There are a few ways to tell if a mens biker leather jacket is made of genuine leather:
Smell: Genuine leather has a distinct smell that is often described as rich and earthy. If the jacket smells like plastic or chemicals, it is likely made of synthetic materials.
Texture: Genuine leather has a unique texture that is not found in synthetic materials. You should be able to see natural variations in the grain and feel the texture of the leather when you touch it.
Price: Genuine leather is generally more expensive than synthetic materials. If the price of the jacket seems too good to be true, it may be made of synthetic materials.
Label: Look for a label that states the jacket is made of genuine leather. Most reputable brands will clearly indicate the materials used in their products.