In terms of fineness, any wool fiber that has a diameter of 20µ (microns) or less will feel very soft to the touch.
Below 17.5µ the wool starts to feel buttery soft against the skin.
Here’s a guide to fineness grading:
- Fine grade (18.6 – 20μ)
- Superfine grade (15.6 – 18.5μ)
- Ultrafine grade (15.5μ and below)
These are the finest wool T-shirts I’ve found:
Men’s Short Sleeve T-Shirts — Ultrafine Merino
- 100% Merino 12 Micro T-Shirt by Loro Piana – $2150 (!)
- 100% Merino 15.5 Micro Shirt by Loow — two-ply compact spun Italian utlrafine merino — 160 g/m2 — $112
Men’s Short Sleeve T-Shirts — Superfine Merino
- 87% Merino 16.5 Micron T-Shirt by Proof — superfine merino from Global Merino, New Zealand — $72
- 87% Merino 16.5 Micron Short Sleeve Shirt by Arcteryx (Veilance) — 100% superfine merino — $150
- 100% Merino 16.5 Micron T-Shirt by Meriwool — superfine merino — 190 g/m2 — $55
- 100% Merino 16.5 Micron T-Shirt by Outlier — top capped MacKenzie 17.5 micron merino — 195 g/m2 — $120
- 87% Merino 17.5 Micron T-Shirt by Ridge — superfine merino — 145 g/m2 — $54
- 100% Merino 17.5 Micron T-Shirt by Minus33 — superfine merino — lightweight jersey knit — 170 g/m2 — $64
- 100% Cashmere T-Shirt by Maison Cashmere — Loro Piana wool — $127

Men’s Long Sleeve T-Shirts – Superfine and Ultrafine Merino
- 100% Ultrafine Merino Crew Sweater by Jema — ultrafine 13.5 micron Saxon merino (a wool known as Jemala) — $382
- 100% Merino Long Sleeve Shirt by Minus33 — 17.5 micron merino — 170 g/m2 — $69
- 75% Merino Dreamweight Shirt by Outlier — 75% 16.5 micron merino, 25% nylon — 110 g/m2 — $120
- 89% Merino Long Sleeve Shirt by Proof — 17.5 micron merino — superfine wool from Global Merino, New Zealand — $98
- Veilance Frame Shirt Long Sleeve Shirt by Arcteryx — 87% superfine merino, 13% nylon — 16.5 micron — $200
Unbound Merino has a 100% merino crew- and v-neck t-shirt at 17.5μ and 190g/m².
Wool & Prince has a 100% merino crew-neck t-shirt at 17.5μ and 210g/m².
Loow T-Shirt is the finest value for an ultrafine merino shirt. Thank for share!
The best value for a ultrafine merino shirt is Loow T-Shirt
I really want a cashmere T-shirt, it’s a pity that summer is not coming soon …
I wash them for years in a regular cycle. They can’t be put in the dryer though.