How supermarket pricing actually works
Plain-English guides to how retail pricing actually works — when supermarket specials change, how often products repeat, what a "was" price really means, and how to read a unit price. Plus an ingredient-by-ingredient look at what the supplement research shows, and whether you could just eat it instead.
When do Coles and Woolworths specials change?
Both retailers turn their catalogue over on the same morning. Knowing which day you're shopping on changes what you pay — and the two ends of the week are not equivalent.
How often does the same product go half price?
Packaged groceries tend to cycle rather than discount at random. Once you know the rough interval, "how much should I buy?" stops being guesswork.
What makes a discount a real discount?
A "was" price only means something if it was genuinely the selling price for long enough. An Australian court has now put a number on how long that is.
The small number on the shelf label that beats the big one
Unit pricing is the only figure that lets you compare two different pack sizes honestly — and it's the one that catches a pack quietly getting smaller.
Supplement ingredient guides
One ingredient per guide, each answering the same two questions: what does the published research actually show, and can you get that dose from food instead? Every study is linked. Where the evidence is contested, we say so.
Glycine
The sleep research used 3 g. The Longevity Mix has 1.2 g. That gap is the most interesting thing about this ingredient.
L-lysine
An essential amino acid you almost certainly already get enough of — a 70 kg adult needs about 2.1 g a day, and an ordinary diet clears that without trying.
Vitamin C
Australia's official requirement is 45 mg a day. One gold kiwifruit already doubles it — so the interesting question isn't whether you can get this from food, it's why the tub has five times the RDI.
Magnesium citrate
The one on this list where a single handful of pumpkin seeds beats the supplement — and where the tub is a top-up rather than the whole job.
Creatine monohydrate
The most-studied supplement in sport, now being examined for the brain — and the one where the food arithmetic is genuinely hopeless.
Calcium alpha-ketoglutarate (CaAKG)
The largest single ingredient in the mix by weight, and the one with the thinnest human evidence. The trial that would settle it is still running.
Taurine
One of the few supplements where the dose researchers landed on and the dose in the tub actually match — and where most of the research is about outcomes we're not allowed to discuss.
Glucosamine sulfate
One of the best-selling supplements in the country, and the higher the quality of the trial, the smaller the effect gets.
L-glutathione
The one where the interesting finding is negative: your gut appears to dismantle most of it before it ever reaches your bloodstream.
L-theanine
The dose used in the trials is exactly the dose in the tub. The interesting question is how many cups of green tea that actually is.
Sodium hyaluronate
The dose in the tub is exactly the dose used in the trials — 120 mg, repeatedly, across multiple placebo-controlled studies. That's rarer than it should be.