💪 Protein Timing "Anabolic Window" Simulator

Workout Completed — Breakdown Outpaces Synthesis

Training briefly tips the balance toward muscle protein breakdown.

• +15%: MPB vs MPS shift (breakdown over synthesis)
• 0.0 h: Elapsed time (immediately post-set)
• 2-3×: Cortisol spike (transient rise)
• ~40%: Glycogen depleted (type II fibers)

Why breakdown rises

Mechanical stress briefly raises muscle protein breakdown.

Not actual muscle loss

This shift is normal turnover, not tissue damage.

Where the myth begins

This moment is the origin of the "anabolic window" idea.

Traditional "Anabolic Window" Belief

Bodybuilding lore demanded protein within a narrow post-workout minute count.

• 30-60 min: Believed window (popular claim)
• 1990s-2000s: Origin era (early sports nutrition)
• Heavy: Supplement marketing (shake timing urgency)
• Few: Strict-window studies (mostly small, flawed)

Where the myth started

Early studies used fasted, glycogen-depleted subjects.

Marketing amplified it

Supplement brands sold urgency around shake timing.

Evidence did not scale

Later meta-analyses found a much smaller effect.

Extended Sensitivity Period — Hours, Not Minutes

Muscle remains receptive to protein for several hours after training.

• 4-6 h: Real sensitivity window (elevated MPS response)
• up to 24 h: Detectable elevation (some MPS studies)
• Extends it: Pre-workout meal effect (amino acids already circulating)
• ~3 h: Sensitivity half-life (gradual decay, not a cliff)

Sensitivity decays gradually

Muscle protein sensitivity fades slowly, not sharply.

Pre-workout meals matter

A meal beforehand extends the effective window further.

No sharp cutoff exists

No study shows synthesis collapsing at minute 61.

Daily Total Intake Accumulates

Every meal across the day adds to cumulative muscle protein synthesis.

• 3-5: Meals per day (typical) (protein-containing meals)
• ~0.4 g/kg: Per-meal MPS ceiling (roughly, per dose)
• 1.6-2.2 g/kg: Daily need (trained) (bodyweight)
• Small: Distribution effect size (vs total intake effect)

Meals stack synthesis

Each protein meal triggers its own MPS pulse.

Distribution has minor effect

Even spacing helps slightly, not dramatically.

Total sets the ceiling

Cumulative daily grams cap how much muscle can grow.

Total Protein Dominates Over Timing

Research consistently ranks total daily protein above timing precision.

• Small: Timing effect size (confounded by total intake)
• Large: Total intake effect size (primary, robust driver)
• Hit daily total: Practical takeaway (timing is secondary)
• Total > timing: ISSN 2017 position stand (expert consensus)

Meta-analysis finding

Controlling for total protein erased the timing effect.

ISSN position stand

Total daily protein ranked as the primary driver.

Practical guidance

Hit your daily target; exact timing stays flexible.