Alpaca Wool vs Merino:
 Which Is Warmer & Which Is Itchier?

Published Oct 08, 2019 | Updated Oct 17, 2024
Reading time: 6 minutes

1.   Lanolin content

Lanolin is an odorless yellow fat found in sheep wool (including Merino wool), produced by the sebaceous glands of sheep.It is an auxiliary pharmaceutical and cosmetic component, since its hydrophobic condition prevents irritation or infection caused by external agents; however, lanolin retains the moisture that is already present in the skin. [1]

So, can wool that contains lanolin be hypoallergenic? A study conducted in the Netherlands between January 2016 and December 2017 involved 594 participants undergoing routine testing with European Baseline Series (EBS), which consists of haptens with such low molecular weight that they do not produce an immune response. This test included a 30% lanolin alcohol solution to investigate dermatological reactions. Only 41 participants had questionable reactions, with 94% presenting atopic dermatitis or mild allergic reactions. [2] The study concluded that the risk of lanolin causing skin issues is very low, although adverse reactions could occur due to specific dermatological characteristics of the individual exposed.

Given this, adverse effects from using Merino wool are highly unlikely, but what about alpaca wool? Unlike sheep, alpacas produce very little to no lanolin. The alpaca wool used in the textile industry contains no lanolin at all. This fiber exhibits excellent moisture resistance (both from external sources and moisture from our own skin), and its lack of lanolin means it retains fewer bacteria and dust particles. [3] As a result, alpaca wool is considered hypoallergenic, significantly reducing the likelihood of allergic reactions. The moisture factor is no longer a concern, so if any reactions do occur, they are likely to be external and rare exceptions.

Mean DLQI over time for the 2 study cohorts. The asterisk (*) indicates a significant reduction in DLQI scores during the given interval. Thedagger (†) indicates that the mean change in DLQI scores was significantly different between the 2 cohorts. Image credits: Joseph F. Fowler, Lynn M. Fowler and Douglas Lorenz

While the study highlights that the diameter of 17.5-micron Merino wool provides a greater sense of comfort compared to cotton, what about alpaca wool? Like ultrafine Merino fibers, alpaca fibers can be as fine as 14.5 microns. So, what differentiates them? It comes down to softness and weight.

3.  Fiber weight and roughness-smoothness ratio.

It's important to distinguish between the diameter and weight of the fibers. For example, 15-micron Merino wool can be up to 33% heavier than 15-micron alpaca fibers. [5]

Additionally, wool fibers have microscopic scales that protrude from the fiber surface, which contribute to that itchy sensation. The smaller and flatter the scales, the softer the fiber will feel. Merino wool has overlapping scales that increase its roughness when sheared. In contrast, when comparing Merino and alpaca wool, the roughness of alpaca is significantly lower—5 to 10 times less—due to the absence of these overlapping scales, making alpaca wool softer and less itchy than Merino. [6]

Structure of Merino wool before and after shearing. Adapted from The Story of Wool, Kondinin Group. Image Credits: Learn About Wool.

Is Alpaca Wool Itchier Than Merino? 

Wool is an excellent insulator even when wet.
However, the key difference lies in the internal structure of the fibers: alpaca fibers have “semi-hollow” cores, while Merino wool relies solely on the crimp of the fibers to trap warm air. This structural difference also contributes to the fact that Merino wool tends to be heavier than alpaca wool.

We can see this difference in the natural decomposition of the fibers. For instance, when comparing Merino wool (17.5 to 21 microns) and Lincoln wool (33 to 41 microns), both sourced from sheep, the initial stages of decomposition show that Merino expands 1.5% more in length and tightens its crimp even further, [7] effectively retaining more heat.

Arms of Andes: Alpaca Wool vs Merino vs Cashmere: Which Is The Best?

On the other hand, fibers that have less dense areas running down the center can be considered “semi-hollow.” Not only do these fibers trap air between them, but the “hollow” areas heat up as well. Therefore, while Merino wool of similar micron size retains significant heat, the even lower density of alpaca wool enhances its heat-retaining potential due to the voids throughout its structure.

In conclusion, alpaca wool naturally regulates temperature thanks to its crimp and semi-hollow core. Alpaca wool clothing traps the heat generated by your body, both inside and between the fibers.

References:
[1] National Center for Biotechnology Information. Lanolin. PubChem Compound Summary [Internet]. [cited 2023 Oct 13]. Available from: https://pubchem.ncbi.nlm.nih.gov/compound/Lanolin
[2] Bokareva I, Ahlberg J, Järvinen T. The effect of different natural fibers on skin irritation: A systematic review. Contact Dermatitis. 2019;81(1):1-12. doi.org/10.1111/cod.13210
[3] Alpaca Information. Alpaca fiber characteristics [Internet]. [cited 2023 Oct 13]. Available from: https://www.alpacainfo.com/academy/article/4562/alpaca-fiber-characteristics
[4] Fowler JF Jr, Fowler LM, Lorenz D. Effects of Merino wool on atopic dermatitis using clinical, quality of life, and physiological outcome measures. [Internet]. [cited 2023 Oct 13]. Available from: https://www.liebertpub.com/doi/full/10.1097/DER.
[5] British Alpaca Society. An overview of alpaca and wool [Internet]. 2018 [cited 2023 Oct 13]. Available from: https://bas-uk.com/wp-content/uploads/2021/06/2018-AN-OVERVIEW-OF-ALPACA-AND-WOOL-scale-heights.pdf
[6] Bokareva I. Analysis of natural fibers and their effects on skin irritation. [Internet]. 2015 [cited 2023 Oct 13]. Available from: https://core.ac.uk/download/pdf/42626878.pdf
[7] D. Rama Rao; V. b. Gupta. (1992). Thermal characteristic of wool fibers Journal of Macromolecular Science - Physic, B31(2), 149-162.