Creatine

The fastest backup battery your muscles have for short, hard efforts.

Mechanisms, studies and evidence grades for each claim above.

Functions

• Buffers ATP during high-intensity effort
• Supports repeated sprint/strength efforts

Mechanism

Phosphocreatine donates a phosphate group to ADP via creatine kinase, regenerating ATP faster than glycolysis or oxidative phosphorylation can — the reason it matters specifically for short, high-intensity bursts rather than endurance output. Synthesized in part from glycine + arginine, tying back to Glycine / Collagen's functional-use section.

Intake

Typical regimen: 3–5 g/day maintenance; optional loading protocol of 20 g/day split across doses for 5–7 days to saturate muscle stores faster.

Deficiency effects

No essential-nutrient deficiency syndrome, but low dietary intake (e.g., low meat/fish consumption) may reduce muscle creatine stores and performance capacity in some people.

Top foods

• Beef
• Pork
• Chicken
• Turkey
• Salmon
• Tuna

TODO — per the Metabolic Health hub's own note, creatine's evidence base (muscle and cognitive) is stronger than everything else in its current Tier 3 supplement slot; this page is a candidate for promotion alongside that decision.

Source page has no linked citations for this entry beyond the mechanism summary in its own text.