Do fat burners really work

Honestly: no 'fat burner' works without a calorie deficit. At best it speeds fat loss slightly.

• Caffeine thermogenics — can curb appetite and add energy; they load the heart and blood pressure.
• L-carnitine — a small effect, only with a deficit and cardio.
• CLA, raspberry ketones, garcinia — little evidence.
• Green tea extract — liver injury has been reported at high doses on an empty stomach.

What works: a calorie deficit (−300 to −500 kcal), high protein (1.8–2.4 g/kg), strength training and 8–10k steps a day. Protein is the most useful supplement here — it keeps you full and protects muscle.