Which vitamin is synthesized by human body?

There are 4 forms of vitamin D, and the important ones are synthesized by the reaction between UV rays and cholesterol in our skin.

Vitamin K2 is synthesized in the guts by bacteria.

Vitamin B3 Niacin is synthesized in small amounts by gut bacteria.

Vitamin B5 Pantothenic Acid is synthesized in small amounts by gut bacteria.

Vitamin B7 Biotin is synthesized in small amounts by gut bacteria.

Vitamin B9 Folic Acid is synthesized in small amounts by gut bacteria.

Vitamin B12 is synthesized in the guts by bacteria.