465: Carbs, Creatine, and Caffeine — What the Research Actually Says

The 3C Supplements Every Runner Should Know: Carbohydrates, Creatine, and Caffeine

After last week's conversation about the optimization trap, we knew the next question would be:

"Are there any supplements that are actually worth taking?"

The answer is yes, but probably fewer than you think.

The supplement industry has done an incredible job convincing runners that they need more products, more powders, and more pills to perform at their best. Meanwhile, many runners are still under-fueling, under-recovering, and under-sleeping.

Before we talk about supplements, let's be clear: no supplement can replace consistent training, quality sleep, proper nutrition, strength training, and recovery. Those will always have the biggest impact on your performance.

That said, there are a few supplements with strong research behind them. We call them the 3 Cs: Carbohydrates, Creatine, and Caffeine.

Carbohydrates: The Most Overlooked Performance Supplement

Technically, carbohydrates aren't a supplement. They're food.

But because so many runners are under-fueling, carbohydrates may be the most effective performance enhancer available.

Your body prefers glucose as its primary fuel source during exercise. When you run, especially at moderate to higher intensities, your muscles rely heavily on stored glycogen and circulating glucose to keep you moving efficiently.

The problem: Many runners try to power through long runs with little to no fuel.

Then they wonder why the last few miles feel terrible, why recovery takes days, why they're ravenous afterward, or why they constantly feel exhausted.

When glycogen stores begin to run low, your body starts conserving energy. Pace slows. Effort feels harder. Recovery becomes more difficult.

For runs lasting longer than 60–90 minutes, research consistently shows that taking in carbohydrates during exercise can improve performance and reduce fatigue. General recommendations often fall between 30–60 grams per hour, though individual needs vary, with well-trained athletes reaching 90g per hour or more.

The bigger message isn't about hitting a perfect number.

It's recognizing that carbohydrates are not the enemy.

Especially for women over 40, the "eat less and avoid carbs" message can become incredibly damaging. We see so many runners trying to train harder while simultaneously restricting the very fuel their bodies need to perform.

If you're running consistently, carbohydrates aren't something to fear.

They're exactly what your body needs to feel and perform at its best.

Creatine: Not Just for Bodybuilders

Creatine has been one of the most researched supplements for decades, yet many runners still assume it's only for people trying to build massive muscles in the gym.

Turns out, it can have benefits for us too.

Creatine helps your body rapidly regenerate ATP, one of its primary energy sources. This can improve your ability to perform high-intensity efforts and recover from them.

For runners (and non-runners as well), the biggest benefits often show up when creatine is combined with resistance training.

Research has shown improvements in strength, muscle preservation, and body composition, even in older adults and women navigating perimenopause and menopause.

What's even more exciting is some of the emerging research suggesting potential benefits for brain health, cognition, and sleep quality, especially for women in peri and post menopause. 

That doesn't mean creatine is magic. Keep in mind that many of these studies are small, so more research is definitely needed.

But the research shows that it may help support the work you're already doing. It doesn’t have these effects on its own. It must be combined with resistance training to gain the desired improvements in strength and bone density. It makes what you’re already doing a little more effective because it lets you push yourself a little more. That’s the key.

So if you want to try it for yourself, what’s the best way to start? 

The most studied form is creatine monohydrate, and most research supports a simple dose of 3–5 grams per day. No loading phase required. Make sure that what you’re taking has one ingredient: creatine monohydrate. Everything else is fluff, unnecessary fillers, or marketing.

Consistency matters more than exact timing, so if you choose to take it, take it at a time of day that you will be most consistent. Research shows that there may be a small benefit of trying to time your intake before or after training, but the benefit is small, especially when compared to consistency of daily intake.

So overall, take it when you can remember to do it everyday.

Caffeine: The Performance Booster Most Runners Already Use

Whether it's coffee before a run or a caffeinated gel during a race, most runners are already familiar with caffeine.

And for good reason.

Caffeine is one of the most consistently effective performance aids available.

Its biggest benefit isn't necessarily giving you more energy. It actually helps reduce perceived effort. The pace feels easier. The workout feels more manageable. The fatigue doesn't hit quite as hard.

That's a powerful advantage during long races and hard efforts.

But caffeine isn't one-size-fits-all.

Some runners thrive on it. Others become anxious, jittery, experience GI distress, or struggle with sleep afterward.

Your response depends on factors like genetics, tolerance, timing, dosage, and overall sensitivity.

That's why race day is never the time to experiment.

If you're considering using caffeine for performance, practice with it during training first and pay attention to how your body responds.

The Lesson Here Isn't About Supplements 

The goal isn't to find the perfect supplement.

The goal is to build a body that can train, recover, and perform consistently.

Carbohydrates, creatine, and caffeine all have strong evidence supporting their use, but their benefits are often small compared to the impact of proper training, sleep, nutrition, strength work, and recovery.

If your foundation isn't solid, start there.

If your foundation is solid, these tools may help you squeeze a little more out of the work you're already doing.

And that's the difference between chasing optimization and making smart, evidence-based decisions as a runner.

REFERENCES: 

CARBOHYDRATES

1. Kerksick, C.M., et al. (2008). International Society of Sports Nutrition position stand: Nutrient timing. Journal of the International Society of Sports Nutrition, 5(17). https://pmc.ncbi.nlm.nih.gov/articles/PMC2575187/
   
   

2. Burke, L.M., et al. (2025). Dietary carbohydrate and the endurance athlete: Contemporary perspectives. Gatorade Sports Science Institute. https://www.gssiweb.org/sports-science-exchange/article/dietary-carbohydrate-and-the-endurance-athlete-contemporary-perspectives
   
   

3. Oliveira, B., et al. (2025). A review of carbohydrate supplementation approaches and strategies for optimizing performance in elite long-distance endurance. Nutrients, 17(5), 918. https://www.mdpi.com/2072-6643/17/5/918
   
   

4. Costa, M.L., et al. (2025). The importance of carbohydrate intake for high-performance athletes in endurance exercises. Research, Society and Development. https://rsdjournal.org/rsd/article/view/48597
   
   

CREATINE

1. dos Santos, E.E.P., et al. (2021). Efficacy of creatine supplementation combined with resistance training on muscle strength and muscle mass in older females: A systematic review and meta-analysis. Nutrients, 13(11), 3757. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619193/ Key finding: Creatine combined with resistance training significantly increased upper- and lower-body strength in older females, especially in programs lasting 24 weeks or more.
   
   

2. Hall, L., Klassen, S., Holbein, J., & Waters, J. (2025). Impact of creatine supplementation on menopausal women's body composition, cognition, estrogen, strength, and sleep. Journal of the International Society of Sports Nutrition, 22(sup1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12291186/ Key finding: 14-week study in peri- and postmenopausal women found meaningful improvements in lower body strength, sleep quality, and cognitive function. One third of postmenopausal women moved from mild cognitive impairment range to normal range. Limitation: Small sample (n=15), quasi-experimental design, self-reported sleep outcomes.
   
   

3. Korovljev, D., et al. (2025). The effects of 8-week creatine hydrochloride and creatine ethyl ester supplementation on cognition, clinical outcomes, and brain creatine levels in perimenopausal and menopausal women (CONCRET-MENOPA): A randomized controlled trial. Journal of the American Nutrition Association, 45(3), 199–210. https://www.tandfonline.com/doi/full/10.1080/27697061.2025.2551184 Key finding: Medium-dose creatine HCl improved reaction time, increased frontal brain creatine levels, and reduced mood swings in perimenopausal and menopausal women. Limitation: Small sample (n=36), 8-week duration, funded by creatine manufacturer (CON-CRĒT by Vireo Systems) — conflict of interest noted.
   
   

4. Baker, P.A., et al. (2025). Creatine monohydrate increases skeletal muscle microvascular blood flow and promotes lipid mobilization in postmenopausal women. Journal of the International Society of Sports Nutrition. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12392431/ Key finding: Five days of creatine monohydrate increased blood flow and lipid mobilization in postmenopausal women, suggesting potential cardiovascular benefit. Limitation: Pilot study, very small sample (n=6).
   
   

5. Kreider, R.B., et al. (2017). International Society of Sports Nutrition position stand: Safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition, 14(18). https://link.springer.com/article/10.1186/s12970-017-0173-z Key finding: Creatine monohydrate is the most effective ergogenic supplement for increasing high-intensity exercise capacity and lean body mass. Long-term use at up to 30g/day for 5 years has demonstrated no detrimental effects in healthy individuals.
   
   

6. Smith-Ryan, A.E., et al. (2025). Creatine in women's health: Bridging the gap from menstruation through pregnancy to menopause. Journal of the International Society of Sports Nutrition. https://www.tandfonline.com/doi/full/10.1080/15502783.2025.2502094 Key finding: Comprehensive review calling for more targeted research on creatine in perimenopausal women, noting distinct physiological differences from men that influence creatine metabolism. Limitation: Authors disclose advisory roles with creatine manufacturers — conflict of interest noted.
   

CAFFEINE

1. Wang, Z., Qiu, B., Gao, J., & Del Coso, J. (2022). Effects of caffeine intake on endurance running performance and time to exhaustion: A systematic review and meta-analysis. Nutrients, 15(1), 148. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9824573/ Key finding: Caffeine intake showed a meaningful ergogenic effect on time to exhaustion in both recreational and trained runners. Limitation: Of 254 total participants across 21 studies, only 19 were women — findings are largely based on male participants.
   
   

2. Ding, L., et al. (2025). Effects of caffeine dose and administration method on time-trial performance: A systematic review and network meta-analysis. Nutrients, 17(23), 3792. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12694421/ Key finding: Moderate caffeine doses (4–6 mg/kg) significantly improved time-trial performance compared to low doses. Limitation: Majority of studies conducted on cyclists, limiting direct applicability to runners.
   
   

3. Souza, D.B., et al. (2025). Caffeine and sports performance: The conflict between caffeine intake to enhance performance and avoiding caffeine to ensure sleep quality. Sports Medicine, 55(7), 1579–1592. https://pmc.ncbi.nlm.nih.gov/articles/PMC12296924/ Key finding: Both habitual and non-habitual caffeine consumers experience similar performance benefits from doses of 3–6 mg/kg. Caffeine's half-life creates a direct tradeoff between performance enhancement and sleep quality — particularly relevant for women navigating perimenopause.
   

TIER 2 SUPPLEMENTS

1. Dominguez, L.J., et al. (2025). The importance of vitamin D and magnesium in athletes. Nutrients, 17(10), 1655. https://www.mdpi.com/2072-6643/17/10/1655 Key finding: Vitamin D and magnesium play essential roles in bone health, muscle function, ATP production, and cardiovascular health in athletes. Supplementation produced the strongest benefits in those with low baseline nutrient status or high training volumes. Limitation: Review notes significant variability in study designs and populations.
   
   

2. Venkatraman, N., et al. (2021). Magnesium and vitamin D supplementation on exercise performance and recovery. Translational Journal of the American College of Sports Medicine. https://journals.lww.com/acsm-tj/fulltext/2021/10150/magnesium_and_vitamin_d_supplementation_on.11.aspx Key finding: Benefits most pronounced in individuals with documented nutrient insufficiency. Results were mixed in adequately nourished populations.
   
   

3. Elo Health. (2021). The best science-backed supplements for runners over 40. https://www.elo.health/articles/best-supplements-for-runners-over-40/ Note: Practitioner-authored summary; not a primary research source. Used for contextual framing only.
   
   

A NOTE ON CONFLICTS OF INTEREST

Several studies cited in this episode — particularly those on creatine — were funded by or conducted in collaboration with supplement manufacturers. We have noted these conflicts where identified. Conflicts of interest do not automatically invalidate research findings, but they are relevant context when evaluating the strength of evidence. Where possible, we have prioritized independent peer-reviewed research and noted where the evidence base is still developing.

A NOTE ON LIMITATIONS OF THE EVIDENCE BASE

The research on creatine, in particular, has historically been conducted predominantly on young men. Studies specifically on peri- and postmenopausal women are newer, smaller in sample size, and shorter in duration than the broader creatine literature. The caffeine research on endurance running similarly underrepresents women. We have tried to reflect these gaps honestly throughout this episode. The goal is always to give you the most accurate picture of what we actually know — and what we are still learning.