Read on Twitter
i wanna be productive so let's talk about skincare again. after covering the basics about cleansers & toners, time to talk about moisturisers 
disclaimers 
part i • https://twitter.com/dunwhalers/status/1247175749162766336?s=20
part ii • https://twitter.com/dunwhalers/status/1247175751486435328?s=20
part i • https://twitter.com/dunwhalers/status/1247175749162766336?s=20
part ii • https://twitter.com/dunwhalers/status/1247175751486435328?s=20
basic skincare talk • part iii: moisturisers things i will talk about include:
• what is a moisturiser
• what it does & who needs it
• types of moisturiser
• moisturiser cheats/hacks or whatever you wanna call it
• products recommendation
what is a moisturiser? a concoction of prepared ingredients, a moisturiser is used to (obviously) moisturise, hydrate, protect and lubricate the skin. contrary to popular and old school beliefs, moisturiser is for EVERYONE regardless your skin type.
old school skincare practices like to think that since moisturiser is meant to lubricate, it is only purposeful for people with dry skin. however, this is FALSE. the key here isn't "let's stop moisturising" but rather "let's find the RIGHT moisturiser for my skin type."
what it does first off, let's get a little science and understand the 3 layers that form our skin:
1. hypodermis
2. dermis
3. epidermis (where our stratum corneum, aka the skin barrier lies)
• hypodermis: consists of layers of fat, blood vessels and nerves
• dermis: sebaceous glands responsible in sebum production
• epidermis: the topmost layer of our skin responsible for protection. it's also where our stratum corneum (aka skin barrier) lies.
• dermis: sebaceous glands responsible in sebum production
• epidermis: the topmost layer of our skin responsible for protection. it's also where our stratum corneum (aka skin barrier) lies.
moisturiser is used to lock water from escaping your skin thus preventing unwanted trans-epidermal water loss, abbreviated as TEWL or TWL through the epidermis. similarly, it's also easy for TWEL to happen due to external irritants/factors.
the reason why i constantly stress the importance of GENTLE cleansers is that like changes in temperature, exposure to irritants (e.g SLES/SLS in your cleanser) will upset your skin's natural balance, removing the lipids therefore causing major increase in TEWL.
for dry skin people, it's self-explanatory that you guys will want moisturisers to prevent TWEL. but for combo/oily skin, not locking that hydration in may lead to a condition called DEHYDRATED skin, leading to damaged stratum corneum (aka more oil, more acne, more irritation)
do take note that it's also possible for dry skin to be dehydrated because it is not a skin type but merely a temporary skin condition. if you already have dry skin and it's dehydrated, your skin will lose the ability to stretch, may consequently craks or even peels.
who needs a moisturiser? EVERYONE
i've seen some people say that they can go on just fine without moisturisers and while they may be referring to products labelled as 'moisturiser', moisturising your skin is more mutable than you think – more on this later.
whatever products you use to moisturise (aka lock in that hydration) your face, you NEED TO MOISTURISE it can be a hydrating serum, an emulsion – whatever, as long as it's something to lock in that hydration.
and this brings us to the next category
TO MOISTURISE it can be a hydrating serum, an emulsion – whatever, as long as it's something to lock in that hydration.and this brings us to the next category
types of moisturisers there are 3 (+1) types of face moisturisers:
humectants emollients occlusives ceramides (+1)
humectants, the absorbers (1/2)
how it works: draw moisture and water from the air to hydrate the skin & increase water content
best for: combination to oily skin, acne-prone; dry skin may benefit from this if you live in a very humid country
humectants (2/2)
key ingredients: glycerin/glycerol, hyaluronic acid/ sodium hyaluronate, urea, AHA, panthenol, sodium lactate, sodium PCA, sorbitol, honey, etcfurther reading on humectants
https://kravebeauty.com/blogs/news/ingredient-series-hello-humectants
emollients (1/2) how it works: fills in the gaps between your skin that are lacking in lipids, soften the skin and may provide occlusive properties best for: extremely dry, dehydrated and mature skin! others proceed with caution 
emollients, the space fillers (2/2) key ingredients: natural plant oils (e.g grapeseed, rosehip, etc), fatty acids, stearic acid, esters (organic acid + alcohol), lanolin, silicone (e.g dimethicone / anything that ends with -cone in its name)
occlusives, the sealers (1/2) how it works: trap moisture in the skin by creating a physical barrier hence why they're generally very thick, heavy and rich in texture best for: mature, dehydrated skin in an environment void of humidity and body moisturisers as well
occlusives, the sealers (2/2) key ingredients: petrolatum, emulsifying wax, stearic acid, paraffin, lanolin, mineral oils, certain natural plant oils, shea butter, cocoa butter, etc*thick occlusive creams are also recommended for super dry, itchy and eczema skin
things to note 
some emollient ingredients are also considered occlusives – for e.g silicones. while it may be difficult to differentiate between the two, however, if you've tried many moisturisers & skincare products in general, you'll spot the difference over time
in the end, even though i classified humectants, emollients and occlusives based on their recommended skin types, everything comes down to the final formulation of a product. besides, in today's world, moisturisers can be a mixture of humectant AND occlusive so 
+1 ceramides (1/2)the reason i decided to dedicate a space solely for ceramide is because:
1. ceramide is naturally present in our skin
2. ceramide is perhaps the star ingredient you'd want to look for or focus on if you have compromised skin barrier
how it works: ceramides are lipids to repair your skin barrier and help retain skin moisture. it's essentially the skin glue, if you will. when you have damaged skin barrier, this means you're lacking in the proper ratio of ceramide best for: skin with damaged skin barrier
ceramide-based moisturisers may be formulated with other occlusives, emollients or humectants to form a ceramide emulsion or cream because it's essentially an ingredient and not really a moisturiser 'type' HOWEVER the purpose that it serves is a little different, i'd say
moisturiser hacks (?)remember when i said some people believe that they don't need moisturiser? yeah, chances are they're still moisturising/hydrating their skin ONLY with a different product aka one that isn't labelled/sold as a moisturiser
serums and/or oilsi'm a fan of serums but usually for targeted treatments like dullness, oil control, etc. some people, however, use hydrating serums (like a hyaluronic acid + vit B5 serum!) or oils like avocado oils*
*be careful if you have combo/oily skin though!
hydrating sunscreen yes it exists! some SPFs are more lightweight & fast absorbing because they're usually targeted for people with oily, acne-prone skin. HOWEVER, hydrating SPFs do exist and some people think they can skip moisturiser if they have this at hand.
sheet masksthey're generally loaded with essences and are known to be very hydrating. i consider sheet masks as single-use disposable hydrators that i don't really like purchasing on daily basis due to unsustainable budget but hey, you do you boo!
that said, although there are people who swear by serums and/or oils to hydrate and moisturise, i personally do not enjoy them. if you have dry skin, serums alone are definitely not gonna suffice so either lock that moisture with face oil or an occlusive/emollient moisturiser
"so, do I need a moisturiser?" 
short answer: YES. you need to MOISTURISE or HYDRATE your skin to AVOID WATER LOSS but HOW you do it (with what product) is all according to what your skin likes. this thread is only to guide you, not tell you what to do.
if you have combination, oily and acne-prone skin and you hear people say that you don't need a moisturiser, it's probably because that person hasn't discovered a hydrator/moisturiser that's fitting for their skin typelike i said before, they key is to find the RIGHT product
in the end, your skin is YOURS to listen to and it doesn't matter if 1739479 aestheticians or dermatologists tell you otherwise because believe it or not, sometimes all they want is to treat you with meds so you'll pay them shit
ADDITIONAL NOTE: Hydrating vs Moisturising 
hydrating: focuses on water content in your skin, absorbs moisture from air. best for combination-oily skin moisturising: traps & locks moisture in to build skin's protective barrier. best for dry skin because you need oils
