now available
Big Sis
SIS is always here for you. Not everyone is lucky enough to have a big sis — I have three, and sometimes you just need one. That's why we're here.
SIS helps you build a calm, factual record of what you've been experiencing. Big Sis turns that record into a personalised companion — for the journey ahead, whatever shape it takes.
She's here now, in the SIS app on iPhone and Android, with a 7-day free trial. She was built with the same calm and honesty as SIS itself, and free SIS stays exactly as it is.
What Big Sis offers
A personalised journey, from where you are now
Whether you're navigating a confirmed diagnosis or still seeking answers, Big Sis shapes itself around your story. Everyone's path is different — let your Big Sis walk it with you.
An intelligence layer for those still seeking answers
Calm, structured information about patterns and possibilities — surfacing relevant communities and reading, never suggesting a diagnosis. The elephant in the room becomes nameable; your healthcare team confirms what's actually there.
Longitudinal reports
Your last six months, twelve months, or longer — clinically scannable and ready to bring to any appointment.
Still to come
Part of the plan, not part of the subscription yet — so you know what you are and aren't buying today.
Medication intelligence
Timing patterns, missed-dose awareness, and gentle correlation between medications and symptom changes — so the conversation with your doctor becomes clearer.
Cloud backup and sync
Your story protected and accessible across all your devices. Optional, secure, always under your control. Encrypted backup you run yourself is already free in SIS today.
Helping the wider system listen
With your explicit permission, Big Sis will feed anonymous patterns and trends — never personal information — back into clinical systems and research. So the experience of being dismissed becomes harder to repeat, for the women who come next. We're working carefully on how to do this safely.
Free SIS is always here for you. Big Sis is for when you need a little more.
The free tier always remains genuinely useful: pattern detection, doctor summaries, appointments and medications, full safety awareness.
We'd love your input
Big Sis is being shaped by women who've lived this. If there's something you'd want from a tool like this, please get in touch at hello@bigsis.health.
— T