Why are nipples darker than the rest of the skin?

It all comes down to puberty and hormones

Cracked Nipples Symptoms, Causes & Common Questions

7 causes of dark nipples and when to see a doctor

Dark nipples: 7 causes and when to see a doctor

My nipples are dark, and I am 25. Do all gals have dark brown

Psoriasis on Nipple and Areola: Pictures, Signs, Relief

Lightening the Dark: Pink Intimate System in Singapore

The 7 things that make your nipples DARKER - and when it could be

Early Detection — Breast Cancer Foundation

Breast Changes in Early Pregnancy: What to Expect

9 Weird Nipple Things That Are Actually Totally Normal

Why do nipples get darker during pregnancy?

研究发现：42%的女生每周自慰超过一次。今天聊聊女性的“自慰自由” - 日记- 豆瓣

Nipples: what's normal and why do we have them?