Our Skin Has A Horny Layer
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Hello hello!
I can’t believe I’m saying this but we’re officially in the one month countdown to my wedding, which means this is the last issue I’m writing before I’m a married woman! Of course, I’m not leaving you hanging. I have some amazing guest posts lined up for you over the next few weeks, written by Hotline Skin community members and fellow skin experts. The first one will be in your inboxes next week and I know you’re going to love it.
Other housekeeping notes:
For paid subscribers, I will still be holding weekly Office Hours for the next few weeks. There will not be Office Hours Labor Day Weekend or the following weekend.
Congrats to Kellee for winning the Daise giveaway last week! If you entered the Instagram giveaway yesterday, the winner will be notified tomorrow via DM.
My appointment schedule at Practise post-wedding is already pretty full, but I intend to add a few more days through the end of October. Add yourself to the waitlist (which will also help me figure out the best days to open up.)
Get your CO2 Lift Mask orders ASAP if you want to get them before I’m off. Info at the end of this issue.
Now the most important thing: ASK ME MORE QUESTIONS! Let’s build a stockpile while I’m out! Give me options! Tell me what you want to know! The more the merrier! I can’t promise every question will get answered in a future issue, but there’s no chance if you don’t ask… I made it even easier than ever before, just click:
Face Skin vs. Body Skin: Part 3
I got tons of great feedback about last week’s issue and I’m so happy to hear that the visuals were helpful and I didn’t waste hours of my life drawing lines on Canva. Now that we have a basic understanding of what the skin structure looks like, it’s time to finally get to the bottom of the differences between face & body skin. If you didn’t get a chance to read last week’s, check it out before reading today’s.
Let’s set the scene: skin is composed of 3 layers, the epidermis (what we see), the dermis (where blood vessels, hair follicles, sebaceous glands, sweat glands, collagen and elastin live/are produced) and the hypodermis or subcutaneous layer (fat). Within these layers are more layers — the epidermis actually has 5 layers and within some, you guessed it, even more layers. There’s a lot here, so I bolded key points.
EPIDERMIS
The thickness of the stratum corneum varies on different parts of the body, ranging from 10-30 layers of hardened dead skin cells, known as corneocytes. Overall, the stratum corneum is much thinner on the face than on the body. Fun fact: the stratum corneum is sometimes called the “horny layer” because the cells are tougher than others, like an animal’s horn.
The stratum corneum is thinnest on the eyelids (~0.01mm thick) and thickest on the palms and soles of the feet (~1.5mm thick). There are about 4-8 layers of corneocytes in the face, compared to about 11-17 on the body. The cells themselves are smaller on the face than the body.
The process of keratinocytes traveling up to the surface, becoming corneocytes and replacing dead cells on the surface is called cell turnover. The full cell turnover cycle, starting from the cell being created in the basal layer to it being sloughed off on the skin surface, takes about 28-30 days and slows down with age. Remember that there are more stratum corneum layers to replace on the body and the cell turnover process takes about twice as long compared to facial skin. This means that body skin is not just thicker in the stratum corneum, but older, drier, duller and at times, flakier. This is why body skin can generally handle more aggressive exfoliation, as there are more, larger and tougher, layers to remove. It’s also why you might have dry skin on your body, even if you don’t on your face.
Palms & Soles
The stratum corneum is thicker on the palms and soles of feet, which need extra protection and padding due to the increased friction and pressure they are exposed to. But that’s not the only difference and I lied a little bit last week when I said that there are 5 layers in the epidermis. This is true for the palms and soles, but most other skin actually only has 4 layers. The additional layer, called the stratum lucidum, is located right below the stratum corneum and only present in thick skin, like palms and soles. It’s a thin, translucent layer of flat, dead skin cells. The clear cells allow light to pass through, which is why the skin color is slightly different in these areas. This extra layer adds additional protection and grip, but excessive friction and pressure can thicken the epidermis further, resulting in things like calluses and corns.
DERMIS
In general, the dermis is thicker than the epidermis, but just like the epidermis, the dermis is thinnest on the face. It is the thinnest on the eyelids, eye area and neck.
I mentioned last week that the dermis is where most of the action is happening. Sure, the epidermis is poppin’, but that wouldn’t be possible without the dermis. The dermis houses our blood vessels and provides nourishment to the epidermis. While most of the cells in the epidermis are dead, and don’t need blood flow, the stratum basale, the innermost layer, is connected to the dermis. It’s the reason new cells are able to be created there!
There are more blood vessels in facial skin compared to body skin. In addition to providing nutrients, blood vessels are important for temperature regulation. Blood vessels expand in hot temperatures to release heat near the surface of the skin. It’s why your face gets flushed. Your face needs more blood vessels because a lot of very important things are there that need oxygen and nutrients, like your brain, sensory organs and structures. More blood means faster wound healing, which is necessary for the aforementioned body parts.
The dermis is also where hair follicles and sebaceous glands are located. Something you may or may not know: what we call pores are actually hair follicles! Sebaceous glands, which produce oil called sebum, are attached to hair follicles in the dermis. Sebum travels up to the surface via the follicle lining, where it’s necessary for waterproofing, lubricating and providing antibacterial protection to the skin. It’s the hair follicle that gets clogged with oil and dead skin, resulting in acne and congested skin. Hair follicles start in the dermis (where they require blood and nutrients to grow hair) and extend through the epidermis, up to the surface. Facial skin has a higher concentration of sebaceous glands and smaller pores compared to body skin, which has a smaller concentration of sebaceous glands but larger pores. The back has the largest sebaceous glands on the body.
Sweat glands are also located in the dermis. There are two types of sweat glands: apocrine and eccrine. Eccrine glands are considered cooling glands, regulating body temperature by releasing water on the surface of the skin, where it evaporates. This type of sweat doesn’t smell. Apocrine glands are a specialized sweat gland that releases a thicker type of sweat that’s responsible for body odor. Eccrine glands are located all over the body, including the face. Apocrine glands are only found in the armpits and pubic region.
Palms and Soles
Just like in the epidermis, the dermis of our palms and soles operate a bit differently. They’re the only places on the body that do not have hair follicles or sebaceous glands, meaning there is no hair and no oil is produced there. These areas have the highest concentration of eccrine sweat glands, aka they get sweaty!
HYPODERMIS/SUBCUTANEOUS TISSUE
The subcutaneous layer is primarily composed of fat, or adipose tissue. The thickness of this layer, and size of the fat-storage cells, has the most variability over our lifetime due to genetic, environmental and lifestyle factors, like diet and exercise. It also depends on your sex (remember, child-bearing hips!) It’s generally the thickest in areas that need the most padding and/or fat storage, so the thighs, hips, butt, and abdomen. Fat is also stored in the upper arms, where this layer may be thicker.
Cellulite occurs when fat cells in this layer enter the dermis. (There’s more to the process, but that’s the gist). It doesn’t have to do with weight and is more common in women because of the positioning of certain things in the hypodermis and dermis.
Overall, the subcutaneous layer is much thinner on the face than the body, which is why we are able to see bone structure there! It’s the thickest on the cheeks.
What This Means for Skin Conditions & Treatments
Body skin, overall and in each layer, is thicker than on the face. However, there is more activity happening within these layers on the face than on the body. On the face, skin cells are younger, the turnover cycle is faster, there are more sebaceous glands and more blood vessels.
ACNE:
For there to be acne, there needs to be dead skin cells and oil (there’s other stuff too, but that’s for another day). We have the most sebaceous glands in the face and cell turnover is faster, meaning there are more skin cells being produced that have the potential to clog.
The body has fewer sebaceous glands, but larger hair follicles, so you’re less likely to get acne overall, but the acne you do get is larger and more inflamed. The back has the most sebaceous glands on the body, which is why bacne is more prevalent (and painful).
There are no sebaceous glands on the palms of your hands or soles of the feet, so you can’t get acne there.
EXFOLIATION:
The epidermis on the body is thicker and more easily able to tolerate aggressive products, like strong exfoliants, because there are more layers of dead skin cells.
Facial skin is thinner and more fragile so you need to be more careful with exfoliating.
Keratosis pilaris (chicken skin) is not acne, but can sometimes be confused with it due to its appearance of small, rough bumps. It’s due to a buildup of keratin in the hair follicle and often genetic. In children it can appear on the face, but in adults it is primarily on body skin, especially the arms. It can be really stubborn, but you can use stronger exfoliants to slough off the dead skin and thicker moisturizers (especially with urea or lactic acid) to soften the skin while also hydrating.
DRYNESS:
More dead skin cells (and fewer sebaceous glands) means the body is more prone to dryness, and scaly skin. The body can generally handle thicker moisturizers and creams without feeling as heavy or clogging.
SIGNS OF AGING:
The dermis, which houses our collagen and elastin (the scaffolding of our skin) is thinner on the face than the body. As we age and this support structure becomes weaker, it’s easier to develop wrinkles and more prone to sagging.
Because our face is also getting significantly more UV exposure than the rest of our body, this aging process is accelerated even more. This is why we wear sunscreen 365 days a year, even on cloudy days!
Since the dermis is thinnest on the eyelids, eye area and neck, we tend to notice the signs of aging in these areas first.
HYPERPIGMENTATION:
It would be way too much to get into specifics here, but the causes of hyperpigmentation on the face and body are generally the same, mainly inflammation and sun damage. Since the epidermis is thicker on the body, it can often be much harder to fade hyperpigmentation than on the face (this is not to say it’s easy on the face!) But at the same time, the body can generally handle more aggressive products for this. On the flip side, the face is exposed to more UV, so that risk factor is much greater. Friction also exacerbates hyperpigmentation, which is why armpits tend to be darker.
Favorite Body Products
No particular order. Anything with * has a discount code below.
LILIS Instant Peel * (talked all about LILIS in Part 1)
Hanni Water Balm Moisturizer Mist * (lazy girls lotion)
Clarins Tonic Body Treatment Oil (I have many clients who like this for cellulite/firming)
Naturium Energizer Mandelic Acid Body Wash * (Cooling, odor reducing)
FOR HAND SPECIFIC RECS:
Office Hours Reminder
Join us for Office Hours on Sunday! This exclusive weekly opportunity is available to paying subscribers.
Every Sunday at 5pm EST, I’ll begin a new thread for the week in Substack Chat, where you can ask me anything. Every Monday from 5-6pm EST, I’ll be in that chat live, answering questions for the hour. That way, if you can’t make it, you can submit any time after 5pm Sunday and still get an answer. If you can make it live, join in! You can ask questions in real time and (hopefully) interact with others in class ;)
Discount Codes
Bioeffect: JOLIE for 15% off (works on most of Dermstore)
Kate McLeod: JOLIE15 for 15% off
LILIS: JOLDEF for 15% off
Naturium: JOLIE for 15% off
TOK Beauty: JOLDEF for 15% off
you can find all of my discount codes here
THANK YOU FOR READING! THANK YOU FOR BEING HERE! I LOVE YOU! Have a great time without me! But not too great!
xx,
Jolie
CO2 Lift Mask Info
CO2 Lift Mask is a carboxytherapy gel mask. Originally used only in medical settings post-procedure, it’s basically like a hyperbaric chamber for your face. When you mix the two packets together, it releases Carbon Dioxide, oxygenating the skin, increasing blood flow, hydration, lifting and more. It’s incredibly healing and reparative, reducing downtime and clinically proven to increase hydration by 117% after 1 use. Doing a series of 3 or 6 is best for healing and improvement in elasticity though. The mask stays on for 45 minutes and is then peeled off. You have the option to have it applied in treatment or take it home with instructions to apply yourself post-facial. I offer it in my facial pop-ups.
I love these masks always, but they’re pricey so I save them for after facial treatments or before big events. I did a series a few weeks ago and will do another 3 the week of my wedding. It’s a mask but thinking of it more like a treatment helps justify the $100 price tag. If you’re interested in purchasing or want more info, email hi@joldef.com. I can give you a discount on 3+.