Elastane is normally made with petroleum distillades that are non-renewable resources. Elastane is used together with other fibers to give the fabric elasticity.
Recycling the other fibers from elastane blend fabric can be difficult. However using elastane is nearly necessary when it comes to lingerie. With elastane it's possible to make skin tight fit, support and stretch to last after after several uses.
Well-known trade names for elastane are e.g. Lycra and Spandex.
There are also recycled elastane fibers which environmental impacts are smaller than with regular elastane. For example Roica Eco Smart -fibers are recycled elastane fibers.
Lyocell is an eco-friendly cellulose fiber witch has a comfortable feeling skin touch. Instead of toxic chemicals it's made with 99% recyclable organic solvents. Consumption of water and energy is significantly lower than with cotton.
Tencel is a well-known trade name for lyocell.
Polyamide is normally made with non-renewable resources and its making process is harmful for nature because of carbon emissions and a huge energy consumption. Because of elasticity polyamide works well in lingerie.
A more environment friendly option for regular polyamide is a recycled one. It can be made for example of surpluses of textile industry or abandoned fish nets. Compared to regular polyamide the environmental impact of recycled polyamide is significantly lower. For example carbon dioxide emissions and water consumption are lower.
For example Q-Nova and Reco Nylon are recycled polyamide fibers.
Cotton is soft and very breathable fiber. In lingerie it's commonly used on the crotch to avoid extra irritation to the intimate area.
However there's some ethical and ecological problems with cotton production. Insecticides and pesticides used in cultivation cause for example health problems for farmers, pollute air and water, damage soil and reduce biodiversity.
There are some alternatives for regular cotton. With Organic cotton production the problems of toxic chemicals are avoided. However the production consumes a lot of water. In some purposes cotton can be replaced with other fibers. For example artificial cellulose fibers have some same features. We recommend you to read about environment friendly lyocell fiber.
For example GOTS is a certification for organic cotton.