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Are supplements worth it?

This is all you need to know about supplements in sport.

Sports supplements are big business for the sports industry. Every day it seems we wake up to the next big ingredient which will boost our performance, burn fat, or aid our recovery.

But is there truth behind these claims? Do supplements give us what they promise? We explore the science behind supplements in sport.

Sports supplements, sometimes known as ergogenic aids, are nothing new. Throughout history athletes have tried weird and wonderful things in the hope of getting a cut above the rest: it is known that Aztec athletes ate human hearts believing it would improve performance, and in the 1800s European cyclists took substances that would probably land you in rehab or jail today.

Thankfully, things have moved on a bit since then. The Australian Institute of Sport (AIS) classifies supplements into four groups according to their effectiveness and safety. We discuss a few in each category below:

Group A: Supported for use in specific situations (worth it… sometimes)


Creatine is one of the most widely used supplements in sport. It is a substance which is involved in energy production and can be synthesised naturally by your liver, pancreas and kidneys. You can also find creatine in foods: red meat and fish are the best sources providing modest amounts at around 4-5g per kg.

Supplementing for a short-term (2-6 days), with around 20g of creatine a day has been shown to enhance high-intensity, short-term exercise and potentially gains in muscle mass [1]. Vegan and vegetarian athletes are the ones likely to benefit most from creatine supplementation, and vegan-friendly creatine is now available to buy.

Beware of the shortcomings: there is large variability in how individuals respond to creatine and you will have an upper limit, meaning any excess will be excreted. Creatine may not be beneficial for endurance-type exercise and side effects can include weight gain (due to greater water retention).


Caffeine is a stimulant, and therefore a well-known ergogenic aid. This historically landed it on the banned list by the International Olympic Committee (IOC) – where up until 2004, they monitored levels within a narrow range.

Most of us will probably not make it into the Olympics team anyway (we can dream…) so how can we use caffeine to our advantage?

It has been found that between 2 and 6 mg/kg body weight, taken about an hour before exercise, can enhance endurance type events, and may also improve feelings of strength [1,5]. This amount is comparable to the amount of caffeine in 2 – 6 cups of coffee, but this depends on the coffee type, and also your body weight.

It is important to remember that caffeine is a diuretic (it promotes water loss from the body through urine). Dehydration can damage performance, so ensure you drink plenty of fluids! In addition, we all recognise the undesirable side effects of too much caffeine: gastrointestinal distress, headaches and dizziness… and some people are more caffeine sensitive than others. So, it’s best to find what works for you. Remember: more does not always equate to better.


Exercise leads to a build up of acidity in the muscles which can cause muscle pain and fatigue – meaning your performance can suffer. Buffers, such as bicarbonate – also known as ‘baking soda’ – can work to neutralise the acidity during exercise.

Consuming a single dose of 0.3 g bicarbonate per kg of body weight, with 1 litre of water, 1-2 hours before exercise, has been shown to improve performance in exercise lasting 0.5 and 6 minutes near maximal performance (high-intensity exercise, such as a sprint) [1].

In small amounts, the use of bicarbonate does not pose any major health risks, but this does definitely not mean you should go necking baking soda from the tub. Even in small amounts baking soda may cause stomach problems, and the benefits are only short-lived. So, if baking soda is really something you fancy instead of your morning protein-shake, stick to the recommended amounts, and no more.

Beetroot juice and nitrates

Who would’ve thought the humble beetroot could have so much potential in fitness and performance? But with proven benefits tonumber of reps, overall power, and time to fatigue [6], it’s easy to understand why it receives attention…

Beetroots are rich in compounds called nitrates which are known to promote vasodilation (widening of the blood vessels) [6] – in other words, more oxygen-giving blood can flow to your muscles. Beetroot can therefore help your body to transport and use much-needed oxygen to where it is needed. The easiest and quickest way to supplement your diet with beetroot is probably through juicing and taking a shot (whilst holding your nose…). But you could also include more beetroot in your diet and reap the added benefits such as fibre.

Group B: Deserving of further research (might be worth it)


Antioxidants are provided in food in the form of essential vitamins and minerals (such as vitamin C, vitamin E, selenium and B-carotene) or in the form of polyphenols (complex structures which exist naturally in plant foods). Antioxidants work by reducing oxidative stress in the body, which is caused by products of metabolism (free radicals), which are thought to be damaging to cells.

Exercise is known to generate a higher amount of oxidative stress, so it may seem logical that a higher quantity of antioxidants is required... However, athletes have also been found to naturally have higher antioxidant levels in the body [1].

So, unless deficient, perhaps athletes do not require any extra supplementation after all?

Vitamin C supplementation has been found to hinder recovery from delayed-onset muscle soreness (DOMS) in athletes [4]. Researchers suggest that antioxidants can interfere with normal metabolism and hamper useful adaptations to training [3].

Currently there are mixed opinions as to whether antioxidant supplements will benefit sport, but there is nothing stopping you trying them to see if they work for you. If you are interested, it is recommended you try a low dose multi-vitamin. The important thing to know is that antioxidants can also be obtained readily and easily from foods. Brightly coloured fruits and vegetables give high amounts, along with other known benefits including fibre and fullness. So, you can’t go wrong supplementing your diet with these.


Carnitine is a compound which exists naturally meat, fish and dairy. It is involved in fat metabolism; therefore, it has been suggested that carnitine may help to ‘burn’ fat and stimulate weight loss. In theory, supplementation could support athletes in protecting their glycogen stores (glycogen is a form of energy prioritised for short bursts of high-intensity exercise).

There is debate about whether carnitine can be stored in your body – in other words, whether excess carnitine simply passes through your body unused. Recent studies have shown that ingesting carnitine along with a large carbohydrate load effectively increases carnitine retention in the muscle [1]. But with a higher number of calories being ingested, this would counteract any beneficial effects of carnitine on fat metabolism…

So, the jury is out on Carnitine. You may want to try to see what personal benefits this supplement gives, but as with all supplements, don’t overdo it.

Group C: No meaningful proof of beneficial effects…. (may not be worth it)

The AIS explains that, if you can’t find it in Group A or Group B, then it probably deserves to be in Group C…. Some examples of supplements within this group include Coenzyme Q10 and Ginseng.

Group D: Banned in sport (potentially harmful, we don’t recommend you go here…)

Group D is a list of names, some of which we can barely pronounce, let alone begin to understand! These substances are on the list for a reason – they could be harmful for your health, so you should question whether you want to put these in your body.

In summary, there is a time and a place for supplements in sport. Some supplements may be beneficial, but some could be an expensive quick fix, which are not guaranteed to work. You should seek advice from a health professional if needed - look for a suitably qualified AfN sports nutritionist or dietitian.

When looking to supplement, context is important - why are you supplementing? Will it benefit the exercise I am doing? Is there anything else to consider? What are my individual needs? And importantly, it is never a case of ‘the more the better’ – you could risk hurting yourself (along with your pride and bank balance…).

The thing which will offer you the highest chance of success is motivation – the harder you push the more you will gain. In the end, it might be worth a shot or two… of beetroot juice – but we never said it would be tasty.


[1] Geissler, C. and Powers, H.J. eds., 2017.Human nutrition. Oxford University Press.

[2]Maughan, R.J., Maughan, R.J. and Gleeson, M., 2010.The biochemical basis of sports performance. Oxford University Press.

[3]Gomez-Cabrera, M.C., Domenech, E. and Viña, J., 2008. Moderate exercise is an antioxidant: upregulation of antioxidant genes by training.Free radical biology and medicine,44(2), pp.126-131.

[4]Close, G.L., Ashton, T., Cable, T., Doran, D., Holloway, C., McArdle, F. and MacLaren, D.P., 2006. Ascorbic acid supplementation does not attenuate post-exercise muscle soreness following muscle-damaging exercise but may delay the recovery process.British Journal of Nutrition,95(5), pp.976-981.

[5]Spineli, H., Pinto, M.P., Dos Santos, B.P., Lima‐Silva, A.E., Bertuzzi, R., Gitaí, D.L. and de Araujo, G.G., 2020. Caffeine improves various aspects of athletic performance in adolescents independent of their 163 C> A CYP1A2 genotypes. Scandinavian Journal of Medicine & Science in Sports, 30(10), pp.1869-1877.

[6]Ormsbee, M.J., Lox, J. and Arciero, P.J., 2013. Beetroot juice and exercise performance. Nutrition and Dietary Supplements, 5, pp.27-35.