Hormone tracking made wearable
Our invisible wearable is designed to track estrogen, progesterone
and LH patterns using thermal signals captured behind the ear.¹
Hormone tracking made wearable
Our invisible wearable is designed to track estrogen, progesterone
and LH patterns using thermal signals captured behind the ear.¹
Hormone tracking
made wearable
Our invisible wearable is designed to track estrogen, LH and progesterone patterns using thermal signals captured behind the ear¹.
Your hormones shouldn't be the
blind spot.
Your hormones shouldn't be the blind spot.
Your hormones are strongly influenced by sleep, stress, nutrition and exercise and metabolic health. From daily energy levels to menstrual symptoms, these hormones influence how you feel each day and your long-term well-being.
Your hormones shouldn't be the blind spot.
Your hormones are strongly influenced by sleep, stress, nutrition and exercise and metabolic health. From daily energy levels to menstrual symptoms, these hormones influence how you feel each day and your long-term well-being.
Your body signals every shift.
We just found a better way to listen.
Built for everyday wear.
Built for everyday wear.
Continuous, 24/7 thermal sensing built into an earring-back. Phira turns your favorite earrings into hormonal intelligence. No strips, no blood, no disruption to your day.
Continuous, 24/7 thermal sensing built into an earring-back. Phira turns your favorite earrings into hormonal intelligence. No strips, no blood, no disruption to your day.
Universal fit – works with most earring posts
Universal fit – works with most earring posts
Biosensing – continuous 24/7 thermal sensing
Biosensing – continuous 24/7 thermal sensing
Set & forget – multi-week battery life, water-resistant
Set & forget – multi-week battery life, water-resistant
Day & night – comfortable to sleep in, discreet for the office
Day & night – comfortable to sleep in, discreet for the office
Satin Champagne
Satin Champagne
Built for everyday wear.
Continuous, 24/7 thermal sensing built into an earring-back. Phira turns your favorite earrings into hormonal intelligence. No strips, no blood, no disruption to your day.
Universal fit – works with most earring posts
Biosensing – continuous 24/7 thermal sensing
Set & forget – multi-week battery life, water-resistant
Day & night – comfortable to sleep in, discreet for the office
Satin Champagne
Designed to disappear.
Designed to disappear.
Designed to disappear.
Designed to track estrogen, LH, and progesterone patterns.
Prior research with invasive intra-vaginal sensors showed that core body temperature and thermoregulatory patterns shift with hormonal changes. Phira is designed to capture these signals non-invasively, across your full cycle.
Location
The posterior ear is a clinical-grade site for measuring core body temperature patterns, unlike extremities like the wrist or finger.
The posterior ear is a clinical-grade site for core body temperature, unlike extremities like the wrist or finger.
Precision
Highly precise sensors designed to detect subtle thermoregulatory shifts correlated with hormonal changes.
Sensors accurate to 0.03°C. Designed to detect subtle thermoregulatory shifts linked to hormonal changes.
Continuous Sensing
24/7 sensing, capturing the patterns that emerge over time and across the cycle. No blood draws or urine tests.
Daily Insights
Daily updates on your hormones and what that means for your cycle, energy, and overall wellbeing.
Daily updates on your hormones and what that means for your cycle, energy & wellbeing.
Designed to track estrogen, LH, and progesterone patterns.
Prior research with invasive intra-vaginal sensors showed that core body temperature and thermoregulatory patterns shift with hormonal changes. Phira is designed to capture these signals non-invasively, across your full cycle.
Location
The posterior ear is a clinical-grade site for measuring core body temperature, unlike extremities like the wrist or finger
Precision
Sensors accurate to 0.03°C detect subtle thermoregulatory shifts correlated with hormonal changes.
Continuous Sensing
24/7 sensing, capturing the patterns that emerge over time and across the cycle. No blood draws or urine tests.
Daily Insights
Daily updates on your hormones and what that means for your cycle, energy, and overall wellbeing.
Figure 1. Our pilot data showing Phira's thermoregulatory biomarkers, consistent with estrogen, LH and progesterone dynamics across the menstrual cycle.
Built on established science.
Expanding what we know.
The link between hormones and thermoregulation is well documented in literature¹ ². Our peer-reviewed publication from our IRB-approved pilot study is now part of that conversation³, and our expanded clinical study is underway.
¹ Reproductive Hormone Influences on Thermoregulation in Women. Comprehensive Physiology, 2024.
² Prediction of the fertile window using a vaginal biosensor for measuring core body temperature. Gynecological Endocrinology, 2018.
³ Physiological Signal Characterization from an Earring-back Wearable. IEEE EMBC, July 2026.
Understand your body, on your terms
Health & Wellness
Get in tune with your body. Understand how your sleep, stress, exercise, and nutrition affect your cycle, hormone patterns and menstrual symptoms. Build habits that put you back in control.
Get in tune with your body. Understand how your lifestyle affects your cycle & menstrual symptoms. Build habits that put you back in control.
Get in tune with your body. Understand how your sleep, stress, exercise, and nutrition affect your cycle, hormone patterns and menstrual symptoms. Build habits that put you back in control.
Longevity
Track your patterns over time so you can make lifestyle choices for your long-term well-being.
Track the patterns linked to menopause and long-term health, so you can make informed decisions for your future.
Track your patterns over time so you can make lifestyle choices for your long-term well-being.
Built on established science.
Expanding what we know.
The link between thermoregulation & hormones is well documented in literature [1,2]. Our peer-reviewed publication from an IRB-approved pilot study is now part of that conversation [3], and our expanded clinical study is underway.
Figure 1. Our pilot data showing Phira's thermoregulatory biomarkers, consistent with estrogen, LH and progesterone dynamics across the menstrual cycle.
[1] Reproductive Hormone Influences on Thermoregulation in Women. Comprehensive Physiology, 2024.
[2] Prediction of the fertile window using a vaginal biosensor for measuring core body temperature. Gynecological Endocrinology, 2018.
[3] Physiological Signal Characterization from an Earring-back Wearable. IEEE EMBC, July 2026.
Hormone tracking is just the beginning
Hormone tracking is just the beginning
We are building the first hormonal health operating system to help you understand not just what your cycle is doing, but how your sleep, training, stress, and nutrition shapes it cycle after cycle.
We are building the first hormonal health operating system to help you understand not just what your cycle is doing, but how your sleep, training, stress, and nutrition shapes it cycle after cycle.
More coming soon.
Built on established science.
Built on established science.
Expanding what we know.
The relationship between hormones and thermoregulation is well documented in literature [1,2]. Our peer-reviewed publication from our IRB-approved pilot study is now part of that conversation [3], and our expanded clinical study is underway.
Figure 1. Our pilot data showing Phira's thermoregulatory biomarkers, consistent with estrogen, LH and progesterone dynamics across the menstrual cycle.
[1] Reproductive Hormone Influences on Thermoregulation in Women. Comprehensive Physiology, 2024.
[2] Prediction of the fertile window using a vaginal biosensor for measuring core body temperature. Gynecological Endocrinology, 2018.
[3] Physiological Signal Characterization from an Earring-back Wearable. IEEE EMBC, July 2026.
From the women who wore it first.
From the women who
wore it first.
Here's what the women who wore Phira during our pilot study experienced.
Here's what the women who wore Phira
during our pilot study experienced.
Maritza
Pilot study participant
"Before Phira, I didn't even realize how out of tune I was with my body. Wearing it let me notice changes in my cycle and hormones that would've otherwise gone unnoticed, and helped me understand my emotional & physiological shifts so much better. It was never inconvenient, even through constant travel."
"Before Phira, I didn't even realize how out of tune I was with my body. Wearing it let me notice changes in my cycle and hormones that would've otherwise gone unnoticed, and helped me understand my emotional & physiological shifts so much better. It was never inconvenient, even through constant travel."
Maritza
Pilot study participant
"Before Phira, I didn't even realize how out of tune I was with my body. Wearing it let me notice changes in my cycle and hormones that would've otherwise gone unnoticed, and helped me understand my emotional & physiological shifts so much better. It was never inconvenient, even through constant travel."
Sophie
Pilot study participant
"It's exciting to see a wearable designed not just for women's bodies, but for women's lives. As someone who works out a lot, a ring gets in the way of lifting so the earring-back format is a huge win for tracking without losing data."
Hannah
Pilot study participant
"As a woman in STEM, I was excited to be part of a study focused on women's hormonal health, something understudied until recently. The device was comfortable, didn't impact my style, and I had no issues sleeping in it. It is a true wear-it-and-forget-it experience."
Sanjana
Pilot study participant
"It was so comfortable to sleep in, I didn't even feel it, and far easier to integrate into daily life than something visible like a watch or ring. Better data and tools like this help women understand their bodies instead of guessing what's normal."
Sophie
Pilot study participant
"It's exciting to see a wearable designed not just for women's bodies, but for women's lives. As someone who works out a lot, a ring gets in the way of lifting so the earring-back format is a huge win for tracking without losing data."
"It's exciting to see a wearable designed not just for women's bodies, but for women's lives. As someone who works out a lot, a ring gets in the way of lifting so the earring-back format is a huge win for tracking without losing data."
Hannah
Pilot study participant
"As a woman in STEM, I was excited to be part of a study focused on women's hormonal health, something understudied until recently. The device was comfortable, didn't impact my style, and I had no issues sleeping in it. It is a true wear-it-and-forget-it experience."
"As a woman in STEM, I was excited to be part of a study focused on women's hormonal health, something understudied until recently. The device was comfortable, didn't impact my style, and I had no issues sleeping in it. It is a true wear-it-and-forget-it experience."
Sanjana
Pilot study participant
"It was so comfortable to sleep in, I didn't even feel it, and far easier to integrate into daily life than something visible like a watch or ring. Better data and tools like this help women understand their bodies instead of guessing what's normal."
"It was so comfortable to sleep in, I didn't even feel it, and far easier to integrate into daily life than something visible like a watch or ring. Better data and tools like this help women understand their bodies instead of guessing what's normal."
FAQs
Does Phira work with any earring?
How does it work without a blood test?
How accurate is the sensor?
What does Phira actually tell me each day?
What stage is the research at?
Can I join the study?
When does it ship?
Get in tune with your body.
Join the waitlist to be part of the research behind Phira
Get in tune with your body.
Join the waitlist to be part of the research behind Phira
Get in tune with your body.
Join the waitlist for early access and the chance to be part of the research behind Phira.
1 Expanded study in progress ahead of commercial launch. Phira is a wellness technology and is not a medical device. Phira is not intended to diagnose, mitigate, treat, or cure any disease. Phira is not a prescreener for any health conditions. Phira is not intended to continuously monitor blood hormone levels and is not a replacement for clinical hormone testing. Phira should not be used for any health condition management or relied on to alter any medications. Consult a medical professional for any questions about your hormonal or metabolic health.
1 Expanded study in progress ahead of commercial launch. Phira is a wellness technology and is not a medical device. Phira is not intended to diagnose, mitigate, treat, or cure any disease. Phira is not a prescreener for any health conditions. Phira is not intended to continuously monitor blood hormone levels and is not a replacement for clinical hormone testing. Phira should not be used for any health condition management or relied on to alter any medications. Consult a medical professional for any questions about your hormonal or metabolic health.