Does Elastane Ruin Merino? Why 95/5 Is Often Better Than 100%

If you’ve been trying to avoid synthetics, it’s totally fair to look at a “95% merino / 5% elastane” label and wonder if that tiny 5% defeats the point.

Short answer: no — a small amount of elastane doesn’t ruin merino. In activewear, it often makes the garment fit better, recover better, and last longer than 100% merino (especially for shorts, bras and leggings).

What elastane actually changes (and what it doesn’t)

Merino is still the hero fibre in a 95/5 blend. You still get the core benefits people love about merino:

Breathability and temperature regulation
Softness (especially in fine merino)
Better comfort across a wider range of conditions

Elastane’s job is more boring — but very useful: it helps fabric stretch and snap back. That matters more than most people realise once a garment gets wet with sweat and starts moving with you.

Why 95/5 often wins for activewear

1) Better fit and “return” (less sagging over time)

100% merino can feel amazing — but in fitted activewear shapes, it can slowly lose its “hold” after repeated wears and washes. A small elastane percentage helps fabric keep its shape through movement.

2) Less riding up, less readjusting

Stretch recovery = fewer moments tugging hems, straps, or waistbands back into place mid-workout.

3) More confidence in fitted pieces (shorts / bras / leggings)

For garments that need to sit close to the body, the blend can feel more secure — without needing heavy compression or thick synthetic fabrics.

4) Improved durability where it matters

Activewear takes stress at seams, edges, and high-movement zones. A small elastane blend can reduce fabric strain and help pieces hold up longer.

So… when is 100% merino the better choice?

100% merino shines when the garment doesn’t need to behave like performance activewear. For example:

Relaxed tees
Base layers
Lightweight layers where stretch recovery isn’t critical

If you prefer a less “fitted” feel, or you’re wearing merino more like a daily staple than a workout tool, 100% can be perfect.

Does elastane make clothes smell?

Not in the way most people think. The “gym smell” problem is usually about how odour-causing bacteria interact with fabric + detergent residue buildup — and this is typically much worse in high-synthetic garments.

If you’re battling stubborn odour, read:

What about microplastics and “plastic-free” goals?

Elastane is a synthetic fibre. If your goal is to minimise plastics, it’s reasonable to prefer the smallest possible percentage that still gives you a garment you’ll actually wear often and keep for longer.

In practice, a well-made 95/5 piece that becomes your go-to for years can be a better real-world outcome than a 100% piece that doesn’t fit as well and stays in the drawer.

95/5 vs 100%: a simple decision guide

Choose 95/5 if you want fitted performance, stretch recovery, and secure feel (especially shorts, bras, leggings).
Choose 100% if you want a relaxed drape, minimal synthetics, and you don’t need “activewear behaviour”.