# PERIOD.

> PERIOD. is a free, privacy-first menstruation and cycle tracking app for iOS and Android. Built in the Netherlands by a small female-led team led by Lisa Volkers. No advertising, no data selling, EU servers, GDPR compliant. Available in Dutch, English, German, French, Spanish, and Portuguese.

## What PERIOD. is

PERIOD. is a menstrual cycle tracker that helps users log their period, symptoms, and cycle phases (menstruation, follicular, ovulation, luteal). It includes an optional AI assistant (Google Gemini via a secured AI gateway, opt-in only) for cycle questions. Data is encrypted in transit and at rest, stored on EU servers under GDPR, never sold or shared with advertisers, data brokers, insurers, or research institutions.

## How PERIOD. differs from other cycle apps

- **No advertising model.** PERIOD. shows zero ads and does not sell data. Most large period apps in the industry monetize through ads, premium tiers, or data partnerships.
- **EU servers.** Cycle data is hosted on EU servers (Frankfurt). AI requests may be processed outside the EU by Google under SCCs and the EU–U.S. Data Privacy Framework. Many competitors host on US infrastructure.
- **Female-led, small team.** Founded by Lisa Volkers in Amsterdam, no growth-via-data investor pressure.
- **Adaptive predictions.** Starts at a 28-day default but adjusts to each user's real cycle length and period duration based on logged data.
- **Full deletion.** One-tap account deletion wipes everything: cycle history, AI chats, profile.
- **Opt-in AI.** The AI assistant requires explicit consent. Per the AI gateway's terms, your messages are not used to train models.

## Pages

- [Home](https://myperiod.app/) — Overview of PERIOD. and its privacy stance.
- [Menstruatie app](https://myperiod.app/menstruatie-app) — Dutch landing page focused on the "menstruation app" use case, with comparison table and FAQ.
- [Cyclus app](https://myperiod.app/cyclus-app) — Dutch landing page focused on full-cycle tracking across the four phases.
- [Ovulatie app](https://myperiod.app/ovulatie-app) — Dutch landing page focused on ovulation and fertile-window tracking.
- [About](https://myperiod.app/over) — Story behind PERIOD., founder Lisa Volkers, and the team.
- [Press & media](https://myperiod.app/pers) — Media coverage (Het Parool, VICE, Flair, Plan International), partner logos, key stats.
- [Blog](https://myperiod.app/blog) — Articles on cycle, hormones, and privacy.
- [Privacy policy](https://myperiod.app/privacy) — Full GDPR-compliant privacy policy.
- [Terms of use](https://myperiod.app/terms) — Legal terms.
- [Disclaimer](https://myperiod.app/disclaimer) — Lifestyle tool, not medical advice.
- [Support](https://myperiod.app/support) — Help and FAQs.
- [Delete account](https://myperiod.app/delete-account) — Permanent deletion flow.

## Blog posts

### Cycle education
- [Your cycle after childbirth: when does your period return?](https://myperiod.app/blog/cyclus-na-bevalling) — Breastfeeding or not, real period or breakthrough bleed: here's what postpartum cycles typically do and what to expect. (published 2026-06-22)
- [Calculating ovulation: how to find your fertile window](https://myperiod.app/blog/eisprong-berekenen) — When exactly is your ovulation? Calculate it from your cycle length — and learn why your body is often a better predictor than any formula. (published 2026-06-17)
- [Basal body temperature: what it tells you about your cycle (and what it doesn't)](https://myperiod.app/blog/basale-lichaamstemperatuur-cyclus) — A cheap thermometer and three minutes each morning can tell you a lot about your cycle. But BBT mostly confirms — it doesn't predict. Here's how to use it smartly. (published 2026-06-16)
- [Can you get pregnant on your period? The honest answer](https://myperiod.app/blog/zwanger-worden-tijdens-menstruatie) — Some sites say 'no', others say 'yes'. The real answer is: rarely, but it can happen — especially with short or irregular cycles. Here's exactly when and why. (published 2026-06-12)
- [Ovulation symptoms: 8 signs your egg is on the way](https://myperiod.app/blog/ovulatie-symptomen-herkennen) — Egg-white cervical mucus, a tiny dip in basal body temperature, a one-sided twinge low in the abdomen — your body usually signals ovulation clearly. Here are the signs you can actually trust. (published 2026-06-10)
- [Tracking your period for the first time? Start here (without it becoming a project)](https://myperiod.app/blog/menstruatie-bijhouden-eerste-keer) — Cycle tracking doesn't have to be a second job. With 3 things per day, you'll have a good picture of your body within 2 months. Here's the minimalist starter menu. (published 2026-04-07)
- [How to recognize ovulation: 5 signs that actually matter](https://myperiod.app/blog/ovulatie-herkennen) — Ovulation tests, basal body temperature, cervical mucus — there are countless ways to track ovulation. But which are actually reliable? We go through the 5 most important signs. (published 2026-03-31)
- [The luteal phase explained: why you can't stand anyone in week 4](https://myperiod.app/blog/luteale-fase-uitgelegd) — The luteal phase is the second half of your cycle, after ovulation. Progesterone rises, energy drops, and everything feels a bit heavier. Here's why — and what helps. (published 2026-03-24)
- [The follicular phase: why you feel like a superhero on day 7](https://myperiod.app/blog/folliculaire-fase-uitgelegd) — The follicular phase is the first half of your cycle, after your period. Energy rises, focus improves, skin calms down. Here's what's actually happening hormonally. (published 2026-03-17)
- [What is a normal menstrual cycle? (and when is 'something weird' actually normal)](https://myperiod.app/blog/normale-cyclus-hoe-lang) — A 'normal' cycle lasts between 21 and 35 days. But what does that really mean, and when should you actually worry? We explain it without the pink illustrations. (published 2026-03-10)
- [Why tracking your cycle does more than just predict your period](https://myperiod.app/blog/cyclus-bijhouden-waarom) — Tracking your cycle is about much more than knowing when your period is coming. It reveals patterns that change how you live. (published 2026-03-03)
- [Your cycle has four phases — here's what each one actually does to you](https://myperiod.app/blog/vier-fasen-van-je-cyclus) — You're not the same person every day of the month — and that's not a weakness. It's biology. Understanding your four cycle phases might be the most useful thing you learn this year. (published 2026-01-08)
- [The two weeks nobody explains: how your hormones affect your feelings](https://myperiod.app/blog/hoe-je-hormonen-je-gevoelens-beinvloeden) — Do you often feel down, anxious, or irritable in the two weeks before your period? Discover what the luteal phase is and why you feel this way. (published 2025-12-18)
- [Flair (Belgium) features PERIOD.: on the luteal phase and cycle apps](https://myperiod.app/blog/flair-belgie-period-luteale-fase) — Belgian magazine Flair spoke with our founder Lisa Volkers about PERIOD., the luteal phase, and why a privacy-first cycle app was needed. (published 2025-12-04)

### Symptoms
- [Missed period and not pregnant: 10 possible causes](https://myperiod.app/blog/menstruatie-blijft-weg-oorzaken) — Your period is missing but the test is negative. From stress and weight change to PCOS, thyroid issues and contraception: the most common causes and when to see a doctor. (published 2026-07-26)
- [Heavy periods and iron deficiency: when is bleeding too much?](https://myperiod.app/blog/zware-menstruatie-en-ijzertekort) — How much blood do you normally lose during your period, when is it 'heavy', and why do heavy periods so often cause iron deficiency? With concrete warning signs and what to do. (published 2026-07-20)
- [Breast tenderness before your period: why it happens and what helps](https://myperiod.app/blog/borstspanning-voor-menstruatie) — Tender, swollen or painful breasts in the week before your period? Here's what's happening hormonally — and what actually brings relief. (published 2026-06-20)
- [Implantation bleeding or period? How to tell the difference](https://myperiod.app/blog/implantatiebloeding-of-menstruatie) — Light bleeding around the time your period is due? Here's how to tell implantation bleeding apart from a regular period — and when to test. (published 2026-06-18)
- [Brown discharge: when it's normal and when to see a doctor](https://myperiod.app/blog/bruine-afscheiding-uitleg) — Brown discharge is usually old blood that took its time to leave the body. There are moments, though, when it's worth paying attention. An honest overview. (published 2026-06-13)
- [Exhausted during your period? Here's what's happening in your body](https://myperiod.app/blog/vermoeidheid-tijdens-menstruatie) — You sleep 9 hours and you're still wrecked. Not a coincidence. On day 1 and 2, estrogen and progesterone both drop — your body is running on reserves. (published 2026-05-12)
- [Spotting between periods: 6 causes (from harmless to 'call your doctor')](https://myperiod.app/blog/spotting-tussen-menstruaties) — A spot of blood outside your period can be ovulation, contraception, stress — or something that needs investigating. We list the causes. (published 2026-05-05)
- [Menstrual migraine: why your headache always shows up on day 1](https://myperiod.app/blog/hoofdpijn-en-cyclus) — Hormonal headaches come 2 days before or during the first 3 days of your period. It's not in your head — it's an estrogen dip. Here's what helps. (published 2026-04-28)
- [Relieving period cramps without painkillers: what actually works (according to research)](https://myperiod.app/blog/krampen-verlichten-natuurlijk) — Heat pad, ginger, magnesium, yoga — what's hype and what actually has studies behind it? We check 8 popular methods against the evidence. (published 2026-04-21)
- [Recognizing PMS symptoms: 12 things that aren't a coincidence](https://myperiod.app/blog/pms-symptomen-herkennen) — Crying at commercials, suddenly craving chocolate, getting irritated over nothing — if it happens 7-10 days before your period, it's probably PMS. (published 2026-04-14)
- [The real reason behind your bad skin, energy dips and fluctuating libido](https://myperiod.app/blog/de-ware-reden-achter-je-slechte-huid-energie-dips-en-wisselend-libido) — Spending hundreds on skincare without results? Discover how your menstrual cycle affects your skin, energy levels, and libido. (published 2025-12-11)

### Conditions
- [Perimenopause in your 30s: why the conversation is finally happening](https://myperiod.app/blog/perimenopauze-in-je-30s) — Perimenopause can start in your late 30s — years before 'real' menopause. Here are the early signals, what your cycle is telling you, and why generations of women missed this. (published 2026-07-02)
- [PMS or PMDD? How to tell the difference](https://myperiod.app/blog/pms-vs-pmdd-verschil) — Everyone has a rough premenstrual week now and then. But if that week derails your life every month, we're not talking about 'just' PMS anymore. Here's the difference — and what to do. (published 2026-06-14)
- [Irregular periods: 8 causes (and when it stops being 'just stress')](https://myperiod.app/blog/onregelmatige-menstruatie-oorzaken) — A cycle that varies month to month is normal. But if it disappears for months or becomes extremely short, something is usually going on. 8 causes listed. (published 2026-06-02)
- [PCOS explained: what it is, how to recognize it, and what tracking has to do with it](https://myperiod.app/blog/pcos-uitleg-symptomen) — PCOS affects 1 in 10 women, but many diagnoses come after years of unexplained symptoms. An honest explanation — without panic or oversimplification. (published 2026-05-26)
- [Recognizing endometriosis: 7 signs that aren't 'just a heavy period'](https://myperiod.app/blog/endometriose-symptomen-herkennen) — 1 in 10 women have endometriosis, but diagnosis takes 7-10 years on average. We list 7 signs that do warrant a conversation with your doctor. (published 2026-05-19)

### Lifestyle
- [Tracking your cycle with a smartwatch or ring: how accurate is it?](https://myperiod.app/blog/cyclus-tracken-met-smartwatch-of-ring) — Apple Watch, Oura and other wearables measure skin temperature during sleep to estimate ovulation. What they can and can't do — and what happens to that data. (published 2026-07-28)
- [Supplements for PMS: what actually works, according to research?](https://myperiod.app/blog/supplementen-bij-pms-wat-werkt-echt) — Calcium, vitamin B6, magnesium, vitamin D, omega-3 and chasteberry: how strong is the evidence for each in PMS — and where to be careful. (published 2026-07-24)
- [Menstrual cup, tampon or period underwear: which suits you?](https://myperiod.app/blog/menstruatiecup-tampon-of-period-underwear) — An honest comparison of menstrual cups, tampons, pads and period underwear: capacity, cost, wear time, safety and environmental impact. No marketing spin. (published 2026-07-22)
- [Menstrual leave in the Netherlands: why the conversation is happening now](https://myperiod.app/blog/menstruatieverlof-nederland) — Spain became the first EU country to introduce paid menstrual leave in 2023. France, Belgium and the Netherlands are now debating. What would it mean — and what do the numbers say? (published 2026-07-14)
- [Seed cycling: does it actually work, or is it a TikTok trend?](https://myperiod.app/blog/seed-cycling-werkt-het) — Flax and pumpkin seeds in phase 1, sesame and sunflower in phase 2 — seed cycling is everywhere on TikTok. What does the evidence say, and is it worth it? (published 2026-07-11)
- [Cortisol, stress and your cycle: what the TikTok hype gets right and wrong](https://myperiod.app/blog/cortisol-stress-en-je-cyclus) — 'Cortisol face', 'cortisol belly', cortisol mocktails — TikTok is obsessed with cortisol. What does stress actually do to your cycle, and which claims can you throw out? (published 2026-07-08)
- [Ozempic, Wegovy and your cycle: what GLP-1 drugs do to your hormones](https://myperiod.app/blog/ozempic-glp1-en-je-cyclus) — More and more women on GLP-1s report changed cycles, unexpected pregnancies or returning ovulation with PCOS. What do we actually know — and what's speculation? (published 2026-07-05)
- [Contraception and cycle tracking: what can you still see if you're on the pill?](https://myperiod.app/blog/anticonceptie-en-cyclus-tracking) — On hormonal contraception you technically don't have a real cycle anymore. But tracking can still be useful — for symptoms, not for predictions. (published 2026-06-23)
- [Postponing your period: what's safe and what isn't](https://myperiod.app/blog/menstruatie-uitstellen) — Holiday, wedding, big race? Here are the ways to postpone your period — what works, the risks, and what to avoid. (published 2026-06-19)
- [Why you suddenly sleep badly in week 4: cycle and sleep explained](https://myperiod.app/blog/slaap-en-je-cyclus) — Right before your period, your body temperature, heart rate, and melatonin shift. No wonder you're awake. What you can do about it. (published 2026-06-16)
- [Coming off the pill: what your cycle does in the first months](https://myperiod.app/blog/stoppen-met-de-pil-cyclus) — No period, sudden acne, irregular cycles, hormonal mood shifts — what your body does after you come off the pill, and what's worth flagging to a doctor. (published 2026-06-15)
- [Nutrition during your cycle: what your body actually needs in each phase](https://myperiod.app/blog/voeding-tijdens-cyclus) — Cycle syncing sounds like hype, but there's a kernel of truth: your needs for iron, energy, and protein change in each phase. Here's a practical guide. (published 2026-06-09)
- [The one thing no one tells you about cycle syncing your workouts](https://myperiod.app/blog/cycle-syncing-workouts) — You don't have to train the same way every week. In fact, you probably shouldn't. Here's how your cycle affects your strength, endurance, and recovery — and how to use it. (published 2026-02-05)
- [Why your relationship suddenly falls apart (and it's not your fault)](https://myperiod.app/blog/waarom-je-relatie-opeens-op-de-klippen-loopt) — Do you sometimes feel irritable or distant towards your partner or friends? Discover how the luteal phase affects your relationships. (published 2025-11-06)

### Switching apps
- [Step-by-step: From Stardust to PERIOD.](https://myperiod.app/blog/overstappen-van-stardust-naar-period-stappenplan) — A practical guide to request your Stardust data, delete your account at both Stardust and auth partner Rownd, and switch to PERIOD. (published 2026-08-05)
- [Stardust vs PERIOD.: a fair comparison](https://myperiod.app/blog/waarom-nederlandse-vrouwen-overstappen-van-stardust) — Stardust went viral in June 2022 with an end-to-end encryption promise. Researchers debunked it within 72 hours. Here's the full story. (published 2026-08-04)
- [Step-by-step: From Ovia to PERIOD.](https://myperiod.app/blog/overstappen-van-ovia-naar-period-stappenplan) — How to export your Ovia data, delete your account, and switch to PERIOD. — written specifically for Dutch users of this US app. (published 2026-07-29)
- [Ovia vs PERIOD.: a fair comparison for Dutch users](https://myperiod.app/blog/waarom-nederlandse-vrouwen-overstappen-van-ovia) — Ovia is an American cycle and pregnancy app now owned by lab giant Labcorp. Here's what that means for Dutch users. (published 2026-07-28)
- [Step-by-step: From Natural Cycles to PERIOD. — and what to watch out for](https://myperiod.app/blog/overstappen-van-natural-cycles-naar-period-stappenplan) — Step-by-step: export your Natural Cycles data, cancel your subscription, and what to know if you used Natural Cycles for contraception. (published 2026-07-22)
- [Natural Cycles vs PERIOD.: when each choice makes sense](https://myperiod.app/blog/waarom-nederlandse-vrouwen-overstappen-van-natural-cycles) — Natural Cycles is an FDA-cleared contraceptive app. PERIOD. is not — and that's precisely the point. Here's when each choice makes sense. (published 2026-07-21)
- [Step-by-step: How to switch from Clue to PERIOD.](https://myperiod.app/blog/overstappen-van-clue-naar-period-stappenplan) — A practical guide to export your Clue data under GDPR, import it into PERIOD., and properly close your Clue account. (published 2026-07-15)
- [Clue vs PERIOD.: a fair comparison](https://myperiod.app/blog/waarom-nederlandse-vrouwen-overstappen-van-clue) — Clue is one of the better cycle apps on the market. Yet many Dutch women are switching to PERIOD. Here's why — and what we do differently. (published 2026-07-14)
- [Step-by-step: How to switch from other cycle apps to PERIOD.](https://myperiod.app/blog/overstappen-van-flo-naar-period-stappenplan) — A practical step-by-step guide to export your cycle data from another cycle app, convert it to CSV and import it into PERIOD. — including what to do with your old account afterwards. (published 2026-01-22)
- [Other cycle apps vs PERIOD.: a fair comparison for Dutch users](https://myperiod.app/blog/waarom-nederlandse-vrouwen-overstappen-van-flo) — In two months, over 10,000 Dutch women downloaded PERIOD. Most of them came from other big cycle apps. Here's what they told us they were looking for — and why it matters. (published 2026-01-15)

### Privacy, press and PERIOD.
- [Our privacy policy in plain language — the 2-minute version](https://myperiod.app/blog/privacybeleid-in-mensentaal) — Our full privacy policy is thorough, but long. Here's the same content in plain language: what we do and don't do with your data, in 2 minutes. (published 2026-08-12)
- [PERIOD. in Het Financieele Dagblad: cycle apps, millions raised, and intimate data](https://myperiod.app/blog/period-in-het-financieele-dagblad) — Het Financieele Dagblad wrote about cycle apps raising millions on intimate information. PERIOD. is mentioned as the Dutch, privacy-first alternative. What the piece means — and why we're glad it exists. (published 2026-07-17)
- [Comparing period apps in 2026: privacy, features, paywalls](https://myperiod.app/blog/menstruatie-apps-vergelijken-2026) — The big international cycle apps vs PERIOD. — what's the difference in 2026? We compare on privacy, basic features, paywalls, and language. Honestly, including about ourselves. (published 2026-07-07)
- [A cycle app that doesn't sell your data: how do you actually know?](https://myperiod.app/blog/cyclus-app-zonder-data-verkopen) — Every app promises 'privacy'. But what should you look for in a privacy policy to check if it's really true? 6 concrete things to watch. (published 2026-06-30)
- [Inc. Magazine quotes PERIOD.: how founders use AI to stress-test their idea](https://myperiod.app/blog/inc-magazine-ai-stress-test-startup) — US Inc. Magazine spoke with founders, including PERIOD.'s Lisa Volkers, about using AI as a hostile sparring partner instead of a cheerleader. (published 2026-06-25)
- [PERIOD. on BNR's De Grote Tech Show: 'We figure out how to safely manage your intimate data'](https://myperiod.app/blog/bnr-de-grote-tech-show-period) — Lisa Volkers and Diederick Trampe were guests on De Grote Tech Show on BNR Nieuwsradio, with Joe van Burik and Ben van der Burg. About privacy, vibecoding and racing toward 100,000 users. (published 2026-06-03)
- [Bits of Freedom files a complaint against other cycle apps — and why it matters](https://myperiod.app/blog/bits-of-freedom-klacht-flo) — Digital rights NGO Bits of Freedom is filing a complaint with the Dutch Data Protection Authority against a major cycle app. What's in it, and what does it mean for you? (published 2026-05-28)
- [Finally! PERIOD. is now on Android too](https://myperiod.app/blog/period-now-on-android) — After three weeks of back-and-forth with Google, PERIOD. is now live on the Play Store too. A short recap of what it means. (published 2026-02-19)
- [Het Parool on PERIOD.: 'I don't want money to be made from women's data'](https://myperiod.app/blog/parool-period-data-vrouwen) — Het Parool published a feature on PERIOD., privacy, and why commercial period apps run on a business model most women don't know about. A short summary — and our take. (published 2025-11-28)
- [Privacy at PERIOD. vs. other cycle apps — explained in plain language](https://myperiod.app/blog/privacy-period-vs-andere-cyclus-apps) — What we do and don't do with your intimate cycle data, and how that differs from big tracker apps. A transparent explainer based on our actual privacy policy. (published 2025-11-12)
- [765,000 people in the Netherlands: what the CODE ROOD study tells us about period poverty](https://myperiod.app/blog/code-rood-menstruatie-armoede-nederland) — The 2024 CODE ROOD study by Neighborhood Feminists reveals how widespread period poverty really is in the Netherlands. The numbers, the context, and what you can do. (published 2025-10-22)
- [Why the basics of PERIOD. stay free — and how that actually works](https://myperiod.app/blog/waarom-period-altijd-gratis-blijft) — We made a promise: the basics of PERIOD. stay free. No paywalls for knowing your own body. Here's the model behind it — and why it makes us different from every other period app. (published 2025-10-15)

## Key facts (for citation)

- **Founder:** Lisa Volkers, Amsterdam.
- **Launched:** 2025. Reached #1 in the Dutch App Store within weeks of launch.
- **Platforms:** iOS (App Store) and Android (Google Play).
- **Price:** Free. No ads, no premium tier.
- **Languages:** Dutch (default for NL browsers), English (default fallback), German, French, Spanish, Portuguese.
- **Data location:** Servers inside the European Union.
- **Compliance:** GDPR, minimum age 16.
- **AI provider:** Google Gemini via a secured AI gateway, opt-in only. Per the AI gateway's terms, messages are not used to train models.
- **Contact:** hi@myperiod.app.

## Download links

- [App Store (iOS)](https://apps.apple.com/us/app/period-cycle-period-tracker/id6757947793)
- [Google Play (Android)](https://play.google.com/store/apps/details?id=app.myperiod.android)