No supplement will burn fat without a caloric deficit. Period. But once you have your diet and training dialed in, a few ingredients can provide a modest boost — increasing metabolic rate by 3–8%, improving fat oxidation, or reducing appetite. Here is what the science actually supports.
TL;DR — Quick Summary
- ✓Caloric deficit is required — no pill replaces eating less or moving more
- ✓Caffeine: increases metabolic rate 3–8%, most studied thermogenic ingredient
- ✓Green tea extract (EGCG): modest fat oxidation boost, works synergistically with caffeine
- ✓L-Carnitine: helps transport fatty acids into mitochondria, most useful for those in a deficit
- ✓Best overall: Jacked Factory Burn-XT — transparent label, clinically dosed caffeine + green tea
- ✓Best stim-free: Jacked Factory Lean-XT — no caffeine, uses acetyl L-carnitine and green tea
- ✓Skip anything promising "rapid fat loss" or "10 lbs in a week" — that is marketing, not science
Ingredients With Actual Evidence
Caffeine (200–400mg)
The most effective thermogenic ingredient available without a prescription. Increases resting metabolic rate by 3–8% and enhances fat oxidation during exercise. Most fat burners are essentially caffeine pills with extras.
Green Tea Extract / EGCG (500mg)
Epigallocatechin gallate (EGCG) inhibits an enzyme that breaks down norepinephrine, extending your body's fat-burning signal. Works best when combined with caffeine.
L-Carnitine (2g)
Shuttles fatty acids into mitochondria for oxidation. Studies show benefits primarily in those who are deficient (vegetarians, older adults) or in a caloric deficit. Not a miracle fat burner, but a useful support ingredient.
Top Fat Burner Picks for 2026
1. Jacked Factory Burn-XT→
Transparent label, clinically dosed, and no proprietary blends. Caffeine, green tea extract, acetyl L-carnitine, and cayenne pepper extract. Does not promise miracles — just honest dosing of evidence-based ingredients.
- Caffeine: 270mg | Green Tea: 500mg | Acetyl L-Carnitine: 700mg
- Price: ~$0.45/serving (60 capsules)
- Best for: people who want a straightforward, evidence-based fat burner
2. Cellucor SuperHD→
A popular mainstream option with caffeine, green tea extract, and added nootropics for focus. Not as transparently dosed as Burn-XT, but widely available and generally well-tolerated.
- Caffeine: 160mg | Green tea, capsimax, B vitamins
- Price: ~$0.50/serving
- Best for: moderate stimulant users who want focus + fat burning
Fat burners with "proprietary thermogenic blends" often hide underdosed ingredients behind impressive-sounding names. If they do not tell you how much of each ingredient is in the product, they have something to hide.
The Bottom Line
Fix your diet first. Then fix your training. Then, if you want the last 3–5% optimization, a fat burner with caffeine and green tea can help. Jacked Factory Burn-XT is our top recommendation for its transparent formula. Compare all fat burners on our comparison page.
