Which Thermal Baselayer Is Best - Merino, Polypro or Merino Fusion?

Traditionally with baselayers people have had a choice of synthetic fibre (polypropylene and lately polyester) or natural fibre (merino wool). Each of these has certain characteristics which make them ideal for active outdoor adventures in cool environments. However, Wilderness Wear in Australia has developed a new line they call MerinoFusion which is a new hybrid weave made up of 50% Tasmanian merino wool and 50% ultrafine Schoeller polypropylene. We look at some of the features below. (I only have limited experience with polyester baselayers so have not discussed them below)

Features of polypro baselayers:
Man made fibre
Lower initial cost
Low weight
Absorption of moisture is low - excellent in very wet conditions
Drying time when wet is reasonably fast
Warmish when wet
Good durability
Can have a stink when worn for a period of time.
Comfort is good
Wicking performance is good

Features of Merino baselayers:
Natural fibre
Higher initial cost
Low weight
Absorption of moisture is moderate
Drying time when wet is slow
Wicking performance is reasonable
Warmish when wet
Durability is good depending on the weight of the merino and quality of the garment
Stink factor is minimal
Comfort is exceptional (can be a personal thing)

So then we have Wilderness Wear's Merino Fusion which is a hybrid weave of Tasmanian merino wool (the best merino available - I may be biased ha ha) and ultrafine Schoeller polypropylene (the best polypro available) that creates a hard wearing soft feeling, moisture wicking, odour resistant material seemingly perfect for baselayer thermals. It combines the best qualities of merino and polpypro to produce a garment that is ideal for outdoor activities in cool environments.

Features of Merino Fusion (MeFu):
Combination of man made and natural fibres
Slightly lower cost than 100% merino
Low weight
Moisture absorption is low
Fast drying time
High moisture wicking
Warmish when wet
Low odour
Good durability
Comfort is exceptional

The Superfine Merino and polypropylene yarns used in MerinoFusion garments observe global ecological guidelines along the complete production and procurement chain:
• EXP – a revolutionary new process that enables the wool to remain machine-washable without the use of chlorine.
• bluesign® – approved fabric label designates textiles that were produced in compliance with especially high environmental standards.
• Öko-Tex Standard 100 – the world’s most widespread textile-label for textiles tested for harmful substances.

The verdict? The key in choosing the right baselayer for you is to know the environment in which you are likely to be adventuring in. If it is a wet, cold environment like Tasmania then I would say that either polypropylene or MerinoFusion will be your best choice due to the faster drying times. In fact due to the better wicking performance I would say MerinoFusion is a good choice for most conditions. At present for us it is hard to pass up the comfort, warmth and lack of stink of the new MerinoFusion by Wilderness Wear.