Glycation is one of the basic root causes of endogeneous (intrinsic) skin ageing and a very challenging one or almost impossible one to reverse. Glycation is an ageing reaction which begins in early life, developing clinical symptoms at around 30, and progressively accumulates in tissues and skin due to the glycated collagens that are difficult to be decomposed. Glycation occurs naturally in the body when sugars react with proteins and lipids to form advanced glycation end products (AGEs). AGEs can be exogenously ingested (through food consumption), inhaled via tobacco or endogenously produced and formed both intracellularly and extracellularly. AGE modifications lead to dermal stiffening, diminished contractile capacity of dermal fibroblasts, lack of elasticity in the connective tissues, contribute to hyperpigmentation and a yellowish skin appearance. The formation of AGEs is amplified through exogenous factors, e.g., ultraviolet radiation. 

AGEs cause changes in the skin through 3 processes:

1. AGEs interact with specific cell receptors, altering the levels of soluble signaling molecules, such as cytokines, hormones, and free radicals.
2. In the process of non-enzymatic glycation reaction, a large number of reactive oxygen radicals are released, creating a state of oxidative stress, leading to a significantly reduced level of glutathione, Vitamin C, and Vitamin E in the body. This causes synthetic disorders of collagen in skin tissues. 
3. AGEs alter the physical and biological properties of the original extracellular matrix proteins, such as collagen. 

Many cells have AGEs receptors on the surface, such as macrophages, mesangial cells, fibroblasts, and endothelial cells, through which their function can be affected. They induce oxidative stress and trigger inflammatory pathways by forming crosslinks, altering protein structure, or by binding to AGEs receptors. AGEs cause cellular dysfunction through the modification of intracellular molecules and accumulate in tissues with ageing. This causes the skin and connective tissue to harden and lose their ability to regenerate healthy cells. They cause damage to extracellular proteins like collagen and elastin fibers, which are crucial for maintaining skin structure and firmness. This damage leads to the breakdown of these fibers. AGEs can also affect intracellular proteins like vimentin. AGEs can act as a catalytic site for free radical formation, exacerbate intracellular oxidative stress, and increase ROS production through a variety of mechanisms, reducing glutathione (skin's own anti-oxidant) storage, and activation of protein kinase C, etc., to accelerate the production and accumulation of AGEs. 

One study published in the Journal of Investigative Dermatology found that levels of AGEs were higher in the skin of older individuals compared to younger ones. The study also showed that there was a correlation between the level of AGEs and the severity of skin ageing. This suggests that inhibiting the production or accumulation of AGEs in the skin is a potential target for anti-ageing interventions or skin ageing management.

AGEs are complex and heterogeneous, more than a dozen AGEs have been detected (however not all) in tissues and can be divided into three categories according to their biochemical properties. 
​AGEs are formed through four pathways:

1. the Maillard reaction (non enzymatic reaction between amino groups of proteins and reducing sugars, binding sugars to proteins)
2. sugars auto-oxidation pathway (metal-catalyzed auto-oxidation of glucose or Wolff pathway) 
3. lipid peroxidation pathway (acetyl alcohol pathway)
4. polyols pathway (glucose is converted into fructose via the polyol pathway, which accelerates the production of AGEs)

GLYCATION INHIBITION IS KEY 
AGEs can be crosslinked through side chains to form a substance of very high molecular weight, which is not easily degraded. The consequences from skin glycation are irreversible. This makes prevention or inhibition of the process the best potential strategy to maintain skin health and ageing skin management. One way to do this is by altering the diet to reduce the intake of sugars and carbohydrates, which are known to contribute to glycation. Several studies have found that reducing sugar intake can result in significant improvements in skin health, including reducing wrinkles and improving skin texture. 

AGE inhibitors
Another potential strategy is the use of topical agents that inhibit the formation or accumulation of AGEs in the skin. One study published in the Journal of Cosmetic Science found that a cream containing carnosine, a peptide that inhibits glycation, improved skin elasticity and reduced the appearance of wrinkles in individuals with ageing skin. Skincare containing NAHP or Acetyl Hydroxyproline inhibits the formation of AGEs significantly (in vitro), most likely through a mechanism where NAHP competes with the proteins for the sugar. Finally, NAHP sacrifices itself in place of the proteins and gets (at least partially) glycated. NAHP also prevents loss of cellular contractile forces in a glycated in vitro dermis model and counteracts the diminished cell-matrix interaction that is caused by glyoxal-induced AGE formation.

​Anti-Oxidants
Moreover, I would suggest to combine those ingredients with an ingredient like Licochalcone A. Numerous high ranked publications support that Licochalcone A protects cells from oxidative stress mediated by e.g. UV and HEVIS (blue light) induced reactive oxidative species (ROS). Due to the activation and nuclear translocation of the transcription factor NrF2, the expression of anti-inflammatory, antioxidant and detoxifying enzymes are induced. These enzymes protect the skin cells (like keratinocytes and fibroblasts) from ROS-induced damage, like lipid peroxidation and DNA as well as protein damage. If Licochalcone A is combined with L-Ascorbic Acid, (the most active form of Vitamin C), it supporting skin's own collagen production, provides superior biological cell protection amongst other relevant benefits. My absolute favourite product is Eucerin Hyaluron-Filler Vitamin C Booster which I use daily as a serum in my morning routine.

GLYCATION AND SKIN HEALTH

Acne
In addition to its role in ageing, glycation in the skin has also been linked to a range of skin health problems. One study published in the Journal of Cosmetic Dermatology found that the level of AGEs in the skin was significantly higher in individuals with acne than in those without acne. The study also showed that treating acne with a topical antibiotic significantly reduced the levels of AGEs in the skin.

Atopic Dermatitis
Another study published in the Journal of Investigative Dermatology found that individuals with atopic dermatitis had higher levels of AGEs in their skin than healthy individuals. This suggests that glycation may play a role in the development of inflammatory skin conditions.

Diabetes + Woundhealing
The correlation between high sugar levels and skin ageing can be seen in diabetic patients, where one-third of this population has skin complications. A prominent feature of ageing human skin is the fragmentation of collagen fibers, which severely damages the structural integrity and mechanical properties of the skin. Elevated levels of MMP-1 and MMP-2 and higher crosslinked collagen in the dermis of diabetic skin lead to the accumulation of fragmented and crosslinked collagen, thereby impairing the structural integrity and mechanical properties of dermal collagen in diabetes. Collagen crosslinking makes it impossible for them to easily repair, resulting in reduced skin elasticity and wrinkles. Keratinocytes and fibroblasts are the main cells involved in wound healing, but due to the high glucose (HG) microenvironment in diabetics, the functional state of these cells is impaired, thereby accelerating cellular senescence (programmed cell death).

Conclusion
We can't completely stop the glycation process, therefore it's important that we inhibit it from a young age onwards, hence monitor the sugar intake of our children, use daily SPF and invest in good dermo-cosmetic products containing ingredients like NAHP and powerful anti-oxidants like L-Ascorbid Acid (Vitamin C is needed for the production of collagen) and Licochalcone A (also anti-inflammatory). Preventing signs of ageing, specifically caused by glycation is most effective. If your skin shows (advanced) signs of ageing, you can get visible improvement using skin component (hyaluron, collagen and elastin) bio-stimulating ingredients like Retinol, Bakuchiol, Arctiin, Creatine or Glycine Saponin. Consult your dermatologist if you wish to improve your skin's appearance or skin health issues.

Take care

Special thanks: Ph.D. dr Julia M. Weise Manager Biological Testing & Dorothea Schweiger Lab Manager Facial Skin Biology Beiersdorf HQ Hamburg

We can support's skin natural exfoliation process in various ways, for example with mechanical or chemical exfoliation. 

Desquamation (shedding of skin cells thus exfoliation) is an important part of the skin's natural regeneration or renewal process.

Already in our twenties, this process slightly, however increasingly starts to slow down (Kligman 1983). As a result, the cells on the surface of our skin (corneocytes) become bigger (Kligman 1989) and a little disorganised. This leads to a duller appearance (loss of radiance) and a more rough texture of our skin.

A very comprehensive comparison of both methods:

The word "acid" unfortunately sounds very harsh and skin-unfriendly. Many acids are actually skin's own, like for example lactic acid is a skin's own natural moisturising factor (NMF) and so is hyaluronic acid. The level of NMF's decrease as we age and our skin my lose the ability to maintain well hydrated. Many years ago the benefits of lactic acid were capitalised by using baths filled with donkey milk. Citric acid is commonly used in skin care products and toners to balance skin's pH. Gluconolactone is only gradually penetrates skin and is very gentle. 

It's unfortunate that "acids" have such a negative connotation, as our skin (healthy and problematic) can benefit if we use them regularly. Moreover, I prefer this method over mechanical exfoliation for all skin types, however particularly if you have dry skin, acne- or redness prone skin, sensitive skin or mature skin. 

The risk of exfoliation is over-exfoliation. Over-exfoliation is damage of our skin barrier and the symptoms are very comparable to dry or (hyper) sensitive skin symptoms, which are: redness, irritation, tightness, excessive dryness, dry patches, flaking skin, uncomfortable stinging, or even burning sensation. Whenever you experience one or more symptoms of over-exfoliation, it's recommended to reduce the number of times you exfoliate and support the skin barrier repair with a moisturiser.

Hope you enjoy healthy skin & take care.

Understandably we want to get rid of pimples as soon as possible and sometimes apply harsh products to our skin in order to shrink them.

Depending on which ingredient is used, you might inflict injury to the skin and it's barrier which is very comparable to a mild burn. There is even a phenomenon called "toothpaste burn". During the healing process there is a risk of scarring. A study published by Tan J. et al in JJD 2017 shows that up to >87% of patients with mild to moderate acne reports atrophic scarring (sunken scar) to some degree.

​A healthy skin barrier and well hydrated skin will support a the healing process. However, as the barrier is impaired and the skin dried out, the skin's regeneration and healing process will take longer.

Therefore be careful with "shrinking" pimples. The same applies for "popping" pimples, as this method by definition will cause injury to the skin. Picking and squeezing pimples will further irritate the skin tissue and delay proper healing. The risk of scarring is increased when the tissue is inflamed. A recent study of prevalence and risk factors of acne scarring confirmed that there is a relationship between the time between onset and effective treatment. Acne scars can be more difficult to treat than acne! It's better to seek expert advice if you have problematic skin. 

Take care.

A high pH value contributes to premature ageing skin!

A study published in British Journal of Dermatology showed that women with an alkaline stratum corneum (outer layer of the skin) developed more fine lines and crow's-feet (wrinkles at the outside corner of the eyes) than those with acidic skin over an eight-year period.

This might be in part because an alkaline epidermis (top layer of the skin) tends to be drier and more fragile than an acidic one. Irritants can enter the skin  and water can evaporate more easily. People with hydrated skin showed a 50% lower rate of wrinkling than those with dry skin. If the acid mantle is not intact, it can make skin more susceptible to inflammation (inflammaging) and lowered enzymatic activity, which again increases the risk of development of signs of ageing. Last but not least, alkaline skin is more prone to sun damage thus photo-aging, because its protective barrier has been weakened.

pH balance is fragile. I just mentioned that alkaline skin tends to be drier, however it’s also known that the oils secreted by our skin impact skin’s pH by increasing it. This is one of the reasons that oily skin types can be more prone to acne, as the skin’s pH influences it's microflora. That's a topic for another blog post.

You’ve maybe seen some of my previous posts on skin’s pH and it’s actually one of my major topics. This is because healthy skin starts with an optimal pH balance. Click below in the featured categories on “Skin pH” if you like to learn more about pH. If there is a specific topic you are interested in missing, please place a comment below and I will see to it that I address it.
 
Take care.

Recently I've read an article in which facial toners were called a redundant step in the cleansing routine. They would not serve any purpose anymore and would be “old-fashioned". I disagree, and will explain why.

Particularly when you prefer wet facial cleansing (water has a pH of 7-8), your skin’s pH goes up and you may consider using a toner to bring it back to normal (~5) before using a moisturizer or serum. This also applies if you use an alkaline cleanser or micellar water. It is common that products which are suitable to be used around the eyes, like micellar water, are adapted to a more “eye-friendly” and less “skin friendly” pH of ~7. Skin prefers a pH of ~5.

In my humble opinion, toners are a very important step in every a.m. and p.m. skin care regimen for both healthy and particularly problematic skin  types. They refresh, remove left-over debris and make-up and moreover instantly rebalance skin’s pH value. A balanced pH value is the cornerstone for healthy skin. An optimal pH supports skin's microbiome (microflora or "ecosystem") and barrier function. Furthermore, the use of a toner usually helps the penetration and thus efficacy of your care product!  

Alternatively, you can use “chemical” exfoliating lotions or pads which contain AHA (glycol, citric and lactic acid), BHA (salicylic acid), PHA (gluconotactone), etcetera. Just be careful using them around the eyes or even avoid this area.

Hope you enjoy healthy skin & take care.