Creatine is the most-studied sports supplement there is — hundreds of randomised trials, a literature deep enough that the benefits can be graded endpoint by endpoint. Almost all of it was run in adults.
Restrict the same search to adolescents and the number collapses. Seven randomised controlled trials, spread across twenty years, three continents and six unrelated research questions. This page is a census of those seven and of who has published a position about them. It is not advice, and it names no amount as suitable for anyone.
The seven trials
| Year | Population | n | What it administered | What it was asking |
|---|---|---|---|---|
| 2009 | Elite junior fin swimmers, mean age 15.9 | 16 | 4 × 5 g/day, 5 days | Anaerobic power and 100 m swim time |
| 2017 | Elite youth soccer players, mean age 17.0 | 19 | 0.03 g/kg/day, 14 days | Wingate peak and mean power |
| 2017 | Healthy children aged 10–12 | 67 | 7 days | Brain creatine content and cognition |
| 2018 | Injured adolescent fin swimmers | 18 | Through rehabilitation | Recovery from tendon overuse injury |
| 2019 | Elite soccer players, 16–21 | 19 | 0.3 g/kg/day 1 wk, then 5 g/day 7 wk | Airway safety |
| 2021 | Patients with juvenile dermatomyositis | — | 6 months | Feasibility, muscle function |
| 2025 | Male basketball players, 13–14 | 40 | 0.3 g/kg/day 5 days + 0.1 g/kg pre-test | Skill under cognitive-motor dual task |
Two of the seven are studies of patients, not of healthy adolescents. One is in children rather than teenagers. Five asked whether creatine improves something. One asked whether it harms something.
The one that asked about harm
The 2019 airway trial is the only entry in this literature whose stated purpose was a safety endpoint, and its opening sentence is the finding that justified running it: no data existed on the safety of creatine for lung function in athletes.
Nineteen elite soccer players aged 16 to 21 were stratified and randomised: nine took 0.3 g/kg/day of creatine monohydrate for a loading week and 5 g/day for seven maintenance weeks; ten took matched maltodextrin. Airway inflammation was measured as exhaled nitric oxide (FENO) and airway responsiveness as the fall in one-second forced expiratory volume after dry-air hyperpnoea, before and after.
| Measure | Creatine (n = 9) | Placebo (n = 10) | p | Effect size |
|---|---|---|---|---|
| Change in FENO | +9 ± 13 ppb | −5 ± 16 ppb | 0.056 | 0.695 |
| Max fall in FEV₁ after dry-air challenge | 9.7 ± 7.5 % | 4.4 ± 1.4 % | 0.070 | 0.975 |
Both differences point the same way and neither clears the conventional significance threshold. Both were more pronounced in the fifteen atopic players — those with allergic sensitisation — than in the group as a whole. The authors' conclusion is worth reading in its own construction rather than in summary: on the basis of the observed trends and medium-to-large effect sizes, they could not exclude an adverse effect on the airways of elite athletes, particularly in those with allergic sensitisation, and further safety profiling of the supplement was warranted.
That is not a finding of harm. Nineteen players is too few to establish one, and a p-value of 0.056 in a sample that size is the statistical equivalent of a shrug. But it is also not the clean result that "creatine is safe in adolescents" implies, and it is the only adolescent trial that went looking. No larger trial has been run since to settle it in either direction.
The asymmetry is the point of this page. Five trials looked for benefit in this age group and mostly found some. One looked for a safety signal and found something it could not dismiss. Those are not equally weighted in how the subject is usually summarised.
The negative result in the youngest sample
The 2017 study in 67 healthy children aged 10 to 12 is the only one to test the mechanism directly in this population. After seven days of supplementation, verbal learning and executive function scores did not differ between groups at baseline or afterwards (all p > 0.05), and in the randomly selected subgroup scanned by proton magnetic resonance spectroscopy, brain creatine content was unchanged in the left dorsolateral prefrontal cortex, the left hippocampus and the occipital lobe.
The authors describe it as proof-of-principle evidence against the hypothesis that dietary creatine drives brain creatine in developing individuals. It is a short trial and a small imaging subgroup, and it is nonetheless the only direct test anyone has run in children. It sits alongside the adult cognitive literature covered in creatine and the brain, which is itself thinner than its marketing.
What the trials found when they looked for benefit
Briefly, because this is the well-covered half:
- 2025, 40 basketball players aged 13–14, crossover with a four-week washout: under cognitive-motor dual-task conditions, dribbling, passing and shooting all improved against placebo (all p < 0.05); under single-task conditions only dribbling and shooting did. Dual-task cost fell for dribbling and passing.
- 2017, 19 soccer players, a deliberately low dose of 0.03 g/kg/day for fourteen days: peak and mean power output on a 30-second Wingate rose after creatine and not after placebo, with a between-group difference in total work.
- 2009, 16 fin swimmers: average power on one minute of continuous rebound jumps rose 20.2 per cent; 100 m swim times fell in the creatine group and were essentially unchanged in placebo.
- 2018, 18 injured fin swimmers in rehabilitation: lean mass fell less during immobilisation in the creatine group (5.6 against 8.9 per cent) and plantar-flexion peak torque differed between groups at two and four weeks of rehabilitation.
- 2021, juvenile dermatomyositis: adherence was good and the study was feasible; there were no statistically significant changes in muscle function, strength, aerobic capacity, disease activity, fatigue, physical activity or quality of life.
Note what the last two share with the airway study and with each other: none of them is a study of healthy teenagers taking a supplement for muscle. Three of the seven trials are clinical.
Who has published a position, and when
The International Society of Sports Nutrition, 2017 position stand. Its safety language is the broadest of any body: short- and long-term supplementation, up to 30 g a day for five years, is described as safe and well tolerated in healthy individuals and in patient populations "ranging from infants to the elderly" (PMID 28615996). The society returned to the subject in a 2021 narrative review that asked explicitly whether creatine is safe and effective for children and adolescents, and again in a 2025 follow-up whose twelfth listed question is "Does CrM enhance performance in adolescents?" (PMID 39720835).
The American Academy of Pediatrics, 2016 clinical report on performance-enhancing substances. It treats the category rather than the compound. Its summary conclusion is that the physical maturation and endogenous hormone production of adolescence are themselves associated with large improvements in strength and performance, and that for most young athletes these substances do not produce significant gains over those from puberty plus appropriate nutrition and training. Its stated concerns about the legal end of the category are high rates of product contamination, correlation with later anabolic androgenic steroid use, and effects on the focus and experience of youth sport (PMID 27354458).
The World Anti-Doping Agency. Creatine appears nowhere on the 2026 Prohibited List, which came into force on 1 January 2026 — not in the non-approved substances of S0, not among the anabolic agents of S1, not in the peptide hormones and growth factors of S2, not in the hormone and metabolic modulators of S4. This site's section-by-section register of the compounds in this market sets out what is on the List and where. An anti-doping rule is not a safety statement, and a substance being permitted in sport says nothing about whether it is appropriate for a fifteen-year-old.
Those three positions do not contradict each other, because they answer different questions: one is about measured adverse events, one is about whether the category is worth using at this age, one is about eligibility to compete. They are frequently quoted as though they were all answering the first.
The honest shape of the evidence
- Quantity: seven randomised trials, a few hundred adolescents, across twenty years. Two of the seven are clinical populations.
- Duration: the longest in healthy adolescents is eight weeks, in nineteen players.
- Direction: performance results are generally positive and short; the single safety-endpoint result is ambiguous and points the wrong way; the single mechanism test in children is negative.
- What is missing: nobody has run a long-term safety study of creatine in healthy adolescents. That absence is not an argument in either direction, and it is a fact about the evidence rather than about the compound.
Anyone making a decision about a young person should make it with a clinician who knows them. This page's job is to say what has been measured and by whom, so that the conversation starts from the record rather than from a summary of it. The adult literature it sits beside — what creatine is, the overall risk picture and the side-effect evidence read as two separate streams — is far larger, and none of it was collected in people this age.