Sources

Updated September 22, 2026 · The same list appears inside the app under Profile › About › Sources

WeekArc records what you log and shows it back to you. The few general health statements in the app and on this site come from the documents below. Nothing here is medical advice — decisions about your health belong to you and your care team.

Protein targets of about 1.2–1.6 g per kilogram per day during active weight reduction; appetite and energy intake often fall on GLP-1 therapy; adequate fluids and fiber encouraged

Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory (Mozaffarian D, et al.)
American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, The Obesity Society — Am J Clin Nutr 122(1):344–367, doi:10.1016/j.ajcnut.2025.04.023, 2025

Day-to-day weight swings are normal and largely reflect total body water, glycogen and other factors; a single reading is not tissue change

Weekly, seasonal and holiday body weight fluctuation patterns (Turicchi J, et al.)
PLOS ONE 15(4): e0232152, doi:10.1371/journal.pone.0232152, 2020

Smart-scale (bioelectrical impedance) body-composition estimates vary between days even under controlled conditions; trends matter more than single readings

Reliability, biological variability, and accuracy of multi-frequency bioelectrical impedance analysis (Looney DP, et al.)
Frontiers in Nutrition, doi:10.3389/fnut.2024.1491931, 2024

Semaglutide: half-life about 1 week, peak 1–3 days, steady state after 4–5 weeks

OZEMPIC (semaglutide) injection — Prescribing Information, section 12.3 Pharmacokinetics
Novo Nordisk, via DailyMed (U.S. National Library of Medicine)

Tirzepatide: half-life about 5 days, peak 8–72 hours, steady state after 4 weeks

MOUNJARO (tirzepatide) injection — Prescribing Information, section 12.3 Pharmacokinetics
Eli Lilly, via DailyMed (U.S. National Library of Medicine)

Liraglutide: half-life about 13 hours, peak 8–12 hours

VICTOZA (liraglutide) injection — Prescribing Information, section 12.3 Pharmacokinetics
Novo Nordisk, via DailyMed (U.S. National Library of Medicine)

About estimated values

Body-composition values shown in WeekArc (fat %, fat mass, lean mass, muscle, water %, visceral fat, BMR, metabolic age) are your own scale's estimates, read from Apple Health or from a screenshot of your scale app. WeekArc does not measure them and does not interpret them. The Estimated Medication Timeline is an educational illustration built from your own dose records and the pharmacokinetic data above; it is not a measurement.