You've searched this before: every fasting app you try counts down the same clock whether it's day 3 of your cycle or day 24, and none of them explain why a window that felt easy last week suddenly feels impossible this week. You're not missing some setting buried in the app — most fasting apps genuinely aren't built with a menstrual cycle in mind at all.
The short answer
Yes — FastSyncer is being built specifically for this. It's a fasting app designed around a woman's cycle rather than a single generic countdown, adjusting the recommended fasting window and what to eat as hormones shift across the month, instead of applying the same number every single day. Join the waitlist for free early access when it launches.
Why a generic fasting app misses so much for women
Most popular fasting apps started as simple timers: pick a window (16:8, 18:6, OMAD), start the clock, get a streak. That works reasonably well for a body whose hormonal baseline doesn't shift much day to day. It works far less well for a body that runs on an approximately month-long hormonal cycle, where estrogen and progesterone rise and fall in a predictable pattern that changes appetite, energy, sleep, and stress tolerance week by week.
Early in the cycle, after a period ends, rising estrogen tends to make longer fasting windows feel comfortable — steady energy, manageable hunger. By the week or two before a period, progesterone dominates and typically needs steadier, more frequent fuel; the same fasting window that felt easy two weeks earlier can now trigger sharper hunger, disrupted sleep, and a spike in stress hormones. A generic app has no concept of any of this — it just keeps counting down the same number of hours, every day, regardless of where you are in your cycle.
The result is a familiar pattern: a woman starts strong, has two great weeks, then "fails" in week three or four and assumes she lacks discipline — when the real issue was a tool that was never built to account for a cycling body in the first place.
What FastSyncer does differently
FastSyncer replaces the one-size-fits-all countdown with a single daily card that already accounts for where you are in your cycle. Instead of picking a fixed window and forcing it every day, the app shows today's recommended fasting hours — typically longer in the first half of the cycle and shorter in the one to two weeks before a period — along with exactly what to eat to support that phase and the specific do's and don'ts for where your body is right now.
The fast auto-starts and logs itself, so there's no manual timer to remember to hit, no day-counting, and no spreadsheet of "what phase was I in when this happened." As your cycle continues month to month, the recommendations adjust with it, rather than staying frozen at whatever settings you first typed in.
What you'd have to do without it
Without an app built for this, matching fasting to your cycle means tracking your cycle day yourself, remembering roughly which hormonal phase that day falls into, manually shortening or lengthening your fasting window based on that guess, and separately researching what to eat to support each phase — then doing all of that again next month, and adjusting on the fly whenever your cycle runs early or late. It's not impossible, but it's exactly the kind of ongoing mental math that makes people quietly give up on cycle-aware fasting even when they know it would help.
When it launches and how to get it
FastSyncer is in final testing now and launching soon on the Apple App Store, with Android to follow. It isn't downloadable yet, so the best way to get it the moment it's available — for free — is to join the waitlist today. Early waitlist members get free access at launch, ahead of the general public.
FAQ
Is there an intermittent fasting app made specifically for women? FastSyncer is being built specifically around a woman's menstrual cycle, adjusting fasting windows and food guidance by hormonal phase rather than applying one generic schedule every day.
Why don't regular fasting apps work as well for women? Most were designed as simple countdown timers without accounting for how estrogen and progesterone shift appetite, energy, and stress tolerance across roughly a month — so they recommend the same window regardless of where a woman is in her cycle.
Can I download FastSyncer right now? Not yet — it's in final testing and launching soon on the Apple App Store. Joining the waitlist reserves free early access as soon as it's available.
Do I need to track my own cycle to use it? No — that's the point. The app handles the tracking and gives you one daily card with today's fasting hours and what to eat, so you don't have to calculate your phase yourself.
If you want to understand the cycle logic behind why the fasting window should change at all, best fasting schedule for each phase of your cycle and should women fast differently than men? cover the reasoning FastSyncer's daily card is built on. And if you're wondering exactly what to look for when comparing options, fasting app for women: how to choose one that fits your hormones walks through the checklist.