Multiple good trials agree. Treat as settled.
A 2003 meta-analysis examined 250 supplements; only six had enough studies to analyse and only two worked. Creatine was one. Modern trials put it at about 2.5 lb of extra lean mass in under-50s — and 3 lb in older adults.
Across 44 studies, losing weight by diet raised total testosterone about 72 ng/dL and bariatric surgery about 208. Vitamin D did nothing. The famous sleep-deprivation figure rests on ten men and a p-value of .049.
Pooled across 28 randomised trials, eggs raise LDL by 5.55 mg/dL — so 'eggs don't affect your cholesterol' is wrong. But adjust for total dietary cholesterol and the egg association with heart disease vanishes entirely. And two meta-analyses disagree about the one thing the 'it's a wash' argument needs.
On an ordinary diet your muscle creatine is already 60–80% saturated, and supplementing fills the rest. Which is why one biopsy study found a six-fold difference in response to the identical dose — the people who gained most started with the most room. Loading only changes how fast you arrive.
Pooled across 143 randomised trials: body mass up 1.9 lb, fat-free mass up 1.8 lb, fat mass unchanged, body fat percentage down — with the studies essentially all agreeing. And the bloat everyone complains about traces to a loading phase that a 1996 study showed was never necessary.
Canning doesn't destroy the omega-3s — canned pink salmon carries more than a gram per 100 g. But albacore packed in oil holds 0.24 g against 0.86 g for the same fish in water, because the fat dissolves into the oil and the oil goes down the sink. Figures pulled from USDA FoodData Central, with the FDA/EPA mercury lists alongside.
Studied at up to 30 g a day for five years, in groups from infants to the elderly. The kidney scare has a real source: creatine raises serum creatinine, the marker doctors read as kidney function — while the kidneys' actual filtration rate stays put. The gauge moved, not the engine.
54 randomised trials, resistance training against people doing no exercise at all, nobody dieting: body fat percentage fell 1.46 points and fat mass fell about 1.2 lb. The percentage moved further than the fat did — because muscle was going on while fat was coming off, and a bathroom scale reports that swap as zero.
6,421 people across 29 countries, measured by doubly labelled water: energy expenditure is flat from 20 to 60, even during pregnancy. It falls about 0.7% a year after that. The decline is real — it just starts four decades later than everyone thinks.
By volume, yes — that is chemistry. But in a 12-week trial people gained about 2.6 lb of lean mass while losing up to 7 lb of fat, so their weight went down, not flat. And the density constant everyone quotes was measured in rabbits and dogs.