Podcast Summary: What's That Rash? – "No-poo: Why do we shampoo our hair?"

Host: Dr. Norman Swan & Norman Swan
Produced by: ABC News
Release Date: September 30, 2025

Overview

This episode delves into a deceptively simple but surprisingly complex topic: why do we shampoo our hair? The hosts, Dr. Norman Swan and Norman Swan, explore the history, science, and cultural practices around hair washing, dissect the development and role of commercial shampoo and conditioner, and discuss the "no poo" movement—those who forgo shampooing. They tackle popular questions: how often should we shampoo, what are the health implications of skipping it, and is it all a marketing ploy? The episode is peppered with wit, skepticism, and personal anecdotes—all in service of giving listeners a science-based perspective on one of life's most enduring hygiene habits.

Key Discussion Points & Insights

The Wondrous Oddity of Human Hair

• [01:04–02:03]
  Norman expresses amusement and discomfort about the human obsession with hair:

  "If I think too hard about them, start to really freak me out. ... We've created whole industries around the maintenance of it and the care of it and the cleansing of it." – Norman Swan [01:06]

• Hair is a focal point of culture and industry, sparking existential musings.

Historical & Linguistic Roots of Shampoo

• [02:20–04:51]
  The history of shampoo dates back millennia, with cultural roots stretching across continents:
  • Shampooing practice likely came from India, the word itself stemming from Sanskrit “chāmpo,” meaning to press or massage.
  • Early shampoos used natural soap berries (sapindis).
  • European adoption and linguistic evolution followed colonial contact.

  "The word comes from Sanskrit. ... It was called shampoo because shampoo comes from the word for massage." – Norman Swan [03:02]

The Science (and Marketing) of Shampoo and Conditioner

• [05:55–09:08]
  Ingredients & Functions:
  • Detergents: Remove grease and scalp oils.
  • Foaming agents: Provide suds mainly for sensory benefit.
  • Conditioners: Restore softness post-detergent; bind to hair’s negatively charged surface.
  • Other additives: Thickeners, opacifiers, fragrances, preservatives, and “luxurious” extracts.

  "The foam has got nothing to do with cleaning your hair. It's to convince you that you're actually using shampoo." – Dr. Norman Swan [06:20]

• Conditioners are formulated to repair or smooth hair, especially damaged areas.

  "Conditioners give a positive charge...reduce static electricity...smooth out the cuticles." – Dr. Norman Swan [08:25]

The "No-Poo" Movement and Its Motivations

• [05:01–11:58]

  • Why skip shampoo?
    • Concerns about chemical toxicity.
    • Potential disruption to the scalp’s microbiome.
    • Environmental worries over plastics and microplastics.
  • The movement encourages dropping commercial shampoos altogether, sometimes only rinsing with water.
  • Hosts note most Australians still use traditional shampoo and conditioner.

• Scientific discussion:

  "There's a microbiome on the scalp...that could be affecting the health of the scalp and risk to the environment because of rinse off plastics." – Dr. Norman Swan [05:19]

  "I think that’s what people talk about anecdotally...a feedback mechanism to the sebum production." – Dr. Norman Swan [11:20]

Do You Really Need to Wash Your Hair?

• [09:08–14:14]

  • Hosts acknowledge hygiene is a long-standing cross-cultural practice, but scientific evidence for or against frequent shampooing is limited.
  • The main purpose of shampoo seems to be social and experiential, not strictly medical.
  • The initial oily phase when quitting shampoo may be related to the scalp recalibrating sebum production.

  "We do the washing with the shampoo. It introduces a bunch of problems that we then treat with a conditioner..." – Norman Swan [09:08]
  "Based on science. We don’t know." – Dr. Norman Swan [13:23]

  • The experts recommend focusing on scalp health and individual needs over marketing.

How Often and With What?

• [13:36–14:29]

  • There’s wide variation in washing frequency; some people do it daily, others weekly or less.
  • Norman admits to daily use of both shampoo and conditioner; Dr. Swan only uses inexpensive paraben-free shampoo, never conditioner.
  • Emphasize getting advice from dermatologists, not advertisers.

  "If you’ve got a healthy scalp, you don’t have dandruff, you don’t have psoriasis, you’re probably not doing yourself any harm if you decide you’re going to wash your hair at a much lower frequency than otherwise or even not at all..." – Dr. Norman Swan [14:14]

Notable Quotes & Memorable Moments

• Norman on Hair Existentialism:

  “If you look at a word for too long or you say a word too many times, it starts sounding super weird in your mouth. I feel like that if I think about hair too much, I get into a weird spiral about it.” – Norman Swan [01:56]

• Dr. Norman Swan on Shampoo Marketing:

  “The foam has got nothing to do with cleaning your hair. It's to convince you that you're actually using shampoo on your hair.” [06:20]

• Norman’s Confession:

  “I love a good shampoo. I love a good sudsy foam. I love it when they’re a little bit, like, sometimes they’ve got, like, a little bit of a pearlescent quality to them.” [07:37]

• On The “No-Poo” Adjustment Phase:

  “The first week or so, their hair’s greasy and oily, and then it gets better and their body gets back into equilibrium again. Is this true?” – Norman Swan [11:07]

• Dr. Norman Swan’s Practical Verdict:

  “If you’ve got a healthy scalp... you’re probably not doing yourself any harm if you decide you’re going to wash your hair at a much lower frequency than otherwise or even not at all, according to some people who are no poos.” [14:14]

Audience Q&A Highlights

Hayfever and Rugby

• [14:39–16:54]
  • Listener Stephanie notices her husband’s hay fever clears up during rugby but not on walks; speculation includes higher airflow and anti-inflammatory effects of exercise.

  "The other theoretical aspect...is that exercise has an anti-inflammatory effect on the immune system..." – Dr. Norman Swan [16:02]

Fish Oil and Hayfever

• [16:56–18:04]
  • Listener Sue Ellen finds high-dose fish oil eases hay fever symptoms.

  "Fish oil...does have anti-inflammatory effects...the skepticism is about fish oil preventing coronary heart disease, not about anti-inflammatory effects." – Dr. Norman Swan [17:30]

Key Timestamps

• 01:04: The strangeness and societal obsession with human hair
• 02:20: Listener question introduces topic
• 02:39–04:51: History and etymology of shampoo
• 05:01–06:15: Ingredients in commercial shampoos and their functions
• 07:37: Psychology and marketing of shampoo experience
• 09:08: Functional need for hair washing
• 11:07: Anecdotes around “no poo” transitional phase
• 13:23: Scientific evidence: inconclusive
• 14:14: Summary advice: follow your scalp
• 14:39–18:14: Audience Q&A (hay fever and alternative remedies)

Tone and Language

The episode is conversational, humorous, slightly skeptical, and gently self-deprecating. Both hosts maintain an accessible, science-informed approach, giving honest “we don’t really know” answers when warranted and poking fun at themselves and the quirks of modern hygiene.

Takeaways

• Shampooing is a deeply entrenched cultural habit, with complex drivers spanning hygiene, marketing, and personal ritual.
• The actual need for commercial shampoo is dubious for healthy scalps—individual tolerance and comfort should guide frequency.
• The “no poo” movement is more about personal philosophy and risk aversion than hard science.
• Conditioners address some of the problems introduced by detergents.
• Always consult medical professionals for scalp or hair concerns—not marketers or influencers.