Why Are Veins More Blue on Some People Than Others? 

The blueness of veins is influenced by several factors, including skin tone, thickness of skin, and depth of the veins. Veins appear blue because of how light interacts with the skin and the blood vessels beneath it.

Skin Tone: People with fairer skin tend to have more visible veins, which can appear bluer due to the contrast against the lighter skin tone.

Thickness of Skin: Thinner skin allows more light to penetrate and reflect off the veins, making them appear more pronounced and blue.

Depth of Veins: Veins closer to the surface of the skin are more visible and can appear bluer, while deeper veins may appear less blue or even invisible.

Amount of Subcutaneous Fat: Subcutaneous fat can act as a filter, affecting how light interacts with the skin and veins. Thinner individuals with less subcutaneous fat may have more visible veins.

Overall, the visibility and blueness of veins vary from person to person due to a combination of genetic, anatomical, and environmental factors.