Ingredient Intelligence
The Sports Nutrition Encyclopedia
Scientific profiles of every major supplement ingredient—mechanisms, dosing protocols, safety data, and evidence grades based on current peer-reviewed literature.
All ingredient information is for educational purposes only. Evidence grades reflect the quality and consistency of published human research. Always consult a healthcare professional before starting any supplementation program.
Evidence Key
The most researched ergogenic aid in sports nutrition. Increases phosphocreatine availability, enhancing ATP regeneration during high-intensity efforts.
Adenosine receptor antagonist with robust evidence for improving endurance performance, power output, reaction time, and perceived effort reduction.
Rate-limiting precursor to carnosine synthesis. Increases muscle carnosine levels, buffering lactic acid accumulation during high-intensity exercise.
Increases plasma arginine and nitric oxide production, improving blood flow, exercise efficiency, and potentially reducing post-exercise muscle soreness.
Fast-digesting, complete protein with a high BCAA content and leucine density. Superior leucine kinetics make it highly effective for stimulating muscle protein synthesis.
Branched-chain amino acids that stimulate muscle protein synthesis via mTOR activation. Evidence for supplemental BCAAs is modest when protein intake is adequate.
Leucine metabolite that may reduce muscle protein breakdown. Evidence is mixed; earlier studies showed greater effects than more recent, better-controlled trials.
Adaptogenic herb with emerging evidence for improvements in VO2 max, strength, and recovery. Cortisol-reducing effects may support muscle-building in stressed populations.
Converted to nitric oxide in the body, improving exercise efficiency and oxygen utilization. Most beneficial for endurance events and sub-maximal intensity exercise.
Deep Dive
Featured Ingredient: Creatine Monohydrate
Creatine is the most extensively studied ergogenic supplement in existence, with over 500 peer-reviewed studies supporting its safety and efficacy.
Proven Benefits
- Significant increases in maximal strength output (1RM)
- Improved performance in repeated high-intensity efforts
- Accelerated phosphocreatine resynthesis between sets
- Modest lean mass increases (partly from intramuscular water retention)
- Potential cognitive benefits, particularly under sleep deprivation
- Neuroprotective effects under investigation
Considerations & Limitations
- Non-responders exist (~25–30% show minimal phosphocreatine increase)
- Transient body weight gain of 1–2 kg from water retention
- Benefits primarily in efforts under 30 seconds; limited endurance impact
- No benefit if dietary creatine intake is already very high (e.g., heavy meat eaters)
- Should be used with caution in individuals with pre-existing kidney disease
Dosing Protocols
| Protocol | Dose | Duration |
|---|---|---|
| Loading phase | 20 g/day (4×5 g) | 5–7 days |
| Maintenance | 3–5 g/day | Ongoing |
| No-load approach | 3–5 g/day | 3–4 weeks to saturation |
Safety Profile
- Decades of human safety data with no verified serious adverse events
- No evidence of kidney damage in healthy individuals
- GRAS (Generally Recognized as Safe) designation
- Endorsed by International Society of Sports Nutrition (ISSN)
- Safe for adolescents under appropriate adult supervision
- Pregnancy and lactation data insufficient – avoid
Deep Dive
Featured Ingredient: Caffeine
Proven Benefits
- Reduces rating of perceived exertion (RPE) during exercise
- Improves endurance performance (time to exhaustion, time trial performance)
- Enhances short-term maximal power output
- Increases vigilance, reaction time, and mental focus
- May improve fat oxidation during submaximal exercise
- Synergistic effects with carbohydrates during endurance events
Considerations & Risks
- Tolerance develops with habitual use, reducing ergogenic effect
- High doses (>9 mg/kg) associated with anxiety, tremors, GI distress
- Disrupts sleep quality if consumed within 6 hours of bedtime
- Dependence and withdrawal symptoms with abrupt cessation
- Individual variation in metabolism (CYP1A2 gene polymorphisms)
- Caffeine pills and pure powder carry overdose risk—use caution
Dosing Guidelines
| Goal | Dose | Notes |
|---|---|---|
| Endurance performance | 3–6 mg/kg BW | 60 min pre-exercise |
| Strength/power | 3–6 mg/kg BW | 45–60 min pre |
| Cognitive effects | 100–300 mg | As needed |
Safety Notes
- FDA considers 400 mg/day safe for healthy adults
- Cardiovascular risk at very high doses in susceptible individuals
- Avoid in pregnancy (limit to <200 mg/day)
- Contraindicated in anxiety disorders, arrhythmias
- Drug interactions: MAOIs, some antibiotics (ciprofloxacin)