Supplements for Runners & Triathletes

As a sports nutritionist, I spend a lot of time discussing supplements with the athletes I support. Social media is full of bold claims about powders, pills, and drinks promising better performance, faster recovery, or improved health. It’s not surprising that many of the athletes I work with arrive already taking several supplements - sometimes five or six at a time.

Supplements certainly have a place in sports nutrition, but they shouldn't be what you reach for first when you're trying to fuel your training or perform well.

Food First

The foundation of good sports nutrition is a balanced, consistent diet. Everyday foods provide the energy and nutrients that support training, recovery, and overall health.

Carbohydrates fuel training sessions. Protein supports muscle repair and adaptation. Fats contribute to hormone production and long-term energy needs. Whole foods also provide vitamins, minerals, fibre, and a wide range of other beneficial compounds that work together in ways that supplements can’t fully replicate.

Before thinking about supplements, it’s worth asking a simple question: Is my day-to-day diet supporting my training? Often, improvements in regular eating habits will have a far greater impact than adding another supplement.

Supplements Are the Icing on the Cake

Supplements are the icing on the cake

A helpful way to think about supplements is as the icing on the cake. The “cake” being a well-structured training programme, adequate sleep, good hydration, and a balanced diet that meets your energy and nutrient needs.

Supplements can add small, marginal gains once those basics are in place. In certain situations they can also be convenient, for example, when travelling, training heavily, or when specific nutritional needs are difficult to meet through food alone. But if the foundations aren’t solid, supplements are unlikely to make a meaningful difference.

Why Runners & Triathletes Take Supplements

Many runners and triathletes start using supplements with good intentions. They want to support their training and make sure they’re doing everything possible to improve performance.

However, without clear guidance, it’s easy for supplements to accumulate without a specific purpose or evidence behind them.

However, with every supplement you take, there is a risk. Supplements are not always regulated to the same strict standards as medication. This means there can be variability between products and even between batches of the same product. You might find:

• Ingredients don’t match what’s listed on the label

• Inaccurate dosing

• Contamination with substances that shouldn’t be present

While many reputable companies work hard to maintain quality, the risk is not zero.

For athletes who are subject to drug testing, supplements require real caution.

Anti-doping systems operate under the principle of strict liability. In simple terms, athletes are responsible for anything that appears in their system, regardless of how it got there.

This means that even unintentional contamination from a supplement could lead to a positive test.

If you are a drug-tested athlete, practical steps include:

• Only considering supplements when there is a clear need

• Choosing products that have been independently third-party tested

• Keeping records of what you use, including batch numbers where possible

UK Anti-Doping has lots of information on its website to help you navigate your responsibilities, but your nutritionist can help you too.

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When Supplements Can Be Useful

Although caution is important, supplements can still have a role in certain circumstances. For example:

• Addressing a diagnosed nutrient deficiency or preventing one, for example, it's crucial to supplement with vitamin D from October to March if you live in the northern hemisphere.

• Supporting nutrition during periods of heavy training to make sure you get the nutrients you need to get the adaptions you are working towards

• Providing convenient options around training sessions because supplements such as protein powders are easier to consume on the move

• In some cases, using evidence-based performance supplements under professional guidance

The key point is that supplement use should be purposeful and individualised, rather than driven by trends.

A Simple Way to Think About It

Before starting a supplement, it can be helpful to ask a few questions:

• What specific problem am I trying to solve?

• Could I address this through food first?

• Is there good evidence supporting this supplement?

• Is the product quality assured?

• Do I actually need it right now?

These questions can help you decide whether supplements are the best option for you.

The Takeaway

Supplements are often discussed as if they are the key to better performance. In reality, they tend to play a much smaller role than many athletes expect.

The most effective sports nutrition strategies usually come back to the basics: consistent eating patterns, balanced meals, adequate fuelling for training, and good recovery habits.

Once those foundations are in place, supplements can sometimes provide a useful finishing touch - but they shouldn't be the starting point.