Best fat burner: a pharmacist’s opinion (2025)

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We studied 14 supplements sold online according to 8 criteria and selected these 3 fat burners:

Best fat burner in capsule form 🥇
> Fat-Burner – Nutri&Co

Best value for money
> Organic Green Tea – Dynveo

Best entry-level
> Active Burner – Nutrimea

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Best effective fat-burning supplements

Our selection criteria

• Active ingredients : list of active ingredients contained in the supplement.
• Form and concentration of active ingredients : the effectiveness of the product depends on these two factors
• Cultivation method : organic, local or intensive farming
• Presence of additives : colorants, preservatives, sweeteners …
• Dosage : form of the dietary supplement (capsule, tablet, gummies..) and method of use.
• Price / day : the price for 1 day of treatment, with the daily dose recommended by the manufacturer.
• Customer reviews: this average of customer reviews for the brand comes from the laboratory’s website, review platforms, or marketplaces such as Amazon.
• Our assessment of the brand: based on the tests of dietary supplement brands we conduct each month and on the analysis of 6 criteria such as transparency and expertise.

The supplements selected below are all made in France and are vegan.

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# Best fat burner in capsule form 🥇

The fat burner offered by Nutri&Co is particularly effective because it contains a patented active ingredient that has been the subject of numerous in vitro and in vivo scientific studies – unlike most supplements on the market.

Sinetrol® Xpur C is a patented complex of grapefruit and orange extracts, supplemented with guarana, with a polyphenol content of 90%.

Its effectiveness has been proven in 5 clinical studies conducted on 300 people. Scientists observed an increase in resting metabolic rate of 180 kcal per day after 16 weeks, and a targeted fat mass loss of 1.8 kg, helping to slim the figure.

The formula is complemented by a green tea extract rich in EGCG, which works in synergy with Sinestrol®.

Nutri&Co is a reliable and transparent brand (read our full review here to learn more). In addition, customer reviews are very good.

This laboratory is based in Aix-en-Provence and places particular importance on the quality of active ingredients and the effectiveness of its dietary supplements.

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# Best value for money

Dynveo’s green tea extract offers an excellent concentration of 90% polyphenols and 10% EGCG. 

The raw material is organic, the harvest is manual, and the extraction of the active compounds is done with water, which ensures the preservation of product quality.

The Dynveo laboratory is located in the south of France. The products are guaranteed pure and free of controversial additives and GMOs. 

Dynveo is transparent about microbiological analyses and guarantees the absence of pesticide residues or heavy metals in these products (see our full test here).

Use promo code DARWIN101 to get 10% off (orders over €75).

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# Best entry-level

The Active Burner supplement from Nutrimea is a good, lower-priced alternative.

It contains 5 ingredients with recognized fat-burning effects, notably guarana, green coffee and cola, which are rich in caffeine.

The supplement’s caffeine content is therefore particularly high (151.11 mg/day), so it is not recommended for pregnant women or children under 12.

Nutrimea is a quality French brand offering supplements concentrated in active ingredients at competitive prices. (our review here). Its product range is particularly extensive.

Use the promo code DARWIN10 to get 10% off (no minimum order).

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How do fat-burning ingredients work?

They boost metabolism

Basal metabolism corresponds to the amount of energy the body needs at rest. It gradually decreases over time, but also after a too restrictive diet : the body stores more energy reserves and promotes weight gain.

On the contrary, physical activity helps maintain our basal metabolism at a stable level. By stimulating and improving this metabolism, fat burners increase the body’s pace.

The body burns more calories, even at rest. Fat is less stored in adipose tissue and is instead used as energy.

They promote fat burning

Fat burners boost thermogenesis, the mechanism that induces heat production in the body. Thus, they increase body temperature and raise caloric expenditure.

At the same time, they influence the lipogenesis – lipolysis balance: lipogenesis ensures the dietary storage of lipids during digestion. If lipogenesis is higher than lipolysis, the balance is disrupted and leads to fat storage.

Fat burners stimulate lipolysis, that is, the activation of the process of breaking down fatty acid molecules, lipids drawn from triglyceride stores. These constitute an important energy reserve in adipose tissue.

They act as appetite suppressants

Some also act as appetite suppressants and contribute to the feeling of fullness. They enable better appetite control and limit the urge to snack.

In this sense, they also contribute to weight loss.

They help with elimination

Several liters of water are filtered and reabsorbed by our blood vessels every day. Poor blood circulation and poor lymphatic drainage cause fluid retention in the tissues, and thus increase the appearance of cellulite.

Due to their draining and/or diuretic action, certain active ingredients capture toxins, fats and excess fluids. They facilitate their elimination and help the body avoid storing them.

They can also have beneficial effects on intestinal transit. This improves the elimination of accumulated waste and contributes to a flat stomach.

How to combat excess weight?

Adopt a varied diet and make it as minimally processed as possible. 

Emphasize seasonal fruits and vegetables, eat enough protein (animal or plant-based), essential for maintaining muscle mass and reducing body fat. Limit sweets and pastries. 

For beverages, favor water, herbal teas and tea. Coffee is not forbidden, as long as it is consumed in moderation and preferably in the morning or at midday.

Finally, do not resort to low-calorie diets! They stimulate the production of ghrelin, a hormone secreted in the stomach and responsible for food cravings.

Which active ingredients should be prioritized?

Green tea

It is the fat burner most commonly found in natural dietary supplements. Its leaves are rich in caffeine and in catechins.

The catechins predominantly present in green tea are EGCG: epigallocatechin gallate. These compounds are very powerful antioxidants.

As observed in this study, EGCG promotes the stabilization of blood glucose (blood sugar levels) and reduces food intake.

They increase thermogenesis and therefore energy expenditure, as shown by this clinical trial.  This trial suggests that green tea consumption contributes to a reduction in body fat, and could help reduce the risk of obesity and cardiovascular disease. 

Finally, green tea has diuretic properties. It promotes the elimination of waste and helps keep a flat stomach. Matcha, a powder made from green tea leaves that are highly concentrated in active compounds, is a good option.

Guarana

Guarana is also very rich in caffeine, referred to here as guaranine. It is an excellent stimulant and metabolic energizer.

It encourages the body to become active and burn more calories, even at rest.  This effect is even more pronounced when combined with green tea: this placebo-controlled study showed that taking capsules containing caffeine and EGCG resulted in a significant increase in energy expenditure over 24 hours.

Finally, as shown by this study, it regulates adipogenesis, that is, the storage of lipids.

Kola nut

This nut is rich in caffeine and in theobromine. These compounds give it stimulating properties and energizing effects. It aids fat metabolism and limits fat storage.

The kola nut is often combined with green tea and guarana in fat-burning dietary supplements. It promotes weight loss and helps with weight control.

Konjac

This plant root contains fibers called glucomannans, which have the ability to swell in the stomach in the presence of water. This phenomenon causes an almost immediate appetite-suppressing effect.

As shown by a clinical study on 72 type II diabetics who received konjac for 65 days, it also promotes the regulation of blood glucose (blood sugar concentration), and has positive effects on cholesterol.

Carnitine

Carnitine is an amino acid involved in the process of fat burning.

It is one of the amino acids known as “fat transporters“. Indeed, it transports fatty acids to the mitochondria so they are converted into energy rather than stored. It is favored by athletes for weight loss and to boost metabolism.

It is available as a supplement, but it is better assimilated from food. Red meat is by far the main source, but it can also be found in dairy products, avocado, and tempeh.

Minerals and trace elements

A deficiency in certain minerals and trace elements seems to be linked to weight gain.

Magnesium, for example, is one of the minerals essential to the normal functioning of our body. 

It is involved in more than 300 enzymatic reactions in the body: it notably contributes to the body’s energy metabolism or to muscle function, and various studies confirm its role in blood sugar regulation. 

Thus, this review of trials indicates that magnesium supplementation in deficient individuals or in people with diabetes could lead to a reduction in BMI (Body Mass Index) and a decrease in waist circumference.

Zinc, for its part, is essential for the processing of fats and carbohydrates. It also supports amino acids in lipid metabolism.

A clinical trial was conducted on 40 people with obesity. In addition to a low-calorie diet, subjects who were supplemented with 30 mg of zinc daily for 4 months experienced greater reductions in weight, BMI, and waist circumference than those who were not supplemented. Their appetite measures were also lower.

Vitamins

Particular emphasis is placed on vitamin C and vitamin B3 (or niacin).

Vitamin C promotes fat oxidation. It also plays a role in the production of carnitine and norepinephrine. Located in adipose tissue, this compound triggers the process of lipolysis and mobilizes fat reserves.

Vitamin B3 is involved in fat breakdown. It converts fats into a source of energy for the body.

In what form?

In capsules and tablets

This is the most commonly encountered format. Capsules and tablets have the advantage of being easy to take and having no taste. However, these supplements do not all have the same concentration of active ingredients.

Make sure to choose a fat burner with adequate potency and good bioavailability. It should also be natural, without additives or preservatives. Preferably choose plant-based capsules that are certified organic.

In powder form

Guarana, amino acids, and green tea are often offered in powder form. This format is minimally processed and generally has a good concentration of active ingredients.

The powder mixes easily into a glass of water or fruit juice. It can also be added to smoothies, beverages, and protein shakes.

As gummies

The gummies are chewable candies. Those intended to burn fat contain various plant extracts, vitamins and/or minerals that support metabolism and fat burning.

These dietary supplements are fun, attractive, and taste good. However, they sometimes contain sugar. They should therefore be consumed in moderation, especially as part of a weight-loss diet.

In ampoules

They are most often plant complexes. In ampoules, the fat-burning actives are present as aqueous extracts. This format is useful for undertaking a short course of a few days or weeks.

They typically contain green tea and guarana in concentrated form. Ampoules are easy to take: simply dilute them in a large glass of water.

The shelf life is often limited, and the taste is more pronounced.

In liquid solution

The liquid form is reserved for aqueous plant extracts, caffeine, vitamin C and amino acids such as carnitine.

These drinkable solutions are often well standardized and are readily absorbed by the body.

As herbal tea and infusions

Fat-burning herbal teas are made from a blend of plants such as green tea, guarana or mate.

They may also contain diuretic plants and draining plants such as meadowsweet, hibiscus, mint or verbena.

They generally need to be taken several times a day to expect a significant effect, and the sometimes strong taste may deter some people.

Purchase criteria

1. Concentration of active ingredients

It’s partly the concentration of active ingredients in the dietary supplement that determines its effectiveness. 

Choose products with the shortest possible ingredient list to increase the chances of a sufficient concentration of active ingredients.

– 500 mg of green tea extract in capsules per day is recommended, or 2 grams (1 teaspoon) of tea leaves three times a day.

– 1000 mg of konjac three times a day, with a large glass of water, help produce an appetite-suppressing effect.

– Zinc should be taken at a dose of 15 mg per day, and magnesium supplementation of 300 mg per day is recommended for a 3-month course.

Finally, for other nutrients, such as L-carnitine, there is no consensus regarding the recommended nutritional dosage. Don’t hesitate to consult a qualified healthcare professional.

2. Bioavailability

Keep to a maximum of 70° for the temperature of green tea infusions, in order to preserve heat-sensitive active compounds. Above this temperature, a loss of the vitamins and minerals present in the leaves is observed.

Be mindful of the form of minerals :

– For magnesium : favor organic salts, better tolerated (magnesium citrate, magnesium malate) and the so-called “chelated” salts, such as magnesium bisglycinate.

– For zinc, prefer the gluconate, picolinate, acetate, or zinc bisglycinate forms.

In both cases, avoid oxide forms, which are insoluble in water and have laxative effects.

3. Cultivation method

In general, favor bulk herbs from local farming and, if possible, organic, less processed and with more effective active compounds.

4. Composition

Products combining a mixture of herbs and minerals are generally less concentrated than a dietary supplement with a single active ingredient.

I recommend choosing products with a maximum of 5 active ingredients: concentrations will be sufficient to expect a meaningful effect, and you will limit additive intake.

Weight loss dietary supplements generally contain a mixture of active ingredients. Each of them has its own precautions for use and contraindications.

Some are contraindicated for pregnant and breastfeeding women. Medical advice is strongly recommended for people suffering from a chronic illness and when taking other medications.

5. Price

Recognized laboratories offering quality products offer more expensive fat-burning supplements, and that’s normal. A higher price is generally justified by quality (local, certified, organic, etc.) and the (high) concentration of the ingredients used.

Be careful: a high price does not always mean quality. Brands such as Brulafine or PhenQ, based abroad, offer products whose price is particularly high, for a quality similar to or even lower than competing supplements that are significantly cheaper.

Moreover, regarding Brulafine, customers find themselves subscribed often against their will to a slimming coaching app if they do not uncheck a box at the time of payment.

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Best fat burner in capsule form 🥇

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Best fat burner in a shot

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Best value for money

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Best entry-level

Report prepared by Louise Talleu (pharmacist) and Julia Perez (health writer)

When you purchase the selected products, a commission may be paid to us in order to support the site, pay our writers and ensure you receive quality information. This does not affect prices.