Are Your Supplements Actually Worth Taking?
If you take any kind of supplement — magnesium, fish oil, vitamin D, a multivitamin — there’s a reasonable chance you’re not getting what you think you’re getting. Not because supplements don’t work, but because the difference between a well-made product and a poorly made one is enormous. And most people have no way of knowing which they’ve got.
This isn’t about whether you should take supplements. It’s about not wasting your time and money on ones that aren’t doing anything.
The form matters more than the name
This is the single biggest thing most people get wrong, and it’s worth understanding because it can be the difference between a supplement that works and one that’s essentially expensive filler.
Take magnesium. If your bottle just says “magnesium” on the front and you flip it over to find magnesium oxide in the ingredients, you’re absorbing as little as 4 percent of what’s in that tablet. Magnesium oxide is cheap and widely used, but most of it passes straight through you. Magnesium glycinate, on the other hand, is well absorbed, gentle on the stomach, and particularly effective for sleep and muscle recovery. Both products can say “magnesium 400mg” on the label. Only one is actually delivering it.
The same applies across the board:
Vitamin D3 is significantly more effective than D2 at raising your blood levels. One study found D3 was roughly three times more potent. Yet D2 is still widely sold — it’s cheaper to produce.
Fish oil in triglyceride form is better absorbed than the ethyl ester form. If your fish oil doesn’t specify, it’s probably ethyl ester.
Curcumin — the active compound in turmeric — is barely absorbed on its own. Taken with piperine (black pepper extract), absorption increases by up to 2,000 percent. A curcumin supplement without piperine or another bioavailability enhancer is largely a waste of money.
Methylfolate is the active form of folate and is directly usable by the body. Folic acid — the synthetic version found in most cheap multivitamins — needs to be converted first, and a significant portion of the population has a genetic variation that makes that conversion inefficient.
If the label doesn’t specify the form of each ingredient, that’s usually because it’s the cheapest version available. A quality product will tell you exactly what’s in it.
When and how you take them matters too
Even if you’ve got the right product, you can still undermine it with bad timing.
Vitamins A, D, E, and K are fat-soluble — your body needs dietary fat to absorb them. Taking your vitamin D with a glass of water on an empty stomach means you’re absorbing a fraction of what you could be. One study found that taking vitamin D with a fat-containing meal increased absorption by 32 percent. Another found that taking it with the largest meal of the day raised blood levels by around 50 percent over two to three months. A handful of nuts, some avocado, eggs — anything with fat in it will do.
Magnesium glycinate is best taken in the evening, 30 to 60 minutes before bed, which aligns with its role in supporting sleep and relaxation. But if you also take iron, you need to space them apart — magnesium can reduce iron absorption. A gap of at least four hours is recommended, which is why iron in the morning and magnesium in the evening is a natural pairing.
Iron itself is best absorbed on an empty stomach, paired with vitamin C, which significantly boosts uptake. A glass of orange juice or a vitamin C tablet alongside your iron supplement is one of the simplest and most evidence-backed absorption hacks there is. But avoid taking iron at the same time as calcium or zinc — they compete for the same transport system in your gut, and calcium can reduce iron absorption by up to 50 percent.
None of this is complicated once you know it. But most people don’t — and the result is months or years of taking something that’s working at half capacity or less.
Where you buy matters more than you think
In 2023, supplement brand NOW Foods discovered 11 counterfeit versions of their products being sold on Amazon by a single seller. When tested, the fakes contained plain rice flour instead of the listed ingredients. Some had trace amounts of sildenafil — the active ingredient in Viagra — with no mention of it on the label. That same year, Fungi Perfecti found 23 separate Amazon sellers selling counterfeits of their Host Defense mushroom supplements, some containing undeclared allergens. In 2024, Amazon seized over 15 million counterfeit products globally.
This doesn’t mean every supplement on Amazon is fake. But marketplace platforms — where third-party sellers can list products without much verification — carry real risk. If you’re buying supplements online, buy directly from the manufacturer’s website or from an authorised retailer. If the price seems too good to be true, it probably is.
How Australia’s system works — and where it doesn’t
Australia has stricter supplement regulation than most countries, which is genuine good news. The Therapeutic Goods Administration — the TGA — oversees what can be sold and requires products to meet safety and quality standards. But the level of scrutiny depends on the category.
Next time you pick up a supplement, look for a small number on the packaging. AUST R means the product is registered — the TGA has individually evaluated it for safety, quality, and efficacy before it went on sale. This is the same standard applied to pharmaceutical medicines.
AUST L means the product is listed. This is where most supplements sit. Listed products are considered lower risk, and they’re allowed onto the market without individual TGA evaluation. The company self-certifies that it meets the requirements. The TGA can audit after the fact, and it does — but it hasn’t reviewed every listed product before you buy it.
That doesn’t make listed products unsafe. But it does mean quality varies between brands more than you’d expect, and the responsibility for checking what you’re getting sits partly with you.
What to look for in 60 seconds
You don’t need to become a supplement scientist. But the next time you’re buying or restocking, run through this:
Check the form of each active ingredient. If it just says “magnesium” or “fish oil” without specifying the type, it’s likely the cheaper, less effective version.
Look for individual ingredient doses clearly listed. If you see a “proprietary blend” or “complex” with only a combined total weight, the brand is hiding how much of each ingredient is actually in there. That’s a red flag, not a trade secret.
Look for third-party testing marks — Informed Sport, NSF, or USP. These mean an independent lab has verified the product contains what it claims. Not every good brand has them, but the ones that do are putting their money where their label is.
Check for the AUST L or AUST R number. If there’s no TGA number at all, ask yourself why.
Buy from the manufacturer or an authorised retailer, not a marketplace seller you’ve never heard of.
The bottom line
Supplements can be genuinely useful — but only if they contain what they claim, in a form your body can actually use, taken in a way that allows absorption. A surprising number of products fail on at least one of those counts.
