If you want to lose body fat there are two fundamentals that are tried and tested: a clean diet and smart training.

However, combining these with the right fat burner can accelerate your results and light a fire under your efforts.

With so many options available we’ll cover the most effective natural fat burners organised by how they work, and ranked by the amount of supporting studies available.

We have also included recommended dosages to help you pick the right ingredients for your needs, and suggested supplements so you can combine them to amplify your results.

Rev up your metabolism with metabolic fat burners

The first category of fat burners we will look at have a positive effect on your metabolic rate, which can result in more calories burned.

Look for these ingredients if you don’t want to rely on stimulants, have a slow metabolism or want to maximise metabolic benefits from your workout:

Bitter Orange (which contains 1-6% p-synephrine)

Bitter orange and its peel contain a unique substance called p-synephrine, which has been found to increase calorie expenditure independent of diet[1].

Supporting studies: 16

Optimal dosage: up to 300mg Bitter Orange peel powder (20-60mg p-synephrine)

Green Tea Extract

Green tea is rich in catechin polyphenols, particularly EGCG which appears to have a positive effect on energy expenditure and fat oxidation[2].

Supporting studies: 10

Optimal dosage: 400-500mg EGCG

Garcinia Cambogia

Garcinia Cambogia is a pumpkin shaped fruit which contains a unique substance called Hydroxycitric Acid also known as HCA.

HCA may have an effect on the citrate lyase enzyme which plays a role in turning excess carbohydrates into fat[3].

Supporting studies: 10

Optimal dosage: 54-2400mg Garcinia Cambogia

Capsicum (cayenne chili extract)

Capsicum extract may have a positive effect on resting metabolic rate, energy expenditure, and metabolism when combined with exercise[4].

Supporting studies: 3

Optimal dosage: 100-200mg

Raspberry Ketone

Early studies have found that raspberry ketone may have an effect on Adiponectin, a naturally occurring weight regulating hormone[5]. For optimal results Raspberry ketone should be combined with other fat burners.

Supporting studies: 3

Optimal dosage: 100-200mg raspberry ketone extract


How to support your metabolism further:

Alongside these fat burners, you can also help support your metabolism by including the following nutrients in your diet:

  • Zinc contributes to normal metabolism of carbohydrates, macronutrients, fatty acids, and vitamin A.
  • Iodine contributes to normal energy yielding metabolism.
  • Chromium is an essential mineral which helps regulate glucose metabolism and insulin sensitivity[6].
  • Vitamin B6 contributes to normal protein and glycogen metabolism.
  • Acetyl L-Carnitine may have an effect on fatty acid metabolism[7]. Combine this with an alkaline rich diet for optimal health.

Recommended supplements:

You can find optimal dosages of these metabolism boosting ingredients in the following supplements:

Get a kick with energy boosting stimulant fat burners

The next category of fat burners we will look at are rich in Caffeine, a popular stimulant used to help boost metabolism and keep fatigue at bay.

The high caffeine content may have thermogenic properties, increasing metabolism and fatty acid oxidation in adults, especially combined with exercise[8].

For optimal results we recommend cycling stimulant fat burners, in other words use a supplement containing these ingredients for 1-2 months, then a break or a different type of supplement before using it again to combat the effects of caffeine tolerance.

Be sure not to combine more than one of these stimulants at a time, unless the dosages are low as they all use the same stimulating mechanism (caffeine).

It is important to note that these types of stimulants should be taken early in the day as these can impair sleep and not be taken if you have high blood pressure or cardiac impairments.

Caffeine anhydrous

Caffeine anhydrous[9] is caffeine extracted from natural sources such as coffee beans or tea leaves, and then concentrated into a powdered extract.

Because it is highly concentrated you need a much smaller dosage for similar results.

Supporting studies: 9

Optimal dosage: 50-200mg caffeine anhydrous powder

Yerba mate

Yerba mate is high in caffeine, and contains a cocktail of xanthines (like caffeine), flavonoids (Quercetin), saponins (ursolic acid), and cinnamic acid compounds (Chlorogenic acid)[10].

Supporting studies: 3

Optimal dosage: 1,000-1,500mg of yerba mate leaf powder.

Guarana (Paullinia cupana)

Guarana is one of the richest sources of caffeine (contains more caffeine than coffee beans) has has historically been used by the Amazonian tribes for its energy boosting properties[11], and a recent anthropological study found it linked with improved metabolic markers.

Supporting studies: 2

Optimal dosage: 100-200mg guarana extract

Recommended supplements:

You can find optimal dosages of some of these stimulant ingredients in the following supplements:

Target blood sugar levels

The typical western diet contains a wide variety of high GI foods which can cause spikes of blood sugar levels. These spikes can contribute to fat storage and a wide range of health problems including diabetes.


According to the American Diabetes Association early studies have found Cinnamon to help reduce the rate at which glucose enters the body and may help type 2 diabetics with blood sugar spikes[12].

Supporting studies: 5

Optimal dosage: 120mg – 2g of cinnamon


Berberine has been used for centuries in Chinese and Ayurvedic medicines, and modern studies have linked it improvements in insulin sensitivity and lowered glucose production. In fact one study found it able to control blood sugar and lipid metabolism as effectively as metformin[13].

Supporting studies: 5

Optimal dosage: 1-1.5g of berberine

Green coffee extract

Green coffee beans are raw, un-roasted coffee beans which contain up to 50% of their weight in chlorogenic acid (CGA). Early studies indicate that the GCA in green coffee may have a positive effect on blood sugar levels as well as help inhibit blood sugar spikes[14].

Supporting studies: 3

Optimal dosage: 800mg green coffee extract @50% Chlorogenic acid

Recommended supplements:

Testosterone & cAMP based fat Burners

Hormones including testosterone and thyroid play a large role in regulating how your metabolism works, which has a knock on effect on your rate of fat burning.


Forskolin is a unique compound found in the Coleus forskohlii plant.

Early studies have found it may promote cAMP enzymes linked to thyroid production and free testosterone levels in men[15], and may mitigate gains in body mass in women[16].

Supporting studies: 4

Optimal dosage: 50mg Forskolin (Available as 250mg of Coleus Forskohlii standardised to 20% Forskolin or 500mg of Coleus Forskohlii standardised to 10%)

Recommended supplements:

Serotonin based fat Burners

Your lifestyle, high levels of stress, and poor nutrition can spike your levels of cortisol and prevent your body from producing enough essential hormones such as serotonin.

And studies have found that low serotonin levels can trigger a wide range of health problems including cravings, emotional eating, anxiety, depression and sleep problems.


Saffron is widely known as being one of the most expensive spices in the world as it is cultivated from the stigmas of the Crocus sativus plant.

What makes saffron unique is it’s safranol and crocin contents, which early studies indicate may have antidepressant effects by modulating the levels of certain chemicals in the brain, including serotonin[17].

Supporting studies: 9

Optimal dosage: 30-200mg saffron

5-HTP (Griffonia simplicifolia seed)

Your body produces serotonin by converting tryptophan found in foods, into an amino acid called 5-HTP which is then used as the building block to produce serotonin.

The Griffonia simplicifolia seed is naturally rich in 5-hydroxytryptophan (5-HTP) and can help provide your body with the raw material needed for natural serotonin production[18].

Supporting studies: 3

Optimal dosage: 100-300mg 5-HTP (from griffonia simplicifolia seed)

Recommended supplements:

Appetite suppressant based fat Burners

Being in control of your diet is essential for your body to be able to burn fat effectively. Conversely giving in to cravings and feeding your body the wrong types of foods will sabotage this finely tuned mechanism.

Appetite suppressants work on 3 different levels:

  • First they help promote a feeling of fullness between meals, making it easier to resist cravings.
  • They also help reduce the feeling of hunger which leads to smaller portion sizes.
  • Lastly they provide your gut with soluble and insoluble fibre which promotes optimal digestion and fat burning.


Glucomannan is a water soluble dietary fibre which can absorb 200 times its body weight, and acts as an expanding gel when combined with water. Studies have found that it may help feel fuller for longer as well as have a positive effect on cholesterol, and body weight[19].

Supporting studies: 14

Optimal dosage: 3g of glucomannan in three doses of 1g each


The Yacon root is one of the richest dietary sources of fructooligosaccharides (FOS) and is also a rich source of inulin dietary fibre which has been linked to improving glycemic indices, boosting antioxidant capacity and helping reduce body weight[20].

Supporting studies: 2

Optimal dosage: 1g Yacon root extract or 1-2 teaspoons syrup

Recommended supplements:


Which types of fat burners can be combined & how long should I take a fat burner?

Before combining more than one supplement, be sure to check the active ingredients list so as to not double down on the same ingredients.

This is particularly important with regards to stimulants. As a general rule, don’t take more than one stimulant based supplement (containing a caffeine source) at a time.

Other than these two rules, different fat burner types can work in synergy to cover more than one objective. For example, a stimulant based fat burner can be combined with an appetite suppressing fat burner or a Serotonin based fat burner based on your needs.

We generally recommend not stacking more than 2 or 3 weight loss supplements at a time, and using weight loss supplements for no more than 3-6 months at a time. You can always restart a cycle a few months later to boost results.

Finally remember that supplements should supplement a healthy diet, rather than substitute it.

As we mentioned earlier, fat burners are short term “rocket fuel” designed to target weak points and help accelerate results alongside a positive dietary changes.

[1]A Review of the Human Clinical Studies Involving Citrus aurantium (Bitter Orange) Extract and its Primary Protoalkaloid p-Synephrine



[2] The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis.


[3] Updates on Antiobesity Effect of Garcinia Origin (−)-HCA


[4] Yoshioka M,et al: Effects of red-pepper diet on the energy metabolism in men., J Nutr Sci Vitaminol 1995; 41: 647-656.

[5] Diez JJ, Iglesias P. The role of the novel adipocyte-derived hormone adiponectin in human disease. European journal of endocrinology / European Federation of Endocrine Societies. Mar 2003;148(3):293-300.

Morimoto C, Satoh Y, Hara M, Inoue S, Tsujita T, Okuda H. Anti-obese action of raspberry ketone. Life sciences. May 27 2005;77(2):194-204.

Park KS. Raspberry ketone increases both lipolysis and fatty acid oxidation in 3T3-L1 adipocytes. Planta medica. Oct 2010;76(15):1654-1658

[6] Chromium picolinate for reducing body weight: meta-analysis of randomized trials.

[7] L-Carnitine in the Secondary Prevention of Cardiovascular Disease: Systematic Review and Meta-analysis


[8] Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women.


[9] Changes in caffeine intake and long-term weight change in men and women


The effects of caffeine and exercise on body weight, fat-pad weight, and fat-cell size.


[10] Thermogenic Effects Of Commercially Available Plant Preparations Aimed At Treating Human Obesity

[11] Habitual intake of guaraná and metabolic morbidities: an epidemiological study of an elderly Amazonian population.


[12] Cinnamon May Help Improve Blood Glucose Levels in Type 2 Diabetes – http://www.diabetes.org/research-and-practice/patient-access-to-research/cinnamon-extract-improves.html


[13] Efficacy of berberine in patients with type 2 diabetes mellitus


[14] Green coffee bean extract has anti-diabetic benefits

[15] Body Composition And Hormonal Adaptations Associated With Forskolin Consumption In Overweight And Obese Men

[16] Effects Of Coleus Forskohlii Supplementation On Body Composition And Hematological Profiles In Mildly Overweight Women

[17] Saffron (Crocus sativus) for depression: a systematic review of clinical studies and examination of underlying antidepressant mechanisms of action.



ANTI-DEPRESSANT HD Mehta (Upadhye)*, SV Mangrulkar, AJ Chourasia

[19] Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis.


[20] Yacon syrup: beneficial effects on obesity and insulin resistance in humans.