Charcoal bamboo is created by burning bamboo inside an oven at temperatures over 800°C. This charcoal is then crushed into fine powder - nano-particle bamboo charcoal powder, which is then mixed evenly with the fiber (no bleaches used). The fibers are then spun into yarn, which is woven or knitted into the fabric.
The charcoal powder is incredibly fine - hence nano-particle (1 nano-meter is 1 billionth of a meter) and is a high surface area material, which means it has amazing absorption properties. The powder acts as activated particles, binding to organic waste and helping remove it.
Because the powder is mixed into the bamboo fiber, it not only retains much of the benefits of the original fiber, but adds in terms of absorbency, breathability, hypoallergenicity, and anti-bacterial properties. Not to mention fabrics made from charcoal bamboo are dye-free (only available in charcoal grey shades).
Rewind - bamboo
Bamboo grow really fast (some species grow as much as as 4 cm in an hour) which makes them one of the fastest growing plants. They grow back from their roots (no re-plantation required) and they do not need nasty fertilizers or pesticides.
They consume less land and water compared to for e.g. cotton. Given the height bamboo reaches, it also gives high yield per unit area. Bamboo binds the soil through it’s roots much more so than cotton, preventing soil-erosion, and also produces more oxygen than the same sized trees. All this makes harvesting bamboo inherently sustainable and easy on environment.
The clothes made from bamboo fiber are amazingly soft, durable, lustrous, comfortable, breathable, hypoallergenic, antibacterial, anti-odor, anti-pilling, easily washable and ... Its just naturally packed with benefits.
Last but not the least
Let me end by saying that no fiber is 100 % eco-friendly and sustainable, as there is always a cost for e.g. transportation/storage/packaging and what not, but that said when you take everything into consideration, bamboo probably provides one of the best mix of environment and performance benefits.
Charcoal bamboo just adds more to all these already existing amazing benefits of bamboo fiber, making it a truly conscious and guilt-free choice.