How to take exogenous ketones: dosage, timing, duration

If you have decided to try exogenous ketones, the most important questions are how much, when, and for how long. There is no universal “correct” scheme: studies used different products and protocols, and the evidence base for an ergogenic effect is modest. The editorial team has gathered practical principles based on scientific data and common sense.

What the dosage depends on

The first thing that determines the dose is the type of product. Ketone salts and ketone esters give a different rise in blood beta-hydroxybutyrate even for the same amount of BHB on the label. Esters create a higher and faster concentration of D-BHB, whereas salts give a more moderate effect and contain a mixture of forms (Stubbs et al., 2017).

The second is body weight. In scientific works the dose is usually calculated per kilogram of weight. For example, in the study of ketone monoester kinetics (Clarke et al., 2012) participants received 140, 357, or 714 mg per kilogram of body weight, and the rise in BHB increased proportionally to the dose. For a person weighing 60 and 100 kg, the same serving will give a different result.

The third is the purpose of intake. For a person who wants to try how ketones affect well-being, one small serving is enough. An athlete experimenting with recovery during a period of heavy loads will act differently. It is precisely the goal that determines whether regular intake is needed or only situational.

The fourth is tolerability. Gastrointestinal symptoms increase along with the dose, and for many people it is precisely these, and not the theoretical “optimal dose,” that become the real limitation.

Serving size in practice

In most commercial salt products, one serving contains approximately 10–15 g of BHB salts. For a first acquaintance, the editorial team advises starting with half a serving to assess the stomach's reaction and general well-being, and only then moving to a full one.

When choosing a dose it is important to take the mineral load into account. Each serving of salts adds sodium, potassium, calcium, or magnesium, so several servings a day can substantially increase the intake of these minerals. For people who limit salt, this is especially important.

Ketone esters are sold mostly as ready-made drinks with a fixed serving. They should be taken exactly per instructions: they are much more potent than salts, and increasing the dose more often leads to nausea, discomfort, and, when butanediol is present, to a feeling of mild intoxication.

Neither for salts nor for esters is there evidence that “more means better.” On the contrary, in sports studies high doses were more often associated with a worsening of results due to digestive symptoms.

When to take: before, during, or after training

In studies of acute effect on endurance, ketones were usually taken 30–60 minutes before exertion, so that the peak BHB concentration would coincide with the start of work. However, the meta-analysis by Valenzuela and colleagues (2020) found no overall advantage of this strategy for performance.

Taking them directly during a workout is the least comfortable option. Against the background of physical exertion, blood flow in the digestive tract decreases, and concentrated solutions are tolerated worse. If you still want to try, it is better to do so during low-intensity workouts.

The most scientifically justified option appears to be taking them after workouts during periods of heavy loads. In the study by Poffé and colleagues (2019), a ketone ester was taken after workouts and before bed for three weeks of very intense preparation, and this was associated with fewer signs of overtraining.

After a workout, ketones should be taken together with carbohydrates and protein, not instead of them. Glycogen restoration and muscle protein synthesis depend primarily on basic nutrition, and ketones at best can be a supplement.

Duration of intake and monitoring the effect

For BHB salts there is no evidence-based “course duration.” Most studies had an acute design, that is, they studied the effect of a single intake. A few works lasted several weeks, but there is little data on the safety and effectiveness of many months of daily intake.

The editorial team advises thinking not in courses but in experiments with a clear goal. For example, over 2–3 weeks of a large training block, assess sleep, appetite, subjective recovery, and training indicators. If there is no noticeable difference, there is no point in continuing.

You can objectively verify the product's action with a household glucose-ketone meter that measures BHB in capillary blood. This makes it possible to confirm that the product really raises ketone levels and by how much. Urine test strips show acetoacetate and are less reliable for this purpose.

• Define a specific purpose of intake before starting.
• Record well-being, sleep, appetite, and training indicators.
• If possible, measure BHB in the blood to assess the product's real action.
• After a few weeks, honestly assess whether there is a benefit that justifies the cost.

Typical mistakes

The first mistake is taking a large dose on an empty stomach before an important workout or start. It is precisely this scenario that most often ends in nausea, bloating, and a worsening of results.

The second is replacing carbohydrates with ketones. Exogenous ketones cannot supply energy for intense work the way glucose and glycogen do. An attempt to “train on ketones” without carbohydrates lowers the quality of training.

The third is expecting a fat-burning effect. Exogenous ketones do not force the body to burn its own fat. On the contrary, when there are enough ketones from outside in the blood, the liver reduces its own ketogenesis, and each serving adds calories.

The fourth is ignoring the mineral composition and interactions with medications. People with hypertension, kidney disease, diabetes, or those taking regular drugs should not start intake without consulting a doctor.

Editorial conclusions

The dosage of exogenous ketones depends on the form of the product, body weight, purpose, and tolerability. For salts it is reasonable to start with half a serving, for esters — to strictly follow the manufacturer's instructions.

Taking them before a workout to increase endurance has no reliable evidence of effectiveness, whereas use after workouts during periods of heavy loads appears the most justified, although it also requires confirmation.

Instead of long “courses,” it is worth conducting short, meaningful experiments with objective monitoring and honestly assessing the benefit relative to the cost and side effects.

We also recommend reading our articles “Exogenous ketones: forms and which to choose,” “What to combine exogenous ketones with,” and “Side effects of exogenous ketones.”

References

1. Clarke K, Tchabanenko K, Pawlosky R, et al. Kinetics, safety and tolerability of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate in healthy adult subjects. Regul Toxicol Pharmacol. 2012;63(3):401–408.
2. Stubbs BJ, Cox PJ, Evans RD, et al. On the metabolism of exogenous ketones in humans. Front Physiol. 2017;8:848.
3. Evans M, Cogan KE, Egan B. Metabolism of ketone bodies during exercise and training: physiological basis for exogenous supplementation. J Physiol. 2017;595(9):2857–2871.
4. Valenzuela PL, Morales JS, Castillo-García A, Lucia A. Acute ketone supplementation and exercise performance: a systematic review and meta-analysis of randomized controlled trials. Int J Sports Physiol Perform. 2020;15(3):298–308.
5. Poffé C, Ramaekers M, Van Thienen R, Hespel P. Ketone ester supplementation blunts overreaching symptoms during endurance training overload. J Physiol. 2019;597(12):3009–3027.
6. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–568.