Your data never leaves your device.
Every log, every symptom, every pattern you record is stored locally via Apple's CoreData. No server receives it. Not ours. Not anyone's.
Every log, every symptom, every pattern you record is stored locally via Apple's CoreData. No server receives it. Not ours. Not anyone's.
We cannot access your data structurally.
We cannot access your data structurally.
This is not a policy decision. HLI has no technical pathway to your Hormonal Fingerprint. Even if we wanted to, we couldn't.
This is not a policy decision. HLI has no technical pathway to your Hormonal Fingerprint. Even if we wanted to, we couldn't.
Deletion is permanent.
Deletion is permanent.
Because your data lives only on your device, deleting your account removes the only copy that exists. There is no backup. There is no server record. It is gone.
Because your data lives only on your device, deleting your account removes the only copy that exists. There is no backup. There is no server record. It is gone.
OUR ROOTS
OUR ROOTS
Womanhood is meant to be a gift.
Womanhood is meant to be a gift.
PJ, Founder and Stanford Product Designer
PJ Vang, Founder & Stanford Product Designer
A Word from the Founder:
A Word from the Founder:
You might be wondering: How is this different from any other app?
Here's the truth:
Existing period apps and trackers are made to collect and sell your data. Thats their entire system. Over months or even years of logging, your app knows as much about you as the first day you started logging.
HLI is an operating system, not a data storage. It uses your logs to build your personal Hormonal Fingerprint. This means the first couple cycles will function the same as your current app. But once it learns your body over multiple cycles, you directly see the relationships between your behaviors, symptoms, and cycle timing. It maps your personal ovulation signals, your phase transitions, and how external factors like stress or nutrition affect your cycle length.
HLI is the only system designed to do this for you, as an individual person, rather than for a population.
It's about time systems are designed for women.
You might be wondering: How is this different from any other app?
Here's the truth:
Existing period apps and trackers are made to collect and sell your data. Thats their entire system. Over months or even years of logging, your app knows as much about you as the first day you started logging.
HLI is an operating system, not a data storage. It uses your logs to build your personal Hormonal Fingerprint. This means the first couple cycles will function the same as your current app. But once it learns your body over multiple cycles, you directly see the relationships between your behaviors, symptoms, and cycle timing. It maps your personal ovulation signals, your phase transitions, and how external factors like stress or nutrition affect your cycle length.
HLI is the only system designed to do this for you, as an individual person, rather than for a population.
It's about time systems are designed for women.
Take control of your body and data.
Take control of your body and data.
so no one else can.
so no one else can.
FAQs
FAQs
Why does it take three cycles to build a Hormonal Fingerprint?
HLI builds your Hormonal Fingerprint from your data. One cycle is a starting point. Two is a pattern forming. Three is enough for the system to interpret your cycle against your own biology rather than a population average.
Why does it take three cycles to build a Hormonal Fingerprint?
My cycles are irregular. Is HLI for me?
Not yet and we want to be honest about that.
HLI is currently built for women with regular cycles. PCOS and PMDD aren't supported in this version. We won't offer an inaccurate system while we build the right one.
If your cycle is irregular, HLI isn't ready for you yet. It will be.
My cycles are irregular. Is HLI for me?
What if I miss logging days?
HLI is honest when its data is incomplete. Sparse data still builds your hormonal fingerprint, just over a longer period. It won't generate interpretations it can't support. The system rewards attention. It's designed for women who want to show up for themselves.
What if I miss logging days?
Why annual-only?
The Fingerprint takes three cycles to develop. A monthly subscription creates the condition to leave before the product becomes useful. HLI was created to deliver value and body literacy for women. Annual membership is designed for that reason.
Why annual-only?
Is HLI scientifically proven?
HLI is built on is established and peer-reviewed studies: basal body temperature, cervical mucus monitoring, hormonal physiology across the cycle. These methodologies are proven and well-researched. HLI's system is built to reveal individualization and its impact on hormones. We are building toward independent clinical validation. We won't claim it before it's true.
Is HLI scientifically proven?
How do I know my data is safe?
It never leaves your device. That's not a promise; It's how the system is built. Every log, every pattern, every Fingerprint is stored locally via Apple's CoreData. HLI has no technical pathway to your data. Neither does anyone else. Delete your account and the only copy that exists is gone. Permanently.
How do I know my data is safe?
