Glycogen Synthesis Calculator

Accurately estimate glycogen synthesis rate based on insulin, glucose availability, exercise status, and muscle/liver specificity using peer-reviewed scientific models.

Plasma Glucose Concentration (mg/dL)

Plasma Insulin Concentration (μU/mL)

Recent Exercise Status

Target Tissue

Recent Carbohydrate Intake (g/kg body weight in last meal)

Body Weight (kg) – optional for absolute rates

Glycogen Synthesis Rate:

About the Glycogen Synthesis Calculator

The Glycogen Synthesis Calculator is a scientifically accurate tool designed to estimate the rate of glycogen resynthesis in skeletal muscle and liver following carbohydrate ingestion and/or exercise. Glycogen is the storage form of glucose in animals and humans, primarily stored in liver and skeletal muscle, and serves as a critical energy reserve during fasting and physical activity.

This Glycogen Synthesis Calculator uses established physiological models based on peer-reviewed research from leading journals such as Journal of Applied Physiology, American Journal of Physiology – Endocrinology and Metabolism, and Diabetes. The calculations incorporate the major regulators of glycogen synthase activity: plasma glucose, insulin concentration, prior glycogen depletion (exercise), and tissue-specific differences.

            Key Scientific Foundations:

            • Maximal muscle glycogen synthesis rate after intense exercise: ~8–12 mmol/kg wet weight/hour (≈ 1.3–2.0 g/kg/h)

            • Insulin-mediated liver glycogen synthesis: up to 4–6 mmol/kg/h

            • Glucose + insulin synergy increases glycogen synthase activity via dephosphorylation (GS activation)

            • GLUT4 translocation in muscle is enhanced post-exercise (insulin-independent phase first 30–60 min)

Why Glycogen Synthesis Matters

Glycogen replenishment is crucial for athletes, people with diabetes, and anyone interested in metabolic health. Rapid restoration of muscle glycogen after intense exercise directly impacts recovery, subsequent performance, and muscle adaptation. In the liver, glycogen synthesis prevents hypoglycemia during fasting and supports whole-body glucose homeostasis.

Impaired glycogen synthesis is a hallmark of insulin resistance and type 2 diabetes. Monitoring potential synthesis rates can help clinicians and researchers assess metabolic flexibility.

How the Calculator Works – Scientific Model

The calculator implements a composite model based on classic studies (Shulman et al., 1990; Price et al., 1996; Jensen et al., 2011; González et al., 2016):

Base rate at fasting glucose/insulin ≈ 0.5–1 mmol/kg/h
Insulin effect: exponential increase in glycogen synthase activity (Hill coefficient ≈ 2–3)
Glucose effect: substrate-driven mass action + allosteric activation of glycogen synthase
Exercise multiplier: 3–5× higher rate in first 4–6 hours post glycogen-depleting exercise due to increased GLUT4 and hexokinase activity
Carbohydrate load: higher recent CHO intake increases intracellular G6P, further activating synthase

When & Why You Should Use This Tool

• Athletes planning post-workout nutrition timing and carbohydrate dosing
• Sports nutritionists designing recovery protocols
• Researchers modeling glycogen turnover in metabolic studies
• People with diabetes or metabolic syndrome assessing insulin sensitivity indirectly
• Fitness enthusiasts optimizing performance and recovery

User Guidelines & Interpretation

Optimal muscle glycogen synthesis (>7 mmol/kg/h or >1 g/kg/h) requires:
– Carbohydrate intake ≥1.2 g/kg/h in the first 4–6 hours post-exercise
– Adequate insulin response (postprandial insulin >30 μU/mL)
– Recent glycogen-depleting exercise

Values below 3 mmol/kg/h suggest suboptimal conditions (low insulin, low glucose, no recent exercise).

Limitations & Accuracy

This tool provides an evidence-based estimate, not a direct measurement. Direct measurement requires 13C-MRS or muscle biopsy. Factors not included: genetic variation in glycogen synthase, cortisol/epinephrine levels, exact timing since last meal/exercise, muscle fiber type distribution.

References & Further Reading

Jensen J, et al. (2011). "Regulation of glycogen synthase in muscle." Acta Physiol.
González JT, et al. (2016). "Liver glycogen metabolism during prolonged exercise." Med Sci Sports Exerc.
Shulman GI, et al. (1990). "Quantification of muscle glycogen synthesis in normal subjects and subjects with NIDDM." N Engl J Med.

For more agricultural and health-related tools, visit Agri Care Hub.

Learn more about the opposite process at Wikipedia: Glycogenolysis.