Creatine vs. HMB: Supplement Choices and Evidence Strength for Endurance Athletes

How the Two Supplements Work

Creatine Monohydrate

Once creatine enters muscle cells, it binds with phosphate to form phosphocreatine (PCr), a fast-acting energy source for ATP regeneration. Supplementing 5g per day can raise muscle creatine stores by 20-30%.

Main benefits:

• Increased power output (short-duration, high-intensity efforts)
• Increased muscle mass (water retention effect + protein synthesis)
• Improved recovery between high-intensity intervals

HMB (β-Hydroxy β-Methylbutyrate)

HMB is a metabolite of the amino acid leucine and inhibits muscle protein breakdown. Supplementing 3g per day can reduce muscle breakdown by 20%.

Main benefits:

• Reduced post-training muscle damage
• Preservation of lean tissue (especially during a caloric deficit)
• Faster post-exercise recovery

Comparing Evidence Strength

Benefit Metric	Creatine	HMB
FTP improvement	Weak evidence (+0-2%)	Weak evidence (+0-1%)
Short-duration power	Strong evidence (+10-15%)	Weak evidence (+2%)
Muscle mass maintenance	Strong evidence (+1-2kg)	Moderate evidence (+0.5kg)
Muscle preservation during fat loss	Moderate evidence	Strong evidence
Post-exercise recovery	Moderate evidence	Strong evidence
Reduction in creatine kinase	Weak evidence	Strong evidence

Which Should Endurance Athletes Choose?

Pure endurance cyclists / runners

Recommendation: Creatine first

Although creatine’s effect on FTP is limited, it improves recovery after high-intensity intervals, which indirectly boosts annual training volume. Take 3-5g daily; a 4-week loading phase is optional before maintaining the dose.

Cyclists in a fat-loss phase

Recommendation: HMB first

A caloric deficit during a cutting phase can lead to muscle loss. HMB helps preserve lean tissue and maintain your power-to-weight ratio. Take 3g daily, split into 3 doses before meals.

Triathletes

Recommendation: Both can work

Triathlon demands both power (sprints, climbs) and endurance. A combination of 3g creatine + 1g HMB can address both needs simultaneously.

Marathon runners

Recommendation: HMB as the primary choice

Marathon running has almost no power demands, but long-distance training causes substantial muscle damage, and HMB can speed up recovery. Take 3g daily, split into morning and evening doses.

3 Myths About Creatine

Myth 1: Creatine adds 1-2kg of body weight, which hurts climbing

Fact: Most of the added weight is intramuscular water, and the increase in power output typically exceeds the increase in body weight, so your power-to-weight ratio still improves.

Myth 2: Creatine damages the kidneys

Fact: 30 years of research confirm that 5g of creatine per day has no effect on kidney function in healthy adults. The only exception is people with pre-existing kidney disease, who should consult a doctor.

Myth 3: You need to cycle on and off creatine

Fact: You can take it continuously for 6-12 months without stopping; there is no evidence that cycling is necessary.

3 Myths About HMB

Myth 1: HMB is more effective than leucine

Fact: HMB is a metabolite of leucine, but the benefits are similar. If you’re already consuming 25-30g of protein daily, leucine intake is likely sufficient, and the marginal benefit of HMB diminishes.

Myth 2: HMB builds muscle

Fact: HMB reduces muscle breakdown, which is not the same as building muscle. It offers a large benefit for untrained individuals, but only about 0.5kg over 12 weeks for those with a training background.

Myth 3: HMB benefits everyone

Fact: Athletes with low training volume (under 3 hours per week) see no meaningful benefit.

Timing and Dosage

Creatine protocol

Loading phase (optional):

• Days 1-5: 20g per day (split into 4 doses)
• Day 6 onward: 5g per day

Slow-loading method:

• 3-5g per day; saturation is reached after 4 continuous weeks

Optimal timing: Within 30 minutes after training, combined with a carbohydrate-containing meal, for the highest absorption rate.

HMB protocol

• 3g per day, split into 3 doses (breakfast, before lunch, after training)
• Taking 1g within 30 minutes after training works best
• Continuous use for 4 weeks is needed before effects appear

Side Effects and Contraindications

Creatine

• Occasional stomach discomfort (can be improved by taking it after meals)
• Not suitable for those with impaired kidney function
• Not suitable for adolescents under 18

HMB

• Very few side effects
• High doses (>10g/day) may cause gastrointestinal discomfort
• Pregnant and breastfeeding women should avoid it

Combining with Other Supplements

Creatine + Caffeine

Studies show taking them together can reduce creatine’s effectiveness by 30%; it’s recommended to space them 4 hours apart.

HMB + Protein Powder

A great pairing — take HMB before meals and protein powder after meals or after training.

Creatine + Beta-Alanine

Good synergy, as both can improve high-intensity endurance; they can be taken together.

Conclusion

Creatine and HMB are two supplements worth considering for endurance athletes, but neither outperforms “adequate sleep, proper training, and balanced nutrition.” Build a solid foundation first, then use supplements to optimize the final 1-2%.

Related Reading

• Evaluating the Evidence for Sports Supplements: A Scientific Look at Creatine, Beta-Alanine, and HMB
• Creatine Isn’t Just for Weight Training: Hidden Uses and Evidence for Endurance Athletes
• Is Creatine Supplementation Useful for Endurance Sports? Scientific Analysis and Recommendations
• HMB and Anti-Catabolic Supplements for Athletes: Evidence, Suitable Populations, and Value for Money Explained