In recent months ketones, the latest performance-enhancing miracle product to appear in cycling, have once again been in the eye of the storm, with several teams openly admitting their use while the Movement for Credible Cycling bans their use by its members and the UCI washes its hands of them by simply discouraging their use.

To start talking about ketones, the first thing to know is what they are. They are actually substances that the human body generates naturally. When we talk about the body using fats as a form of energy in low-intensity activity or when the energy provided by carbohydrates is exhausted, it is not strictly true that fats are what is consumed.

Fatty acids are complex substances that cannot be used directly by the body but must first be broken down in the liver. The result of this breakdown is precisely ketones after a process called ketosis. Ketones can then be used as a source of energy.

How do ketones improve performance?

What if we were to provide ketones directly to make things easier? It was under this premise that supplements rich in this compound began to be used a few years ago, taking into account that the fat reserves of cyclists are already minimal due to their limited weight.

The purpose of ketone supplementation is to provide the cyclist with another easily accessible source of energy, the body does not have to spend energy on breaking down fats, we already provide the result of this process. A source of energy that allows to safeguard the limited and precious glycogen deposits to be used in the key moments of the races, when the intensity is maximum and any small factor can tip the balance to one side or the other.

In any case, it is still a product introduced relatively recently and the way it is used to obtain the best results is still not clear, in fact, some recent studies suggest that its intake could be more efficient not during the competition itself but after it, when the glycogen reserves are already depleted and the body needs energy to start producing proteins to regenerate the damage caused by the intense effort.

Are they considered doping and why do they want to ban them?

The problem with ketones is the decision of the Movement for a Credible Cycling to put the cross on this substance based on the side effects that have been appearing with its use such as vomiting or stomach problems, by the way, side effects that also appear naturally when the body is in ketosis for a more or less prolonged period.

Besides, since it is a novel substance, on which there are hardly any studies, it is unknown what the effect of the use of ketones could be in the long term, i.e., the MPCC seems to be putting the bandage before the wound. For its part, the UCI does not prohibit the use of ketones, although it does advise against their use with the sole argument of possible side effects.

The controversy over the use of ketones in cycling started in 2020 with the harsh statements of Tom Dumoulin describing as hypocritical the attitude of the MPCC towards the use of ketones and announcing that he was abandoning this movement, partly also because his team, Jumbo-Visma, has been one of the main promoters of the use of ketones.

In any case, despite the MPCC’s policy regarding ketones, they can in no way be considered doping, but would fall, at least under current regulations, into the category of supplements. This is something that, in recent months, some cycling figures are trying to change. Figures such as the veteran TotalEnergies director Jean-René Bernaudeau or cyclists such as Guillaume Martin or Romain Bardet have spoken out against the use of ketones and have urged the UCI to ban them.

At the other extreme, there is the increasingly widespread use of ketones within teams, such as recently Alpecin-Deceuninck, which has added DeltaG Ketones, a supplementation firm specializing in marketing ketones, as one of its new sponsors for 2024.