Fitness and nutrients: the compact guide hub
Creatine, electrolytes, magnesium, protein, vitamin D: the staples people ask about most. The fitness aisle is crowded, so this is a small, selective set rather than the whole thing.
Each guide picks out the real question behind the ingredient instead of listing every possible use. It's compact on purpose: a clear answer on a handful of staples.
The guides in this group
- Creatine: strength, running and the actual question: What creatine does for strength, what the evidence says about running and endurance, and where kidney, hair and focus claims stand.
- Electrolytes: what is in the mix?: Sodium, potassium, magnesium and chloride, who needs added electrolytes, the risk of overdrinking, and a worked label example.
- Magnesium forms: what's actually different?: How forms differ in magnesium per gram, absorption and gut effects, and what labels only imply.
- Protein and collagen: what are you actually buying?: Protein norms, whey versus plant, and what collagen trials show for skin, joints and tendons.
- Vitamin D in the Netherlands and Europe: Who Is Advised to Supplement and What the Numbers Mean: Who is advised to supplement in the Netherlands, EFSA's upper limit and what blood-test numbers mean.
Where to start
Magnesium forms is a good first stop; for label reading in general, see How to read a supplement label (and a lab certificate). After that, start with whichever ingredient matches what you're doing.
Related guides
- How to read a supplement label (and a lab certificate): Portion first, then the nutrient amount, then the claims.
- Supplements, herbs and medication: how to check a combination: Why "natural" is not a safety category, and what to bring to a pharmacist.
Where to shop
Orangefit is relevant for reading a plant-based shake or hydration mix label, and Upfront for creatine, electrolytes and running formats, which are the products the creatine and electrolyte guides keep returning to.
Last updated: 12 October 2026