Every topic, explained from A to Z.

Scalp Barrier

The scalp barrier is the protective outer layer of the skin on your head. Learn what it is made of, what weakens it, and how it relates to dandruff and itch.

Sebum

Sebum is the scalp's natural oil, made by glands beside each follicle. Learn what it does, why levels vary, and how it relates to oily scalp and dandruff.

Shedding

Hair shedding is the normal daily loss of hairs that have ended their cycle. Learn how much is normal, how it differs from hair loss, and when to seek help.

Sleep

Sleep is when the body carries out much of its repair. Learn what research says about sleep, the body clock and hair, and where the evidence is still thin.

Stress

Stress is the body's response to pressure. Learn how severe stress can affect hair, why shedding often appears months later, and when to seek help.

The Journal

Thoughtful articles inspired by everyday life.

Soumm Papers

Long-form research, explored in depth.

Soumm Answers

Clear answers to the questions asked most.