No charting. No strips. No app to interpret. The whole practice is press, wait, and read. We'll walk you through each step.
The moment you wake up, before getting out of bed, place Daysy under your tongue and press the single button. The sensor takes a basal body temperature reading to ±0.05°C, the precision threshold the science is built on.
Daysy vibrates when it's finished. The reading is automatically saved to the device. If you're using Daysy (not Lady-Comp or Pearly), it also syncs to the free DaysyDay app via Bluetooth. No strips. No charting. No data entry.
A small light tells you where you are in your cycle. The algorithm, refined since 1986 on millions of cycles, decides. That's the whole product. You can check the app for charts and history, or not.
When you start using Daysy, the algorithm spends the first 2 to 3 cycles learning your specific patterns. During the learning phase, you'll see more yellow lights than green or coral. This is normal. The device is establishing your baseline.
After the learning phase, Daysy resolves your cycle position more confidently. Most users report seeing meaningful patterns by cycle 3, and stable patterns by cycle 4 or 5.
We mention this up front because it's the most common reason people return the device before giving it a fair chance. If after two full cycles your results aren't stabilizing, our 30-day money-back guarantee means a full refund.
Read the science behind the learning phaseOne minute a day. No subscription. 30-day money-back if it isn't right for you.
Shop Daysy · $249Ancient knowledge married with modern technology.