When shopping for eco-friendly clothing made with cotton material ask if the production of the material used meets either sustainable, fair trade or even organic production standards. Often time’s retailers will proudly state what practices went into the production of the material, but if a clothing label simply indicates "green production methods", or they can't tell you the source of the cotton it may not be.
One of the most luxurious and animal lover clothing categories uses wool. Sweaters, jackets, hats and scarves are all be made of wool. Because the material comes from animals there are multiple facets to what constitutes eco-friendly clothing made of wool. Wool can be organic, based on what is feed to the sheep producing the product. However, a more important metric is how the sheep are raised. While more expensive, sheep that are grass feed and free range usually indicates the animals eat a natural diet and have a humane upbringing. This contrasts to large production farming of animals which is done simply for their wool.
Animal lover t shirt raised in this way are not organically fed, nor raised in a sustainable manner so look out for that. There are now a lot of choices available to consumers in terms of what can be worn that is considered green in material origin and production. The key is to be educated and ask your retailer to confirm that their eco-friendly clothing meets organic, fair trade and sustainable standards.