Skin Care, Ingredients

The Secret Skin Care Ingredients : Kojic Acid, Salicylic Acid and More

The Secret Ingredients to Glowing Skin

Essential Popular Skincare Ingredients

Some things are just meant to be together. We could list some, but let your imagination wander. Other things are better suited on their own—especially when it comes to certain skincare products. Powerful ingredients such as retinol, Vitamin C, benzoyl peroxide, and even certain acids demand to be the star of the show. Sharing the stage could lead to major drama in the form of irritation, redness, temporary staining, or just a general lack of desired results. “There are so many great active ingredients out there and it may seem like using more of them would give you better results, but that’s not always the case,” says Aegean Chan, a board-certified dermatologist based in Santa Barbara, California.


Unsure if you’re giving your favourite serums and creams the spotlight they need? Well, we asked Chan and many other board-certified dermatologists to share which skin-care ingredients you should not mix together—*ever—*as well as alternatives they recommend.

Kojic Acid

Kojic acid is a natural skin brightening agent derived from several types of fungi. It works by inhibiting melanin production, which helps fade dark spots, age spots, freckles, and other areas of discoloration.

Kojic acid prevents tyrosine from forming, which slows down melanin production. Melanin is responsible for skin pigmentation, so decreasing melanin leads to brighter, more even toned skin.

In addition to its skin brightening properties, kojic acid also has anti-inflammatory effects. This helps soothe irritation and redness. The combination of reducing hyperpigmentation while calming inflammation makes kojic acid effective at improving a wide range of skin discoloration issues.

Research shows kojic acid is effective when used regularly over several weeks. It takes time to see results, but gradual lightening of pigmented areas is possible with continued use. Since kojic acid is derived naturally from mushrooms, it is generally well-tolerated compared to harsher synthetic brightening agents.

Salicylic Acid

Salicylic acid is a beta hydroxy acid (BHA) that is derived from the bark of the willow tree. It is a popular ingredient in many skin care products, especially those targeted for acne-prone skin.

Salicylic acid works as a chemical exfoliant by dissolving the bonds that hold skin cells together, allowing dead skin to shed more easily. This makes it effective at clearing pores and preventing acne breakouts by keeping pore lining smooth. The exfoliating properties also help improve skin texture and reduce the appearance of fine lines and wrinkles.

In addition to exfoliating, salicylic acid has anti-inflammatory properties that help reduce redness and swelling associated with breakouts. By fighting inflammation, salicylic acid helps calm existing breakouts and prevent new ones from forming. It is able to penetrate and dissolve the buildup of sebum and bacteria in pores that leads to acne.

Salicylic acid is generally well-tolerated, but can cause dryness, peeling, stinging or irritation in some people, especially with higher concentrations. Starting with a low percentage and building up tolerance slowly can help minimize side effects. It is considered safe for most skin types, but should be used with caution on sensitive skin.

Overall, salicylic acid is a multi-tasking ingredient that offers chemical exfoliation, clears acne, reduces inflammation, and improves skin texture. When used properly, it can be a powerful part of an acne-fighting skin care routine.


Niacinamide is a form of vitamin B3 that offers several benefits for skin. It helps restore and repair the skin barrier, keeping moisture in and irritants out. Niacinamide reduces inflammation, redness, and blotchiness, making it effective for soothing many skin conditions.

One of the standout effects of niacinamide is evening out skin tone. It inhibits the transfer of melanosomes, which are pigment granules that give skin its color. By slowing down this transfer, niacinamide keeps hyperpigmentation and dark spots at bay. It’s also beneficial for lightening areas of previous damage and discoloration.

In addition, niacinamide minimizes the appearance of pores by controlling sebum production. The vitamin limits the amount of oil the sebaceous glands release, preventing pores from becoming congested and enlarged. With smoother, more even texture, niacinamide gives skin a youthful, radiant look.

Niacinamide is gentle and well-tolerated by most skin types. It hydrates without causing greasiness or breakouts. The vitamin works well when paired with other brightening or acne-fighting ingredients. Overall, niacinamide is a versatile ingredient that targets many common skin concerns.

Sulfur Skin Care Ingredients

Sulfur is a natural mineral that has been used for centuries for its medicinal properties. When applied topically, sulfur has the ability to treat several skin conditions thanks to its potent antibacterial and anti-inflammatory effects.

Some of the key benefits of using sulfur for skin care include:

  • Dries and disinfects skin: Sulfur has keratolytic properties, meaning it can help to dry out and peel the top layers of skin. This helps to disinfect the skin and get rid of acne-causing bacteria. The drying effects also help clear up oily skin.

  • Treats acne: By drying out the skin and acting as an antibacterial agent, sulfur is highly effective at clearing up inflammatory acne lesions like papules and pustules. It helps to prevent new breakouts and calms existing ones.

  • Removes dead skin cells: The keratolytic properties of sulfur make it a great exfoliant to remove dead skin cells that can clog pores. This helps improve skin texture and reduce congestion.

  • Anti-inflammatory properties: In addition to being antibacterial, sulfur also has anti-inflammatory effects which help to reduce redness and swelling associated with acne breakouts. This soothes and calms the skin.

  • Treats psoriasis: The skin-clearing effects of sulfur are beneficial for reducing the scaly, inflamed patches caused by psoriasis. Sulfur removes scales and decreases inflammation and itch.

With its multi-faceted effects on the skin, sulfur is an effective natural ingredient to treat all kinds of acne as well as other inflammatory skin conditions for clearer, calmer skin. It brings together disinfectant, keratolytic and anti-inflammatory properties in one simple natural ingredient.

Zinc Oxide

Zinc oxide is a natural mineral that is used as a physical sunscreen ingredient in many skin care products. It sits on top of the skin and acts as a barrier to protect against both UVA and UVB rays from the sun.

Unlike chemical sunscreens that absorb UV rays, zinc oxide reflects and scatters them away from the skin. This makes it an effective broad spectrum sunscreen ingredient.

In addition to UV protection, zinc oxide is also known to help soothe and heal irritated skin. It has anti-inflammatory properties that can reduce redness and inflammation. The mineral is especially beneficial for sensitive skin types that are prone to irritation, rashes, and dermatitis.

When applied topically, zinc oxide helps promote wound healing. It stimulates skin cell regeneration and growth. The protective barrier it provides also prevents infections and speeds up recovery.

Overall, zinc oxide is a versatile ingredient that protects the skin from sun damage while also soothing and healing it. Its natural mineral properties make it a safe and effective addition to sunscreens and other skin care products.

Activated Charcoal

Activated charcoal has become a popular ingredient in skin care products in recent years due to its many benefits for the skin. When applied topically, activated charcoal acts as a magnet to draw out impurities from the skin. Some key benefits include:

  • Adsorbs toxins, bacteria, dirt from skin – The porous structure of activated charcoal has a negative electrical charge, which allows it to bind to and trap positively-charged toxins, bacteria, dirt and other microparticles on the skin’s surface. This helps pull impurities out of pores.

  • Clears pores to prevent acne – By adsorbing excess sebum, dead skin cells and other pore-clogging substances, activated charcoal can help prevent acne breakouts and clear existing breakouts. The deep cleansing of pores also allows other acne treatments to penetrate better.

  • Removes excess oil – Activated charcoal can control oily skin by absorbing excess sebum production. This helps reduce shine and balances the skin’s pH levels. Those with oily, acne-prone skin can benefit from using activated charcoal.

  • Brightens complexion – In removing impurities, activated charcoal reveals a more even, bright and radiant complexion. Some studies have found it can reduce hyperpigmentation and melasma. Its deep cleansing action unveils smoother, glowing skin over time.

Overall, activated charcoal offers a gentle but effective deep clean for the skin, making it useful for those with acne, oily skin, dullness and congested pores. When combined with other skin care actives, it can enhance their absorption and effectiveness.

Using Ingredients Together

When using multiple skin care actives together, it’s important to understand how they interact and combine for maximum efficacy. Some ingredients work synergistically to boost each other’s effects, while others may cause irritation or reduce effectiveness if used together.

  • Kojic acid works well with vitamin C, arbutin, and niacinamide to inhibit melanin production and brighten skin tone. However, kojic acid can be sensitizing, so gradual introduction is recommended, especially with other exfoliating acids.

  • Salicylic acid complements niacinamide nicely to reduce acne, inflammation, and sebum production. However, salicylic acid shouldn’t be paired with retinoids which can cause dryness and irritation.

  • Niacinamide is very versatile and can be combined with most ingredients. It enhances the benefits of retinoids, peptides, vitamin C, and sunscreen actives. The only exception is vitamin C derivatives like ascorbic acid which can interact poorly.

  • Sulfur works well with salicylic acid and benzoyl peroxide to combat acne, but can dry out skin. Hydrators like glycerin should be used to counteract this. Sulfur also shouldn’t be used with retinoids.

  • Zinc oxide is soothing and can be paired with most ingredients. However, it shouldn’t be combined with chemical exfoliants that diminish its effectiveness.

  • Activated charcoal may interfere with other actives, so careful formulation is required. Using it separately from acids, retinoids, and vitamin C allows each ingredient to work optimally.

When combining multiple actives, especially on sensitive skin, it’s best to introduce them slowly one at a time. Check for any adverse effects like dryness, irritation, and photosensitivity before adding new ingredients. Sometimes less is more when it comes to piling on active ingredients!

Side Effects

When using skin care ingredients, it’s important to be aware of potential side effects. Some ingredients may cause irritation or allergic reactions in people with sensitive skin. Others can increase photosensitivity, making skin more prone to sun damage. Here are some potential side effects to watch out for:

Irritation or allergic reactions – Ingredients like salicylic acid, sulfur, and activated charcoal can potentially cause redness, itching, burning or peeling, especially when overused. People with sensitive skin may experience irritation or allergic contact dermatitis. Start slowly with new products and discontinue use if any reaction occurs.

Photosensitivity – Certain ingredients like kojic acid can make skin more prone to sun damage and burning when exposed to UV light. It’s important to use sun protection when using photosensitizing ingredients.

Safety guidelines – To minimize risk, do a patch test before widespread use of any new product. Introduce actives slowly into your routine. Use only as directed and avoid overuse. Sun protection is recommended when using photosensitizing ingredients. Those with very sensitive skin should exercise caution. Consult a dermatologist if any severe reaction occurs. With proper precautions, these powerful ingredients can be used safely for skin benefits.


Many of these ingredients have been shown to be effective in clinical studies when used at the right concentrations.

Kojic acid, for example, was found in one study to have a significant lightening effect on hyperpigmentation when used twice daily at a concentration of 2% for 8 weeks. Most kojic acid products contain 1-4% concentrations.

Salicylic acid is effective at exfoliating skin and clearing acne when used at 0.5-2% concentrations. One study found that a cleanser with 2% salicylic acid used for 6 weeks reduced acne lesions by nearly 50%.

Niacinamide has been shown in studies to improve skin texture, hyperpigmentation, redness, and moisture when used at 2-5% concentrations. A 4% niacinamide gel applied twice daily for 8 weeks reduced hyperpigmentation significantly better than a placebo.

Sulfur concentrations between 2-10% have been found effective for treating acne, seborrheic dermatitis, and rosacea through its antibacterial and anti-inflammatory properties. One study using a cleanser with 10% sulfur for 12 weeks reduced acne lesions by 72%.

Zinc oxide between 5-20% is effective as a physical sunscreen active ingredient due to its broad spectrum protection. Studies confirm it protects against both UVA and UVB rays. Concentrations of 20% provide an SPF of 19-20.

Activated charcoal at concentrations between 1-3% has absorbent properties that can help remove dirt, oil, and impurities from skin. However, there are limited clinical studies on its efficacy. Anecdotal evidence suggests it may help improve acne and skin texture. More research is still needed.

When using multiple actives together, it’s important to pay attention to concentrations to avoid irritation. Starting with lower percentages and slowly increasing frequency of use can help build tolerance. Consulting a dermatologist is advised, especially if you have sensitive skin.


The key skin care ingredients covered in this article each provide unique benefits for different skin concerns. Kojic acid, salicylic acid, niacinamide, sulfur, zinc oxide, and activated charcoal can all be effective, but it’s important to choose the right ones for your skin type and issues.

Main takeaways:

  • Kojic acid helps lighten dark spots and hyperpigmentation
  • Salicylic acid exfoliates to treat acne, blackheads, and whiteheads
  • Niacinamide brightens, smooths, and strengthens the skin barrier
  • Sulfur dries and clears up acne-prone skin
  • Zinc oxide soothes irritation and inflammation
  • Activated charcoal draws out impurities and absorbs excess oil

Which ingredients to look for:

Focus on kojic acid, niacinamide, and salicylic acid for dark spots and uneven tone. Those with acne-prone skin will benefit most from salicylic acid, sulfur, and activated charcoal. Sensitive, irritated skin needs soothing relief from niacinamide, zinc oxide, and activated charcoal. Review your own skin concerns and try products with the ingredients that can best target those issues.