---
id: supplementation
name: Evidence-Based Supplementation
aliases: [supplements, creatine, caffeine, beta-alanine, sports supplements]
category: nutrition
applies_to: [all_systems]
related: [protein_requirements, energy_balance, nutrient_timing]
sources:
  - title: "International Society of Sports Nutrition Position Stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine"
    author: "Kreider, R. B., Kalman, D. S., Antonio, J., et al."
    year: 2017
    journal: "Journal of the International Society of Sports Nutrition"
    volume: 14
    pages: "18"
    doi: "10.1186/s12970-017-0173-z"
    credibility: expert_consensus
  - title: "International Society of Sports Nutrition Position Stand: caffeine and exercise performance"
    author: "Guest, N. S., VanDusseldorp, T. A., Nelson, M. T., et al."
    year: 2021
    journal: "Journal of the International Society of Sports Nutrition"
    volume: 18
    pages: "1"
    doi: "10.1186/s12970-020-00383-4"
    credibility: expert_consensus
  - title: "International Society of Sports Nutrition Position Stand: beta-alanine"
    author: "Trexler, E. T., Smith-Ryan, A. E., Stout, J. R., et al."
    year: 2015
    journal: "Journal of the International Society of Sports Nutrition"
    volume: 12
    pages: "30"
    doi: "10.1186/s12970-015-0090-y"
    credibility: expert_consensus
---

# Evidence-Based Supplementation

Most supplements sold to strength athletes lack sufficient evidence to justify their cost. Three supplements consistently clear the bar for evidence quality, safety profile, and practical benefit for resistance-trained athletes: **creatine monohydrate**, **caffeine**, and **beta-alanine**. This entry covers these three only. All other supplements should be evaluated against the same standard before use.

## Tier Structure

| Tier | Criteria | Supplements |
|------|----------|-------------|
| Tier 1 (strong evidence) | Multiple RCTs, meta-analyses, known mechanism | Creatine, caffeine |
| Tier 2 (moderate evidence) | Consistent but smaller evidence base; clear mechanism | Beta-alanine |
| Tier 3 (insufficient evidence) | Mixed results, weak mechanism, or industry-funded only | Everything else |

---

## Creatine Monohydrate

**The most evidence-supported performance supplement in existence.** Over 500 published studies. The mechanism is well-established: creatine increases intramuscular phosphocreatine (PCr) stores, which are the primary high-intensity energy buffer for the first 10 seconds of maximal effort. Higher PCr stores allow more work per set before fatigue onset.

### Effects
- Strength and power output: **+5–15%** increase in maximal strength across studies (larger effect in beginners, ~5% in trained athletes)
- High-rep endurance: 1–2 additional reps at a given load before failure
- Lean mass: 1–2 kg of additional lean mass over 4–12 weeks (water retention in muscle + improved training capacity)
- Recovery: reduced muscle cell damage markers; faster PCr resynthesis between sets

### Protocol
| Approach | Protocol | Notes |
|----------|----------|-------|
| Loading (optional) | 20 g/day for 5–7 days (4 × 5 g doses), then 3–5 g/day | Saturates stores faster; not required |
| Standard | **3–5 g/day** indefinitely | Saturates stores within ~4 weeks; simpler |
| Timing | Any time of day | Post-workout may have marginal advantage; effect is small |
| Form | Monohydrate | Other forms (HCl, buffered) are not superior and cost more |

### Safety
Creatine monohydrate has a 30-year safety record across clinical populations. It is not harmful to healthy kidneys. The ISSN 2017 position stand explicitly states no known adverse health effects in healthy individuals at recommended doses. The only noted side effect is water retention (1–2 kg of intramuscular water, not subcutaneous fat — not cosmetically visible).

---

## Caffeine

**The most widely used and best-documented performance-enhancing substance.** Mechanism: adenosine receptor antagonism — blocks the neural signal for fatigue, reduces perceived exertion at a given workload.

### Effects
- Strength and power: **+2–7%** improvement in 1RM and peak power output
- Muscular endurance: ~12% increase in total reps to failure
- Aerobic performance: well-documented ~3–5% improvement
- Alertness and focus: consistent reduction in perceived exertion and improved task attention

### Protocol
| Parameter | Target | Notes |
|-----------|--------|-------|
| Dose | **3–6 mg/kg body weight** | 210–420 mg for a 70 kg individual |
| Timing | **45–60 minutes before training** | Peak plasma levels at 60 min |
| Form | Any (coffee, anhydrous powder, capsules) | Anhydrous may have slight advantage over coffee for consistency |
| Frequency | Not daily | Tolerance builds within 1–2 weeks of daily use; cycle off or reduce |

**Caffeine tolerance**: Daily use causes upregulation of adenosine receptors, reducing the acute performance benefit. A 7–10 day washout every 4–6 weeks restores full sensitivity. During washout: 2–3 days of headaches and reduced alertness is normal and expected.

**Sensitive populations**: High responders experience anxiety, increased heart rate, and sleep disruption at doses above 3 mg/kg. Starting at 1–2 mg/kg and titrating upward allows identification of individual tolerance. Caffeine consumed less than 6 hours before sleep impairs sleep quality even when sleep onset is not subjectively affected.

---

## Beta-Alanine

**The primary carnosine buffer precursor.** Mechanism: beta-alanine is the rate-limiting substrate for intramuscular carnosine synthesis. Carnosine buffers the drop in intramuscular pH that occurs during high-rep sets, attenuating the "burning" sensation and extending time to muscular failure.

### Effects
- High-rep muscular endurance (60–240 second work efforts): **+2–3%** improvement
- Effective range: efforts lasting **1–10 minutes** at near-maximal intensity
- Minimal benefit for single heavy sets (≤5 reps) or very long submaximal efforts
- Small but consistent effect on high-rep hypertrophy work (sets of 10–20)

### Protocol
| Parameter | Target | Notes |
|-----------|--------|-------|
| Daily dose | **3.2–6.4 g/day** | Split into 1.6 g doses to reduce paresthesia |
| Timing | Any time; consistent daily use | Effect is chronic (muscle carnosine accumulates over weeks) |
| Duration | 4+ weeks to reach saturation | Full benefit requires sustained supplementation |
| Loading | Not applicable | Unlike creatine, there is no acute loading strategy |

**Paresthesia**: A harmless skin tingling (pins and needles) occurring 15–30 minutes after ingestion, lasting 60–90 minutes. It is dose-dependent and can be eliminated by splitting doses to ≤1.6 g. Slow-release formulations also attenuate paresthesia.

---

## What Not to Take (Unless Evidence Changes)

The following supplements are frequently marketed to strength athletes but lack Tier 1 evidence at the doses marketed:

| Supplement | Status | Evidence summary |
|-----------|--------|-----------------|
| BCAAs (when protein targets met) | Not needed | No benefit when total daily protein (1.6+ g/kg) is adequate; leucine already in protein meals |
| HMB (β-hydroxy β-methylbutyrate) | Weak evidence | Effect seen primarily in untrained individuals; minimal effect in trained athletes |
| Pre-workout blends | Variable | Often contain effective doses of caffeine + beta-alanine, but with undisclosed dosing ("proprietary blends") and fillers; buying ingredients separately is more cost-effective |
| Testosterone boosters | Not supported | No commercially available supplement meaningfully raises testosterone in healthy males |
| Fat burners | Not supported | Stimulant effects; no meaningful fat loss beyond caffeine's modest thermogenic contribution |

## How Systems Differ

- **Powerlifting / Strongman**: All three Tier 1 and Tier 2 supplements apply. Creatine is the highest priority. Beta-alanine has modest value given most competition efforts are under 10 seconds; it benefits accessory hypertrophy work more than competition sets.
- **Bodybuilding**: Creatine during mass phases is standard. Contest prep creates a dilemma: creatine causes 1–2 kg of intramuscular water retention — some athletes discontinue in the final 4–6 weeks before competition to minimize this. The performance cost is real; the aesthetic benefit depends on individual water distribution.
- **Olympic Weightlifting**: Creatine is high value — the sport demands repeated explosive outputs across a training session. Beta-alanine has minimal direct benefit for single clean or snatch attempts. Caffeine sensitivity matters more: excess caffeine impairs the fine motor control required for precise technique at near-maximal loads.
- **CrossFit**: All three supplements apply. The mixed-modal format creates sustained high-intensity work in the 1–10 minute range where beta-alanine provides its clearest benefit.
- **Calisthenics**: Body mass minimization makes creatine's 1–2 kg water retention a potential concern for strength-to-bodyweight ratio. In practice, intramuscular water increases contractile hydration and may improve force output enough to offset the mass penalty.