Zinc, everything you need to know about this active ingredient.

Zinc is a essential micronutrient, present in small amounts in the human body, less than 50 mg/kg. It is vital to the body's health due to its critical roles in growth and development, bone metabolism, the central nervous system, immune function, and wound healing, which is the focus of this article.

Zinc is a vital cofactor for the function of over 10% of proteins encoded by the human genome, which represents no less than 3000 proteins and enzymes ! Zinc-dependent proteins play numerous indispensable roles within cells, such as transcriptional regulation, DNA repair, cell death, metabolic processing, regulation of the extracellular matrix (ECM), and antioxidant defense.

Zinc is particularly important for the skin. The skin contains a relatively high zinc content (about 5% of the body content), mainly associated within the epidermis (50-70 μg/g of dry weight). Due to its abundance in the epidermis, it is observed that a zinc deficiency results in rough skin and an impaired barrier function. The skin becomes increasingly dry. In addition, an alteration in wound healing is also correlated with this dietary deficiency.

Zinc is a mineral that is particularly prevalent in skin and hair care products. Its concentration is restricted in Europe according to cosmetic regulations to 1% zinc in the final product. Zinc is present in more than thirty cosmetic ingredients, some of which are more controversial than others, and have diverse actions (antimicrobial, surfactant, foaming agent, pH regulator...). Among the most common zinc-based compounds, we can mention zinc oxide, zinc PCA, zinc lactate, and zinc gluconate.

What are the benefits of zinc for the skin?

When applied topically, zinc is a comprehensive anti-acne agent. This trace element possesses anti-inflammatory, antibacterial, and healing properties that are highly beneficial for acne. Indeed, it inhibits the growth of the bacteria responsible for acne, Propionobacterium Acnes, which is the primary bacteria implicated in this skin condition. Moreover, zinc reduces the activity of the sebaceous glands due to its anti-androgenic activity. Thus, it helps regulate sebum production and thereby prevents blemishes.

What are the benefits of zinc for hair?

Zinc and its derivatives are primarily recommended for the health of the scalp, which directly influences the condition of the hair. Two main actions are associated with the external application of zinc in topical use.

• Combating dandruff.

  Zinc possessespurifying andantibacterial properties. It helps regulate sebum production, thus preventing the excess that leads to oily and imbalanced scalps. Consequently, it helps limit the occurrence of oily dandruff, and is therefore found in many hair care products targeting this issue.

  It should be noted that it is primarily the zinc pyrithione (INCI: ZINC PYRITHIONE) that was found a few years ago in the main anti-dandruff hair treatments. However, this active ingredient is now highly controversial ( suspected mutagen, potential reproductive toxicant, potential aquatic ecotoxicity) and most importantly banned in Europe (Annex II/1670 of the cosmetic regulation). Instead, zinc-PCA or zinc gluconate are used, which are much gentler and pose no risks to health and the environment.

• Limiting itchiness.

  Zinc possesses soothing properties. It acts as a regulator of interleukin 1-alpha, a mediator of inflammation. Thus, it alleviates scalp discomforts such as itching, tingling, tightness, and other unpleasant sensations.

What are the benefits of zinc for nails?

Zinc has the unique property of strengthening nails, as it aids in the synthesis of keratin, the primary protein that makes up nails. Beyond strength and growth, zinc gives your nails a well-groomed appearance. A treatment containing a sufficient amount of zinc is applied directly to the nails. Circular massages help the treatment penetrate. A course of a few weeks can restore a beautiful appearance to your nails.

Notably, due to its antimicrobial action, we also find zinc-based ingredients in toothpastes (anti-plaque properties) as well as in deodorants and antiperspirants.

Zinc oxide is primarily aUV-protective filter. It is used in sunscreens, acting as a shield on the skin's surface. Indeed, it iseffective in blocking and deflecting UVA and UVB rays, thus protecting the skin from the harmful effects of the sun.

Beware, in some products, it may be of nanometric size. The health risks are as follows: psuspected percutaneous penetration, suspected reproductive toxicity, suspected genotoxicity, suspected carcinogenicity. Moreover, regarding the environment, there is also suspected aquatic ecotoxicity. Despite this, this UV filter remains bio-compatible according to the COSMOS standard.

At Typology, we apply the precautionary principle and exclude nanoparticles from our formulas. Oursunscreenface SPF30 with aloe vera contains non-nanometric zinc oxide.

However, it is important to clarify that whether zinc oxide is nano or not, exposure to high concentrations of this mineral compound can potentially cause inflammation of the respiratory tract as well as lung problems. For this reason, the European regulation has banned the presence of zinc oxide (nano or not) in spray formulas since February 24, 2018.

Furthermore, zinc oxide is listed in ANNEX VI of the European regulation that governs UV filters. Whether it is nanometric or not, its maximum allowed concentration as a UV filter is 25%.

There are a vast number of zinc-derived ingredients used in skin and hair care. Among these, some are controversial, such as the following i-compounds.

• The zinc oxide nanoparticles

  Used as UV filters in sun care products, the health risks are associated with percutaneous penetration, suspected reproductive toxicity, suspected genotoxicity, and a suspected carcinogenic effect.These nanoparticles are also potentially ecotoxic for aquatic environments. These compounds are part of our blacklist of ingredients, they are excluded from our products.

• The zinc chloride and the zinc acetate

  These compounds are used as antimicrobials, soothing agents, astringents, and oral hygiene agents. However, they are suspected endocrine disruptors. Additionally, they also poserisks to the environment:bioaccumulative substances, persistent substances, aquatic ecotoxicity.

• The zinc Pyrithione

  This active ingredient,known for its anti-dandruff, anti-seborrheic, hair conditioning, and preservative properties, is banned in Europe. It is a suspected mutagen and potential reproductive toxin.

At Typology, the zinc-based compound found in certain products is the zinc PCA. This active ingredient does not present any contraindications, nor health risks.

We use a plant-based zinc, derived from beetroot. It is then combined with L-PCA. The latter is a physiological vector, meaning it's an active ingredient that aids in the absorption of zinc by skin cells.

To take advantage of the properties of zinc for your skin and scalp, you can select one or more of our following treatments.

• Thepurifying cleansing gelcontains 2% zinc PCA combined with bamboo extract. Bamboo naturally contains porous particles that absorb excess sebum on the skin. This high absorption capacity helps to reduce skin shine. Therefore, this compound is particularly recommended for combination to oily skin types.

• Specifically designed for oily skin, thematifying serumis concentrated with zinc PCA, azelaic acid (10%) of plant origin, and organic bamboo extract to reduce excess sebum. Of plant origin, azelaic acid is known for its anti-comedogenic and anti-bacterial effects. Indeed, this molecule works to unclog pores and decrease the formation of "open" comedones (also known as blackheads). It also helps to combat the bacteria involved in acne.

• Due to its content of sebum-regulating and antibacterial actives, ourpurifying face creammade with 4% zinc PCA and bamboo extract is ideal for moderating sebum secretion, refining skin texture, and preventing the appearance of unsightly blackheads. It should be applied daily to clean, dry skin, over yourface serum, using small circular movements during application until the cream is fully absorbed. However, this cream is not recommended for pregnant and breastfeeding women due to the essential oils it contains.

• For oily dandruff, the purifying hair serum allows for long-lasting removal, it is necessary to rely on sebum-regulating active ingredients. Our purifying scalp treatment is composed of 4% of zinc PCA and nettle extract which are known for their purifying and sebum-regulating properties. In addition to this, it contains essential oils of peppermint andeucalyptus globulus which, thanks to their antibacterial and antifungal virtues, help to sanitize the scalp by fighting against the proliferation of microorganisms responsible for dandruff.

• Thelocalized imperfection serumcontains2% salicylic acidand1% zinc, for aanti-bacterialandpurifyingoverall action. It is typically used as atreatment, over a limited period of time, inlocalized application: a single drop is enough for an isolated pimple.

• The purifying body serum made from zinc PCA and tea tree extract is applied locally to blemishes. It helps to combat pimples that do not only appear on the face but can also be found on the body.

• GUPTA M. & al. Zinc therapy in dermatology: A review. (2014).

• KERI J. E. & al. The role of zinc in the treatment of acne: A review of the literature. Dermatologic Therapy (2017).

• ABENDROT & al. Zinc-containing compounds for personal care applications. International Journal of Cosmetic Science (2018).