The ingredients, one by one

L-carnitine

L-carnitine is a compound formed from the amino acids lysine and methionine. The body produces it and also takes it in through food, chiefly red meat. Inside the cell it plays a role in transporting long-chain fatty acids into the mitochondria.

In the sports and fitness sector it has been among the best-selling single ingredients for decades. It is not, however, authorised for health claims in the EU or UK.

Green coffee extract

Green coffee is simply unroasted coffee. Roasting destroys a portion of the chlorogenic acids, which is why extracts from the unroasted bean contain considerably more of them. The extract also carries naturally occurring caffeine.

That caffeine is the practical point to note with Slim Coffee Booster, because the amount in the sachet stacks on top of the coffee you stir it into.

Capsicum

Capsicum refers to extracts from peppers and chillies; the characteristic compound is capsaicin, responsible for the heat. In this formula it accounts for the powder's faintly spiced edge. If you have a sensitive stomach, that heat can be noticeable — in which case take the booster with a proper meal.

Multivitamin blend

The box lists a multivitamin blend without breaking out the individual vitamins on the front panel. You'll find that detail in the supplier's nutritional table.

Worth noting: this is the only part of the formula for which authorised health claims exist at all. Where a product contains a legally defined minimum amount, it may state, for example, that vitamins B6 and B12 contribute to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. Whether and to what extent that applies here comes down to the amounts printed on the label.

What else the box says

• "No Added Sugar": no sugar added to the formulation.
• Vegan, gluten-free, non-GMO: according to the supplier.
• "Food Supplement": the regulatory category — explicitly not a medicine.