Lactate as Fuel: Latest Research on Gel-Based Exogenous Energy for Performance

Lactate has carried an unfair reputation for decades. Many athletes still think of it as the stuff that makes legs burn and performance collapse. The research tells a different story.

Lactate is not simply a waste product. It is a usable fuel (providing 4kcals per gram), a signalling molecule, and a way for the body to move energy between tissues during hard work. That shift in understanding has raised a practical question for endurance sport and high-intensity performance: if the body already uses lactate as fuel, could a gel deliver lactate from the outside and add another energy source during exercise?

The answer is promising, but not settled. A lactate gel is not just a normal carbohydrate gel with a new label. It needs the right chemistry, taste, mineral load, gut tolerance, and evidence that it improves performance in the real world.

Lactate gels are being explored as a new way to deliver fuel during hard efforts.

Lactate is not the enemy of performance

The old story was simple: hard exercise causes lactic acid to build up, and that causes fatigue. It was neat, memorable, and incomplete.

During intense exercise, muscles break down glucose quickly through glycolysis. This process produces pyruvate. When the demand for energy is high, a large amount of pyruvate is converted into lactate. That conversion helps the cell keep glycolysis running, which means the body can keep producing energy at a fast rate.

In the body, the relevant molecule is mostly lactate, not lactic acid. The burning feeling during a brutal interval has more to do with changes in acidity, ion balance, and the wider stress of intense contraction than lactate itself.

The more useful view is the lactate shuttle. This model, strongly associated with exercise physiologist George Brooks, describes lactate as a carrier of carbon and energy. Some cells produce it. Other cells take it up and burn it.

That means lactate can move:

• From fast-working muscle fibres to more oxidative muscle fibres

• From working muscle to the heart

• From muscle to the liver, where it can help make glucose

• Potentially between muscle and the brain under some conditions

  
  

This is why blood lactate does not simply mean “fatigue level”. It reflects the balance between production, transport, and use.

How the body uses lactate as fuel

Lactate enters cells through transport proteins known as monocarboxylate transporters, often shortened to MCTs. Two important ones in exercise are MCT1 and MCT4.

MCT4 is often linked with lactate export from highly glycolytic fibres. MCT1 is often linked with lactate uptake and oxidation in more endurance-trained, mitochondria-rich tissues. Training can improve this transport system, which is one reason well-trained athletes can produce and clear lactate at high rates.

Once lactate enters a cell, it can be converted back into pyruvate. From there, it can enter the mitochondria and be used in aerobic metabolism. In plain terms, lactate can become a direct feedstock for energy production.

That matters because hard exercise is not powered by one fuel at a time. Even during high-intensity work, the body uses a mix of carbohydrate, fat, phosphocreatine, and lactate. The proportions shift with pace, training status, duration, nutrition, and fatigue.

Lactate is better understood as an energy currency in motion, not a dead-end by-product.

Recent exercise metabolism research, especially studies using labelled tracers, has strengthened this view. These methods allow researchers to follow where molecules go in the body. They show that lactate turnover can be high during exercise, meaning the body can produce and consume lactate rapidly at the same time.

This is the core idea behind Lactate as Fuel. If lactate is already part of the body’s energy system, a carefully designed gel may be able to supply it from outside the body.

Endurance exercise depends on a changing mix of fuels, including lactate.

Why put lactate in a gel?

Energy gels work because they solve a practical problem. During long or repeated hard efforts, the body needs fuel that is portable, quick to take, and easy to digest while moving.

Most sports gels use combinations of glucose, maltodextrin, and fructose. These fuels are well studied. They support performance because they maintain carbohydrate availability, help preserve blood glucose, and supply working muscles with usable energy.

A lactate gel would aim to do something different. It would provide an exogenous lactate source, meaning lactate taken in from outside the body. The idea is not to “flush lactate” or block lactate build-up. The idea is to provide a molecule the body can already oxidise.

There are several reasons researchers and product developers are interested in this.

Lactate may provide a fast oxidative substrate

Because lactate sits close to pyruvate in metabolism, it may be readily used by tissues with high oxidative capacity. The heart, endurance-trained muscle, and other tissues can all use lactate well.

This raises the possibility that ingested lactate could add to the fuel pool during prolonged or repeated efforts. In theory, this may help when the athlete needs energy but wants to avoid relying only on standard sugars.

The key phrase is “in theory”. The body’s ability to use lactate does not automatically mean any lactate gel will improve performance. It is also accurate to say that different individuals will have different abilities to process lactate in order to benefit from it.

Lactate may pair with carbohydrate

A practical gel may not use lactate alone. It may combine lactate with familiar carbohydrates.

That makes sense for several reasons. Carbohydrate fuels have strong evidence behind them. Lactate may add another substrate, but it probably should not replace glucose and fructose in situations where high carbohydrate delivery is the main goal.

A combined gel could aim to provide:

• Rapid carbohydrate availability

• Exogenous lactate as an additional oxidisable substrate

• Electrolytes from lactate salts, if the formula uses sodium, calcium, or magnesium lactate

• A different taste profile from very sweet gels

  
  

Lactate may affect perception and tolerance

Many athletes struggle with sweetness fatigue during long events. Lactate salts can taste salty, sour, or mineral-like, depending on the formula. That may be a benefit for some people and a drawback for others.

Gut tolerance is just as important as metabolism. A gel that looks good in a lab but causes nausea, bloating, or urgent toilet stops will fail in sport.

What the latest research suggests

The current research picture is exciting but early. The strongest evidence supports lactate’s role as an internal fuel and signalling molecule. The evidence for lactate gels as performance products is still developing.

Several areas are worth watching.

Exogenous lactate can raise blood lactate

Studies using oral or infused lactate show that the body can absorb or receive lactate and change blood lactate availability. That part is not controversial.

The harder question is what happens next. Does the extra lactate get oxidised during exercise? Does it spare muscle glycogen? Does it change perceived effort? Does it improve power output, time-trial performance, or repeat sprint capacity?

Those outcomes are more difficult to prove.

Lactate oxidation depends on intensity and training

A trained endurance athlete may handle lactate differently from a sedentary person. Training increases mitochondrial capacity and lactate transport. That can make lactate a more useful fuel during exercise.

Intensity also matters. At low to moderate effort, there may be enough oxygen availability for lactate oxidation. At very high intensity, lactate production may exceed the body’s immediate ability to clear and use it.

This does not make lactate bad. It means a lactate gel may work differently depending on the session:

Exercise setting	Possible role for exogenous lactate	Main uncertainty
Long steady endurance	Extra oxidative substrate alongside carbohydrate	Whether it improves performance beyond standard fuelling
Tempo or threshold work	Support for high lactate turnover	Whether gut tolerance holds up at higher intensity
Repeated intervals	Possible fuel between efforts	Whether timing and dose matter more than total intake
Team sports	Portable energy during repeated bursts	Whether the gel is practical during match play

Lactate may signal adaptation

Lactate does more than supply energy. It also appears to act as a signalling molecule linked with training adaptation. Research has explored its role in pathways related to mitochondrial development, gene expression, and tissue communication.

That does not mean swallowing lactate will equal a training adaptation. Exercise itself drives the adaptive signal through mechanical, metabolic, hormonal, and nervous system stress.

Still, it opens an interesting question: could exogenous lactate support training quality or recovery signalling in specific contexts? That remains a research question, not a proven product claim.

A useful lactate gel depends on formulation as much as physiology.

The formulation challenge is bigger than it looks

Making a lactate gel is not as simple as adding lactate powder to syrup. The form of lactate matters.

Most practical forms are lactate salts, such as sodium lactate, calcium lactate, or magnesium lactate. These bring minerals with them. That can help electrolyte delivery, but it can also create a high mineral load. Too much may affect taste, osmolality (which affects absorption)

A gel developer has to balance several factors.

The gel needs enough lactate to matter

A tiny amount may look good on a label but have little physiological effect. A meaningful amount may affect taste, texture, mineral content, and stomach comfort.

This is the classic sports nutrition problem: the dose that works in theory has to fit inside a product people can actually take during exercise.

The gel must protect the gut

During hard exercise, blood flow shifts away from the gut and towards working muscles. That makes digestion harder. Highly concentrated gels can pull water into the gut, which may lead to cramps or diarrhoea.

A lactate gel needs careful control of:

• Total carbohydrate concentration

• Mineral load

• Acidity

• Osmolality

• Texture

• Recommended water intake

• Serving size

  
  

If the gel uses sodium lactate, the sodium contribution must be counted alongside any other electrolytes. If it uses calcium or magnesium lactate, the formula must consider how those minerals behave in the gut.

Taste may decide adoption

Athletes will tolerate a lot, but not endlessly. Lactate can bring a tangy, salty, or slightly bitter profile. That might work well in a citrus or cola-style gel. It may clash with flavours that rely on clean sweetness.

This sounds less scientific than substrate oxidation, but it matters. A gel only works if someone can stomach it at race pace.

How lactate gels compare with standard carbohydrate gels

Standard carbohydrate gels remain the benchmark. They have decades of practical use behind them, and their benefits are clear in endurance events where carbohydrate availability limits performance.

A lactate gel would need to earn its place. It may be useful as an add-on, a mixed-fuel product, or a specialist option for certain sessions.

Feature	Standard carbohydrate gel	Lactate-based or lactate-added gel
Main fuel	Glucose, maltodextrin, fructose, or blends	Lactate salt, possibly with carbohydrate
Evidence base	Strong for endurance performance	Early for gel-specific performance claims
Taste	Usually sweet	Salty, sour, tangy, or mixed
Electrolyte contribution	Added separately if needed	May come partly from lactate salts
Best current use	Proven race fuelling	Experimental or specialist fuelling strategy
Main risk	Gut upset from high intake	Gut upset, mineral load, uncertain dosing

The sensible view is not that lactate will replace carbohydrate. It is more likely that lactate, if supported by enough evidence, becomes another tool in sports nutrition.

Who might benefit first?

If lactate gels prove useful, the first benefits may appear in sports where athletes already have high lactate turnover and strong oxidative capacity.

That could include:

• Road cycling

• Middle-distance running

• Rowing

• Triathlon

• Cross-country skiing

• Repeated-effort team sports

• High-volume interval training blocks

NB. It has become clear that at least one team in the 2026 Tour De France was using a lactate/carbohydrate mix gel)

The best candidates would likely be trained athletes who can use lactate efficiently. For recreational athletes, the gains may be smaller or harder to notice, especially if basic fuelling is not already in place.

The foundation still matters:

• Eat enough carbohydrate for the work required

• Practise fuelling in training before racing

• Match fluid intake to conditions

• Avoid trying new gels on event day

• Track gut comfort, power, pace, and perceived effort

  
  

A lactate gel cannot compensate for poor fuelling habits. It would sit on top of the basics, not underneath them.

New fuel strategies still need to work in real training conditions.

What needs to be proven next

For lactate gels to move from interesting concept to trusted sports product, research needs to answer practical questions.

The most important one is performance. A gel should be tested against a proper comparison, not just against nothing. For example, researchers need to compare lactate-added gels with standard carbohydrate gels that contain the same energy or similar carbohydrate content.

Useful studies would look at:

• Time-trial performance after prolonged exercise

• Repeat sprint or interval performance

• Lactate oxidation using tracer methods

• Muscle glycogen use where practical

• Gut symptoms during race-like intensity

• Differences between trained and less-trained participants

• Dose response and timing

  
  

Real-world testing matters too. A gel that works on a bike in a controlled lab may not work during running, where gut jostling is higher. Heat, dehydration, altitude, and event stress can all change tolerance.

The research also needs clear safety data. Lactate salts can add meaningful electrolyte loads. People with medical conditions, those taking relevant medication, or anyone unsure about high mineral intake should seek qualified advice before experimenting. This article is for general information only and is not medical guidance.

The practical takeaway for athletes and coaches

Lactate has moved from villain to valuable fuel. The body produces it, transports it, and burns it, especially during exercise. That makes the idea of a lactate gel scientifically plausible.

Plausible does not mean proven.

Right now, the strongest case for lactate sits in physiology, not finished gel products. The body clearly uses lactate as fuel. Exogenous lactate delivery is possible. A gel format could be practical. Yet the performance advantage over well-formulated carbohydrate gels still needs stronger evidence.

For now, the best approach is measured curiosity:

• Treat lactate gels as experimental until more performance data is available

• Do not replace proven carbohydrate fuelling for key races without testing

• Watch for gut comfort, taste fatigue, and total electrolyte intake

• Use training sessions to trial any new fuel

• Look for products that publish clear dosing and testing information

  
  

The future of sports fuelling may not be sugar alone. Lactate could become part of a more flexible approach to energy delivery, especially for athletes working near the edge of their metabolic limits. The science is moving in that direction, but the gel has to prove itself where it counts: in the gut, in the muscles, and on the clock.

Lots for you to 'digest' there!

Paul