What Are Lactate Gels, And Are They The Future Of Marathon Fueling?

For most of the last century, lactate was the villain of the story. It was the thing that made your legs burn, the waste product you blamed when you blew up at mile 20. Now companies are putting it in gels and selling it as the next big thing in endurance fuel. One of them says it helped fuel Yomif Kejelcha’s 1:59 marathon debut in London.

So what is actually going on here, and should everyday runners care?

Lactate Was Never The Enemy

The first thing to clear up is the old myth. Lactate is not a waste product, and it is not what makes your muscles hurt. That idea was overturned years ago.

What your body actually produces during hard exercise is lactate plus hydrogen ions. The hydrogen ions cause the acidity and the burn. The lactate itself is a fuel. Research known as the “lactate shuttle,” pioneered by University of California, Berkeley physiologist George Brooks, established decades ago that muscle, heart, and brain tissue burn lactate directly for energy, and that it also works as a signaling molecule telling the body which fuels to use. That part of the science is settled.

Your body already makes and reuses large amounts of lactate every time you run hard. That is exactly what made supplement companies ask the obvious question: what if you could just eat more of it?

Why Nobody Could Make It Work

The idea of swallowing lactate is not new. The problem was always that it is close to impossible to stomach. An early “polylactate” product from 2002 was described as inedible, and even Tadej Pogačar’s UAE Emirates team reportedly tried mixing a lactate product with carbohydrate before giving up on the taste, as Velo reported.

The breakthrough, such as it is, came from a Spanish project pairing sport scientist Aitor Viribay, a former lead scientist for the INEOS Grenadiers cycling team, with food scientists from the Basque Culinary Center and chefs from the Michelin-starred restaurant Mugaritz. Their company, From Lab to Field, says it found a way to buffer lactate chemically and wrap it in a texture that is actually palatable. “We have used chemical and physical properties to ‘tame’ our friend lactic acid,” Viribay told Outside’s Alex Hutchinson.

How A Lactate Gel Is Supposed To Work

The pitch is that lactate acts as a separate, parallel fuel alongside carbohydrate. There is a real precedent for that logic. The reason runners can now absorb up to 120 grams of carbs per hour is that glucose and fructose use different intestinal transporters, so combining them lets you take in more. Lactate uses yet another set of transporters, called MCTs, so in theory it stacks a third fuel stream on top of the two you already have.

Lactate also reaches the bloodstream within about five minutes, faster than glucose and fructose, which need processing in the liver first. And depending on intensity, it can nudge the body toward burning either fat or carbs, sparing your limited glycogen for when you need it.

The current products lean on this. Santamadre’s Lactate 60, the gel tied to Kejelcha’s London run, pairs 40 grams of carbohydrate with 60 millimoles of lactate and follows an independent MCT pathway on top of the usual carbs.

The Catch: The Evidence Is Thin

Here is the part the marketing skips. The human performance evidence for eating lactate is somewhere between modest and non-existent, and the people selling it admit the research is still young.

A 2024 randomized, double-blind pilot trial found no change in VO2peak or lactate threshold from an oral lactate supplement, and only a 4% bump in a 20-minute time trial. A separate 2024 study in 16 trained cyclists using calcium lactate found no time-trial benefit at all, though it did lower perceived effort. From Lab to Field’s own pilot data showed an average 8% improvement in time to exhaustion, but that was driven by two outlier subjects, so it tells us very little. Viribay himself has a paper under peer review and says it may take years to understand how the molecule really behaves.

The most useful comparison is ketones, which swept the pro cycling world a decade ago on the strength of great theory and have since settled into a much smaller, more nuanced role. Lactate gels may follow the same path.

Should Runners Care Yet?

For elite marathoners chasing seconds, lactate gels are worth watching, and the pros are already testing them in races. For everyone else, the honest answer is not yet. The gels are food-grade and not banned by anti-doping rules, but they can cause dose-dependent stomach trouble, they will launch at high-end gel prices, and the proven benefit so far is that a hard effort feels slightly easier, not that you actually go faster.

The smarter takeaway is the one that has been true all along: most runners still underfuel. Nailing your carbohydrate intake and training your gut to handle it will do far more for your marathon than any exotic new molecule. Lactate might turn out to be a genuine tool at the very top of the sport. It is not the shortcut the headlines are selling.