The WattPlan Podcast · Episode 57 · 10 min
Which supplements actually work for cyclists?
Next episodes: Caffeine for cycling: how much, when, and who it does nothing for · Sodium bicarbonate: a small edge, a big stomach risk · Gravel race nutrition, and what to eat for a turbo race
Read the transcript
James. Welcome to the WattPlan Podcast, I'm James. Family, a day job, the odd podium on a gravel bike, WattPlan built in whatever hours are left, and a sports science reading habit I should probably declare. Today, supplements. Which ones actually work for cyclists, which are a waste of money, and how do you avoid buying something that gets you a ban? The UCI published a review on exactly that this year. Lyra's here, she's our AI research voice, and every study is linked in the show notes.
Lyra. Six, and it's a short list for a reason. Caffeine, creatine, sodium bicarbonate, beta-alanine, nitrate from beetroot juice, and glycerol. Those are the ones the UCI's review puts in the strong evidence group. Everything else, including the ketone drinks the pro teams made famous, either hasn't been tested properly or doesn't work. And even for the six, the gains are a few percent, in efforts most of us don't race.
James. Where's this from? Because supplement advice usually comes from whoever's selling the tub.
Lyra. This one comes from the UCI's Sports Nutrition Project. It's a review by Jamie Whitfield and colleagues, published this year in the International Journal of Sport Nutrition and Exercise Metabolism, one of the papers behind the UCI's nutrition position statement. They start from the Australian Institute of Sport's framework, which grades supplements by the evidence, and they keep to its top group. [1]
James. And the pros really take this stuff? All of it?
Lyra. Most of them take something. The surveys the review cites find somewhere between eighty five and a hundred percent of national level riders using supplements. The authors are honest about one catch, though. An audit of the whole supplement literature, over eighteen hundred studies, found fewer than a quarter of the participants were women, and only a small fraction of anyone was elite. So most of this was measured in competitive club level men. [1]
James. Which, to be fair, is most of our listeners. Okay, go through them. Start with creatine, because I've got a tub in the cupboard I haven't opened this year.
Lyra. Creatine's the sprinter's one. It tops up phosphocreatine in the muscle, the fuel for the first few seconds of an all out effort. In the cycling trials the review describes, five days of loading raised power in repeated thirty second sprints by around six percent. The authors' reading is that it suits races decided by surges and a finish, which includes road and gravel.
James. So why's it only a maybe for road in the UCI table?
Lyra. Weight. Creatine pulls water into the muscle, about half a kilo to a kilo in the first days on average, and more in some people. For a climber that's a real cost against a gain measured in sprints. So the position statement gives creatine a tick for track and BMX, and a question mark for road and gravel. [2]
James. That tracks with me, honestly. In some build phases I've done a cycle of creatine. Not this year, and I haven't missed it, which is interesting given how positive people are about it.
Lyra. And that's a fair observation, not advice either way. What the evidence says is that if your racing has sprints and surges in it, creatine does something measurable, and if your racing is a long steady climb, the kilo matters more than the sprint.
James. Beetroot juice. Everyone was on it a few years ago.
Lyra. Nitrate from beetroot juice makes the muscle a bit more economical, so you hold the same power for slightly less oxygen. Pooled across eighty studies, the effect is small but real. The problem is who it works for. In the best trained riders, the ones with a very high VO2max, the pooled effect is essentially zero. And the handful of women only studies found nothing significant. [1]
James. So the fitter you are, the less it does.
Lyra. That's the pattern. If it's for you, it's about five hundred millilitres of juice, two to three hours before. And don't use an antibacterial mouthwash that day, because the bacteria in your mouth do the first step of turning nitrate into something useful.
James. Beta-alanine. That's the one that makes your face tingle.
Lyra. It is. Beta-alanine builds carnosine in the muscle, which soaks up acid during very hard efforts, and it takes weeks of daily doses to build up. A meta-analysis of forty placebo controlled studies in the British Journal of Sports Medicine found a small overall effect, biggest in efforts of thirty seconds to ten minutes, and bigger still when it's combined with sodium bicarbonate. We did a whole episode on bicarbonate, so I'll leave that one at the headline. It's for efforts of one to ten minutes, taken an hour or three before, and the stomach is the problem. [3]
James. Let me push back, though. These are all two or three percent gains in a lab, in trained men, in efforts of a few minutes. If I've got ten hours a week and a job, does any of this really matter for me?
Lyra. Mostly, no, and the UCI says so in its own way. The position statement has a decision tree for supplements, and the first steps aren't about supplements at all. Is your energy availability right, are you fuelling your rides, are you sleeping, are you recovering. Only when those are in place does it ask whether the evidence is strong, whether the product's been batch tested, and whether you can trial it in training and measure the result. [2]
James. So the boring stuff first.
Lyra. The boring stuff is where the big percentages live. A badly fuelled long ride costs you far more than beta-alanine ever gives back.
James. What about the ketone drinks? Because that was the big pro cycling story for a while.
Lyra. The review has a table of thirteen trials in trained riders, and they go both ways. One found a two percent gain in a half hour time trial. Others found losses of a similar size, including in elite riders. The authors say plainly there isn't a strong evidence base for ketones on race day, and the position statement puts a cross against them in every discipline. [1]
James. Right. Now the bit that worries me. Contamination.
Lyra. This is the part every amateur should hear. The review cites a 2022 analysis of fifty surveys, more than three thousand supplements tested, and over a quarter of them contained something banned that wasn't on the label. Mostly stimulants and anabolic steroids, and mostly in fat burners, pre workouts and muscle gain products. [1]
James. A quarter. But surely that's a pro problem? I'm not getting drug tested at a regional gravel race.
Lyra. You could be. Anti doping rules apply to riders at every competitive level, and under strict liability the rider is responsible whatever the label said. So the advice is plain. Buy from a batch tested programme, which in the UK means Informed Sport, stick to single ingredient products, and leave the fat burners and pre workouts on the shelf. Testing lowers the risk. It doesn't remove it.
James. Okay. Make this useful for people in different places.
Lyra. If you're new to this, you don't need any of the six. Get the plan, the food and the sleep right first, and if you want one thing for an event day, it's caffeine, which is the one supplement with a tick in every discipline in the UCI table. [2]
James. And if you train with power?
Lyra. If you train with power, you've got the tool to find out whether a supplement does anything for you. Trial it in training, two or three times with and without, on the same loop or the same turbo session, and compare the numbers rather than the feeling. WattPlan's plan shows each coming session and its Load, so you know which days to test on, and the player reminds you to eat on longer rides, because carbohydrate is the sports food that actually matters.
James. And if you race?
Lyra. If you race, pick from your discipline's column. Road and hilly events get caffeine, beta-alanine and glycerol, which is a way of holding extra fluid before a long hot race. Gravel gets caffeine alone. And a ten mile time trial or a hill climb is exactly the one to ten minute effort bicarbonate was tested on. For a long one, WattPlan's Route analysis, part of Premium, writes a nutrition section for the route, including where caffeine fits on a long day, and the Coach is told never to recommend a supplement for a health problem, and to send a medical question to your GP.
James. What can't the review tell us?
Lyra. Who it works for beyond club level men. Fewer than a quarter of the participants in this whole literature are women, and the elite riders are a sliver. Nobody's properly tested combinations, or repeated doses across the stages of an event. And nobody can tell you how much of a two percent gain is the supplement and how much is believing you've taken it.
James. So, my version. Food, sleep and the plan first. Caffeine on event day if I want one thing. Anything else gets a proper trial in training with the power meter, from a batch tested tub, and the fat burners stay in the shop.
Lyra. And the review's own last word is the best one. The gains are small, the risks are yours, and the food comes first.
Lyra. The full article and every study we mentioned are on the WattPlan blog, linked in the show notes. And if you've enjoyed this, follow the WattPlan Podcast wherever you're listening, so you don't miss the next one.
James. And if you want a plan built around the time you've actually got, get WattPlan on the App Store or Google Play. Thanks for listening.
Voices produced with ElevenLabs. James's voice is a clone of his own, Lyra is an AI voice, and James reviews every episode.
Supplements for cyclists with strong evidence come to six in the UCI's review by Jamie Whitfield and colleagues, published on 1 May 2026. Caffeine, creatine, sodium bicarbonate, beta-alanine, dietary nitrate and glycerol each have a dose and a job, most gains are a few percent, and a 2022 review found undeclared banned substances in 28% of products tested.
Which supplements work for cyclists?
The review is part six of our series on the UCI's nutrition position statement. Whitfield, of the Australian Catholic University, and co-authors from Dublin, Madrid, Ghent and São Paulo report that 85% to 100% of national-level riders surveyed use some supplement. They keep to the six products the Australian Institute of Sport's framework puts in Group A, the ones with a strong evidence base, and add exogenous ketones because professional cycling made them famous.
An audit of 1,826 supplement studies with 34,889 participants found 23% of them women, and only 9% of the men and 19% of the women elite, so most of what follows was measured in competitive male riders.
The position statement sorts the six by discipline. Road gets a tick for beta-alanine, caffeine and glycerol and a question mark for creatine, nitrate and bicarbonate, gravel gets a tick for caffeine alone, cyclo-cross and mountain biking swap glycerol for bicarbonate, and ketones get a cross in every column.
| Supplement | Dose and form | When | What the trials found | Side effects |
|---|---|---|---|---|
| Caffeine | 3 to 6 mg per kg, drink, tablet or gum | About 1 hour before, gum 15 minutes before | 1 km time trial 3% faster, 40 km 3.5% more power | Headache, jitters, poorer sleep |
| Creatine | 20 g a day for 7 days then 3 g, or 3 g a day for 28 days | Daily | Repeated 30 second sprints 6% more mean power | 0.5 to 1 kg of water weight |
| Sodium bicarbonate | 0.3 g per kg, enteric capsules or hydrogel | 1 to 3 hours before | 4 km time trial about 2%, 40 km 1.4% | Stomach upset, 0.27 g of sodium per gram |
| Beta-alanine | 4 to 6 g a day, slow release | Daily for 4 weeks or more | 4 km time trial about 2%, pooled effect size 0.18 | Tingling skin |
| Dietary nitrate | 8 to 16 mmol, usually beetroot juice | 1.5 to 2 hours before | Pooled effect size 0.17, nothing at a VO2max of 65 or more | Cancelled by antibacterial mouthwash |
| Glycerol | 1 to 1.5 g per kg with 15 to 30 ml per kg of water | 1 to 1.5 hours before | 2% to 5% better in long rides in the heat | Bloating, nausea, weight |
| Exogenous ketones | Dose unknown, trials used 286 to 573 mg per kg | 1 to 2 hours before | One 30 minute time trial 2% better, another 2.4% worse | Stomach upset, dizziness |
Doses and timings are the review's Table 2.
Should amateur cyclists take creatine?
Creatine raises the phosphocreatine in your muscle, the fuel for the first seconds of a sprint. In one cycling trial the review cites, 5 days at the 20 g loading dose raised mean power in repeated 30 second sprints by 6%, and the review's reading is that creatine suits events decided by repeated surges and a finish, including road and gravel races. The cost is weight, 0.5 to 1 kg of water in the first days on average and 2.5 kg in extreme cases, which is why the position statement leaves creatine with a question mark for road and gravel.
Does beetroot juice work for cyclists?
Jeffrey Senefeld and colleagues pooled 80 studies in Medicine and Science in Sports and Exercise in 2020 and found a small improvement, an effect size of 0.174 with a 95% confidence interval of 0.120 to 0.229. In the 26 studies of well-trained riders with a VO2max of 65 or more the effect was 0.021 and not significant, and the six women-only studies found nothing significant either.
So beetroot juice is for riders who are not yet highly trained. The pooled trials typically used about 6 mmol, roughly 500 ml of juice, 2 to 3 hours before the effort, below the 8 to 16 mmol of the review's dose table, and never after an antibacterial mouthwash, which stops the conversion in the mouth.
What about beta-alanine, bicarbonate and glycerol?
Beta-alanine builds muscle carnosine, which buffers acid inside the muscle, and it takes weeks of daily doses. Bryan Saunders and colleagues pooled 40 placebo-controlled studies with 1,461 participants in the British Journal of Sports Medicine in 2017 and found an effect size of 0.18, 95% confidence interval 0.08 to 0.28, largest in efforts of 30 seconds to 10 minutes and larger still with sodium bicarbonate added, 0.43.
Sodium bicarbonate works in the blood over 1 to 10 minutes and has its own post, sodium bicarbonate for cyclists.
Glycerol, taken with 15 to 30 ml of water per kg before a long ride in the heat, holds about 40% more of that fluid in the body. Jardine and colleagues reviewed 38 hyperhydration studies in Sports Medicine in 2023, 361 of the 403 participants men, and found time trials 5.7% to 11.4% faster in two studies, with stomach symptoms reported in 26 of the 38. The UCI review calls it less advisable for rides under an hour or in cool conditions.
What does the UCI review say about ketones?
The review's Table 3 lists 13 trials of ketone drinks in trained riders. One found a 2% gain in a 30 minute time trial, others found losses of 1.5% to 2.4%, and the authors write that there is currently not a strong evidence base for ketone esters on the day. Two studies found erythropoietin 20% to 25% higher for a few hours after exercise, which the review calls interesting for recovery and unproven.
How do you avoid a contaminated supplement?
Vanya Kozhuharov and colleagues at the Medical University of Plovdiv reviewed 50 analytical surveys in 2022, covering 3,132 supplements. 875 of them, more than 28%, contained substances not on the label that WADA bans, most often sibutramine and anabolic steroids. Under WADA's strict liability rule the rider is responsible whatever the label said, and the review notes that anti-doping rules apply at every competitive level, which includes a British Cycling licence.
The review's answer is a product whose batch has been tested by a third-party programme, such as Informed Sport in the UK, no multi-ingredient fat burners, pre-workouts or mass gainers, and the knowledge that testing lowers the risk without removing it. The position statement's decision tree starts earlier, asking whether energy availability, fuelling, hydration, recovery and sleep are in order before any supplement, and only then whether the evidence is strong, the product is batch tested and a trial in training can measure the result.
What does this mean for an amateur rider?
Our view at WattPlan is that an amateur's supplement list starts and ends with caffeine on event day until the plan, the fuelling and the sleep are sorted, because the position statement's own decision tree puts those first and the other five add a few percent to efforts most sportives don't contain. Caffeine is the one with a tick in every discipline, and our caffeine guide gives the dose and the timing.
The review treats sports foods as food. In WattPlan's workout player, feed reminders run on structured workouts of 60 minutes or more and on free rides, asking for 60 g of carbohydrate with 500 ml of fluid every 45 minutes, about 80 g an hour, and a banana meets the reminder as well as a gel does. On the Route analysis page, a Premium feature, the AI Race Strategy writes a nutrition section for the route, and for a ride of over 3 hours it is asked to cover caffeine. The Coach is told never to recommend a supplement for a health problem, and to answer a medical question as one for your GP or physio.
What to do before trying one
- Check the foundations first. Eat for the ride, sleep, and get the carbohydrate right on long days, as in our UCI guidelines post.
- Find your discipline's column. Road and hilly sportives get caffeine, beta-alanine and glycerol, gravel gets caffeine alone, and a 10 mile time trial or hill climb is the 1 to 10 minute effort bicarbonate was tested on.
- Trial it in training, two or three times with and without on the same loop or turbo session, and write down the power and any stomach, sleep or tingling effects.
- Buy a batch-tested product from a single-ingredient range, keep the batch number, and leave fat burners, pre-workouts and mass gainers on the shelf.
- If you take any medication, have a heart condition or are under 18, talk to your doctor before any of them. The review says performance supplements are generally discouraged for junior riders.
What we don't know yet
Women are 23% of the participants in the supplement literature and only 0% to 8% of studies tested women alone, so the doses above come from men. Few trials used elite riders, and the nitrate effect disappears in the fittest group. Nobody has properly tested combinations, repeated doses across the stages of an event, or how much of a 2% gain is belief.
Sources
- UCI Sports Nutrition Project: Considerations and Applications for the Use of Sports Foods and Supplements to Improve Performance in Cycling, International Journal of Sport Nutrition and Exercise Metabolism
- UCI Sports Nutrition Project: Position Statement on Nutrition for Cycling, International Journal of Sport Nutrition and Exercise Metabolism
- β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis, British Journal of Sports Medicine
- Ergogenic Effect of Nitrate Supplementation: A Systematic Review and Meta-analysis, Medicine and Science in Sports and Exercise
- Dietary Supplements as Source of Unintentional Doping, BioMed Research International
- The Effect of Pre-Exercise Hyperhydration on Exercise Performance, Physiological Outcomes and Gastrointestinal Symptoms: A Systematic Review, Sports Medicine