Choosing Supplements: The Evidence Behind Beta-Alanine, Creatine, and BCAAs

The sports supplement market is worth tens of billions of dollars every year, with countless products claiming to boost performance, speed up recovery, or build muscle. Faced with so many options, how can cyclists make science-based decisions? This article focuses on three of the most thoroughly researched supplements in sports science — Beta-Alanine, Creatine, and Branched-Chain Amino Acids (BCAAs) — and takes a deep look at their real-world benefits for cyclists.

Basic Principles for Choosing Supplements

Before diving into individual supplements, let’s establish a framework for evaluating them scientifically:

Hierarchy of evidence (from strongest to weakest):

1. Systematic reviews and meta-analyses (most reliable)
2. Randomized controlled trials (RCTs)
3. Observational studies
4. Case reports
5. Manufacturer claims (least reliable)

Always prioritize in this order: A complete diet > basic supplements (protein, electrolytes) > performance-enhancing supplements

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Beta-Alanine: An Amino Acid That Buffers Muscle Acidity

How It Works

Beta-Alanine is a non-essential amino acid and the rate-limiting precursor for synthesizing carnosine. Carnosine is stored in muscle and plays an important buffering role during high-intensity exercise:

1. High-intensity exercise → lactate accumulation → rising hydrogen ion (H⁺) concentration → falling pH (muscle acidification)
2. Carnosine binds H⁺ → buffers the acidic environment → delays the onset of fatigue
3. Muscle pH stays at a more favorable level → muscle contraction efficiency is maintained for longer

Evidence of Effectiveness

Over 60 randomized controlled trials and multiple meta-analyses confirm the benefits of Beta-Alanine:

Exercise Type	Effect	Magnitude of Benefit
High-intensity exercise lasting 1–4 minutes (optimal range)	Significantly delays fatigue	High
Moderate-intensity sustained exercise lasting 4–10 minutes	Mild to moderate improvement	Medium
Long-distance endurance exercise (>10 minutes)	Limited effect	Low to none
Sprinting/climbing ability	Helps improve repeated sprint ability	Medium

Specific use cases for cyclists:

• Short-duration individual time trials (ITT): 1–8 km
• Sprinting on key climbing sections
• End-of-race group sprints
• Recovery capacity during repeated high-intensity interval training (HIIT)

How to Use It

Dosage: 3.2–6.4 grams daily, split into 3–4 doses

Loading phase: Requires 4–6 weeks of continuous intake to significantly increase muscle carnosine content (about a 60% increase). Taking it just before an event will not produce the intended effect.

Side effect: Paresthesia

• A tingling or itching sensation on the skin, commonly on the face, neck, and hands
• Harmless and typically subsides within 30–60 minutes
• Taking smaller, more frequent doses or using a sustained-release formula can greatly reduce this side effect

Cost-effectiveness: Moderate (approximately US$3–5/week)

Best suited for: Riders competing in short, high-intensity events or who prioritize sprinting ability

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Creatine: One of the Most Thoroughly Researched Supplements

How It Works

Creatine is stored in muscle as phosphocreatine (PCr), which serves as the emergency raw material for the rapid resynthesis of ATP (adenosine triphosphate):

• ATP is the direct energy currency for muscle contraction, but stores are extremely limited (enough for only 2–3 seconds of maximal output)
• Phosphocreatine can rapidly replenish ATP within 10 seconds
• Supplementing with creatine → increases phosphocreatine stores → extends the duration of maximal power output

Evidence of Effectiveness for Cyclists

Benefit	Strength of Evidence	Notes
Short-duration sprint power	Very high	Significantly improves repeated sprint ability
Recovery between repeated high-intensity efforts	High	Faster recovery between sets
Increased muscle mass	High	Mainly due to increased muscle water retention
Long-distance endurance (>30 minutes)	Low	Limited benefit
Tolerance to hot environments	Medium	Increased muscle water content may aid heat dissipation
Post-training recovery	Moderate	Research findings are inconsistent

Special note: Creatine causes a slight increase in body weight (0.5–2.5 kg, mainly intramuscular water). For climbing-focused riders who prioritize power-to-weight ratio, this may be a consideration.

How to Use It

Option 1: Loading protocol

• First 5–7 days: 20 grams daily (split into 4 doses of 5 grams each) for rapid loading
• Maintenance phase: 3–5 grams daily

Option 2: Low-dose protocol (recommended)

• No loading phase needed — take 3–5 grams daily from the start
• Reaches the same stored levels after 4–6 weeks, with fewer side effects

Optimal timing: Take after training along with carbohydrates and protein, using the resulting insulin response to enhance muscle uptake.

Form: Creatine monohydrate is the most extensively studied and most cost-effective form. Other forms (such as creatine ethyl ester or buffered creatine) do not yet have sufficient evidence to support superiority.

Best suited for: Riders who prioritize explosive power, sprinting ability, or high-intensity interval training

Not recommended for: Lightweight riders focused purely on climbing performance who are sensitive to weight gain

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BCAAs (Branched-Chain Amino Acids): An Overhyped Star Supplement?

What Are BCAAs?

BCAAs refer to three branched-chain amino acids:

• Leucine: Activates the mTOR signaling pathway and is the primary regulator of muscle protein synthesis
• Isoleucine: Involved in glucose uptake and metabolism
• Valine: Involved in energy metabolism and related to the central fatigue hypothesis

Evidence of Effectiveness: More Limited Than You Might Think

BCAAs have been one of the best-selling sports supplements for decades, but recent systematic research has cast doubt on their benefits:

Claimed Benefit	Actual Evidence	Notes
Reduced muscle catabolism	Limited	Only significant when dietary protein intake is insufficient
Promotes muscle protein synthesis	Conditional	Far less effective than complete protein
Reduces delayed-onset muscle soreness (DOMS)	Slight	Effect is small
Delays central fatigue	Theoretically plausible	Human trial results are inconsistent
Improves endurance performance	Almost none	Low level of research support

Core problem: BCAAs are an incomplete protein source — they contain only 3 amino acids, while muscle protein synthesis requires all 9 essential amino acids. Consuming an equal-calorie amount of complete protein (such as whey protein) provides more leucine while also supplying all EAAs, resulting in better synthesis outcomes.

Key conclusion from a major 2017 review: “When dietary protein intake is adequate, additional BCAA supplementation provides very limited benefit for muscle protein synthesis or exercise performance.”

When BCAAs May Help

• Vegan athletes: As a temporary supplement during or after training when complete plant protein isn’t immediately available
• Fasted training: To help protect against excessive muscle breakdown (though complete protein is still more effective)
• Ultra-long training sessions: May theoretically provide a small amount of energy and delay fatigue

Alternatives to BCAAs

Rather than spending money on BCAAs, consider prioritizing:

• Whey protein (contains the full set of EAAs, lower cost, better results)
• Whole protein foods (eggs, chicken, fish)
• Essential amino acid (EAA) supplements (if amino acid supplementation is genuinely needed, EAAs are more complete than BCAAs)

Summary Comparison of the Three Supplements

Supplement	Best Suited Rider Type	Research Support	Cost-Effectiveness	Estimated Monthly Cost
Beta-Alanine	Short-duration high-intensity efforts, time trials, sprints	High (for 4–6 minute efforts)	Good	NT$500–800
Creatine	High-power output, explosive riders	Very high (short-duration high intensity)	Best	NT$300–500
BCAA	Generally recommended to skip	Medium (limited when diet is adequate)	Low	NT$800–1,500

Priority Order for Supplement Investment

1. Optimize your basic diet (most important)
2. Electrolyte supplementation (essential for long distances)
3. Caffeine (the best cost-to-benefit performance enhancer)
4. Creatine (for explosive-power riders)
5. Beta-Alanine (for sprint/high-intensity riders)
6. Whey protein (when protein intake is insufficient)
7. BCAA (rarely necessary)

Conclusion

Supplements are meant to “supplement” your diet, not replace it. Before investing money and effort into supplements, make sure your daily diet already meets your basic macro- and micronutrient needs. If you do decide to use supplements, choose products backed by solid research, understand the situations in which they are most effective, start with a low dose to test your individual response, and continue to track the results. Using supplements scientifically and cautiously is the only way to truly enhance your cycling performance.

Related Reading

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• 運動補充品科學：咖啡因、β-丙氨酸與肌酸的研究支持與使用建議
• 運動補充品科學解析：咖啡因、β-丙胺酸與肌酸對騎乘表現的影響
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