Lactate gels have a smart theory.

Jonah Rosner

September 9, 2026

Lactate is a genuine fuel. Turning that physiology into a useful race-day supplement is a separate problem.

In April 2026, Yomif Kejelcha ran 1:59:41 in his marathon debut. Weeks later, Santamadre began selling the lactate gel it says helped fuel that performance.

The timing makes the product story compelling. For much of the last century, physiologists blamed lactate for the burn and fatigue of hard exercise. Santamadre now presents it as a new endurance fuel.

The physiology behind that reversal is real. The case for drinking lactate during a race remains uncertain.

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Lactate is fuel, not metabolic waste

People often use lactate and lactic acid as if they are the same thing. They are not, and the difference matters.

Your body carries lactate and hydrogen ions separately. The hydrogen ions contribute to the burning sensation during hard exercise. Lactate does not cause that acidity. Its production slows acid buildup rather than driving it, as Robergs and colleagues (2004) explained.

That makes blood lactate a useful marker of exercise intensity. It is not waste accumulating until your legs fail.

Berkeley physiologist George Brooks (2018) explained the modern view through lactate shuttle theory. Lactate produced in fast muscle fibers can travel to slow fibers, the heart, and the brain. Those tissues take it up and use it as fuel. During hard exercise, lactate turnover can even exceed glucose turnover.

This separates two questions that supplement marketing often blends together. Lactate is an important fuel inside the body. Whether swallowing more of it improves endurance performance is still unresolved.

Why a lactate gel makes sense on paper

Endurance fueling already uses a similar transport strategy. Glucose and fructose move through different pathways in the gut. Combining them allows athletes to absorb more carbohydrate than glucose alone, a principle supported by Currell and Jeukendrup (2008).

Lactate uses another route. In theory, it could become a third fuel lane alongside glucose and fructose. A successful form might add usable energy without forcing more carbohydrate through the same intestinal pathways.

Infusion studies support one part of this concept. When researchers place lactate directly into the blood during exercise, the body oxidizes it and can spare blood glucose.

An intravenous infusion bypasses the central commercial problem. A gel must deliver enough lactate through the gut without making the athlete sick. That is the gap between an elegant mechanism and a useful race product.

Three delivery problems stand in the way

The first problem is dose. The proposed meaningful range is roughly 10 to 25 grams of lactate per hour. Santamadre says each Lactate 60 gel contains about 5 grams of lactate and 40 grams of carbohydrate.

Three to four gels per hour provide about 15 to 20 grams of lactate and 120 to 160 grams of carbohydrate, likely unrealistic for most runners.

The second problem is the gut. Santamadre's current ingredient list includes lactic acid, sodium lactate, and calcium lactate pentahydrate. The company does not disclose how the gel's 60 millimoles of lactate are divided among those forms. Its nutrition panel lists 250 milligrams of sodium per gel. A meaningful lactate dose can create a substantial mineral and osmotic load. That can draw fluid into the intestine and raise the risk of gastrointestinal distress.

McCarthy and colleagues (2024) tested oral sodium lactate in five men across 15 conditions. They used 41.5 to 163 milliliters of a 60 percent sodium lactate solution, without one fixed elemental sodium dose. Blood lactate barely rose. Most participants reported moderate to severe gastrointestinal symptoms, and some vomited.

The third problem is palatability. Lactate salts can taste salty and metallic, which matters when an athlete must consume them repeatedly for several hours. New forms claim to improve taste and tolerance. Those claims still need independent performance data.

The performance evidence is small and mixed

The published studies have tested cycling, not endurance running. Their results do not point in one direction.

Ewell and colleagues (2024) tested calcium and magnesium lactate capsules in 15 recreational subjects. Each capsule provided 372 milligrams of lactate, producing a mean dose of 19 plus or minus 1 milligrams per kilogram. Mean power was about 4 percent higher, but aerobic capacity and threshold measures did not change. The study was industry funded, so the isolated positive result deserves caution.

In one small study, Bordoli and colleagues (2024) tested 16 trained cyclists. They gave 120 milligrams of lactate per kilogram as 147 milligrams of calcium lactate per kilogram, 70 minutes before exercise. They reported altered acid-base balance and slightly lower perceived effort during about two hours of interval exercise. Performance did not improve, while gastrointestinal symptoms were higher.

A separate company webinar reported an unpublished average improvement of about 8 percent in seven riders. Two large responders drove that average. This preliminary company result is not the published Ewell finding, and it is not peer-reviewed evidence.

Together, these results do not show that an oral lactate gel improves endurance running performance. They also do not prove that every future form will fail. They show that the delivery problem remains unresolved. A plausible mechanism is not enough.

There may be a narrower use case in short, severe efforts where acid buildup limits performance. Sodium bicarbonate already targets that problem with a much larger evidence base.

A marathon or long-course triathlon is not the clearest test of that use case.

What endurance athletes should do now

Build race nutrition around the fuel with the strongest evidence. For running, work toward 60 to 90 grams of carbohydrate per hour from glucose and fructose, then practice that plan in training. Some cycling protocols go higher, but those intakes are not an automatic target for running.

If you are curious about lactate gels, look for three things: independent replication, tolerance at a meaningful dose, and results from realistic endurance events. An elite athlete using a product can generate a useful hypothesis. It cannot tell us how much the product contributed.

Lactate deserves its rehabilitation as a central fuel. A lactate gel still has to earn its place in a race plan.

By Jonah Rosner, founder of Marathon Science

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