The science
No black boxes. Every formula, explained.
Built on published research in female physiology — cited inside the app, and written in plain language.
Four things the formulas get wrong.
Energy availability, not just calories
Low energy availability is what drives the downstream problems — cortisol elevation, blunted recovery, lean mass loss. Counting calories without accounting for what training takes back out misses the mechanism entirely.
Mountjoy et al., 2023
Fat-free mass beats total weight
Once body composition shifts, equations built on total weight begin to drift. Cunningham and Katch-McArdle use lean mass instead — more accurate, provided you know your numbers.
Cunningham, 1991 · Katch & McArdle
Protein rises with anabolic resistance
Midlife muscle needs a larger leucine stimulus to trigger the same response. Targets calibrated on younger populations sit too low, and the standard safety caps sit lower still.
Gatorade SSI, 2025 · Colenso-Semple, 2025
Phase effects are real — but modest
Energy needs shift after ovulation and nutrient demands vary across the cycle. The evidence on phase-based training is far more mixed than the internet suggests, and the app says so plainly rather than overclaiming.
Citation to be confirmed
Every figure in Sérénité Active is traceable to a published source, and the app shows you which one. Where the evidence is genuinely mixed, it says so — rather than presenting a preference as a finding.
Most apps ask for your blind trust. I’d rather earn it.
Every formula in Sérénité Active is drawn from published female clinical research, cited transparently inside the app, and explained in plain language.
You are never asked to trust a number you can’t interrogate.
Where you are today
Research, turned into a daily number.
Calculated, not guessed
Three setup models, so your targets start from your body rather than a population average.
Adaptive, within reason
Targets recalibrate as your metabolism shifts — inside a research-supported range, never a crash.
Honest about limits
Where the science is uncertain, the app tells you, rather than filling the gap with confidence.