Supplements: what's defensible, what's junk

Psyllium has the best case — roughly ~2 kg over months at ~10 g before meals, plus real satiety and glucose benefits, and a good safety profile (take with plenty of water). Glucomannan is weaker (the best meta-analysis was null) and carries a genuine choking/obstruction hazard — never dry, and tablets are best avoided. Evidence ●●●○○ psyllium; ●●○○○ glucomannan

Not a fat-burner — a convenient way to hit a protein target that aids satiety and protects muscle in a deficit (see the protein section). If you already get enough protein from food, powder adds only convenience. Graded strong, but as a food tool, not a supplement with independent magic. Evidence ●●●●○

The nickname is marketing, not mechanism. Berberine works mainly through AMPK, not the GLP-1 receptor, and its effect on body weight in trials is not statistically significant (its real signal is a modest glucose and lipid improvement, from low-quality studies). It is a mild metabolic optimiser, not a weight-loss drug — and shares none of semaglutide’s ~15% effect. Evidence ●●○○○ for weight

A real but tiny thermogenic effect — on the order of ~1 kg at best, mostly caffeine-driven, and tolerance erodes it. The more important note is safety: brewed green tea is fine, but concentrated green-tea extract can cause liver injury. Net: not a meaningful weight-loss tool. Evidence ●●○○○

Effectively null or trivial, and some unsafe: apple cider vinegar (hype; enamel/throat harm), chromium (safe but ~doesn’t work), Garcinia cambogia (null — and a cause of acute liver failure), CLA (~1 kg but worsens HDL and insulin), raspberry ketones (no human evidence, pure mouse-study extrapolation), bitter orange/synephrine and yohimbine (cardiovascular risk), capsaicin and L-carnitine (trivial). Evidence ●○○○○

The real hazard isn’t weak efficacy — it’s that supplements aren’t pre-approved for safety, and regulators have found hundreds of weight-loss products spiked with hidden pharmaceuticals (most often sibutramine, a drug pulled for causing heart attacks and strokes, plus a former laxative suspected of being carcinogenic and even prescription antidepressants). With a ‘proprietary blend’ you cannot know the dose, the true contents, or whether it contains a withdrawn drug.