Are Supplements Safe for Young Athletes?

For the parents, coaches and young people who want the truth — not the marketing.

Fuelling the next generation - what they put in their bodies now matters more than they know

Walk into any Holland & Barrett, scroll through any athlete's Instagram feed, or stand on the sidelines of a Sunday league match, and you will not have to look hard to find supplements. Protein powders, creatine, energy drinks - all being consumed as casually as a bottle of water. Supplement use among young athletes is not a niche issue, it is widespread, it is growing, and based on the latest research I have been reading recently, it is happening largely without the knowledge or guidance needed to make it safe.

I want to talk about this honestly, because I think it is one of the most important conversations we are not having about the next generation.

What the research tells us

Two recent peer-reviewed papers paint a detailed picture of the current state of affairs. 

A 2025 narrative review published in Nutrients, reviewed 30 years of literature on nutritional strategies and supplement use in athletes aged 8 to 20. A 2024 systematic review also published in Nutrients, looked specifically at acute supplementation effects in athletes aged 10 to 17, analysing 16 studies across Europe, North America, South America and Asia.

Both papers arrive at the same uncomfortable conclusion that young athletes are using supplements designed and tested in adults and applying adult dosing protocols, with what looks to be little understanding of the effects. The evidence bases to support most of supplement use simply does not exist.

A Swiss study cited in both reviews of nearly 500 elite adolescent athletes found widespread supplement use, with vitamin supplements, carbohydrate and electrolyte drinks, creatine, protein bars and energy drinks all commonly consumed. The same study found a low level of knowledge about the effects and purposes of those supplements among the athletes using them. Parents and coaches were identified as among the most significant influences on whether young athletes supplement, which means the responsibility does not sit with the young person alone.

Why young athletes are not just small adults

He looks up to you. Make sure the advice does too.

Here is something I wish more coaches and parents knew Young athletes are not simply smaller versions of adult athletes. They are growing and their bodies are developing in ways that make the stakes of inappropriate supplementation categorically different. As De Zan and colleagues note, 90% of peak bone mass is reached by age 18, this is a critical developmental window and one where nutritional choice have long-term structural consequences that go far beyond performance on a Saturday morning.

The maturation stage matters enormously. The Gruska systematic review highlighted that how a young athlete responds to supplementation is significantly influenced by their stage of puberty, yet seven of the sixteen studies included failed to even report maturation status. We are making decisions for young bodies using data that does not account for where those bodies are in their development stage. There is also something nobody talks about enough: contaminated supplements. Products marketed to adults, and increasingly to young people, are not regulated in the same way as medicines. Contamination with banned substances is a documented risk, and for a young athlete, that is not just a performance issue, it's a safeguarding one.

This is why, if supplements are being used at all, it is essential they carry a certified sports certification (such as Informed Sport or NSF Certified for Sport). These programmes batch-test products specifically for banned substances and provide a level of assurance that standard supplement labelling simply cannot.

The knowledge gap is the real problem

Even in my own early years in sport, and now working with clients in my practice, I have seen the same pattern emerge time and again. The supplement conversation in youth sport is driven primarily by two things: what peers are doing, and what performance promises are being made. Neither of these is a sound basis for a decision about a developing body.

The research highlights that many young athletes are making supplement choices without professional guidance, without understanding the evidence, and without awareness of the risks. If a teenager is using creatine because their teammate is, or drinking energy drinks before training because they believe it will improve their performance, the question is not whether they made a bad choice. It's whether they have the right people around them to have that conversation in the first place, a coach who understands the evidence or a practitioner who can guide them properly.

What the evidence actually supports

So what does work? Here is an honest summary based on the current research.

Emerging evidence but no substitute for the pillars that build strong performance

Carbohydrates have the strongest and most consistent evidence for performance in young athletes, particularly for endurance activity. Consuming around 1g / per kg of body mass before prolonged exercise is supported. Form matters too, concentrations that are too high can cause gastrointestinal discomfort, so this is not simply a case of more is better.

Vitamin D and iron are the micronutrients most likely to need addressing, but only when a deficiency is present. When a young athlete is deficient in vitamin D, correcting that deficiency has been shown to improve physical performance. When levels are already adequate, additional supplementation does not confer additional benefit. Iron deficiency is particularly relevant in female athletes and can significantly impair endurance performance but again, the solution is correction of a deficiency, not routine supplementation in the absence of one.

Creatine shows promising data in adolescents for high-intensity and anaerobic performance, and the International Society of Sports Nutrition considers it potentially safe under professional supervision. However, the long-term safety data in this age group remains limited, most of it is self-reported, and it should absolutely not be used without professional input.

Caffeine at doses of around 3 milligrams / per kg of body mass may have ergogenic effects in adolescents for anaerobic performance, but even low doses can disrupt sleep, which is arguably the single most important recovery tool available to a young athlete. The Gruska review excluded caffeine and energy drinks from its analysis specifically because of concerns around sleep impairment and hormonal disruption in this age group.

Beetroot juice, beta-alanine and omega-3 fatty acids all have biological plausibility, but the evidence in adolescent populations is either inconsistent or largely extrapolated from adult data. In my opinion, and as with everything I advocate for in this article, a food first approach is always the priority and these are not appropriate first-line recommendations for young athletes.

What I would say to any parent, coach or young athlete reading this

Before any supplement conversation, ask whether the basics are covered. Is the young athlete eating enough to fuel both their growth and their training? The research on Relative Energy Deficiency in Sport (REDs), something I am deeply passionate about, shows that under fuelling in young athletes has serious consequences for hormones, bone health, immunity and long-term development. No supplement addresses that, food does.

Is the young athlete sleeping enough? Sleep is where adaptation happens, where growth hormone is released, where the gains from training are actually made. If sleep is being disrupted by caffeine or energy drinks consumed before training, no supplement stack in the world compensates for that loss. Are there deficiencies that have been identified through testing? If so, that is the appropriate starting point for supplementation, under professional guidance, with a clear rationale and a plan to reassess.

Supplements are not a shortcut. In a developing body, they carry risks that adults simply do not face to the same degree. The most powerful performance tool available to a young athlete is a well-nourished, well-rested body and that is built through food, sleep, and appropriate training. That's my empowering opinion. and the research agrees.

References:

De Zan D, et al. Use of Nutritional Strategies, Bioactive Compounds, and Dietary Supplements in Young Athletes: From Evidence to Potential Risks — A Narrative Review. Nutrients. 2025.

Gruska N, et al. Enhancing Performance in Young Athletes: A Systematic Review of Acute Supplementation Effects. Nutrients. 2024.