The Fat-Loss Evidence Table
We sell fat-loss products. We are also going to tell you that most of this category does far less than the advertising implies, including some of what sits on our own shelf. That is an odd way to run a supplement company, and it is the reason we have been here since 2003.
The thing nobody selling you a fat burner will lead with
Every meaningful result in this category comes from an energy deficit. Supplements operate at the margins of that — a few percent, sometimes less, and only while the deficit is already in place.
That is not a reason to dismiss all of them. A few percent, sustained, is real. But it does reorder the shopping list: the interventions with the largest effect sizes are protein intake, daily movement, sleep and resistance training, and none of those are sold in a tub. What follows is what is left over, rated on what the research actually supports.
The table
| Ingredient | Typical dose | What the evidence supports | Verdict |
|---|---|---|---|
| Protein | 1.6–2.2 g/kg daily | The best-supported intervention in the category. Increases fullness, has the highest thermic effect of the three macronutrients, and protects lean mass in a deficit so more of the loss is fat. Not glamorous, and not close. | Worth it |
| Fiber | 25–38 g daily | Slows gastric emptying and increases fullness. Most people eat about half the recommended amount, so for most people this is a genuine gap rather than an optimisation. | Worth it |
| Caffeine | 3–6 mg/kg | A modest, genuine increase in energy expenditure and fat oxidation, plus better training output. The effect blunts as tolerance builds, which is the catch nobody mentions. | Worth it, with a caveat |
| Creatine | 3–5 g daily | Not a fat-loss supplement and never was. It earns a place here because it helps you hold strength and lean mass in a deficit, which is what determines whether the weight you lose is the weight you wanted to lose. | Worth it, indirectly |
| Green tea extract | 250–500 mg EGCG | Small increases in energy expenditure in some trials, largely alongside caffeine, and inconsistent across studies. Real but minor. High-dose concentrated extracts have liver safety signals worth respecting. | Modest |
| Capsaicin / capsimax | 2–10 mg capsaicinoids | A measurable but small thermogenic effect, plus some appetite reduction. Magnitude is on the order of a few dozen calories a day. | Modest |
| Glucomannan | 1 g before meals | A soluble fiber that expands with water. Some trials show modest weight loss through fullness. Must be taken with a full glass of water — it is a genuine choking risk dry. | Modest |
| Yohimbine | 0.2 mg/kg fasted | Some evidence for fat mobilisation, particularly fasted. Also raises heart rate and anxiety, interacts with several medications, and is poorly tolerated by many. The side-effect profile does most of the deciding. | Conditional |
| Berberine | 500 mg, 2–3× daily | Genuine effects on glucose metabolism. The “nature's Ozempic” framing is marketing — the magnitude is not remotely comparable. Interacts with a number of medications. | Overhyped, not useless |
| CLA | 3–6 g daily | Mixed results across human trials. Where an effect appears it is very small — the kind of number that is statistically detectable and practically invisible. The dramatic findings came from animal studies that did not translate. | Weak |
| L-carnitine | 1–3 g daily | Essential for transporting fat into mitochondria, which is why the story is so appealing. But healthy, well-fed people are not short of it, and oral supplementation raises muscle carnitine poorly. Topping up a system that is not the bottleneck. | Weak for fat loss |
| Garcinia cambogia | — | Tested repeatedly in humans, including well-designed trials, and did not produce meaningful weight loss. | Skip |
| Raspberry ketones | — | Popularity traces to a television segment, not a literature. Essentially no human evidence for weight loss at any realistic dose. | Skip |
| Chromium picolinate | — | Meta-analyses find effects on body weight that are too small to matter. | Skip |
Read the table this way: the four at the top are worth your money and three of them are not even marketed as fat burners. Almost everything sold specifically as a fat burner sits in the middle or the bottom.
Why the weak ones sell so well anyway
They are usually taken alongside a diet.
Someone starts a deficit and a fat burner in the same week, loses weight, and credits the capsule. The deficit did the work. This is the single most common way an ineffective product earns a loyal customer.
Stimulants feel like they are working.
Caffeine and its relatives produce warmth, alertness and appetite suppression within an hour. That sensation is real, and it is easy to read as fat loss. It is mostly just caffeine, which you can buy for a great deal less.
Animal data gets reported as human data.
A striking result in rodents, at doses that would be implausible in a person, becomes a headline and then a label claim. CLA and raspberry ketones both travelled this route.
What we would actually spend on, in order
If the budget is fixed — and it usually is:
- Hit your protein target. Food first; a protein powder only to close the gap on days you cannot.
- Close the fiber gap. Cheap, unglamorous, and the deficit most people actually have.
- Creatine. Not for fat loss — to keep the muscle you are trying to keep.
- Caffeine, if you tolerate it. Coffee counts and costs less than a fat burner.
- Everything else, only once the four above are genuinely handled.
Yes, we sell things in the bottom half of this table. People buy CLA and L-carnitine for reasons of their own, and if you want them, ours are honestly dosed and honestly labelled. We would just rather you bought them knowing what the research says than believing an advertisement we did not write.
We would rather lose the sale than sell you the story.
That is the whole company, and it is what goes out by email — honest breakdowns, no daily discount blasts. Plus our high-protein recipe book free, and 10% off your first order.
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Related reading: Does CLA work for weight loss? · What L-carnitine actually does · Protein powder for weight loss · Protein calculator
General information for healthy adults, not medical advice. Talk to your healthcare provider before starting any supplement, particularly stimulants or berberine, and especially if you take prescription medication or have a heart condition.
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.