Medically reviewed by Minimalist Health Specialist -  Written by Mahek Chawla (Dietitian & Nutritionist)  on 18th Sep 2020

Zinc Oxide - A Magical Shield For Your Skin

How Zinc Oxide Protect Your Skin

Many millennials swear by quite a few essential products without which they don’t step outside their home. And this has influenced a lot of others around who have now increasingly started taking good care of their skin. Thanks to advancements in technology and research, a lot of compounds are being formulated for skincare. And one such ingredient is zinc oxide.

Tracing back in time, the use of pushpanjan, probably zinc oxide, as a salve for eyes and open wounds, is mentioned in the Indian medical text the Charaka Samhita, thought to date from 500 BC or before. This ointment is believed to be the first form of zinc oxide. It is an inorganic compound insoluble in water and is synthesized naturally or chemically. There are numerous cosmetics, skincare products, and prescription drugs with zinc oxide as an active ingredient: the mineral zinc and gaseous molecule oxygen combined to form this biologically essential compound.

In today’s times, zinc oxide is generally used to address skin damage, like burns or scars, irritations; and may even act as a protective layer on the skin to lock the moisture. It is a key ingredient in many diaper rash creams, calamine lotions, mineral sunscreens, vitamin supplements, and acne treatments sold in drug stores. Now that we know what zinc oxide is, its presence in different products affects us needs to be discussed.  

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Line of action

The primary line of zinc oxide action is to deliver the benefits of zinc and oxygen combined, which happens by creating a physical barrier over the skin. The overall astringent, soothing, healing, antibacterial, and photoprotection properties of zinc oxide makes it an essential ingredient for most skin products. Please look at the commonly used products with zinc oxide as one of its essential ingredients. 

Sunscreens

The most common skincare product that contains zinc oxide in a high concentration is a sunscreen. The white ashy texture that we get post-application of sunscreen is due to this. Zinc oxide is a white powder added to a base like cream or gel that suits the skin to formulate sunscreens. Without its presence, no other ingredient in any sunscreen provides the physical barrier. Extensive studies have proved its effect of reflecting the UVA and UVB rays from the surface.

Unlike other organic sunscreens, inorganic sunscreens containing zinc oxide provide a protective barrier. The former provides a chemical barrier that absorbs the rays and doesn’t let it seep into the skin. Because of its photoprotective property, it is also known to be a broad spectrum shield. Not only does it protect the skin from sun damage but combined with Titanium Dioxide, it prevents the absorption of other ingredients into the skin.
Zinc oxide is photostable, non-photoreactive, and non-photocatalytic. It has very little potential for irritation or sensitization.

How much should zinc oxide be present in our sunscreen?

SPF or sun protection factor is the most important thing while selecting a sunscreen. The higher the SPF, the better the protection, right? Absolutely! But also remember, the percentage of zinc oxide should correspond to the SPF. 1% of zinc oxide provides 1.6 SPF, i.e., for every 10%, you get 16 SPF. Hence, any sunscreen with less than 20% SPF is technically providing you less protection. Though zinc oxide has not been reported with any malabsorption or toxicity, it is considered safe to use a maximum percent of 25-30% zinc oxide depending on your skin. To be sure, always do a patch test before applying any product with active ingredients.  

Creams / BB Creams / Tinted creams

Ever wondered what is present in white creams that leave a white tint on your skin? Well, it's nothing else but zinc oxide. Most of the white creams used pre-makeup or very soft shades of BB creams or concealers contain zinc oxide as a tint. The fact that it leaves a slight tint is why it is also used in many oil paints.

In today’s medicine, it is synthesized chemically, back in the time it was derived naturally from mineral salts and alloys. The addition of natural zinc oxide makes a product safer to use, but the synthetic version has given similar results without any side effects. High-end brands claim to contain natural zinc oxide giving you a tint and healing your skin while using the product.  

Loose powder / Talc

From high-end cosmetics for adults to baby powders, all have a small percentage of zinc oxide. It is extensively used for oil control or reduction in greasiness caused due to oil. Though there is limited research on this, acclaimed makeup artists and dermatologists have stated this. Loose powders have recently been added into the makeup essentials because prepping up the skin by reducing the shine, pores, and matte look has become important. An oil-based foundation or cream is applied post loose powder to give the perfect matte yet a dewy look.

Zinc oxide is an important ingredient in powders and creams for babies as it is soothing, antibacterial, and treats skin irritations. Rash creams and powders have this as their main ingredient due to this reason.  

Besides these cosmetics, there are also some over-the-counter (OTC) ointments with their main ingredient is zinc oxide because it is a dermatologically tested ingredient and has a lot more to offer like:

  • Helps to lower skin inflammation associated with rashes, allergies, or irritation
  • Protects skin cancer /neoplasias
  • Improving wound healing and preventing bacterial infections
  • Aiding in recovery of burnt or damaged tissue
  • Helping to treat acne breakouts
  • Keeping moisture locked in dry skin
  • Treating warts
  • Lowering inflammatory dermatoses
  • Treating pigmentary disorders
  • Preventing aging of the skin
  • Improving synthesis of collagen and forming of new connective tissues

Zinc oxide, which is being extensively used in many products, is insoluble in water and always needs a carrier to be delivered to the skin. It’s commonly added to topical products like makeup, mineral sunscreens, salves or balms, and moisturizers. Some lotions or creams contain zinc oxide so that the oily substances don't seep into the skin; zinc forms a barrier over them.

Other uses:

Zinc oxide in treatment ointments is highly beneficial for acne as per studies. It is usually combined with other anti-inflammatory or anti-bacterial zinc substances, including antioxidants, zinc gluconate or zinc sulfate, and sometimes antibacterial agents. Together, these elements lower the appearance, severity, duration, and pain of cystic acne/blemishes and breakouts.

A 2013 study printed in the Journal of Drugs in Dermatology and other research regarding zinc for acne shows that there are several ways in which zinc oxide can prevent acne:

  • Reduces antimicrobial and antibacterial trigger points
  • It lowers inflammation that is triggered in response to acne and clogged pores.
  • Reduces the chance of recurrent acne that usually will reappear once the skin becomes resistant to antibiotic substances.
  • Regulates oil/sebum production.
  • Acts as an astringent, which helps to dry excess oil and shrink, constrict, or tighten the appearance of damaged skin and large pores.

Research suggests that zinc used topically on the skin either alone as well as in combination with other agents, is effective mostly due to its anti-inflammatory activity. It can reduce P. acnes bacteria by inhibition of P. acnes lipases and free fatty acid levels. For cases of severe and persistent acne, sometimes dermatologists prescribe antibiotics to help stop bacteria from clogging pores.

However, studies have found that acne-related bacteria can become resistant to treatment after some time. Therefore pills/lotions stop working for some people. Antibiotic acne treatments also tend to cause side effects, including redness, increased sensitivity to sunlight, dryness, and peeling. The good news is that zinc oxide treatment can continue to be useful even for antibiotic-resistant acne.

Use of nanotechnology

Consider it a boon, technology in this generation has reached a place where it is also possible to decrease the size of particles that are barely visible to the naked eyes. Nanotechnology has brought another way for us to include zinc oxide and, i.e., nanoparticles. Why this? Although according to the FDA, zinc oxide has been considered a safe and mild ingredient for topical use, for extensive reach without any undesirable effects in any skin, dermatological institutes have come up with nanoparticles that have a chance of getting absorbed into the uppermost layer but not beneath. This technology gives a better texture and feels to the consumer after applying the products as a smaller size tends to even out more rapidly on the skin.

Side effects

Although the study so far has not recorded any side effects, it is a debatable topic as to whether zinc oxide shows any potential or general side effects. It is recommended to go for a patch test while trying any product with active ingredients because each cell reacts to each product differently. An ingredient used even in child care products, it is non-allergic and considered safe, but the absorption of nanoparticles is still under research. Keeping that in mind, all brands must mention the percentage of active ingredients present, especially when it is used daily. With this, people can use the product without much worry.  

Caution

It is not advisable to use a higher percentage of sole zinc oxide ointments on open wounds. While slight irritation or itching is normal, if it becomes mild to high, it should be reported to a dermatologist or doctor.

Takeaway

Zinc oxide is an astringent that reduces oil production and controls bacterial growth. It is an antibacterial compound that hinders the growth of certain bacteria, a photoprotective ingredient without which sunscreen is not a sunscreen. Also, lastly, a mineralized compound that provides all the benefits of zinc like soothing, wound healing, collagen synthesis, et all. With this, we are sure you will include a good sunscreen in your daily routine because nobody likes tan unless you are on a beach.