Non-stimulant fat burners do not contain caffeine, so they do not increase blood pressure and heart rate in large amounts. For this reason, they can be used by people with vardiovascular disease, only with a doctor's permission.
One of the main active ingredients in stimulant-free burners is l-carnitine. L-carnitine is involved in the functioning of the mitochondria responsible for energy production within the cell. The mitochondrion is the "engine" of the cell where nutrients (protein, carbohydrates and fat) are broken down and ATP (adenosine triphosphate, the body's primary source f energy) is produced. L-carnitine is involved in the breakdown of fats. Studies have shown that l-carnitine supplementation can have weight-loss effects, the most potent form being acetyl-l-carnitine. It is more bioavailable and can help maintain performance during dieting.
Another common ingredient is conjugated linolenic acid (CLA), an Omega 6 fatty acid. CLA helps to break down fat cells by preventing these cells from absorbing sugar, thus affecting insulin metabolism. Several studies report its effects on reducing body fat and improving insulin resistance. It also enhances the effects of l-carnitine. Hence it is a popular fat burning agent.
HCA - hydroxycitric acid, inhibits the storage of fatty acids by inhibiting the enzyme ATP-citrate lyase. This enzyme is responsible for the production of fatty acids. An excellent source of HCA is the Garcinia Cambogia plant.
MCT oil is a healthy fat burning oil. MCT oil has a unique way of stimulating the production of ketone bodies and therefore can benefit any individual following a low carbohydrate diet or ketogenic diet.
Chromium is a non-essential mineral, but is of particular importance for weight loss and diabetes sufferers. Chromium helps to maintain healthy carbohydrate metabolism and insulin levels, thereby indirectly preventing fat storage - because if carbohydrates stores are used properly, fat storage will be lower. Other blood sugar regulations are cinnamon extract and apple cider vinegar.