Professional cycling is developing rapidly, with sports science increasingly being used to push performance to new levels. One development that caught the attention of many following this year’s Tour de France was the use of exogenous lactate gels on selected stages. This raises an obvious question: if lactate has traditionally been associated with fatigue, why would cyclists consume more of it?

For many years, lactate was incorrectly viewed as a waste product responsible for the burning sensation experienced during hard exercise. We now know this is outdated. The Lactate Shuttle Hypothesis, developed by Dr George Brooks, describes how lactate is continually produced and transported between tissues during exercise. Oxidative muscle fibres can take up lactate and convert it back to pyruvate, which can then enter mitochondrial metabolism and contribute to ATP production. Rather than simply being something the body needs to remove, lactate can therefore act as an important fuel substrate.

So, if the body already produces and uses lactate as a fuel, could consuming additional lactate improve cycling performance?

What does the science say?

The evidence so far is interesting, but far from conclusive. A small, randomised crossover pilot study by Ewell et al. (2024) found that acute lactate supplementation increased mean power during a cycling time trial by approximately 4%. However, it did not change VO2 peak, ventilatory threshold or lactate power threshold.

In contrast, Bordoli et al. (2024) studied 16 endurance-trained male cyclists who consumed 120 mg/kg of exogenous lactate or a placebo 70 minutes before a high-intensity cycling protocol. Although lactate supplementation increased blood bicarbonate levels and reduced ratings of perceived exertion (RPE), it did not improve overall cycling performance. This highlights an important distinction: physiological changes do not necessarily translate into better performance.

Earlier research by Morris et al. (2011) reported a 17% increase in time to exhaustion following exogenous lactate consumption compared with placebo. However, the study was very small and, like the more recent research, is difficult to directly apply to road racing or time-trial performance.

What does this mean?

Exogenous lactate may provide an additional oxidisable substrate and influence acid-base balance, potentially reducing the perceived difficulty of high-intensity exercise. However, the current evidence is limited and inconsistent, with studies differing in their protocols, doses and performance measures.

The use of lactate-containing products by elite cyclists is certainly intriguing, but it should not be interpreted as proof that they improve performance. As with many emerging sports nutrition strategies, the science is still catching up with what we are seeing at the elite level. It is also important to note that lactate was consumed alongside carbohydrates and did not act as a fuel replacement in any way. 

Key takeaway

Lactate is not simply a waste product and is not considered the primary cause of muscle fatigue. The Lactate Shuttle Hypothesis highlights its important role as a fuel during exercise, while early research suggests that consuming additional lactate may influence metabolism, acid-base balance and perceived effort. However, there is currently insufficient evidence to conclude that lactate gels improve cycling performance.

References:

• Brooks, G.A., 2018. The science and translation of lactate shuttle theory. Cell metabolism, 27(4), pp.757-785.
• Bordoli, C., Varley, I., Sharpe, G.R., Johnson, M.A. and Hennis, P.J., 2024. Effects of oral lactate supplementation on acid–base balance and prolonged high-intensity interval cycling performance. Journal of Functional Morphology and Kinesiology, 9(3), p.139.
• Ewell, T.R., Bomar, M.C., Brown, D.M., Brown, R.L., Kwarteng, B.S., Thomson, D.P. and Bell, C., 2024. The influence of acute oral lactate supplementation on responses to cycle ergometer exercise: a randomized, crossover pilot clinical trial. Nutrients, 16(16), p.2624.
• Morris, D.M., Shafer, R.S., Fairbrother, K.R. and Woodall, M.W., 2011. Effects of lactate consumption on blood bicarbonate levels and performance during high-intensity exercise. International journal of sport nutrition and exercise metabolism, 21(4), pp.311-317.

About me:

Olivia is an aspiring sports nutritionist going into her final year of studying Sports Nutrition at LJMU where she hope to progress onto a masters in the same subject. She is passionate about endurance sport, mainly triathlon and cycling, and balance these hobbies alongside her part-time job in a local leisure centre. You can find out more about Olivia here