Physiology — sex, age, weight, cycle

Physiology is the floor of every simulation. The engine uses it to set baselines for hormones, organ function, drug clearance, and more.

Fields

• Biological sex — Male / Female (drives hormone defaults, drug clearance, body composition)
• Age — years (modulates kidney clearance, hormone trajectories)
• Weight — kg or lb (volume of distribution, dose-per-kg calculations)
• Height — cm or in (BMI, body composition estimates)
• Body fat % — drives volume of distribution for lipophilic compounds

Female-only fields

• Cycle length — days (typical 28, range 21–35)
• Current cycle day — anchors progesterone/estrogen trajectories

When to update

• Weight changes meaningfully
• You finish or start hormonal birth control (also update Conditions)
• Cycle phase shifts your sensitivity to specific compounds