Circadian: Your Natural Rhythm

Natural Cycles

In-app purchases

About this app

🌟 OPTIMIZE YOUR NATURAL CYCLES & BIORHYTHMS TO RISE, SLEEP, THINK, AND EAT AT IDEAL TIMES
Do you ever feel out of sync with your natural cycles? Circadian is the leading circadian rhythm app. By tuning into your circadian rhythm and honoring your biorhythms, you enjoy better sleep, balanced hormones, and a healthier lifestyle.

☀️ ALIGN WITH SUNLIGHT & SEASONS
Why dissect every sleep cycle or follow a fixed sleep calendar when natural cycles guide you best? This circadian rhythm app harnesses diurnal patterns—risen dawn, UVA/UVB rise & set, solar noon, sunset, and darkness—to set consistent rise & sleep reminders and wind-down alerts. Trust your internal clock to help you establish a smooth sleep rhythm and a natural circadian sleep pattern.

🛏️ BEDTIME CALCULATOR & BIORHYTHM CALCULATOR
Plan your optimal hours of sleep and fasting windows with our seasonal bedtime calculator and robust biorhythm calculator. Swap rigid schedules for nature’s timing: anchor bedtime to dusk and wake with rise sun. Our bedtime calculator uses your rise time and the optimal seasonal sleep duration to calculate your bedtime. Studies confirm syncing with natural cycles outperforms any sleep cycle tracker. Let the natural cycles guide you to entrain your biorhythm with optimal reminders for better sleep, meal, work & exercise times.

🍴 EAT & FAST IN SYNC WITH NATURE
Intermittent fasting and time-restricted eating work best when aligned to daylight. Front-load calories at sunrise and close your eating window by dusk to match your circadian rhythm. Research shows skipping breakfast or dining late disrupts this rhythm and harms metabolic health. With Circadian, set eating & fasting reminders that honor this timing for balanced blood sugar and deeper sleep.

🧬 THE SCIENCE OF CIRCADIAN RHYTHMS
Built on Nobel Prize–winning chronobiology, this circadian app explains how your internal clock and biorhythms regulate melatonin, cortisol, and vitamin D production. Getting the right circadian cues—light/darkness, food & exercise—at the right time is non-negotiable for a healthy body, mind, and heart. Use Circadian and its extensive learn & research section for tons of actionable insights on your sleep rhythm, artificial light, exercise timing, diurnal living and much more to transform your natural life.

🌅 YOUR NATURAL ALARM CLOCK
Wake gently with circadian rhythm alarm clock features: rise with the sun to greet the day. Getting natural light into your eyes for 5 minutes upon waking improves your sleep quality the next night by 20 %! Make rise sleep, rise sun, solar-noon check-ins, and sunset wind-downs part of your day. Let the surrounding natural life be your health clock tuning your biorhythms.

☘️ ENJOY TRUE RHYTHM & HEALTHY LIVING
As a top choice among health and wellness apps, Circadian focuses on pure nature-driven guidance—no complicated integrations. Enjoy better sleep and harmonious days shaped by your true rhythm.

🗝️ KEY ASPECTS
• Natural cycles: dawn, sunrise, UVA/UVB rise & set, solar noon, sunset, and dusk
• Bedtime calculator & biorhythm calculator: optimize your hours of sleep across the seasons
• Circadian rhythm alarm & health clock: custom alerts for medication, rise sleep, and much more
• Intermittent fasting in sync with nature: set your eating window to nature’s timing for better sleep, metabolism, and health
• Diurnal guidance: honor your true sleep rhythm—not a static sleep calendar or dissect every sleep cycle
• Core circadian library: 20+ deep-dive articles on melatonin, sunlight, menstrual cycles, grounding, and diurnal living science
• Embrace circadian sleep, vibrant energy, and a rhythm set by nature

Ready to unlock better sleep, balanced energy, and happier days?
Download Circadian: Your Natural Rhythm now — your ultimate circadian app and biorhythm calculator for natural cycles and optimal living.

Ratings and reviews

I love the idea behind this. So much so that I did buy the full membership, so I own it forever now. Having said that, the app does seem really glitchy. After the second day I stopped receiving notifications. I emailed customer service and although the response time was good, the answer received was not helpful and did not solve my problem. I force stopped the app, which did seem to help for 12 hours or so, but as of right now, zero notifications. Not even alarms are going off.

Update - was emailed promptly about this issue, which is rare these days for apps. They corrected the issue within a few hours of me reaching out. I absolutely LOVE this app and have been using it for years. It really has helpede be more aware of my time spent inside, reminding me to get outside. A+ app and customer service Update erased my plan and settings, and is telling me I now have to pay a one time fee to use all the notifications that I previously used and paid for with my annual plan.

Not very user friendly. I had trouble understanding what toggles I was setting and why. And the free trial is very limited, I literally had no idea what "upgrades" I would be getting with the paid subscription. And the worst part is the limited time frames you're allowed to select. I wanted an app that would help me identify my PERSONAL peak productivity time, this felt like an alarm app telling you when to do certain activities. I don't need an app to tell me when to eat, I eat when I'm hungry.

What’s new

We are very happy to introduce translations.
You can now select English, Chinese, German and Spanish.

We're actively working to improve Circadian.
Feel free to contact us at [e-mail] if you have any issues, feedback, suggestions, or questions.

Mind your rhythm, mind your light ☀️
Team Circadian