A coach that reads the research, then reads you.
BYRN AI is a conversational health and performance coach. Evidence-cited answers, adapted to your body and your history.
Example conversations with BYRN AI
Jumper's knee recovery
You: Knee's sore again after yesterday's session. Skip legs tomorrow?
BYRN AI: Quick note — this is general info, not a diagnosis. Day-after soreness is normal while you're rehabbing a tendon; the call isn't to skip, it's to manage the load and type.
BYRN AI: The research is clear: a patellar tendon responds better to continued loading than to rest — total rest just delays recovery. That doesn't mean repeating yesterday; it means dialing back intensity and leaning on isometric wall sits, genuinely the best painkiller you have before a leg session. (Source: Patellar Tendinopathy: Clinical Diagnosis, Load Management, and Advice for Challenging Case Presentations — Malliaras et al., 2015, Journal of Orthopaedic & Sports Physical Therapy)
BYRN AI: So tomorrow: wall sits fresh (5 × 45s), then pain-free work — leg extensions, calf raises, controlled RDLs. Skip deep squats and leg press; move them later in the week if you need to.
Caffeine dosage
You: Does my 4pm coffee actually matter that much?
BYRN AI: It genuinely does. A 4pm coffee — about 95 mg of caffeine in a standard mug — still leaves measurable amounts in your system at bedtime, and even that tail cuts total sleep by a meaningful amount. (Source: Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed — Drake et al., 2013, Journal of Clinical Sleep Medicine)
BYRN AI: Caffeine's half-life is 5–6 hours, so you've still got roughly 50 mg in your blood at 10pm — and a teenage nervous system is more sensitive to it than an adult's, so it hits harder. An hour of lost sleep a night stacks fast against strength gains and recovery.
BYRN AI: Better move: front-load it. A morning cup has the whole day to clear; after 1pm you're playing against your own sleep.
Is creatine worth it?
You: Is creatine actually worth taking, or is it just hype?
BYRN AI: Creatine isn't hype — it's one of the most studied supplements there is, and it genuinely works: you gain more muscle and strength on it than off it when you're training hard. Three to five grams a day with food is the standard dose. (Source: Creatine Supplementation and Aging Musculoskeletal Health — Candow et al., 2022, Nutrients)
BYRN AI: That said, it's a marginal win, not magic — maybe 5–10% on top of what training and enough protein already deliver, and it shows over months, not weeks. Sleep, protein, and consistency matter far more than whether you're on it.
BYRN AI: Where it earns its place right now: it helps preserve muscle when you're not moving as much — useful while you're rehabbing the knee. It's harmless and compounds over time, so keep taking it.
Focus areas
Three systems. One coach.
Fitness, recovery and nutrition aren't separate problems — they feed each other. BYRN AI coaches them as one system, with the research to back every call.
Fitness
Progressive training around your history and joints. BYRN learns what actually drives adaptation—from the research and from you. Your workouts adjust as you do.
Recovery
Sleep is where training compounds. Tell BYRN how you slept and how you feel, and it knows when rest beats another session. Recovery is the advantage most people skip.
Nutrition
Evidence-based guidance on fueling and protein timing—in conversation, like everything else. Meal plans come in a later update. For now, the science behind how to fuel yourself steadily, without the crash cycles.
How it learns
Your context in. Science applied. Advice that sticks.
BYRN AI doesn't hand out generic plans. It holds what you've told it, checks it against the research, and answers with advice specific enough to act on.
01 — what you tell it
- left knee — patellar tendinitis
- getting ~6h sleep
- goal: 10k under 45
- coffee at 2–3pm most days
- trains mornings
- scrolls in bed most nights
02 — what the research says
- Malliaras et al., 2015
- Drake et al., 2013
- Chang et al., 2015
03 — what you get
Fitness
Skip tomorrow's intervals — the tendon heals from the right load, not pushing through. Swap in heavy, slow strength. No jumping or running. Isometric holds first to settle pain, then build over weeks.
Sleep
Caffeine's half-life is 5–6 hours — your 2pm coffee is still circulating at 8. Even 6 hours before bed, it measurably cuts your sleep. Move it before noon, or skip it on school days.
Cognition
Screens in bed delay melatonin and cut REM sleep. That's the 6-hour nights — and the slower mornings. Phone out of the room 30–45 min before sleep.
Build your rhythm. Sustain it. Measure it.
In the lab
BYRN is a brand, not a single app.
BYRN AI is first. More tools are coming — each one built with the same care, each one deepening the same understanding of you.
Minimalist Launcher
ExploringA phone that asks less of you. Attention is recovery too.
Health App
ExploringYour sleep, training and recovery signals in one quiet place.
Calorie Tracker
ExploringLogging without the moralizing. Food as data, not judgment.
Be first. No countdown, no pressure.
We’ll reach out with early access when BYRN AI is ready.
We’ll only use your email for BYRN AI — a quick note now, and one more when it’s ready. Leave the waitlist anytime from the email we send.