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Which supplements help you lose fat (and which do not)
The short answer. What holds up with sources is short: whey protein (concentrate) and creatine, about €17.70 a month at the dose used in the studies. This page lists 4 supplements with evidence for this goal, and 3 sold for it that you do not need.
It is the goal with the most hot air per square metre. What has evidence does not burn fat: it holds on to muscle while you eat less and helps you train just as hard with less energy available.
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The basics, and what they cost
Whey protein (concentrate)
€16.90a month
20 to 40 g per serving. What counts is the daily total: 1.4 to 2.0 g per kilo of body weight.
Cheapest at that dose: HSN Sport Series Evobasic whey 2Kg from HSN, €20.00/kg.
Creatine
€0.80a month
3 to 5 g a day, every day, whether you train or not.
Cheapest at that dose: Firm Foods Creatina 2 kg (2x 1 kg) from Zumub, €8.95/kg.
€17.70 a month in total, adding up whey protein (concentrate) and creatine at one effective dose a day with the cheapest product that reaches that dose. It is not a medical recommendation or a plan: it is what the evidence-backed options cost today, in the stores this site compares.
The 4 with something behind them
By evidence level and monthly cost
| Supplement | Evidence | What has been measured | Per month |
|---|---|---|---|
| Caffeine3 to 6 mg per kilo of body weight, 30 to 60 minutes before. | Strong evidence86 products compared · best score: Cafeína - 500 Comprimidos - 200 mg por Comprimido from Amazon | Endurance: where it works bestGuest NS et al. ISSN position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18:1. Dosis ergogenica de 3-6 mg/kg, 30-60 minutos antes; sin beneficio adicional por encima de 9 mg/kg. | €0.76 |
| Creatine3 to 5 g a day, every day, whether you train or not. | Strong evidence223 products compared · best score: Firm Foods Creatina 2 kg (2x 1 kg) from Zumub | Maximal strength and power: +5 to 15 %Kreider RB et al. ISSN position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. | €0.80 |
| Whey protein (concentrate)20 to 40 g per serving. What counts is the daily total: 1.4 to 2.0 g per kilo of body weight. | Strong evidence251 products compared · best score: HSN Raw Series 100% Whey protein concentrate 2Kg from HSN | Strength (1RM): +2.49 kgMorton RW et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. 49 estudios, 1863 participantes. | €16.90 |
| Whey protein isolate20 to 40 g per serving; the daily total is still 1.4 to 2.0 g per kilo. | Strong evidence182 products compared · best score: Bulk Whey Protein Isolate, Sin sabores añadidos, 1 kg from Amazon | Lactose: almost nonede Wit JN. Nutritional and functional characteristics of whey proteins in food products. J Dairy Sci. 1998;81(3):597-608. Los aislados parten del 90 % de proteina y los concentrados comerciales van del 35 % al 80 %. | €18.40 |
The 3 they will try to sell you for this
Weak evidence, supplement price
Reviews find no consistent effect. It is listed because it sells, not because it works.
| Supplement | What has been measured | Per month |
|---|---|---|
| L-carnitineCarnitine carries fatty acids into the mitochondria, and from that biochemistry fact came the idea that taking it burns fat. | Fat loss: no consistent effectKerksick CM et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15:38. La L-carnitina figura entre los suplementos con evidencia limitada o mixta; 2-4 g diarios son la dosis habitual de los estudios. | €3.08 |
| GlutamineGlutamine is the most abundant amino acid in the body and it is used by muscle and gut. | Sports performance: no demonstrated effectKerksick CM et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15:38. La glutamina aparece entre los suplementos con evidencia limitada o nula. | €2.47 |
| BCAABCAAs are three amino acids: leucine, isoleucine and valine. | Muscle protein synthesis: not sustained aloneWolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30. | €2.62 |
Weak evidence is not fraud. It means the effect does not show up when diet already fills the gap, or that the studies behind it are small, short or paid for by the seller. Each guide says in which specific case it does make sense, which almost always exists and is almost never the case of the person buying it.
Questions about supplements for: lose fat
Answered with the data on this page
- Which supplements should you take to lose fat?
- The minimum you can defend with sources is whey protein (concentrate) and creatine, which at the dose used in the studies comes to €17.70 a month buying the cheapest that reaches that dose. Beyond that, this page lists another 2 with evidence behind them, each for a specific case.
- And l-carnitine, glutamine, bcaa?
- L-carnitine, Glutamine, BCAA have weak evidence for this: Reviews find no consistent effect. It is listed because it sells, not because it works. They are sold a lot for this goal and each has its own guide with the sources, so the decision does not depend on what a label says.
- Where do these prices come from?
- From the 4065 products this site collects across 19 Spanish stores, with prices from October 15, 2026. The monthly cost is one effective dose a day for 30 days, with the cheapest product that reaches that dose. The evidence was reviewed on September 4, 2026.
Other goals
The same list, another question