How to fix your itchy scalp: the science

00:16:05
https://www.youtube.com/watch?v=ZBSAXC6DsK0

Summary

TLDRIn this video, Michelle, a cosmetic chemist, explains the science behind itchy scalps and how to effectively treat them. She identifies three main causes: microbial imbalance (specifically malassezia yeast), dry scalp, and potential allergens. Many scalp products fail to address these issues and can worsen the condition. Michelle emphasizes the importance of understanding the root cause of scalp irritation and recommends specific ingredients and products that can help alleviate symptoms. She also discusses the significance of maintaining scalp moisture and avoiding harsh products that can strip the scalp of its natural oils.

Takeaways

  • 🦠 Understand the role of microbes in scalp health.
  • 💧 Moisturize your scalp to prevent dryness.
  • 🚫 Avoid harsh shampoos that strip natural oils.
  • 🔍 Check for allergens in your scalp products.
  • 🧴 Use anti-dandruff products even without flakes.
  • 🌡️ Be cautious with hot water and hair dryers.
  • 🧪 Look for effective ingredients like piroctone olamine.
  • 🧴 Consider serums for scalp treatment between washes.
  • 💦 Hard water can irritate your scalp.
  • 🧼 Regular washing is key for scalp health.

Timeline

  • 00:00:00 - 00:05:00

    The video discusses the common issue of itchy scalp, which can be caused by various factors that are often misunderstood. Michelle, a cosmetic chemist, explains that many scalp products fail to address the root causes, leading to ineffective treatments. The first major cause is the overgrowth of malassezia yeast, which can irritate the scalp even in the absence of visible dandruff. This yeast feeds on sebum, producing irritating substances that cause inflammation and itching. Michelle emphasizes the importance of understanding the specific cause of scalp issues to find effective solutions.

  • 00:05:00 - 00:10:00

    In addition to microbial imbalance, dry scalp is another significant factor contributing to itchiness. The scalp, like the skin, requires proper moisture levels to maintain comfort. Harsh products can strip the scalp of its natural oils, leading to dryness and irritation. Michelle highlights the importance of using gentle shampoos and avoiding hot water, as these can exacerbate dryness. Hormonal factors can also play a role, leading to an oily yet dehydrated scalp, complicating the issue further. Identifying the correct cause is crucial for effective treatment.

  • 00:10:00 - 00:16:05

    The final cause discussed is potential allergens in scalp products, particularly preservatives like MI and MCI, which can trigger allergic reactions. Michelle advises viewers to be aware of their reactions to different products and suggests patch testing for allergies. She then outlines effective treatments for itchy scalp, including anti-dandruff shampoos containing key ingredients like selenium sulfide, zinc pyrithione, and piroctone olamine. Proper application techniques and the importance of moisture management are also emphasized to help alleviate scalp issues.

Mind Map

Video Q&A

  • What are the main causes of an itchy scalp?

    The main causes are microbial imbalance (malassezia yeast), dry scalp, and potential allergens.

  • Can I use anti-dandruff products if I don't have flakes?

    Yes, anti-dandruff products can still be beneficial even if you don't have visible flakes.

  • What ingredients should I look for in scalp products?

    Look for ingredients like selenium sulfide, zinc pyrithione, piroctone olamine, and ketoconazole.

  • How can I tell if I'm allergic to a scalp product?

    If you experience itching after using a product, it may indicate an allergy. Patch testing with a doctor is the most reliable way to check.

  • What should I avoid if I have an itchy scalp?

    Avoid harsh shampoos, oils, and certain allergens like MI and MCI preservatives.

  • How can I maintain scalp moisture?

    Use gentle shampoos, avoid hot water, and consider using serums with antioxidants.

  • Is hard water bad for my scalp?

    Yes, hard water can irritate the scalp and contribute to issues.

  • What is the best way to wash my hair if I have an itchy scalp?

    Focus on massaging the shampoo into your scalp and follow the instructions on the bottle.

  • Can dry shampoo help with an itchy scalp?

    Dry shampoo can absorb oil but should not replace regular washing.

  • What should I do if I suspect I have a microbial issue on my scalp?

    Consider using anti-dandruff shampoos and maintaining scalp moisture.

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  • 00:00:00
    your scalp's itchy inflamed maybe  even raw and none of the products
  • 00:00:04
    you've tried seem to be working and  now maybe your hair is even thinning
  • 00:00:09
    here's the problem most scalp products aren't  treating the right cause and no one's really
  • 00:00:13
    explaining what that is and a lot of scalp  products - well - they actually make things worse
  • 00:00:19
    I'm Michelle chemistry PhD cosmetic science  nerd and I used to scratch my scalp raw
  • 00:00:25
    it took me years of going through the research and
  • 00:00:27
    trying different products before I  worked out what was really going on
  • 00:00:31
    so in this video I'll break down the real science  behind itchy scalp and how to fix it for good
  • 00:00:39
    there are three major causes of itchy scalp we
  • 00:00:41
    need to understand and they all  need to be treated differently
  • 00:00:44
    if you miss one, a product might work for a  while but then your scalp just gets itchy again
  • 00:00:49
    cause one is microbes
  • 00:00:52
    now you might be thinking "I've heard  malassezia yeast causes dandruff,
  • 00:00:55
    but my scalp's just itchy - I don't have flakes."
  • 00:00:58
    But this is still important it's one of the  most misunderstood causes of itchy scalp
  • 00:01:03
    you see malassezia is on everyone's scalp  and this is a good thing when everything
  • 00:01:07
    is balanced just don't think too  hard about all of those microbes
  • 00:01:11
    it helps keep more harmful microbes in check
  • 00:01:14
    but when things are out of balance when this  yeast overgrows that's when things go wrong
  • 00:01:20
    the problem comes from malassezia  microbes interacting with sebum
  • 00:01:23
    which are the oils naturally on your  scalp it feeds off this oil and turns
  • 00:01:27
    it into a bunch of irritating substances  these make your scalp inflamed and itchy
  • 00:01:32
    and this happens even if you  don't see any dandruff flakes
  • 00:01:35
    in this study inflammatory markers rose after 3
  • 00:01:38
    days and people reported itching but it  took 3 weeks to start seeing more flakes
  • 00:01:44
    so a lot of people don't realize these  microbes are a big part of their problem
  • 00:01:48
    this was me I was hovering in this  sort of itchy region but it wasn't
  • 00:01:52
    quite at the flake stage so I thought  dandruff products just weren't for me
  • 00:01:56
    and a lot of other scalp products actually feed
  • 00:01:58
    this yeast so I was making things  worse without even realizing it
  • 00:02:02
    but just tackling the microbes usually isn't  enough you also need to understand dry scalp
  • 00:02:09
    your scalp is skin there's a whole bunch of hair  and extra oil but it still has the skin barrier
  • 00:02:14
    structure and it's still more comfortable  when it's the right level of moisturized
  • 00:02:19
    if you use really harsh products that  strip your scalp too much it can dry
  • 00:02:22
    out and feel itchy and tight just  like the skin on your face and body
  • 00:02:26
    if you're a skincare nerd you might  already know the wrong cleanser can
  • 00:02:30
    really mess up your skin I talk about this  in my other videos and my skincare eBook
  • 00:02:35
    from a formulation point of view a shampoo  is just a special type of cleanser if you
  • 00:02:40
    use the wrong shampoo the cleaning  ingredients the surfactants they can
  • 00:02:44
    stay in your scalp after rinsing and mess  up your barrier it gets leaky it lets out
  • 00:02:49
    water more easily and it lets irritants  in more easily as well so you get itchy
  • 00:02:54
    and some of your habits might dry it out  even more if you use really hot water in
  • 00:02:58
    the shower or you use a really hot blow  dryer or if you just have really dry and
  • 00:03:03
    cold weather and you use a heater  all of this can dry out your scalp
  • 00:03:08
    hormones can also be a big part of this and  this can still be an issue if your scalp is oily
  • 00:03:14
    you might have heard that oily skin can still  benefit from moisturizer if it's losing too
  • 00:03:18
    much water you end up in this oily but dry  situation you have too much oil but that
  • 00:03:24
    oil is not keeping the water in your skin the  exact same thing can happen with your scalp
  • 00:03:29
    so you might already see the big problems we have  here if your scalp issues are caused by these
  • 00:03:34
    dandruff microbes but you think it's dry scalp  then you might wash your hair less you might put
  • 00:03:39
    oils on your scalp but these will actually make  the microbes grow more and your itching gets worse
  • 00:03:45
    if you're using an anti-dandruff shampoo at the  same time it might seem like it's not helping and
  • 00:03:50
    you give up on it thinking it might not be either  of these it might be some secret third issue
  • 00:03:56
    foreshadowing
  • 00:03:57
    so you really need to work out  which of these apply to you
  • 00:04:00
    this microbe situation is more common and it's
  • 00:04:03
    even more likely to be this if you've  ever had dandruff before about half
  • 00:04:06
    the population is prone to dandruff and  we're more likely to have an itchy scalp
  • 00:04:11
    also if your scalp and skin is generally oily  if you don't wash your hair that much if you
  • 00:04:16
    live somewhere humid this is probably part of  your problem but if you've never had dandruff
  • 00:04:21
    and none of your relatives have (genetic  susceptibility is a big part of dandruff)
  • 00:04:25
    your skin is very dry you might even have eczema  and you wash and dry your hair regularly then you
  • 00:04:31
    might be in the less common situation where  dry scalp is an issue but not the microbes
  • 00:04:36
    but if you have this microbe situation you  probably also have dry scalp because these
  • 00:04:42
    substances from the microbes they will actually  make your scalp barrier more leaky and a lot of
  • 00:04:47
    dandruff treatments also dry out your scalp  so this becomes a bit of a vicious cycle
  • 00:04:53
    I didn't really make this connection  until I got deep into researching my
  • 00:04:56
    book The Science of Beauty if you're finding this
  • 00:04:59
    video helpful check it out as well as  hair it covers skin nails and makeup
  • 00:05:03
    luckily there are lots of products and tips that
  • 00:05:05
    work for both of these without  making the other one worse
  • 00:05:09
    but before we can talk about products we  need to look at the last piece of the puzzle:
  • 00:05:13
    potential allergens because if you're allergic  to something that you're using you can still
  • 00:05:18
    itch even when the other problems are  fixed and there is a really common
  • 00:05:22
    allergen in shampoos and that is the main  product type for dealing with scalp issues
  • 00:05:27
    here is a cosmetic chemist insider  tip: wash off products like shampoos
  • 00:05:31
    they are formulated differently from  leave-on products wash off products
  • 00:05:35
    don't stay on your skin for long so it's  safe to put higher levels of ingredients
  • 00:05:39
    in them and this is generally fine except  for allergens if you're allergic to them
  • 00:05:44
    I really need to stress this: if you aren't
  • 00:05:47
    allergic to an ingredient  you do not need to avoid it
  • 00:05:50
    allergies are when your immune system  overreacts to something that is normally safe
  • 00:05:55
    I'm allergic to cats that doesn't  mean everyone needs to avoid cats
  • 00:05:59
    but sometimes if your scalp is itchy  after you use particular products
  • 00:06:03
    that can be a sign of an allergy  that you haven't discovered yet
  • 00:06:06
    the two big ones are MI and MCI these  are even nicknamed "the itchy Ms" these
  • 00:06:12
    are preservatives that became more  common after brands started getting
  • 00:06:15
    rid of parabens because of misinterpreted research
  • 00:06:18
    it was mostly for marketing purposes  but parabens are actually super safe
  • 00:06:22
    very few people are allergic to them and  brands still needed preservatives because
  • 00:06:27
    products will go moldy so MI and MCI started  getting more popular even though they weren't
  • 00:06:32
    researched as much and it turns out a  lot more people are allergic to them
  • 00:06:36
    when I looked this up in PubMed  I found 23 articles with the word
  • 00:06:40
    "epidemic" in the title this is very  strong language for science papers
  • 00:06:45
    these were suddenly the second  most common allergen after nickel
  • 00:06:48
    again if you're not allergic these are  not a problem but it's estimated that
  • 00:06:53
    at least a few % of the population  are allergic to these including me
  • 00:06:57
    and the most annoying part these are really  common in scalp products it's gotten better
  • 00:07:02
    but I found MI or MCI in all of these shampoos  specifically claiming to help itchy scalp so if
  • 00:07:09
    you didn't know you were allergic these  might actually make your scalp itchier
  • 00:07:13
    there's a related preservative that's super  common in liquid laundry detergents so if
  • 00:07:17
    your clothes make you itchy sometimes there is  a good chance you're also allergic to MI and MCI
  • 00:07:23
    here are some other common allergens if a lot of
  • 00:07:26
    shampoos make you mysteriously itchy  you might want to look into these
  • 00:07:30
    the most reliable way to check is patch  testing with a medical doctor but if you
  • 00:07:34
    keep track of shampoos and products that do and  don't make you itchy you might see some patterns
  • 00:07:39
    there are other causes but these  three are the most likely if itchy
  • 00:07:42
    scalp is something you've had for a  long time and there's no rashes or
  • 00:07:46
    other obvious things suddenly changing  if you do have those go see a doctor
  • 00:07:51
    now that we know the big causes of itchy scalp and
  • 00:07:53
    how to work out which ones you  have let's talk about fixing it
  • 00:07:57
    first microbes here is the big  takeaway you don't need to have
  • 00:08:01
    dandruff to benefit from anti-dandruff products
  • 00:08:04
    I think a lot of people overlook them  because they don't have flakes and for
  • 00:08:07
    some weird reason the sensitive scalp products  usually aren't near the anti-dandruff products
  • 00:08:12
    there are four heavy-hitting ingredients that
  • 00:08:14
    control malassezia and they're mostly  in shampoos as well as some serums
  • 00:08:18
    disclaimer I've done sponsored posts in the  past for some of these products but I wasn't
  • 00:08:22
    obliged to include them here I'm recommending  them because I genuinely think they're good
  • 00:08:27
    selenium sulfide is orangey yellow and it smells a
  • 00:08:30
    bit like rubber but it's very effective  some people don't mind the smell but my
  • 00:08:34
    nose is super sensitive to sulfur  I worked with it a lot in the lab
  • 00:08:38
    the best smelling ones I've tried are the Dercos
  • 00:08:40
    anti-dandruff DS shampoos to me Selsun  Blue's fragrance is just a bit too strong
  • 00:08:45
    zinc pyrithione is another big one Head  and Shoulders pioneered a lot of its use
  • 00:08:50
    it works really well the main  downside is that it's insoluble
  • 00:08:53
    the tiny particles can make  your hair feel a bit gritty
  • 00:08:56
    it was recently banned in the  EU even though it was found to
  • 00:08:59
    be safe at under 1% and that means that  it should still not be harmful at 100%
  • 00:09:05
    I talk more about safety assessments in this video
  • 00:09:08
    this is an EU regulations quirk  - ingredients that have specific
  • 00:09:11
    health effects get banned just in case but  it is still available in other countries
  • 00:09:16
    piroctone olamine is a newer ingredient that's  getting more popular and this one is really nice
  • 00:09:21
    because it's soluble it doesn't smell so shampoos  with it look and feel just like normal shampoos
  • 00:09:27
    I was actually using one for ages  without realizing the Essano Scalp
  • 00:09:31
    Refresh and I was amazed that I could go  three days without feeling itchy usually
  • 00:09:35
    it's just a day sometimes it's actually  less because my scalp is just super fussy
  • 00:09:40
    piroctone olamine is in tons of shampoos  now you have a massive range of options
  • 00:09:45
    I found it in so many scalp products  even some that didn't say dandruff
  • 00:09:49
    the Head and Shoulders Bare range  might be a good option if you think
  • 00:09:52
    you have an allergy these have less ingredients
  • 00:09:55
    there's also ketoconazole this is antifungal
  • 00:09:57
    and it's im Nizoral climbazole  is the weaker cosmetic version
  • 00:10:00
    there are some malassezia species that  are resistant to it so if this isn't
  • 00:10:05
    working for you maybe try one of the other actives
  • 00:10:08
    also the other three are more  broadly antimicrobial so if you
  • 00:10:12
    have say scalp acne those can also help with that
  • 00:10:15
    some other ingredients for dandruff  aren't as effective for controlling
  • 00:10:18
    malassezia but they can help with other  aspects like flakes or soothing your scalp
  • 00:10:23
    look carefully at the ingredient  list to check what you're getting
  • 00:10:26
    now some common mistakes with anti-dandruff  shampoos number one the microbes are on your
  • 00:10:31
    scalp and mostly inside the hair follicles  so focus on massaging it all over your scalp
  • 00:10:37
    number two follow the instructions on the  bottle there's a common myth that these
  • 00:10:41
    shampoos work better if you leave them for a few  minutes but this only works for some shampoos
  • 00:10:47
    other shampoos have the active ingredients in  little bubbles called coacervates they only
  • 00:10:52
    release the actives when you dilute it when  you're rinsing so leaving these ones on your
  • 00:10:56
    scalp for longer you might just be making  your scalp dry and itchy for no good reason
  • 00:11:01
    if you use a conditioner on your scalp afterwards  you'll actually wash away some of the actives
  • 00:11:06
    so either keep the conditioner under your ears  or condition with an anti-dandruff conditioner
  • 00:11:12
    shampooing regularly usually works  better for itchy scalp if you're
  • 00:11:15
    using anti-dandruff shampoo that means  you are putting more of the active onto
  • 00:11:20
    your scalp but on top of that you're also  getting rid of the oils and the microbes
  • 00:11:25
    you can also get anti-dandruff  ingredients in serums these are
  • 00:11:28
    great between washes although they  don't really replace a proper wash
  • 00:11:32
    most of these have piroctone olamine  there's also some with zinc pyrithione
  • 00:11:36
    another thing worth thinking about if microbes are
  • 00:11:38
    your problem is moisture this can make  it easier for the microbes to multiply
  • 00:11:43
    it's a good idea to dry the hair around your scalp  faster use a hair dryer rather than leaving it to
  • 00:11:49
    air dry especially if it's cold or humid but to  protect the scalp barrier don't have this too hot
  • 00:11:55
    my hair dryer has a special scalp mode that's the  perfect temperature but hopefully your hair dryer
  • 00:12:00
    has a setting that feels comfortable  if it's too hot move it further away
  • 00:12:04
    hats and helmets can also trap moisture and  make things worse especially when you're
  • 00:12:08
    sweaty try to have some air flow in there  and wash your hair soon after you sweat
  • 00:12:11
    now on to some things for dry  scalp which are also important
  • 00:12:14
    for microbes remember the microbes  produce irritants which lead to a
  • 00:12:18
    leaky scalp barrier and this first point  is especially important gentle shampoo
  • 00:12:23
    you want something that won't make your  scalp feel stripped because it's drying out
  • 00:12:27
    your barrier it's also making it easier for these  irritating substances to get in and cause itching
  • 00:12:33
    again like with your face skin you don't want  to use anything that's too harsh in general a
  • 00:12:38
    slightly acidic skin friendly pH is better for  your scalp somewhere between like four and seven
  • 00:12:44
    pH isn't that important for your  hair which is another whole mess
  • 00:12:48
    we need to talk about in a different video
  • 00:12:51
    also avoid using conditioner on your  scalp the surfactants and conditioners
  • 00:12:55
    are actually more irritating than  the ones in shampoo the hair near
  • 00:12:58
    your scalp is nice and undamaged  it doesn't really need conditioning
  • 00:13:02
    antioxidants they're a really safe  option they're great for protecting
  • 00:13:06
    against irritation and improving your scalp  condition and the way that these malassezia
  • 00:13:10
    microbes make these irritating substances it's  through oxidation so they can also help with that
  • 00:13:16
    some studies show antioxidants can reduce  hair shedding which makes a lot of sense
  • 00:13:21
    your scalp is where your hair grows  and oxidative stress is thought to
  • 00:13:24
    be a contributor to hair loss the Dercos  Serum 10 is the one I've used the most it
  • 00:13:29
    has piroctone olamine as well as a bunch of  antioxidants and centella which is soothing
  • 00:13:33
    I also really like this nozzle which makes it  super easy to apply and it doesn't leave any
  • 00:13:38
    sort of stickiness or weighing down after  it dries I can't tell I've used anything
  • 00:13:43
    there are tons of scalp products with antioxidants
  • 00:13:45
    just make sure they don't have oils  in them if microbes are an issue
  • 00:13:48
    your tap water can be a big issue in some places
  • 00:13:51
    especially hard water this is when  there's metal ions dissolved in the
  • 00:13:55
    water and you might be able to see chalky  water stains and buildup around your taps
  • 00:13:59
    hard water can be really irritating it  can make your hair feel like there's a
  • 00:14:03
    film on it some metal ions  can also speed up oxidation
  • 00:14:07
    the best solution is a whole house  water softening system but there
  • 00:14:10
    are also inline softeners you  can get just for your shower
  • 00:14:13
    filters usually get rid of  chlorine but not hard water
  • 00:14:17
    ions so make sure you check what  exactly the product is going to do
  • 00:14:20
    there are some products you  really want to be careful
  • 00:14:22
    with if microbes are part of your  problem and the main thing is oils
  • 00:14:27
    most oils aren't actually that good  at sealing in water malassezia feed
  • 00:14:31
    on oils and makes them grow faster and they  turn it into those irritating substances so
  • 00:14:36
    I would recommend avoiding plant oils  in any sort of leave-on scalp products
  • 00:14:41
    some people do find oils helpful but I think  it's mostly the massaging massaging anything
  • 00:14:46
    can help get residue off the scalp especially  for people who use a lot of product and don't
  • 00:14:51
    wash their hair that often if you're in this  category and you think you might have this
  • 00:14:55
    microbe problem maybe try massaging a serum that  has anti-dandruff ingredients instead of an oil
  • 00:15:01
    dry shampoo this can be helpful  for soaking up oil and removing
  • 00:15:05
    some of those irritants but it can't  really replace actual shampoo a lot of
  • 00:15:10
    people who are using dry shampoo should  really just be washing their hair more
  • 00:15:14
    spraying a dry shampoo too close to your  scalp can also be drying and irritating
  • 00:15:19
    scalp scrubs and brushes this is really personal  preference but I personally don't find them very
  • 00:15:25
    helpful for my hair type and routine I find  it pretty hard to get the scrub through my
  • 00:15:29
    hair I feel like it's mostly just scrubbing  my hair which is damage I don't really need
  • 00:15:34
    I don't mind brushes but I have nails  and that just works much better for me
  • 00:15:39
    chemical exfoliants is similar it might be  helpful if you have a lot of buildup but I
  • 00:15:43
    wash my hair almost every day and I don't use much  product so that just hasn't made much difference
  • 00:15:49
    if you've thought about trying rosemary oil I
  • 00:15:51
    would recommend against it  this video has more on why
  • 00:15:55
    if you're wondering about dry hair I have a video
  • 00:15:57
    all about hair and hydration my  hair science playlist is here
  • 00:16:01
    let me know what else you're wondering  about see you in the next video
Tags
  • itchy scalp
  • malassezia
  • dandruff
  • scalp care
  • cosmetic science
  • allergens
  • dry scalp
  • hair health
  • shampoo
  • scalp products