Which magnesium is ideal for your longevity journey?
Magnesium is not just magnesium. You’ve probably stood in front of a shelf before and picked the cheapest option. 400 mg of magnesium, low price, quick decision. This article shows you why that’s often not the best choice and what really matters.
You probably know the situation: You’re standing in a drugstore or supermarket in front of a shelf full of supplements. At the very end, there’s a seemingly unbeatable offer. Magnesium for under three euros. 400 mg per tablet.
Feels like a good deal. A quick grab, a checkmark next to your health.
But it’s not that simple.
Because this product is neither necessarily a bargain nor does it automatically do your body any good.
Before we go deeper, one thing is important: Magnesium can be a useful supplement, especially if you have a deficiency. It plays a central role in many functions in the body.
If you want to understand why magnesium matters, you can read more here: Magnesium: A silent multitasker for your longevity journey
This article explains the why. Here, we focus on the more important question: Which form of magnesium actually makes sense?
Magnesium always comes in the form of a salt
Magnesium never appears as a pure element in supplements. It is always bound to another compound, a so-called magnesium salt.
Common forms include:
- Magnesium oxide
- Magnesium citrate
- Magnesium bisglycinate
- Magnesium chloride
This is where the real difference lies.
The type of salt determines how well magnesium dissolves in the body, how much is absorbed, and whether it actually reaches where it is needed.
Magnesium itself is not the product.
The magnesium salt is what matters.
What the label says
|
Drugstore |
Premium |
|
|---|---|---|
| Active ingredient | 400 mg magnesium | 300 mg magnesium |
| Price per package | €2.95 | €8.90 |
| Capsules/Tablets | 60 tablets | 120 capsules |
At first glance, the decision seems obvious: lower price, higher dosage.
What’s actually inside
Drugstore |
Premium |
|
|---|---|---|
| Magnesium per unit | 400 mg (per tablet) | 100 mg (per capsule) |
| Magnesium salt | Oxide | Citrate |
| Bioavailability | Very low | Significantly higher |
| Primary effect | Local (gut) | Systemic |
| Typical use | Laxative | Supplementation |
| Ingredients | Magnesium oxide, cellulose, hydrogenated fat, hydroxypropyl cellulose, calcium carbonate, maltodextrin, carboxymethyl cellulose, magnesium salts of fatty acids, silicon dioxide | Magnesium citrate, hydroxypropyl methylcellulose |
This makes one thing clear: it’s not just about the milligrams.
The core issue: bioavailability
Not every form of magnesium is absorbed equally well by the body.
Studies show:
- Magnesium citrate is well absorbed [1]
- Magnesium glycinate, chloride, lactate and aspartate are also well absorbed [1][2][3]
- Magnesium oxide and carbonate are absorbed poorly [2]
Important to understand: Solubility affects absorption.
Bioavailability describes how much actually reaches the body.
Typical absorption comparison [1]
- Magnesium oxide: approx. 4–22%
- Magnesium citrate: approx. 25–35%
- Magnesium glycinate: approx. 20–30%
- Magnesium aspartate: approx. 40%+
That means: If you take 400 mg of magnesium oxide, often only around 16 to 88 mg actually reaches your body. With magnesium citrate, it’s around 100 to 140 mg.
The difference is not the amount, but the form.
The second issue: what else is inside
In many products, magnesium is just one component among many.
Typical additives include:
- Cellulose
- Maltodextrin
- Hydrogenated fats
- Magnesium salts of fatty acids
- Silicon dioxide
These ingredients serve technical purposes. They stabilize tablets, improve production, and ensure consistency.
But they don’t provide any real health benefit.
This means you are not just consuming magnesium, but a product optimized for industrial manufacturing.
What else to look out for
Magnesium complexes
Multiple forms may sound high-quality, but are often dominated by cheaper compounds. What matters is the main source.
Buffered magnesium citrate
Example: 444 mg magnesium per serving, but only 30% citrate. That’s about 133 mg from citrate and around 311 mg from other forms. This is usually cost-optimized, not effect-optimized.
400 mg magnesium
The number is correct, but incomplete. What matters is the form.
A quick look at the ingredient list is always worth it. Not every high dosage is automatically effective, and not every cheap product is truly cheap.
If you understand which form of magnesium is included, you can better assess what your body actually receives and avoid poor choices.
Sources
- [1] Bioavailability of magnesium food supplements: A systematic review, Nutrition (2021 Sep)
- [2] Ranade VV, Somberg JC. Bioavailability and pharmacokinetics of magnesium salts, American Journal of Therapeutics (2001)
- [3] Ates M et al. Dose-Dependent Absorption Profile of Different Magnesium Compounds, Biological Trace Element Research (2019)