Skin is the human body's largest organ. Recent research suggests that superfine wool base layers – "next-to-skin" as they say in the business – helps wearers maintain healthy temperature and moisture levels in the skin, qualities of great benefit to all and especially to sufferers of chronic skin conditions such as eczema (atopic dermatitis).
Read more about it here: Superfine Merino good for skin
Putting an end to wool "allergy"
It is a common misconception that wool is an allergen, something that causes an allergic reaction. Studies show that all fibres, not only wool, can provoke a prickle sensation on the skin if the fibre end is coarse enough. This prickle can be itchy and cause irritation,but it is not allergy. Wool fibre exists in many levels of fineness, measured in microns. When the average diameter of the fibres in the fabric exceeds 22 microns, or there is more than 5% of fibre exceeding 30 microns, the prickle factor appears. Commercially available superfine Merino wool is 15-18.5 microns. Ultrafine Merino garments are 11.5-15 microns.
In fact, dermatological surveys report few records of people showing an allergic skin reaction when wearing woollen garment. Clinical allergy skin patch tests are available for wool allergy. Studies show people may find a wool jacket “itchy” and have symptoms such as reddened skin yet do not react to clinical allergy testing.
Notably, so-called allergic reactions to wool garments have decreased within the last 50 years, coinciding with the banning of many finishing products previously used in the textile industry such as formaldehyde and chrome.
The truth about cats and dogs
Some people may conclude that because they are allergic to cat and dog hair, and that they will also be allergic to wool because it is "sheep hair." However, with cat and dog hair allergies, the allergen is generally not the hair itself but the dander and saliva of the animals.
Wool used in clothing or bedding, on the other hand, has been thoroughly cleaned prior to being made into the finished product.
Moreover, the hair of all mammals – whether cat, dog, sheep or human – is made of the same protein: keratin, and it would be very rare to be allergic to keratin. That would be like being allergic to your own hair.