Also known as: Beta-hydroxybutyrate, BHB salts, Ketone esters, Ketone salts, D-BHB
Fat MetabolismEmerging evidence
Ketones taken directly rather than produced by the body. They do raise blood ketones, and that is not the same thing as burning fat — a distinction the marketing depends on you missing.
Typical dose
10.0–12.0 g per day
Around training or fasting periods, if used at all
What it is
Beta-hydroxybutyrate is the main ketone body the liver produces from fat when carbohydrate is scarce. Exogenous ketones supply it directly.
Two forms exist and they are very different. Ketone salts bind BHB to sodium, calcium, magnesium or potassium, which limits how much you can take before the mineral load becomes a problem. Ketone esters deliver far higher blood levels, cost considerably more, and taste genuinely awful.
There is also a stereochemistry issue. The body uses the D isomer; many cheaper salts are a racemic mixture containing roughly half L-BHB, which is poorly used. A product not specifying D-BHB may be delivering half of what the label implies.
How it works
BHB is a fuel that muscle and brain can use, and it also acts as a signalling molecule influencing gene expression and inflammatory pathways.
Here is the central point that the marketing avoids. In normal ketosis, blood ketones are high because you are breaking down fat to make them. Taking ketones raises blood ketones without any fat being broken down at all.
Worse, raising blood ketones signals to the body that fuel is plentiful, which suppresses the release of fat from fat cells. Being in ketosis and burning body fat are not the same state, and exogenous ketones deliver the reading without the process.
What the evidence shows
Raising blood ketones is well demonstrated and not in question. Both salts and esters do it, esters far more effectively.
For fat loss, there is no good evidence that exogenous ketones cause it, and a reasonable mechanistic argument that they work against it by suppressing fat release. Anyone buying them to burn fat has the mechanism backwards.
Performance research is mixed to negative, with several trials finding impaired rather than improved performance, often due to digestive distress. The most promising area is recovery and possibly cognitive function under fatigue, where evidence remains early.
Dosing
Ketone salt doses of 10 to 12 g are needed for a meaningful rise in blood ketones. Many products supply far less, which raises ketones trivially and achieves nothing measurable.
At that dose the mineral load is substantial. Ten grams of BHB salts can supply well over a gram of sodium alongside other minerals, which is worth counting.
If the goal is fat loss, this is the wrong product regardless of dose. If the goal is raising ketones for a specific reason, esters do it far better than salts, at considerable cost and with a taste most people find genuinely difficult.
At a glance
Common forms
BHB mineral salts, Ketone esters, D-BHB (preferred isomer), Racemic BHB, Combined with MCT
Half-life / duration
Blood ketones rise within 30-60 minutes and return to baseline within a few hours
Timing
Around training or fasting periods, if used at all
Competition status
Permitted — not on the WADA Prohibited List
Category
Fat Metabolism
Safety and side effects
Digestive distress is common at effective doses: nausea, cramping and diarrhoea. This is the most frequently reported problem and the reason several performance trials found impaired results.
The mineral load from salts is the more substantive concern. At the doses required, sodium intake becomes significant, which matters if your blood pressure is being managed.
Speak to your doctor before use if you have been told your kidneys are not working normally, given the mineral load, or if you take regular medication.
Who should avoid it
Take care if your blood pressure is being managed, given the substantial sodium load from ketone salts. Speak to your doctor before use if you have been told your kidneys are not working normally, or if you take regular medication. Expect digestive distress at effective doses. Not established in pregnancy or breastfeeding.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
