Why particle size matters
For an ingredient to be absorbed, it usually has to dissolve. Poorly soluble compounds dissolve slowly, so making the particles smaller increases their surface area and can speed dissolving and improve absorption [1]. That's the rationale behind 'micronized' and 'nano' supplements.
Micronized: an established idea
Micronization grinds particles to the micrometer scale. It's a well-accepted way to improve the dissolving of some poorly soluble ingredients — for example, micronized creatine dissolves more easily (though absorption of ordinary creatine monohydrate is already good), and micronized forms of some other compounds can modestly aid uptake. The benefit is real but often incremental, and it depends on the specific ingredient.
Nanoparticles: promising but less settled
Nanoparticle (nano) formulations go much smaller and can dramatically change how a substance behaves in the body. For a few compounds this improves absorption, but for supplements broadly:
- The absorption benefit is product-specific and not guaranteed by the word 'nano.'
- Safety at the nanoscale is an active research area; very small particles can behave differently in the body, so long-term data are limited.
- Marketing sometimes outpaces the evidence (see [decoding marketing terms](/learn/supplement-marketing-terms-decoded)).
The bigger picture
Particle size is just one input to bioavailability — dose, the chemical form, and whether it's taken with food often matter more. A 'nano' label doesn't override a too-low dose or a poorly studied ingredient.
Practical guidance
- Micronized is a reasonable, established feature for some poorly soluble ingredients, with usually modest benefit.
- Be cautious with 'nano' claims unless there's evidence for that compound and reassurance on safety.
- Judge the whole product — dose, form, and [third-party testing](/learn/supplement-certification-seals-compared) — not the particle-size buzzword [2].