A 15-year-old runs cross country in the fall, swims all winter, and plays club soccer most weekends. He eats an enormous dinner and almost nothing before three in the afternoon. His race times have been sliding since August. His parents buy protein powder.
Protein is almost never the problem. Total energy usually is.
A teenage athlete is doing two expensive things at once. Training is the visible one. Growing is the invisible one, and it doesn’t pause for the season or show up anywhere on a training plan. When intake falls short of what both jobs need, the body starts making cuts, and it doesn’t ask which ones you would have preferred.
Below, we look at what the research supports for young athletes, what the supplement aisle is selling them, and the handful of signs that mean it’s time to call a doctor instead of buying something.
The problem is almost never protein
Start with the baseline. The CDC’s physical activity guidance asks children and teenagers ages 6 to 17 to get at least 60 minutes a day of moderate-to-vigorous activity, with vigorous activity, muscle-strengthening and bone-strengthening each happening on at least three days a week. A kid on a travel team clears that in one practice.
That matters because most nutrition advice aimed at teenagers is written against the floor, not a competitive schedule. An athlete training 10 or 15 hours a week is somewhere the general advice was never pointed.
Protein gets the attention anyway. A national survey of roughly 21,000 US college athletes cited in the NIH Office of Dietary Supplements fact sheet on performance supplements found protein was the most commonly reported product at 41.7%, followed by energy drinks and shots at 28.6% and creatine at 14.0%. The same office notes that athletes who get enough protein from food probably don’t need a supplement at all. The American Academy of Pediatrics says the same thing on HealthyChildren.org, adding that studies have not shown protein or creatine supplements improve sports performance in young athletes.
Meanwhile, the actual gap in most teenage athletes’ days is the school day. Breakfast is small or skipped, lunch is 20 minutes long and often social, and then practice starts at four. That’s the arithmetic that moves performance, and no powder fixes it.
What happens when a young athlete runs short on fuel
Sports medicine has a name for this. The International Olympic Committee introduced the term relative energy deficiency in sport, shortened to REDs, in 2014 and published an updated consensus statement in the British Journal of Sports Medicine in 2023.
The underlying idea is simple enough to explain at a kitchen table. Energy availability is what’s left over for everything the body does after exercise has taken its share. Breathing, thinking, healing, immune function, hormones and, in a teenager, growth all come out of that remainder. When the remainder gets too small, the body downgrades the functions it can live without in the short term.
The 2023 consensus describes a field that has moved fast. More than 170 original research papers appeared between the 2018 and 2023 statements, and the newer document adds evidence on low carbohydrate availability specifically, on the overlap with mental health, and on how low energy availability plays out in male athletes, who were underrepresented in the early research.
Two older frameworks describe where it lands. The 2014 Female Athlete Triad Coalition consensus statement, also in the British Journal of Sports Medicine, defines three linked components: low energy availability with or without disordered eating, menstrual dysfunction, and low bone mineral density. A 2021 consensus statement on the male athlete triad in the Clinical Journal of Sport Medicine describes a parallel syndrome of energy deficiency, suppressed hormones and impaired bone health, most common in adolescent and young adult male athletes in sports that emphasize a lean physique, particularly endurance and weight-class sports. It recommends screening during adolescence specifically, because of how much bone is being built then.
The bone cost is the part worth sitting with. A 2019 review in The Physician and Sportsmedicine reports that about half of peak bone mass is acquired during adolescence and that catch-up growth cannot be expected in athletes who lose bone development during that window. The same review puts stress fracture risk at 15% to 20% for female athletes showing one component of the triad, rising to 30% to 50% for those showing more than one.
A companion paper in the 2023 IOC series is direct about prevention. It calls for education and for de-emphasising body weight and leanness, naming young and subelite athletes in particular, and it addresses that message to the people around the athlete: coaches, parents and managers. Adults set the environment here.
Signs that need a clinician, not a coach
Four patterns should trigger an appointment rather than a schedule change:
- Periods that become irregular or stop. Losing a menstrual cycle is not a normal side effect of hard training. The Female Athlete Triad consensus treats menstrual dysfunction as a core component of the syndrome, and it’s often the earliest visible one.
- A bone stress injury or stress fracture. One deserves a conversation about fueling. A second one deserves a workup.
- Fatigue that doesn’t clear with rest days. Tired after a hard week is normal. Tired after an easy week is information.
- Performance that keeps declining while training holds steady or increases. This is the signal athletes rationalize longest and clinicians find most useful.
If any of this shows up alongside eating that has become restrictive, rule-bound or secretive, that is a different and more urgent conversation. For the warning signs of a developing eating disorder, see our article on body image. The National Alliance for Eating Disorders runs a free helpline staffed by licensed therapists at 1-866-662-1235, 9am to 7pm ET, Monday through Friday.
Carbohydrate, fluid, and the stuff that moves performance
The 2023 IOC consensus singles out low carbohydrate availability as a growing concern, and it’s the piece teenagers cut first, often because they’ve absorbed something from a feed about carbs being optional. They aren’t. Carbohydrate is the fuel for hard efforts, and a kid who skips lunch is doing a 4pm session on nothing.
The practical fix is unglamorous: food before practice, food after practice, and something in the gap the school day creates. The USDA’s MyPlate guidance for teenagers makes the same case without the sports framing, pointing toward variety across the five food groups, portable snacks, and water rather than sugary drinks.
On fluids, keep it simple. Water is the default. The AAP’s 2011 clinical report in Pediatrics is emphatic that sports drinks and energy drinks are different products that should not be treated as interchangeable, and sports drinks have a narrow role in long, hot or unusually intense sessions rather than as something to drink during a 45-minute practice. The AAP’s current consumer guidance tells families to focus on fluids, calories, training, conditioning and rest, which is a short and honest list.
Food-first is also the anti-doping answer, for reasons that become clear below. A sandwich cannot fail a drug test.
Nothing on that shelf was approved before it was sold
This is the fact that reframes the whole aisle, and most parents don’t know it.
Medicines must be approved by the FDA before they can be sold. Dietary supplements do not. As the NIH Office of Dietary Supplements explains, unless a product contains a new dietary ingredient introduced after October 15, 1994, a company is not required to give the FDA its safety evidence before putting the product on the market. Manufacturers are responsible for making sure their products are safe and their labels truthful. The FDA can act against an unsafe product, but mostly after it’s already being sold. The Federal Trade Commission handles the advertising claims.
So the bottle in your hand was never reviewed by anyone before it reached the shelf.
On whether any of it works, the Office of Dietary Supplements is blunt: performance supplements cannot substitute for a healthy diet, a few ingredients have reasonable evidence behind them, and many have little or none. Among the ones it places in the little-or-no-evidence group are Tribulus terrestris, deer antler velvet, ginseng, ribose, tart cherry, quercetin, glutamine, betaine, citrulline, arginine, branched-chain amino acids and the antioxidant vitamins. The office also notes that most ingredient combinations, which is what the average pre-workout product is, have never been studied at all.
For this age group it gets more pointed. The fact sheet states that in most cases only adults should use performance supplements, and that talking to an expert matters if you’re a teenager. It cites the AAP’s position that performance supplements don’t improve teenage athletes’ abilities beyond what proper nutrition and training already provide.
A 2025 narrative review in Nutrients looked specifically at supplements and bioactive compounds in athletes aged 8 to 20 and reached the same place: most of the evidence comes from adults, pediatric-specific data remain limited, and current evidence does not support routine use in this population. The authors flag three recurring problems, including misuse, absence of professional guidance, and potential contamination with banned substances.
Contamination is its own subject, and this library covers it in the article on supplement contamination and third-party testing. The short version from the AAP’s consumer page: purity studies find high rates of contamination with potentially harmful substances, and many products don’t contain what their labels claim.
One more uncomfortable finding, from the Office of Dietary Supplements’ professional fact sheet. When the AAP reviewed adolescent supplement use, protein, creatine and caffeine were the most commonly used ingredients, use rose with age, and teenagers who weren’t playing organized sports often took them to change their appearance. That’s a body image issue wearing athletic clothing, and the body image article handles it.
Creatine, the question parents ask
Creatine deserves a straight answer in both directions, because the honest answer is genuinely mixed.
In adults, creatine has the strongest evidence of any performance ingredient. The Office of Dietary Supplements credits it with improving short, intense efforts with brief recovery, the sprinting and weightlifting end of the spectrum, with little value for endurance work. Weight gain from water retention is common. The office considers it safe for healthy adults over weeks to months, and possibly for years.
Then it adds the caveat that matters here: much of that research was done in young healthy men, not in teenagers.
A 2023 review in the Journal of Orthopaedics went looking for the adolescent evidence. The authors screened 9,393 articles and found 13 studies of creatine in healthy children and adolescents. Those 13 studies included 268 participants in total, with mean ages from 11.5 to 18.2, and 85% of them involved soccer players or swimmers. The reviewers judged the overall study quality poor, found no consistent effect on athletic performance, and reported that no study had been designed to address safety.
That last clause is the one to hold onto. The absence of reported harm in a body of research that never set out to look for harm is not the same thing as evidence of safety.
A 2021 review in Nutrients covering the same territory reads slightly more favorably, noting that the small adolescent studies generally report performance improvements and consistently report no adverse events, while acknowledging that less is known about whether adult benefits carry over to this age group at all.
Against that thin evidence base, the professional guidance for minors is consistent. The AAP’s consumer page says studies have not shown creatine helps young athletes’ performance and that it offers no clear added benefit during puberty. The Office of Dietary Supplements says most performance supplements are for adults. Nobody is saying creatine is dangerous for teenagers. They’re saying nobody has shown it helps them, and nobody has properly checked.
There’s also a practical observation worth making. A 15-year-old who wants creatine almost always has a fueling, sleep or coaching problem underneath the request, and creatine will not solve any of the three.
Caffeine and energy drinks are not the same product
The AAP’s 2011 clinical report draws a hard line here. Sports drinks are carbohydrate and electrolyte products. Energy drinks are stimulant products. The report’s conclusion is quotable and worth quoting exactly: “caffeine and other stimulant substances contained in energy drinks have no place in the diet of children and adolescents.”
On amounts, the Office of Dietary Supplements’ professional fact sheet reports that the American Medical Association recommends adolescents consume no more than 100 milligrams of caffeine a day, against 500 for adults, and that the FDA considers 400 milligrams a day unlikely to cause dangerous effects in healthy adults. Those are published agency figures, not a prescription for your kid. What a specific teenager should do, especially one taking any medication, is a question for their pediatrician.
The regulatory gap makes it harder. The AAP notes that the FDA regulates caffeine in foods and beverages but not in supplements, which is the category many energy products fall into, so the actual caffeine content can be difficult to know. Concentrated powders and pills are a particular hazard. The AAP also flags that young athletes taking ADHD medication should be especially careful with stimulant-containing products.
There’s a quieter cost too. A 5pm energy drink buys alertness and spends sleep, and sleep is what a growing athlete can least afford to lose. The teen sleep article in this library covers why that trade runs so badly in adolescence.
One contaminated tub can end a season
For any teenager who competes under organized rules, or hopes to, there’s a risk category that has nothing to do with health.
The US Anti-Doping Agency states plainly that using supplements means always assuming some risk of testing positive for prohibited substances, and that it cannot tell from a label whether a product is safe or free of banned substances. USADA describes three specific failure patterns: a banned ingredient listed on the label but not in the product, a prohibited substance present but not listed, and a product whose contents differ from batch to batch. Its summary line is unambiguous: “no dietary supplement can be guaranteed to be 100 percent risk-free.”
USADA recommends choosing products certified by a third-party program that tests for prohibited substances, and currently names NSF Certified for Sport as the best option, while stating clearly that USADA itself does not certify, approve or endorse any supplement or company. The Office of Dietary Supplements also names Informed-Choice and the Banned Substances Control Group among third-party certifiers.
This is the mechanism in plain terms. Certification means an independent lab tested batches of that product against the banned list. It lowers the odds of a surprise. It doesn’t make the product necessary, and in anti-doping, what ends up in the sample is the athlete’s problem regardless of how it got there.
The stakes are real for a high schooler with college ambitions. The NCAA maintains its own banned list and, according to the Office of Dietary Supplements, prohibits caffeine above a urinary threshold. A positive test does not care that nobody read the label.
Before you buy anything, and what to do instead
Five questions to run first
Work through these before a product goes in the cart:
- What is this supposed to fix, and is the honest answer food, sleep or coaching?
- Has it been studied in people this age, or only in adults?
- Does this athlete compete under NCAA, USADA or state association rules?
- Has the pediatrician seen the actual label, including the proprietary blend?
- Is it third-party certified, and does everyone involved understand that certification lowers risk rather than removing it?
If question one has a real answer and questions two through five all come back clean, you’re having a reasonable conversation. If question one doesn’t, the rest doesn’t matter.
The change that pays
The move with the highest return costs nothing. Find the hole in the school day and fill it. Most teenage athletes are not underperforming because they lack an ingredient. They’re underperforming because they ate at 7am, trained at 4pm, and expected that to work.
Then watch for the four signals. Periods that stop. A stress fracture. Fatigue that survives rest days. Performance that keeps falling while training doesn’t. Any of those means an appointment, and it helps to bring two things: the training schedule as it’s being done, and an honest record of a few days of eating.
Sources
- NIH Office of Dietary Supplements. “Dietary Supplements for Exercise and Athletic Performance (Consumer Fact Sheet).” ods.od.nih.gov
- NIH Office of Dietary Supplements. “Dietary Supplements for Exercise and Athletic Performance (Health Professional Fact Sheet).” ods.od.nih.gov
- NIH Office of Dietary Supplements. “Dietary Supplements: What You Need to Know.” ods.od.nih.gov
- US Food and Drug Administration. “Dietary Supplements.”
- Centers for Disease Control and Prevention. “Physical Activity for Children and Adolescents.” cdc.gov
- American Academy of Pediatrics (HealthyChildren.org). “Performance-Enhancing Substances and Supplements for Young Athletes.” healthychildren.org
- US Anti-Doping Agency. “Supplement Connect: Supplement 411.” usada.org
- US Department of Agriculture, MyPlate. “Teens.” myplate.gov
- American Academy of Pediatrics Committee on Nutrition and Council on Sports Medicine and Fitness. “Sports drinks and energy drinks for children and adolescents: are they appropriate? Pediatrics, 2011. PubMed. DOI: 10.1542/peds.2011-0965.” doi.org
- Mountjoy et al.. “2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 2023. PubMed. DOI: 10.1136/bjsports-2023-106994.” doi.org
- Torstveit et al.. “Primary, secondary and tertiary prevention of Relative Energy Deficiency in Sport (REDs): a narrative review by a subgroup of the IOC consensus on REDs. British Journal of Sports Medicine, 2023. PubMed. DOI: 10.1136/bjsports-2023-106932.” doi.org
- De Souza et al.. “2014 Female Athlete Triad Coalition Consensus Statement on Treatment and Return to Play of the Female Athlete Triad. British Journal of Sports Medicine, 2014. PubMed. DOI: 10.1136/bjsports-2013-093218.” doi.org
- Fredericson et al.. “The Male Athlete Triad: A Consensus Statement From the Female and Male Athlete Triad Coalition Part II. Clinical Journal of Sport Medicine, 2021. PubMed. DOI: 10.1097/JSM.0000000000000948.” doi.org
- Metzger et al.. “Creatine supplementation in the pediatric and adolescent athlete: a literature review. Journal of Orthopaedics, 2023. PubMed. DOI: 10.1016/j.jor.2023.03.010.” doi.org
- Jagim and Kerksick. “Creatine Supplementation in Children and Adolescents. Nutrients, 2021. PubMed. DOI: 10.3390/nu13020664.” doi.org
- De Zan et al.. “Use of Nutritional Strategies, Bioactive Compounds, and Dietary Supplements in Young Athletes: From Evidence to Potential Risks. Nutrients, 2025. PubMed. DOI: 10.3390/nu17132194.” doi.org
- Abbott et al.. “Part I: epidemiology and risk factors for stress fractures in female athletes. The Physician and Sportsmedicine, 2019. PubMed. DOI: 10.1080/00913847.2019.1632158.” doi.org
- National Alliance for Eating Disorders. “Home (free helpline staffed by licensed therapists, 1-866-662-1235).” allianceforeatingdisorders.com