Skincare Ingredients Not to Mix

Skin Care Ingredients Full Guide: Effects, Results, & Interactions

Navigating the skincare aisle can be seriously confusing. So many different ingredients have overlapping benefits, and it's hard to distinguish skin care that actually works from those that don't. Luckily for you, we've compiled a list of some of the most common skincare ingredients, how to apply them, and what skincare products not to mix. This way you can focus on your specific skin concerns with confidence. Get ready for skincare 101!

Eight Saints Skincare Ingredients

At Eight Saints, our goal is to simplify skincare. We found the eight best ingredients for skin care that actually work and designed natural products you can trust. Our products incorporate the skincare holy grails that dermatologists have established as necessities in everyone's routine. Whether you seek color correction, skin tightening, or acne treatment, these essential ingredients will give you more youthful, clear skin. Let's take a look at how each component works:


Free radicals break down collagen, accelerating oxidative damage and aging. Antioxidants neutralize free radicals, reducing the appearance of wrinkles, age spots, and loose skin. Vitamins C and E are two components with these antioxidant properties that we include in our products to promote young, glowy skin.

skin care ingredients

Vitamin E

This leads us to Vitamin E, a powerful anti-inflammatory and antioxidative source. This skin care ingredient protects from UV damage and even heals prior sun spots. We love it because it provides natural anti-aging without harshness or synthetic chemicals.

Hyaluronic Acid

Hyaluronic Acid or Hyaluronan is a naturally occurring compound in the skin that keeps connective tissues, skin, and joints lubricated and hydrated. When used topically, it helps the skin retain moisture for a dewy, youthful appearance. Though the name contains "acid," it's not at all harsh on the skin and can be used daily!


You've probably heard of collagen, the protein in our bodies that keeps connective tissues tight and strong. As we age, we produce less collagen, which is one reason the skin loosens and sags. Peptides are amino acids found in collagen. As a skincare ingredient, they aid in collagen production, helping you achieve more youthful, firm skin.

Vitamin C

Vitamin C also promotes collagen production but goes a lot further. This citrusy nutrient also acts as an antioxidant to reverse sun damage including photodamage and immediate sunburn swelling! You can use it up to twice a day - it's not harsh and is typically tolerated well.


MSM or Methylsulfonylmethane is a sulfuric compound found in plants, animals, and humans. It aids in collagen production, reduces inflammation, and increases cell wall permeability. This helps nutrients enter, while allowing toxins to exit more efficiently. MSM comes in capsules (for treating arthritis and joint pain), powder, or topical creams.

Glycolic Acid

Glycolic Acid is an AHA, or a non-abrasive exfoliator that helps the skin shed dead cells. This new-found turnover unveils a layer of new, unmarred skin, making dark spots and acne scars fade faster. It also allows for easier absorption of the skin care ingredients you apply, because there's less dead skin in the way.


This non-comedogenic, natural oil helps the skin retain moisture. Extra helpful in dry, arid climates, Squalane prevents excess moisture loss and makes the skin appear more vibrant. Research suggests it may also protect the skin from pollutants and impurities.

Best Ingredients for Skin

We've done our best to research this for you so you don't have to spend hours looking up every ingredient in your products. Our clients benefit from the selective nature in which we've formulated our line - with results-driven skin care natural ingredients.

Mixing Skincare Ingredients

If you’re into skincare, you likely have a vanity full of amazing products for your skin, such as skincare actives, serums, and moisturizers meant to hydrate, smooth, and slough away stubborn spots or dead cells. And it’s true that a comprehensive routine is necessary if you want to see real results.

But not all ingredients for skin care play nice with one another - and while some go together like PB&J, other mixtures should be avoided at all costs. Here, we’ll break down the do’s and don’ts of mixing skin care ingredients so you’ll always get the perfect glow, not a face full of oh no!

skin care ingredients

First Thing’s First: What Are Active Ingredients?

Generally speaking, when we talk about skincare products that react with one another (either positively or negatively) that reaction usually has to do with skincare active ingredients in the product. Active ingredients in skin care are the ingredients that actually work to address the problem that the product is meant to target.

If you’re getting a serum to treat acne, for example, the active ingredient could be glycolic acid. If you want dark spots to fade away, vitamin C is one of our favorite actives for daily use. Importantly, skincare actives are proven to work: generally, they have been proven effective in a lab, so you won’t be dealing with snake oil. Active skincare categories include:

  • Signs of aging: SPF-boosting ingredients (e.g. zinc oxide, titanium dioxide, avobenzone, oxybenzone), vitamin C, vitamin E.
  • Dryness: Hyaluronic acid, vitamin E.
  • Pigmentation issues: Kojic acid, AHAs, BHA, vitamin C.
  • Acne: Salicylic acid, benzoyl peroxide, glycolic acid, azelaic acid.
  • Rosacea: Various antibiotics, azelaic acid, sulfur.
  • Psoriasis: Steroids, vitamin D, glycolic acid, urea, lactic acid, anthralin, tacrolimus, pimecrolimus.
  • Eczema: Steroids, tacrolimus, pimecrolimus.

Skin Care Ingredients That Really Work Together

Vitamin C + Vitamin E

Vitamin C and E are two antioxidant powerhouses that go together flawlessly - and you won’t have to worry about getting too much of a good thing. Each vitamin combats different types of UV damage, which means that the combination - especially if you add some real SPF to the mix - will give you ultra-comprehensive sun protection.

Additionally, using both will give you double the antioxidant protection to fight free radical damage.

In fact, one study found that applying the combination every day can reduce the effects of sun damage - aka dark spots and wrinkles - on your skin by up to 4 times!

vitamin c skincare ingredients in Eight Saints products

Vitamin C + Vitamin E Interactions

Now, let’s address one of the most common concerns here - can’t loading up on double the goodies actually cause skin irritation? The short answer? No! (yay). Neither product is recommended for particularly sensitive or reactive skin (and vitamin E is not great for oily skin either) but the reality is that we’re not dealing with acids or anything harmful. Instead, we’re talking about regenerative, restorative antioxidants, so you shouldn’t worry about the combination causing any kind of harm.

Where to find them:

If you’re following a comprehensive Eight Saints routine, you’re already using these two skin care active ingredients (woo hoo!). But just in case you’re not sure what to use (or if you want to double-check that you’re making the most of this powerful duo), you can find:

Vitamin C in:

Vitamin E in:

Sunscreen + Antioxidants

Roughly 80-90% of facial skin aging is caused by sun damage, which is why sunscreen on its own is such an important part of any skincare routine. A typical run-of-the-mill sunscreen primarily protects against UVB rays, which are known to cause the reddening that is typically associated with sunburn and, in the long run, skin cancer.

A broad-spectrum sunscreen will protect against both UVB and UVA rays. These rays can reach deeper layers of the skin and damage collagen and elastin. An SPF 30, in particular, will protect against 97% of these harmful rays (not too shabby). That said, sunscreen on its own can only protect against about 55% of free radicals caused by UV exposure.

What Are Free Radicals?

Free radicals are unstable molecules (caused by sun damage, environmental pollutants, etc) that steal electrons from within cells to try to stabilize themselves, disrupting the cell membrane, setting the mitochondria on a self-destructive path, and creating errors in the DNA within the nucleus - yikes!

If this process goes unchecked, you’ll have a face full of unstable cells that are destroying their neighbors and stealing from each other. This wreaks havoc on the skin, leading to:

  • Premature and accelerated aging of the skin, including wrinkles and loss of elasticity
  • Hyperpigmentation
  • Inflammatory conditions, such as acne and rosacea
  • Skin cancer
That’s why you should add antioxidants to your SPF - they can help and reduce these free radicals by up to 78%. Plus, many also block harmful UV rays, making SPF and antioxidants the ultimate sun protection duo.

Where to find them:

Our Chase the Sun SPF 30 Face Moisturizer contains skincare actives. This sunscreen is a blend of mineral and clean chemicals that provide invisible, complete protection from harmful UVA/UVB rays - along with hyaluronic acid, squalane, and aloe vera.

Green Tea + Caffeine

Green tea has anti-inflammatory properties, antioxidant effects, and protective benefits. Green tea is very beneficial and it can help with:
  • Puffy eyes: You can put green tea bags on your eyes to reduce puffiness; it works because compounds in green tea reduce irritation and redness while speeding along the decongestion and de-stressing of your system.
  • Blemish control: The catechins in green tea have antimicrobial properties. This can destroy stubborn acne-causing bacteria on the skin.
  • Sunburn repair: Green tea activates EGCG, a super compound believed to reduce the metabolic changes in the skin that lead to skin cancer and wrinkles (not to mention help with sunburn) - yay!
Some research suggests that caffeine enhances the antioxidant effects of green tea polyphenols and that both ingredients together may help prevent free radical production and UVB-induced skin cancer.

Where to find them:

Our Pep Rally Face Serum is loaded with organic green tea extract, hyaluronic acid, and vitamin C - which means you can kiss those burns and fine lines goodbye.

Can You Use Glycolic Acid With Vitamin C?

So, can you use Glycolic Acid with Vitamin C? Although this combination may not be suitable for all skin types, glycolic acid and vitamin C make a powerful pairing. Both boost collagen levels in the skin, and it appears that their effects may be additive. Additionally, vitamin C and glycolic acid are both effective at inhibiting tyrosinase and decreasing melanin production. As a result, when used together, they demonstrated an ability to significantly improve hyperpigmentation and dark spots, as well as reduce pore size and improve skin texture.

Where to find them:

Vitamin C is a key ingredient in our Down to Earth Gel Cleanser, Cloud Whip Face Cream, and Pep Rally Face Serum. You'll benefit from the revitalizing power of glycolic acid when you use our Soulmate Brightening Treatment and Bright Side Cream Cleanser.

What Skin Care Products Not To Mix?

AHA/BHA and Retinol

Retinoids (the umbrella term for retinol creams) are ultra-potent skincare ingredients that come in multiple forms. There’s:
  • Retinoic acid: This is the “magic ingredient” that you’ll find in a lot of prescription anti-aging products.
  • Retinol: This vitamin A derivative is a non-prescription alternative to retinoic acid (and it’ll be converted to retinoic acid at a cellular level). It biochemically does the same thing as the prescription stuff - it’ll just take a little bit longer for you to start seeing results.
  • Pro-retinols: This includes ingredients like retinyl palmitate, retinyl acetate, and retinyl linoleate. This is the gentlest of the bunch.

Retinoids are not exfoliants. Any peeling they cause is a side effect of irritation - not an intended effect. Instead, retinols primarily work by affecting gene expression and causing enhanced collagen production, skin smoothing, and an evening of pigmentation.


What Is AHA And BHA?

AHAs and BHAs, on the other hand, are chemicals that work to “unglue” the bonds that hold dead skin to the face, thereby helping to gently exfoliate the skin. Over time, you will notice these BHA and AHA benefits for skin:
  • Improve look and feel of the skin
  • Smooth texture and decrease imperfections
  • Hydrate
  • Diminish fine lines and wrinkles


Why are these skin care ingredients not to mix?

Retinol is extremely unstable and using it with acids is hard on the skin.

Together, they may cause dryness, sensitivity, and irritation - particularly if you already have sensitive skin or use strong concentrations.

Can You Use Benzoyl Peroxide With Retinol/Tretinoin?

Benzoyl peroxide is an effective acne-fighting ingredient that can reduce the amount of acne-causing bacteria on the skin. But when retinol products are combined with benzoyl peroxide products, their effects cancel each other out. Can you use Benzoyl Peroxide with Retinol/Tretinoin?

When considering which skincare actives not to mix, these are a big no-no! That's because BHA and retinol can deactivate each other on the skin. So, if you have to use both, you should do so at different times so the products don’t interfere with one another.

oil vs water based skincare ingredients in products

Oil-Based + Water-Based Products

This one isn’t as much a statement about what not to do as it is a guideline about how unlikely it is for you to get these skincare ingredients to mix. Oil and water don’t mix - when it comes to skincare, this means that oil-based products leave a film on the skin that water-based products won’t be able to penetrate. If you follow an oil-based cleanser with a water-based vitamin C serum, for example, you won’t see your dark spots start to lighten.

You might think a faulty vitamin C product is to blame. Of course, this is not a hard-and-fast rule against all oil and water mixtures. Botanical face oils can be effectively used on top of water-based products at the end of your skincare routine to seal everything in. This can work as a shield for the skin, keeping vitamins and nutrients in, giving the skincare actives an opportunity to sink in more deeply, and preventing trans-epidermal water loss.

Niacinamide and Vitamin C

Niacinamide cancels out all of the good properties of vitamin C and turns it into a substance that causes redness. Acne breakouts can also be triggered when these products are applied directly on top of one another. If you’re going to use both, space the application out by at least 10 minutes between each product to avoid any irritation. And remember - always pay attention to your skin! If you notice any redness, irritation, itching, or other symptoms, re-evaluate your routine and get to the bottom of it before the problem gets worse.

How Long Do Skincare Products Really Take to Work?

You read about the best ingredients for skin. You research the best brands on the market. You buy top-rated products, it's important to know what skincare products not to mix. You’re ready to see the results. And if you don’t see anything, you lose interest and move on to the next best thing. It’s human nature. Part of the problem is impatience and wanting to see results now. But the biggest issue is a lack of information and misleading marketing that promises you’ll “see results in as little as two weeks!*” (just don’t look at the fine print next to the asterisk). That’s why we want to demystify this timeline and break down exactly what to expect (and when) from all your skincare essentials.

BHA and AHA products

Time Frame:

AHA (glycolic, lactic, etc) - Right away, peaks at 12 weeks BHA (salicylic acid) - Right away, peaks at 12 weeks

How and why:

Alpha hydroxy acids (AHAs) and beta-hydroxy acids (BHAs) are exfoliants that work by dissolving the bonds that hold dead skin cells to the surface of your skin. This provides an even exfoliation, encourages cell turnover, increases skin repair, and helps nutrients reach the inner layers of the skin.


Don’t overuse AHA/BHA skincare in hopes of getting faster results. Overusing AHAs and BHAs is an increasingly common practice that can lead to redness, burns, dryness, photosensitivity, and overall confused skin. As a rule of thumb, you shouldn’t use these products more than every other day, and don’t mix a bunch of different AHA and BHA together either!

How Long Does It Take For Hyaluronic Acid To Work?

Time Frame:

Hyaluronic acid starts working in a few minutes and can continue doing its job for up to 2 months.

How and why:

This is one of those miracle natural skin care ingredients that starts giving you results right away. As a humectant, it moisturizes using the water that’s already in your body, drawing up moisture from the deepest layers of your skin. And it’s extremely effective: just one gram (0.03oz) of hyaluronic acid can hold up to six liters of water, and it’s capable of binding 1,800 times its own weight in water - whoa! Even better? It can actually regulate moisture levels within your cells so you don’t get too much hydration. Be patient if you have skin that’s flaky, peeling, or tight to the touch. These are all signs of severe skin dehydration. If your skin is that dry, there’s not much moisture in the surrounding environment for hyaluronic acid to use.


Time frame:

12 weeks

How and why:

Niacinamide is a popular jack-of-all-trades and one of the most popular skincare ingredients that can address things such as:
  • Fine lines
  • Hyperpigmentation
  • Acne
  • Oily skin
  • Dehydration
  • Uneven skin tone
How can it accomplish all of this, you ask? This is achieved by strengthening the skin’s natural barrier. It boosts the production of ceramides - the proteins that actually make up the barrier, or the “bricks." This keeps infections and bacteria out while keeping moisture and nutrients in (yay!). It can also reduce sebum production, which makes it particularly useful at preventing acne and other issues related to oily skin. None of this happens overnight. Though you’ll notice some effects immediately, most studies show that niacinamide produces significant results after about 8-12 weeks. Also, look for products that contain 5% of this ingredient - that’s the concentration that’s shown to give the best results without causing irritation.

Vitamin C

Time frame:

3+ weeks

How and why:

Vitamin C is a potent antioxidant that:
  • Reduces signs of aging and wrinkle formation
  • Repairs damaged skin
  • Accelerates collagen synthesis
  • Corrects hyperpigmentation
  • Fights acne (Just a 1% concentration of SAP was shown to have a strong antimicrobial effect against acne for a full 8 hours!)
You'll find it in Eight Saints products listed as Sodium Ascorbyl Phosphate (SAP). This is the most stable form of vitamin C - it will never oxidize or decrease in effectiveness with time. It easily penetrates the skin, unlike ascorbic acid, which is not easily absorbed. To see the effects - like plumper skin - vitamin C needs to build up in skin cells over the course of several weeks. So be patient and get ready for major results.


Time frame:

12 weeks

How and why:

Peptides are proteins found naturally in the skin that communicate with cells to stimulate fibroblasts and trigger collagen production. This active skin care ingredient minimizes wrinkles and plumps skin, promoting healthy, youthful skin. So here’s the science. Collagen is a protein that’s abundant in our skin when we’re under 30 (and decidedly less abundant as we age - ugh). Proteins - taking it back to high school bio - are long chains of amino acids. Peptides are small links in those chains, and they can do quite a lot. Specifically, they:
  • Increase collagen
  • Regenerate the skin
  • Improve hydration
  • Support elastin synthesis
  • Decrease inflammation
Since peptides are essentially giving your body a boost to produce its own collagen, getting full results takes a pretty significant amount of time.

Give it Time

Now that you're armed with the skin care ingredients that really work, it's time to start a solid routine and give it time to start taking effect! It's totally possible for your skin to reject an ingredient or scent. Listen to your body and use what feels good on you!