- The TriDoc Podcast-in Supplement form
- Posts
- Episode 178: Creatine/Silas Eastman
Episode 178: Creatine/Silas Eastman
A brief synopsis of the episode's main discussions and takeaways as well as extended references
Jeff Sankoff
August 29, 2025
Back from holiday but still talking about all things Dutch Antilles! In this episode I get to wistfully revisit one of my favorite islands in spirit, Saba, as I discuss with my guest an upcoming competition that he is planning for that unspoiled Queen. Plus, we dig in to the evidence-AGAIN-around creatine.
Table of Contents
Creatine supplementation-NO evidence to support any benefits for endurance athletes! Some evidence to support its use for other reasons
Creatine has for a while now, been the darling among supplements that nutritionists and coaches have been pushing on athletes. It seems like every day there is someone else telling you that this magic powder will make you stronger and faster and benefit many other aspects of your health. I first reviewed the science around creatine all the way back in episode 11 and at that time I was not too impressed. But since then I have been asked many, many times about it and so I thought that it was time to revisit the subject and do a new literature search to see if anything had changed. What we found is not that ambiguous-creatine does NOT benefit endurance athletes in any way, shape or form. In fact, there is some evidence to suggest it is detrimental. There is science to show that this supplement can be helpful for other kinds of sports and for different non-athletic health matters but for triathletes, creatine remains very much on the do not use list.
Silas Eastman-Bringing Roller skiing to the Caribbean
Silas Eastman is the director of the Jackson Ski Foundation, a nordic ski park in New Hampshire. He joins me on this episode to discuss cross country skiing and roller skiing, specifically how both these pursuits can be a worthy inclusion for triathletes during their off season. They are excellent whole body workouts that are not hard to learn and can provide an alternative to the traditional swim/bike/run without any pounding or risk of interactions with cars.
Silas also talks to me about a competition that he is working on for roller skiers on the Dutch island of Saba in the Caribbean. Not a locale that most would think about for this kind of activity but Saba does push boundaries when it comes to endurance sport with their triathlon and running races on its 20-30% incline road.
This September, roller skiers will attempt to climb those same hills and Silas tells me what they can expect and what brought this idea to life.
A typical road in Saba. Roller skiers will climb and not descend!
Episode takeaways:
Creatine's hype may overshadow its actual benefits for endurance sports, leading to confusion among athletes regarding its necessity.
Creatine supplementation may not significantly benefit endurance athletes but could have protective effects for cognitive health.
Roller skiing is gaining popularity in the off-season for endurance athletes, offering a unique way to maintain cardiovascular fitness.
Cross-country skiing provides an excellent full-body workout, effectively engaging both upper and lower body muscles for triathletes.
Finding the right equipment for roller skiing can be a bit challenging, but used gear is often available at a fraction of the cost.
References used for the MMB
Creatine
Cleveland Clinic
Key Points:
Creatine is naturally produced in the body and can be gained from a protein-rich diet
Creatine monohydrate supplements, specifically, increase muscle performance for short-term, high-intensity resistance exercises, including weight lifting, sprinting, and bicycling
Creatine increases energy to improve performance without affecting aerobic endurance, and aids in muscle recovery and injury prevention by:
Converting into phosphocreatine, which helps produce ATP
Helping to activate satellite cells in muscles, which helps heal micro tears in muscles
Helping to hydrate muscle cells
Creatine helps increase muscle growth in people aged 18-30
Creatine supplementation is common in bodybuilding, football, hockey, and wrestling
Creatine may help with short-term memory and reasoning, and protect nerve cells from injury/damage in people aged 60+
Studies are being conducted to assess the effects of creatine on conditions, like dementia
Creatine supplements are approved for use by the IOC and the NCAA
Creatine supplements can help build muscle mass
UCLA Health article from January 26, 2024
Key Points:
Creatine is an organic compound that is mostly synthesized by the liver and stored in skeletal muscles in the form of phosphocreatine
Bodies rely on creatine to power muscle contractions and release, transmit nerve signals, and synthesize proteins for tissue repair
Creatine supplements are useful during intense anaerobic exercises, such as weight lifting and short-distance sprinting
Studies show that creatine can help build body mass when complementing resistance training
Research suggests improved blood panel results, skin elasticity, symptoms of Parkinson’s disease, increased muscle recovery speed, and cognitive benefits for brain injuries
Individuals on a meat-free diet can benefit from creatine supplements
Taking large quantities may cause gastric symptoms
Creatine for Exercise and Sports Performance, with Recovery Considerations for Healthy Populations
Wax et al. 2021
Key Points:
Creatine supplements are well-studied and have constantly shown to have positive ergogenic effects on both single and multiple bouts of short-duration, high-intensity exercises
Creatine supplements increase the intracellular pool of creatine and creatine phosphate (PCr), improving the resynthesis of ATP, contributing to increased max strength, work output, power production, sprint performance, and fat-free mass
Skeletal muscle biopsies have confirmed increased PCr content with creatine ingestion, resulting in ~30% less ATP loss
Helps resynthesize ATP and delivers it to working muscles
~70% of the literature showed that increases in intramuscular PCr concentrations lead to 5-15% improvements in exercise performance measures during bouts of exercise
Volek et al. (1999) and Syrotuik et al. (2000) studies suggest that the ergogenic effects of creatine may come from creatine enhancing fat-free mass and muscle morphology by facilitating the increase in training intensities and volumes, rather than creatine directly improving performance
When subjects were encouraged to increase exercise intensity and training volume throughout a 12-week study, the creatine group displayed greater increases in training volume and intensity. However, when a study controlled the resistance training volume and intensity, greater ergogenic effects of creatine were not observed relative to the placebo group.
Separate collegiate football player studies suggest that creatine dosage factors into its effect on strength gain.
Creatine has been shown to increase muscular strength in both trained and untrained populations for both males and females
The effects of creatine supplementation on intermittent and endurance activities are contradictory
Exercise bouts >2 to 3 minutes rely predominantly on the oxidative synthesis of ATP
The majority of studies show that as exercise duration increases, the ergogenic potential of creatine decreases
Few studies report improved blood lactate concentration at a given workload and lactate threshold
Creatine does not appear to be as effective in improving endurance performance for sports like running, swimming, and soccer, where gains in body mass can increase energy demands and counter the effects of creatine
The benefits of creatine are most observed in strength/power sports, where creatine supports higher training intensity and recovery
Creatine appears to be effective for sprint performance and may also be associated with increased agility and jump performance
Creatine has been shown to enhance recovery
Important to note that this study is funded by Alzchem Trotsberg, GmhH, which is a chemical manufacturer that makes Creapure (this is a brand of creatine monohydrate)
Introduction: Creatine, a supplement commonly used by athletes, is an amino acid found in skeletal muscle. Creatine supplementation is reported to benefit anaerobic exercise. However, evidence surrounding their effect on endurance performance is limited.
Methods: 180 articles included in final review. PubMed, Medline, Google Scholar, and EBSCO-host were searched for this review. Articles were screened by title, abstract, and keywords. 200 non-monohydrate creatine, conference abstracts, non-peer-reviewed, and therapeutic creatine use articles were excluded.
Results: Previous reviews report ~70% of the literature shows 5-15% improvements in exercise performance measures due to increases in intramuscular PCr concentrations. In some cases, short-term improvements are reported within 2 weeks of supplementation. Long-term training adaptations of creatine have been observed. When subjects were encouraged to increase exercise intensity and training volume throughout a 12-week study, the creatine group displayed greater increases in training volume and intensity. However, when a study controlled the resistance training volume and intensity, greater ergogenic effects of creatine were not observed relative to the placebo group. Two separate studies showed that in a 5-week study of collegiate football players, creatine increased bench press, squat scores, and lower body power, but in another 8-week study, only athletes supplemented with 300 mg/kg of creatine showed significant strength gains relative to the placebo.
Effects of Creatine Supplementation on Athletic Performance in Soccer Players: A Systematic Review and Meta-Analysis
Mielgo-Ayuse et al. 2019
Key Points:
Soccer combines both anaerobic high-intensity sprints, accelerations, and jumps, as well as low-intensity phases that are sustained by aerobic systems. During a match, a player covers 8-12km, with 1-12% being high-intensity phases.
While creatine improves high-intensity exercise performance, results on soccer performance have been inconclusive due to a lack of consideration of the energy system used in the sport.
This study investigated the performance effects of creatine on soccer depending on the type of metabolism (aerobic, phosphagen, and anaerobic) to assess if creatine provides energy and benefits to each phase of the sport.
A review and meta-analysis of 9 studies did not show significant effects of creatine on aerobic performance or phosphagen metabolism.
20-30g/day of creatine supplemented for 1-9 weeks showed significant improvements in anaerobic performance.
This study supported past studies that showed performance benefits of creatine on high-intensity exercises while clarifying the effect of creatine on soccer performance.
Since endurance sports are primarily aerobic, this study suggests that consuming creatine supplements will not benefit endurance sports.
Methods: Literature published in Medline/PubMed, Web of Science, Cochrane Library, and Scopus until January 2019 was reviewed. Double-blind, randomized experimental studies with a placebo group. Duplicates were removed and assessed for eligibility, considering the sports, co-interventions, and performance assessments.
Results: 101 articles identified; 9 articles included in final meta-analysis. Creatine dosage ranged from 0.03g/day in one study, 20g/day in six studies, 0.3g/kg in one study, and 30g/day in another study. Creatine supplementation did not show significant effects on the aerobic performance (SMD, −0.05; 95% CI, −0.37 to 0.28; MSMD, trivial; I2, 0%; p = 0.78) or phosphagen metabolism performance (SMD, 0.21; 95% CI, −0.03 to 0.45; MSMD; small; I2,43%; p = 0.08). Only two studies on treadmill runs and ball-sport endurance and speed showed the favorable effects of creatine. However, a significant effect of Creatine was found for anaerobic performance (SMD, 1.23; 95% CI 0.55–1.91; MSMD, large; I2, 81%; p <0.001) with creatine supplementation also showing significant effects on the Wingate test (SMD, 2.26; 95% CI, 1.40–3.11; MSMD, large; I2, 72%; p <0.001).
Creatine supplementation and endurance performance: surges and sprints to win the race
Forbes et al. 2023
Key Points:
This review discusses the potential mechanism of creatine’s effect on endurance performance
Endurance performance is defined in this study as “as large muscle mass activities that are cyclical in nature and are >~3 min in duration”
Creatine supplements increase PCr in skeletal muscle, increase ATP resynthesis, and buffer hydrogen ion accumulation
Creatine ingested with carbohydrates can enhance glycogen resynthesis and storage, which would be beneficial in supporting high-intensity aerobic exercise
In a study of 14 males who cycles to exhaustion with a diet of >80% carbohydrate calories, those supplemented with 20g/day creatine showed elevated creatine and glycogen levels in 24h that lasted for 6 days.
In another study where 18 elite cyclists consumed 20g/day for 5 days + 3g/day for 9 days of creatine or placebo with high (12g/kg) or moderate (6g/kg) carbohydrate doses, creatine showed significant improvement in power output in the closing sprints. In this study, increased body mass from creatine did not have negative effects on performance
Creatine may increase calcium reuptake into the sarcoplasmic reticulum to increase force production
In a study with trained female participants, 20g/day creatine increased power output at EMG fatigue threshold (highest power output sustainable for an extended period without neuromuscular fatigue) by 14.5%, shedding light on implications for endurance exercises that are performed close to max metabolic steady state.
Studies have found reduced rises in levels of PGE2, TNF-alpha, IF-alpha, IL 1-beta in elite athletes supplemented with creatine before an ironman, relative to placebo.
This aligns with animal model findings that show the benefits of creatine in enhancing biomarkers of recovery following aerobic exercise.
Varying results on time to exhaustion have been reported, likely due to methodological differences
No exercise is purely anaerobic or aerobic
The tradeoff of creatine is that it has the potential to increase body mass, which can result in more required energy use, which would offset the positive effects
The time trial performance effects of creatine are not consistent
Creatine supplementation seems more beneficial to sports that require multiple surges in intensity or sports that require spurts at the end
This article reports that the enhanced anaerobic capacity may be beneficial for cross-country skiing, mountain biking, cycling, triathlons, rowing, kayaking, and track cycling, which involve high-intensity burst, multiple surges, or finishing end spurts
For non-weight-bearing endurance activities, 20g/day creatine for 5-7days can saturate muscle creatine stores, but for weight-bearing endurance athletes, where gains in body mass and water retention may be detrimental, 3-5g/day is enough to saturate creatine stores (+20%) over 4 weeks.
Creatine stores vary by sex, which may influence the effects of supplementation
Effects of Creatine Monohydrate on Endurance Performance in Trained Population: A Systematic Review and Meta-analysis
Fernandez-Landa et al. 2023
Key Points:
This article evaluated the effects of creatine monohydrate supplementation and showed that they are ineffective on the endurance performance of trained populations
Methods: Human trials controlled with placebos on PubMed/MEDLINE, Web of Science, and Scopus databases were reviewed until May 19, 2022.
Results: 13 studies included in review and analysis. Meta-analysis showed no significant effect of creatine supplementation on endurance performance (p=0.47). Trivial negative effect observed.
The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis
Xu et al. 2024
Corrigendum: The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis
Xu et al. 2025
Key Points:
This review and meta-analysis examined the effects of creatine monohydrate supplements in memory, executive function, attention, and information processing speed of adults, including the elderly, and patients with neurodegenerative diseases.
An error in the language translation of this article was corrected recently
While individual studies showed varying degrees of creatine effects on cognitive function, executive function & executive function time, attention scores, and processing speed scores, there were no significant effects when studies were assessed together.
Significant positive effects of creatine were observed for attention time, memory function, and processing speed time.
This suggests that creatine decreases the time required to complete attention tasks, improves memory performance, and shortens the time required to complete tasks.
Aligns with findings from past studies that reported enhanced memory performance in complex tasks.
However, due to the low certainty levels, there is a need for further research to draw further conclusions.
In a subgroup analysis of attention, creatine was more beneficial to individuals with diseases and those between 18-60 years old.
The study reports that the findings suggest creatine significantly reduces attention time in 3 studies for individuals with illnesses and in 5 studies for the 18-60 age group, but not in healthy individuals or those aged 60+.
The duration of creatine intervention did not significantly influence the effect.
In a subgroup analysis of processing speed time, 4 studies showed a significant effect of reducing processing speed time in female participants, suggesting that creatine effects on processing speed time may be sex-specific.
In the brain, creatine may increase energy reserves, reduce oxidative stress, and increase the synthesis and neurotransmission of acetylcholine, which in turn may improve cognitive performance and mitigate oxidative cell damage.
Methods: Literature published in PubMed, Web of Science, and Scopus between January 1993 and June 2024 was reviewed. Excluded studies with participants under 18, not written in English. Randomized controlled experimental studies included. Double-blind screening process using titles and abstracts. SMD was calculated as the difference in mean outcome between the creatine and placebo/control groups divided by the standard deviation of the outcome among participants. Hedge’s g was used to measure effect size.
Results: 2,326 articles identified; 1855 proceeded to initial screening. 16 articles included in final analysis. 4 studies conducted in Brazil, 3 in UK, 2 in US, 2 in Germany, and 1 in China, Iran, New Zealand, Belgium, and Israel. Dosage ranged: 0.3 g/kg/day, 3g/day, >3g/day, 5g/day, 10g/day, and 20g/day. Six studies involved either only females or only males. 492 participants included for final meta-analysis (age 20.8 to 76.4 yrs). All studies used creatine monohydrate supplementation. While individual studies showed varying degrees of creatine effects on cognitive function, executive function & executive function time, attention scores, and processing speed scores, there were no significant effects when studies were assessed together. 8 studies with 211 participants show a significant positive effect of creatine on attention time (SMD −0.31, 95% CI: −0.58 to −0.03, heterogeneity 18%, Z-value 2.20, p = 0.03; Hedges g −0.3004, 95% CI: −0.5719 to −0.0289). 24 studies with 1000 participants show a significant positive impact on memory function (SMD 0.31, 95% CI: 0.18-0.44, heterogeneity 21%, Z-value 4.72, p < 0.00001; Hedges g 0.3003, 95% CI: 0.1778 to 0.4228). 8 studies with 185 participants show a significant positive impact on processing speed time (SMD -0.51, 95% CI: -1.01 to -0.01, heterogeneity 63%, Z-value 2.01, p = 0.04; Hedges g -0.4916, 95% CI: -0.7852 to -0.1980). In a subgroup analysis of attention, when grouped by health status, age groups, and intervention duration, individuals with illnesses and those aged 18-60 showed a significant effect (p=0.02 and p=0.002), respectively. When grouped by sex, female participants had significant effects for processing speed time (p=0.01). Removing each study and assessing the combined effects of creatine showed that excluding any single study will not change the overall conclusions.
Creatine shows potential to boost cognition in Alzheimer’s patients
University of Kansas Medical Center
Kristi Birch June 4th, 2025
Key Points:
This article shares a pilot study on the effect of creatine on Alzheimer’s and dementia patients.
19 patients between the ages of 60-90 with Alzheimer’s took 20g/day of creatine monohydrate for 8 weeks.
Blood and MRI data showed an 11% increase in brain creatine levels and improved cognitive function.
However, this study is limited to participants and a control group.
Dr. Matthew Taylor, an assistant professor of dietetics and nutrition at KU, shares that the preliminary results show creatine’s potential to moderately improve working memory and executive function, but notes the need for further investigation.
Researchers theorize that creatine will help increase energy in the brain to enhance the thinking process.
Effect of Creatine Monohydrate on Clinical Progression in Patients With Parkinson Disease
Kieburtz et al. 2015
Key Points:
Long-term Study 1 aimed to assess whether creatine monohydrate was effective in slowing the long-term clinical decline of Parkinson's disease.
When participants were randomized to 10g/day of creatine or placebo for 5 to 8 years and followed up, there was no benefit observed in disease progression from using creatine.
Methods: Multicenter, double-blind, placebo-controlled, parallel-group 1:1 randomized efficacy trial. All investigators were blinded to creatine levels. Enrolled patients with <5 years from Parkinson’s diagnosis and had taken levodopa or dopamine agonist for 90 days to 2 years. Participants received 2x5g/day creatine monohydrate or placebo. 860 participants needed per group, with 5-year follow-up would allow for the detection of 1-year difference in clinical progress using a global statistical test.
Results: 1741 enrolled. 1328 (~75%) actively observed). First interim analysis conducted with 28% of the cohort reached eligibility for 5-year follow-up (median follow-up time: 4 yrs). Second analysis after 55% were eligible. Trial terminated early based on futility observed during interim analysis. In patients with early and treated Parkinson’s, creatine did not improve clinical outcomes relative to the placebo.
Dietary creatine intake and depression risk among U.S. adults
Bakian et al. 2020
Key Points:
Creatine’s antidepressant potential emerged from a randomized Parkinson’s pilot study, where patients treated with creatine for 2 years had significantly reduced depressive symptoms.
Studies have since largely demonstrated creatine’s potential to enhance/accelerate antidepressant response, although some results are not supportive of this.
Meat, poultry, fish, and seafood are the largest dietary contributors of creatine.
This was the first study to examine dietary creatine intake and risk of depression in the U.S.
MDD prevalence followed a step-wise decrease correlating to increases in dietary creatine consumption, with depression being 42% higher in adults with the lowest quartile (0-0.26g) consumption of creatine compared to the highest quartile (0.7-3.16g)
The depression prevalence of the lowest quartile mirrors that of individuals with chronic medical conditions.
Taking into account lifestyle variability, the highest quartile of creatine consumption had a 31% lower risk of depression.
While dietary creatine's effect on depression risk was statistically significant for the entire population, sex dimorphism in the relationship between creatine and depression was observed, with female participants driving this relationship.
An extra gram of creatine consumed by women decreased depression risk by 18%.
Result of this study support findings from animal studies that demonstrated greater reduction in depressive and anxious behavior in female rats with creatine than in male rats.
Age, sex, and medication influence the effectiveness of creatine consumption in reducing the risk of depression.
Methods: National Health and Nutrition Examination Survey data from 2005 to 2012was used. Health questionnaire, dietary creatine intake, and covariates were obtained for 22,692 participants aged 20-85+. Sensitivity analysis conducted.
Results: Of the 22,692 participant sample, 19,361 had depression screener data (males N=9549, females N=9812); 1696 participants were positive for MDD (7.33/100 persons). An inverse step-wise relationship between dietary creatine and depression was observed. 2-day dietary creatine was highly protective against depression (odds ratio (OR) = 0.54, 95% CI: 0.42–0.69, p < 0.0001). The confounder variables adjusted models stratified by sex showed a protective association between dietary creatine intake and depression risk of females (adjusted OR = 0.62, 95% CI: 0.40–0.98, p = 0.04). The relationship failed to reach statistical significance among males (adjusted OR = 0.72, 95% CI: 0.49–1.05, p = 0.08). Age-group stratified models showed significant association among participants aged 20–39 years (adjusted OR = 0.52, 95% CI: 0. 0.34–0.79, p = 0.002) but not among participants aged 40–64 (adjusted OR = 0.85, 95% CI: 0.57–1.25, p = 0.40) or ≥ 65 (0.66, 95% CI: 0.35–1.23, p = 0.19). Significant inverse relationship identified between dietary creatine and depression risk of individuals not taking antidepressant or anxiolytic medication (adjusted OR = 0.58, 95% CI: 0.43–0.77, p < 0.0001). For participants taking antidepressants or anxiolytic medication, the effect of creatine on depression risk was not significant.
Not a subscriber to the podcast? Click here!
Support the podcast: TriDoc Podcast Patreon site
Need an endurance coach? TriDoc Coaching
Reply