Your period
Inner Winter
Estrogen and progesterone are at their lowest. Your energy drops with them. Rest is the right call this week.
Cycle, hormones & mood tracking · iOS & Android
Finally see the patterns in your cycle, mood and body.
Made for women who want to understand themselves. Track cycle, hormones, mood, energy and sleep in one app. See the connections that explain your week.
★★★★★
App Store rating
60+
Psychology tools
Free
On iOS & Android
The pattern you've been missing
Same hard week, every month? That's a pattern.
Across one cycle, estrogen and progesterone shift dramatically. Those shifts change your brain chemistry, which changes how you think, feel, sleep and react. No one really tells you that. So we blame ourselves. We call it stress. We apologize a lot.
Day 8Coffee tastes incredible. You text three people back. Everything feels possible.
Day 14You say yes to the brave conversation. Your hair looks suspiciously good.
Day 22The fog rolls in. You read the same sentence four times. Reach for snacks.
Day 25Cry at a coffee commercial. Eat chocolate in bed. Convince yourself everyone secretly hates you.
My Body's BFF tracks the patterns across your cycle, mood, sleep and energy. So the week that always feels heavy stops feeling random.
Inner Seasons
Meet your Inner Seasons.
Inner Winter, Spring, Summer and Autumn are the four hormonal phases of your cycle. Estrogen and progesterone shift across all four, and that's why each one feels different. Where they fall is different for every woman, so the app maps them to your cycle instead of to a calendar. Once you know which phase you're in, the week makes a lot more sense.
After your period
Inner Spring
Estrogen rises and so does your curiosity. Things you've been putting off suddenly feel doable. Your "I'll just start it" week.
Around ovulation
Inner Summer
Your peak. Sharper, more social, more sure of yourself. Brave conversations feel less brave. Hair, suspiciously, looks better.
Before your period
Inner Autumn
Progesterone is falling and small things take up more space. The week where having the patterns mapped out really matters.
What's inside
Everything you need to actually start understanding your body.
Built the way women think about their cycles, in moods and energy, not just calendar dates. And around the things that actually help when a week gets heavy.
Pattern detection
Mood, energy, sleep, food, stress and cycle phase, all in one place. After a few cycles, the app shows you the patterns you'd never spot on your own.
Inner Seasons
Four phases in plain language. So instead of "I'm in my luteal phase" you can say "I'm in Inner Autumn, and that explains a lot."
60+ psychology tools
Short, evidence-based CBT and ACT exercises for the moments that need them. For crying at 11pm. For the brain fog you can't think through. For the days when "have you tried a bath?" really doesn't cut it.
Flow & Friction
What the phase you're in is good for, and what tends to trip you up in it. Named in plain words, so you know what to lean on and what to watch for this week.
Inside the app
Two screens you'll actually use.
Log how today actually felt.
Mood, energy, stress, sleep. Plus the feelings that match: anxious, calm, brain fog, sensitive. Two minutes a day, no streaks to keep up with.
See the patterns surface.
After a few cycles, the app points things out for you. "Bloating shows up around your luteal phase." "Sleep dipped this week. Mood followed."
How it works
Two minutes a day. A few cycles in, your body starts to make sense.
01
Log how you actually feel
Mood, energy, sleep, stress. It takes less time than scrolling Instagram. No 28-day textbook to live up to. Just how today actually feels.
02
Let the patterns show up
After two or three cycles, the connections start to surface: what consistently drains you, what sharpens you, what your day 24 actually needs.
03
Live with your body, not against it
Plan a little more gently around your harder weeks. Lean into the ones where everything flows. The rhythm starts to feel like yours.
Why this app exists
There wasn't a cycle app that connected mood, hormones and patterns. Now there is.
"Most cycle apps focus on prediction. My Body's BFF focuses on understanding. Mood, energy, sleep and cycle, connected into patterns you can actually use."
Your cycle is not a problem to manage. It's a compass. Our mission is to help one million women understand their hormones, recognize their own patterns, and make choices that fit their natural rhythm. Read the full mission.
Why this works
There's real chemistry behind how your week feels.
In the second half of your cycle, progesterone climbs and then drops sharply, a few days before your period. The calming compound your body makes out of it, allopregnanolone, drops with it. That's the chemistry behind the irritability, the brain fog, the I-can't-do-this feeling around day 24. Once you can see it on a screen, it stops feeling random.
My Body's BFF doesn't tell you how you should feel. It helps you notice how you actually feel.
~80%
Women who report meaningful mood or energy shifts across their cycle
1–3 cycles
When your first patterns start to surface, some already from cycle 1
60+
CBT & ACT-based tools built into the app for hard moments
What tracking reveals
Three moments tracking tends to surface.
"I'm not crazy on day 24. I'm in Inner Autumn. That changes everything."
"My brain fog is real and predictable. I stopped scheduling deep work for week 4. My life feels less random."
"My worst moods follow my worst sleep, every cycle, same days. I changed one thing and it changed everything."
From the App Store
5.0 on the App Store.
★★★★★Rated 5.0 from 3 ratings. Here's what early users say.
★★★★★
Works super well
"It really finds my patterns I did not know about."
★★★★★
Good app
"Good app."
FAQ
Questions women ask us most.
Why do I feel terrible the week before my period?
Because progesterone drops sharply 3 to 5 days before your period, and so does allopregnanolone, the calming compound your body makes out of it. It works on the receptors that carry your brain's main calming signal, so when it falls away, that signal goes quiet. The result is irritability, brain fog, low mood and that I-can't-do-this feeling. Full explanation here.
How do I know if my mood swings are hormonal?
By tracking when they happen across your cycle. If your mood dips consistently land on similar cycle days (typically 3 to 7 days before your period), they're likely hormonal. After 2 to 3 cycles of tracking mood alongside cycle phase, the pattern usually becomes clear. More on how pattern detection works.
Is there an app that tracks both my cycle and my mood?
Yes. My Body's BFF tracks cycle phase alongside mood, energy, sleep, stress and symptoms, and surfaces the patterns between them. Most period apps only predict your next bleed. This one explains why this week feels heavier than last week. Free on iOS and Android.
What is My Body's BFF?
My Body's BFF is a cycle, hormones and mood tracking app for women. It tracks mood, energy, sleep, stress, symptoms and cycle phase together, then surfaces personal patterns you wouldn't spot alone (like why your low mood on day 25 keeps following poor sleep on day 22). The app uses Inner Seasons (Winter, Spring, Summer, Autumn) instead of clinical terminology and includes 60+ short psychology-based tools for the harder moments.
What are Inner Seasons?
Inner Winter is your menstrual phase. Lowest hormones, quietest mind, permission to rest. Inner Spring is follicular, the stretch after your period. Estrogen rising, curiosity returning. Inner Summer is ovulation. Peak focus and confidence. Inner Autumn is luteal, the stretch before your period. Progesterone falling, patience thinning, when patterns matter most.
Who is My Body's BFF for?
Women aged 18 to 45 who feel completely different from one week to the next and want to understand why. Especially women with PMS that affects work, relationships or sleep; women who've come off hormonal birth control and are learning their natural cycle; and women who've tried other cycle apps and felt they were built for someone else's body.
Is My Body's BFF free?
Yes, free to download on iOS and Google Play. Daily logging, Inner Seasons, Flow & Friction and the psychology toolkit are free. There is nothing to buy.
How is My Body's BFF different from Flo, Clue or Stardust?
My Body's BFF differs in three specific ways. First: pattern detection across multiple data types (mood, energy, sleep, food, stress and cycle phase together, not in separate silos). Second: Inner Seasons as plain-language names for the four hormonal phases, instead of clinical menstrual/follicular/ovulatory/luteal terminology. Third: 60+ built-in CBT and ACT psychology tools for hard moments. Overall focus: explaining how you feel across your cycle, not just predicting your next period.
Is my data private?
Your data stays yours. We don't sell user data to advertisers, insurers or third parties. Cycle and mood data is among the most personal information a person can record, and the app is built with privacy as a non-negotiable. Full details in our privacy policy.
Does My Body's BFF work for irregular cycles or after coming off the pill?
Yes. The app doesn't require a 28-day textbook cycle. It tracks how you actually feel day by day, so it works for irregular cycles, post-pill cycles (which often take 3–9 months to regulate) and cycles affected by stress, travel or life changes. Inner Seasons are described by hormonal pattern and how you feel, not by rigid calendar days.
When you're ready
Your body has been talking. Time to listen.
Turn your cycle into insight. Free to download. Your data, yours alone.