A self-initiated product concept for women's hormonal health. The challenge: most apps treat the cycle as a countdown to the next period — ignoring the hormonal shifts that move energy, mood, skin and sleep all month. Luna turns the cycle into context, not a date.
Design goalConnect each hormonal phase to daily life, so tracking feels useful, not clinical.
I benchmarked the category — Clue, Flo, Apple Health. They predict the next period well, but the cycle is flattened into a countdown. The other three weeks, where most of the hormonal story actually happens, go unexplained.
Most apps answer "when is my next period?" — almost none answer "why do I feel like this today?"
The home is a single number: days until the next period. It says nothing about the phase you're in today or what it means for your energy and mood.
Symptoms are dense grids of tiny icons to tap through. It feels like data entry for a doctor, not a daily check-in with yourself.
Most apps demand an account and sensitive data up front, with no plain explanation of what's stored or why. Trust is assumed, never earned.
Four apps against the five things that actually matter for understanding the whole cycle. The gaps clustered in the same places — and that became Luna's brief.
Three principles reframed the product: lead with the current phase, make logging feel human, and always translate data into one plain-language insight.
The home adapts to the current phase — menstrual, follicular, ovulatory or luteal — surfacing what matters today instead of a generic dashboard.
Instead of a grid of icons, Luna asks one question at a time — lowering cognitive load and making the daily check-in feel natural.
Raw numbers are always translated into one plain sentence — "Your energy tends to peak in the next 3 days."
The home shows one insight at a time; depth is opt-in. A first glance never overwhelms someone who just wants to feel better.
One question, one answer. Logging reads like a chat, so it feels personal and takes seconds instead of a clinical form.
Luna explains what is stored and why before asking for anything — and works with no account, on-device first.
The flow from first open to daily insight, reconstructed in high fidelity. Each screen keeps one job and translates the body's data into something you can actually use today.
Before we start, here's exactly what Luna does — and doesn't — with what you log.
A small, documented foundation: one warm magenta for brand and action, four hormonal-phase hues that carry meaning across the app, and a type pairing tuned to sound like a knowledgeable friend.
A crescent carved from a single circle — the moon that names the app, and a quiet nod to the cycle it follows. It holds up as a 30px tab glyph or a 48px lockup without redrawing.
The same moment — opening the app — before and after. A countdown to one event becomes context for every day of the month.
As a solo, self-initiated project, speed mattered. I used AI to compress the mechanical work — synthesizing benchmarks, drafting copy, pressure-testing edge cases — so the time went to judgment, not busywork.
I compared Clue, Flo and Apple Health and clustered the gaps into three: no phase context, clinical logging, late privacy. The brief wrote itself from the patterns.
I mapped the four hormonal phases to what each one changes — energy, mood, skin, sleep — and turned that into the home's information architecture and the cycle ring.
I drafted and iterated the conversational copy and insights until they sounded like a knowledgeable friend — plain, kind, never clinical and never alarmist.
I used AI as a devil's advocate: what if cycles are irregular? what about users who don't want predictions? Questioning each choice surfaced edge cases before prototyping.
The hardest design problem wasn't the interface — it was deciding how much hormonal complexity to surface without overwhelming someone who just wants to feel better. Every screen is a tradeoff between depth and clarity. Luna's answer: one insight at a time, depth always opt-in.