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  • Writer's picturePenn Smith

Active skincare ingredients

Updated: Jan 12, 2023

You'll often hear people talking about skincare 'actives' when they talk about things like retinoids, Vitamin C and AHAs. But what exactly is an active ingredient and how do you know which ones are right for you?

Effectively a skincare active is the ingredient that might alter the skin in some way- typically the way that the product claims. For example: if you're buying a serum that claims to fight free radicals, the active in the bottle or tube might be green tea, resveratrol, vitamin C or a number of other active ingredients that fall into the 'free radical busting' category.

I consider the inactive ingredients the "supporting cast" in an ingredient deck. While the main characters (those active ingredients) lead the play, it wouldn't be much of a performance without the entire cast. Inactive ingredients often serve as an uber for the active ingredients-carrying them where they need to go. Ok ok...enough of the bad analogies :).

Inactive ingredients can do things like balance the PH, add fragrance, act as preservatives and change the viscosity of a formula.

If you've watched my videos, you know I have my favorite active ingredients. In my mind the ⭐️⭐️⭐️s of the show are the A-B-Cs (vitamin A or retinoids, vitamin C and niacinamide). But these are just a start - there are so many interesting ingredients to consider. The key is determining your biggest skincare concerns and then prioritizing. I've created this overview chart to help you determine which ingredients are right for your specific skincare concerns. I'm hopeful that this 'cheat sheet' will help you make the very best choices when you invest in new products. Note that there will be an entirely separate blog post dedicated to SPF, likely the most important group of active ingredients that exist!



VITAMIN A - retinoic acid (Tretinoin) and derivatives

Retinoic acid is perhaps my favorite active ingredient. It is the most widely studied of all actives, and the ‘gold standard’ for anti-aging that ALL dermatologists agree on. Retinoic acid is the active form of vitamin A (so our skin can actually use it directly) and can significantly improve wrinkles whether caused by sun damage or just chronological aging. It can also help to fade unwanted pigmentation, improve skin elasticity and smooth rough skin texture.

Along with all of these benefits comes a price: irritation. It is important to choose wisely and implement vitamin A products carefully to mitigate irritation as much as possible. Thankfully there are many forms of vitamin A to choose from with varying levels of irritation (and efficacy). In order of strength and irritation are retinol, retinaldehyde and then tretinoin.

For even more more detail right away, do have a look at my recent Understanding Retinoids video.

Type: exfoliating, antioxidant, cell communicating

Best for: Acne and sun-damaged skin, surface wrinkles, fine lines, and darks spots.

Results after: For over-the-counter retinol, it can take up to six months so see a difference in skin tone and fine lines. Depending on the strength, tretinoin can deliver not only quicker but more profound results.

When to use: Before bed, 30 mins after washing face and before other topicals.

Do/don’t mix with: Take care when combining retinoids with other strong ingredients that act as exfoliators. This might include AHAs, BHAs, and ascorbic acid. Also avoid too much physical scrubbing with topical exfoliators or cleansing devices. Always take care in using lasers, IPL, RF and other modalities, whether at home or stronger in-clinic version. It should always be disclosed to a practitioner that you are using retinoids before getting facial waxing, dermaplaning or microdermabrasion. I recommend being cautious and following manufacturers and/or practitioners instructions - retinoids can be powerful and need to be treated with respect!

Clinical proof: ROBUST

What to look for:

Tretinoin in strengths of .025, .05 and .1% are the three most commonly used with .1% being the highest you'll typically be prescribed. It is not uncommon to start at .025 and work up to a .05%. Some people never graduate to a .1% and have excellent results all the same. The key is to use the percentage that can be administered in the long term and not stopped because of irritation. When people go too high and/or use too often they can find themselves needing to discontinue...forgoing all results!

If over the counter is your choice you may want to investigate retinaldehyde. It is important to know that this is also called retinal in an ingredient deck. Retinaldehyde requires one enzymatic conversion to become retinoic acid (remember this is the active form of the vitamin that our skin can actually use) in your skin. We depend on our body to make retinaldehyde active (which it normally does).

Another "level down" is retinol. Just like retinaldehyde, retinol requires enzymatic action for it to become active in our skin. This time its two enzymatic conversions (first to retinaldehyde then to retinoic acid) to become active. I do like retinol but it is the weakest of the vitamin A choices that I recommend...there are weaker versions, I just don't recommend them. Those derivatives are retinyl palmitate and retinyl propionate. As I said above, these are even weaker forms of the vitamin and may offer more irritation than results.

My picks:

*Penn Smith Skincare is a participant in the Amazon Services LLC Associates Program, an affiliate program. Many links are affiliate links, meaning I am compensated when you shop through these at no extra fee to you.

Retin-a (Tretinoin or ‘Tret’ for short) - by prescription


Osmosis Renew or Correct (use code penn20 for 20% off)

Avene RetrinAL

Mychelle Retinaldehyde


Drunk Elephant

Sunday Riley Luna

Cos de Baha


Many people know niacinamide for its skin brightening and pigmentation tackling attributes - and they're not wrong! As you've heard me say, tackling pigmentation takes a multi-prong approach that should include vitamin C, arbutin, kojic acid and others. But when you add niacinamide you get an ingredient that works differently. Niacinamide suppresses the transfer of melanosomes (melanin carriers) from melanocytes (melanin producer) to keratinocytes (cells in the outermost layer of the skin), while most other hyper pigmentation fighting ingredients block tyrosinase (an enzyme that plays a critical role in melanin production). So using niacinamide alongside these other ingredients enables us to tackle pigmentation issues from different angles at the same time, resulting in a quicker and more comprehensive solution.

In addition to its skin brightening attributes (think skin tone), studies show that niacinamide significantly improves skin appearance by reducing fine lines and wrinkles, hyper-pigmented spots, red blotchiness, and elasticity. It also helps to improve our skin barrier leading to decreased trans-epidermal water loss (and potential dehydration). Unless you're sensitive to it, nicainamide is a must try!

Type: All round anti-ager

Best for: Brightening skin, fading brown spots, and helping improve barrier function (which will improve skin hydration). Helps improve acne and rosacea. Niacinamide may also help with the appearance of enlarged pores.

Results after: I find Niacinamide can work quite quickly - in the first two weeks you might notice some brightening and evening of the skin as well as pore size reduction (the appearance) and this impact seems to develop more over time.

When to use: You can use it in both morning and evening

Do/don’t mix with: Niacinamide plays well with most all other actives! That's one of my favorite things about it - you don't need to worry about it wreaking havoc with your other skincare BFFs!! Some people may be sensitive to niacinamide so start slow and increase accordingly.

Clinical proof: ROBUST

What to look for: Niacinamide is best when used at 4-5% concentration - more than that can be irritating for many. I love using Niacinamide as a toner ingredient - that way it isn’t just one more serum to layer on.

My picks:

Good Molecules Niacinamide Toner

UK- Inkey list Niacinamide Toner

Cos De Baha Niacinamide 10% serum


Most of us have heard of the benefits of Vitamin C. Topical Vitamin C is a proven and powerful antioxidant that can help to guard against skin damage from free radicals. L-ascorbic acid, the ‘active’ form of vitamin C is the most researched of the variants but it’s also one of the most irritating (I can’t tolerate it personally!). Additionally, it’s the most unstable - meaning it quickly loses its potency after being exposed to air. The net result is that Vitamin C as L-ascobic acid can be tricky to integrate into a regime. Thankfully, there are a host of other options! I'm working on a dedicated Vitamin C blog but in the mean time do have a look at my video Top Three Reasons to use Vitamin C.

Type: Antioxidant, skin brightener and all around anti-ager

Best for: Vitamin C is great for protecting against free radical damage, evening skin tone, and supporting the production of that all important collagen!

Results after: You'll see an increased glow pretty quickly - likely within a few weeks depending on the type and concentration you choose. Increasing collagen takes time and dedication so those results will come after three months minimum.

When to use: Typically I prefer to use my Vitamin C in the morning, layered over my essences. However, because I love a derivative (THD) I have the option to use this at night with my retinoid and/or copper peptide.

Do/don’t mix with: Vitamin C (l-ascorbic acid) can be quite potent so you'll want to take care using it with any of the AHS or BHAs. It is definitely OK to use a vitamin C after an AHA or BHA toner but always watch for irritation. With the l-ascorbic acid form of Vitamin C you should avoid using at the same time as retinoids as they can make your Vitamin C unstable and less likely to penetrate the skin. The exception is Vitamin C as tetrahexydecyl ascorbate (THD). As mentioned above, using the derivative THD increases the cocktailing possibilities (ok with retinol, ok with copper peptides).

Clinical proof: ROBUST

What to look for:

Vitamin C is an unstable molecule that will oxidize when exposed to light, so you'll want to consider product packaging carefully. There are three 'packaging' choices that I prefer. One is the obvious airless pump. The second is Vitamin C that is enclosed in single dose biodegradable capsules. The third is 'packaging that's inside the packaging' - in the form of lipophilic formulation. Effectively this is when you have little lipsomic spheres encasing the unstable Vitamin C, shielding it from exposure until it is released on your skin. Of course there are some very effective Vitamin C products in eye dropper packaging - these are perfectly fine to buy, just ensure that you keep them out of light, recap quickly and tightly and use up one before opening a second.

Like retinoids, Vitamin C is such a powerful yet complex creature that lots of research has been done to identify derivatives that give lots of punch without the irritation found in l-ascorbic acid. Furthermore, certain derivatives have been found to give benefits beyond antiaging. These are my favorite forms:

1. L-ascorbic acid (LAA) - the 'Anti-aging Angel'

2. Tetrahexyldecyl Ascorbate (THD) - the 'Anti-aging Angel - for Sensitive skin'

3. Sodium Ascorbyl Phosphate (SAP) - the 'Acne Slayer'

4. Magnesium Ascorbyl Phosphate (MAP) - the 'Hyperpigmentation Hero'

My picks:

1. L-ascorbic acid (LAA) - the 'Anti-ageing Angel'

Drmtlgy CE Ferulic Use Code M9HH1 for 20% off and to let them know I sent you, it is affiliate and I appreciate your support!

Paula's Choice C15 Super Booster

2. Tetrahexyldecyl Ascorbate (THD) - the 'Anti-ageing Angel - for Sensitive skin'

At SkinBeautifulRX if you use the code "Penn20" you get 20% off. I get an affiliate commission and lets Leah (one of my favorite humans ever!) know I sent you. I appreciate when you use my code and let her know you heard about this from me!

3. Sodium Ascorbyl Phosphate (SAP) - the 'Acne Slayer'

4. Magnesium Ascorbyl Phosphate (MAP) - the 'Hyperpigmentation Hero'

Globiotics Advanced Vitamin C Brightening Serum Use the code "Penn20" for 20% off


Green tea (or Camellia Sinensis Leaf Extract) has been studied as a treatment for a variety of skin concerns including acne, rosacea and anti-aging. It works on a number of levels to both protect and repair the skin. The active parts are called polyphenols, or more precisely catechins (EGCG is the most important of the catechins). Green tea acts as a powerful antioxidant that scavenges free radicals caused by environmental factors such as UV rays. The EGCG compound is powerful stuff - it actually promotes DNA repair within skin cells-literally skin rejuvenating. Something that I find particularly amazing is that green tea is de-puffing (thanks to its caffeine content). So green tea is a moisturizing, free radical scavenging, puff-reducing superhero in my book!

Type: Antioxidant

Best for: Acne, rosacea, psoriasis, general anti-aging

Results after: Green tea and other antioxidants are as important for prevention as they are for repair (as we all know "an ounce of prevention is worth a pound of cure"!). Don't expect big changes in your skin when using products with green tea (or slathering on the tea itself)... it has a quiet but profound effect, when included as part of a regular routine.

When to use: Morning and/or evening - often I use twice a day. One small study shows that the application of green tea 20 minutes in advance of red light therapy can speed the effect of the red light by tenfold. It is notable that is was a very small study but given what we now know about green tea it is not a far stretch to credit green tea with boosting LED results!

Do/don’t mix with: Green tea is such a friendly ingredient and will mix well with nearly anything in your routine. I love to combine my green tea toner and serum with a daily dose of red or green LED. As far as other ingredients go, green tea is fantastic when combined in products (or layered by you) with other antioxidants. This mingling of antioxidants adds synergy to your skincare routine (the more the merrier when it comes to antioxidants); vitamin C helps prevent the degradation EGCG (epigallocatechin gallate, the amazing polyphenol in green tea) while EGCG boosts the antioxidant effect of Vitamin C.

Clinical proof: ROBUST

What to look for: Green tea is one of the most researched natural ingredients. The best extracts contain 50-90% catechins (the ingredient that makes the product brown). Additionally, it should be stored in a dark, airtight container to prevent oxidization.

My picks:

Isntree Green Tea Toner:


Green rooibos tea (or Aspaalthus linearis Leaf Extract) is also rich in polyphenols because, like green tea, it is extracted from the fresh leaves, which are not oxidized. The main flavonoid in rooibos is called Aspalathin.

Recent research on green rooibos shows that it is a powerful antioxidant for cosmetic application, as well as supports wound healing. Like green tea, rooibos is anti-inflammatory and antibacterial. Rooibos is rich in Superoxide dismutase, as well as rich in AHAs and zinc. In support of anti-aging, rooibos has antiglycation properties, helping to prevent collagen cross-binding, which can contribute to a dysfunctional collagen matrix. Green rooibos has a novel property, helping to protect and repair preadipocytes (fat stem cells). Loss of fat stem cells, found in sub-cutaneous adipose tissue in the face, leads to sunken eyes, skin folds and fine lines and wrinkles. Studies show that rooibos protects and repairs these fat stem cells, helping to maintain skin fullness and a youthful appearance.

Maysama Rooibos Serum (not green tea but green rooibos which has similar properties)

Use Code Penny10 to get 10% off this powerhouse antioxidant :)


Estrogen is a key component of skin function (who knew?!?) It's been shown to be vital to skin elasticity, hydration and thickness. As women age, we experience a normal decrease in estrogen. Estrogen deficient skin is less bouncy (loss of elastin) has less structure (loss of collagen) and less suppleness/glow (loss of hydration.) And it is exactly that - decreases in elastin, collagen and hydration - that contribute most to making us look older.

Enter MEP. MEP is a non-hormonal way to activate skin estrogen receptors. It's what's known as an 'estrogen analog' that interacts with estrogen receptors in the skin but unlike topical estrogen Its effect is entirely local (in the skin). Studies show MEP is quickly dismantled into an inactive metabolite and expelled without being absorbed in the body. I'm fascinated by the topic of what happens to our skin during perimenopause and menopause and will be covering this topic extensively in the future. In the mean time, check out my post Estrogen deficient skin - what's the deal?

Type: Non‐hormonal Estrogen Receptor Agonist (NERA)

Best for: Estrogen-deficient skin (characterized by dryness, wrinkling, thinness and itching in women who have entered perimenopause or menopause, either chronologically or otherwise.) Currently MEP is a found exclusively in the brand Emepelle.

Results after: Emepelle studies found after 14 weeks a 54% increase in hydration, a 39% increase in luminosity and a 19% increase in firmness.

When to use: There is a serum for use in the morning as well as a night cream. You could choose one or both (study results noted above were using both serum and night cream, although if you only use one I'd recommend the night cream as it has a higher concentration of MEP)

Do/don’t mix with: Take care using it alongside Vitamin A and Vitamin C as it already includes these ingredients (no need to avoid, just pace yourself!)

Clinical proof: SOLID

What to look for: Emepelle is the only brand that contains MEP

My picks:

Emepelle US:

Emepelle UK

The code to enter is: EMEP054

This code gives you 2 free Heliocare products when you purchase the Emepelle duo (saving of £65.99)


Superoxide Dismutase such an exciting ingredient. It's a naturally-occurring enzyme found in the body that protects cells from highly reactive, cell-damaging superoxide radicals. Superoxide dismutase is the most abundant antioxidant in our body but like so many things, as we age we get depleted. I like to think of superoxide dismutase as a crime fighter and superoxide is the bad guy...We want that crime fighter on duty as much as possible! Superoxide dismutase doesn't like to work it scavenges free radicals (those pesky things that age us on a cellular level) it signals other antioxidants to come help. It is really a remarkable work horse that I think should be in every skincare routine!

Type: Antioxidant

Best for: Overall anti-aging and antioxidant protection. Oxidative stresses are everywhere and the constant assault is aging. SOD helps to protect against that aging assault!

Results after: results are ongoing- many products with SOD also contain a whole host of hydrating ingredients and other antioxidants...This can improve the appearance of skin immediately and also over time.

When to use: I like to use NIOD SOD immediately after washing my face and let it dry before applying serums.

Do/don’t mix with: Mixes with most anything

Clinical proof:

What to look for: I love applying SOD in a mist, and especially love it when combined with a Sacchaide as in the NIOD product. Do look for it as an ingredient in serums (I use Maysama Green Rooibos serum for the extra SOD kick contained in green rooibos!)

My picks:

NIOD Superoxide Dismutase Mist: Do NOT buy it on ebay for more than it sells for normally.


There are a host of different AHAs out there, but my favorites are lactic and glycolic. AHAs work on the surface, eating away at dead skin to reveal a brighter, glowing complexion. They also work beneath the surface and help to even skin tone and texture while encouraging new cells to come to the top. I feel strongly that AHAs should be essential component to most person's anti-aging routine. However, they can be drying and irritating. If your skin is prone to sensitivity, you'll want to go 'low and slow'. Lactic acid is not only more gentle than Glycolic acid, it is also a humectant. This means that lactic acid is a great place to start if you are dry while glycolic is a little more potent and best suited for those without dry skin issues. This doesn't mean that my dry skin friends can never use glycolic acid. Just always watch for irritation and think "gradual progression" with acid percentage and frequency.

Type: Exfoliant

Best for: Glow and cellular turnover.

Results after: You'll note a glow after the first use, with more visible results with continued use.

When to use: I like to use my AHAs in toner form in the morning.

Do/don’t mix with: Be careful using AHAs with Tretinoin or other strong retinoids… pace yourself!

Clinical proof: SOLID

What to look for: most AHAs are best at PH ranges below 4 and concentrations of 4-10%

The lower the PH the more intense the acid (and also more potential irritation). Just because the percentage of the acid is high won't mean it is intense. A low PH and middle range acid percentage can equal an effective exfoliator. Example: an AHA with a PH of 3.5 with 8% glycolic will be nicely effective. That same product with a PH under 3 might be too harsh and irritating. This balance is important.

My picks:

REN Ready Steady Glow

Youth To the People 11% AHA Power Toner:

Perfect Image Tri-clarity Peel Pads

Perfect Image Hydro-Glow Peel Pads

QrxLabs Glycolic Acid 20% Resurfacing Pads for Face & Body

Obagi Exfoderm Forte (this is a combo of glycolic and lactic acid in a lotion form. A long time favorite!)


Salicylic acid is the most well known BHA and is oftentimes included in products to address acne and clogged pores. This is because it’s oil-loving, meaning it can get deep into your pores and help exfoliate the pore lining enabling dirt, debris and makeup to be washed down the drain. Salicylic acid is also anti-inflammatory-making it the perfect first line of defense for acne and congestion (blackheads).

Type: Exfoliator

Best for: Acne and congested skin

Results after: Salycylic acid goes straight to work at desincrustation; dislodging dead skin and dissolving the stuff that blocks pores, but you’ll seen best results with continued use.

When to use: Depending on your skin concerns and sensitivity you may want to start with two to three times a week and work yourself up to daily use of a salycytic acid toner. Gels can be applied as needed to address specific areas of breakout. Salicylic washes are also a great choice as SA is one of the few acids that are efficacious even in a wash off form.

Do/don’t mix with: As with AHAs, be careful about combining BHAs with other potent active ingredients such as retinoids and ascorbic acid. Always watch for irritation (yes, I know I say that a lot lol).

Clinical proof: SOLID

What to look for: As with AHAs, look for a PH under 4. SA is great in percentages from .5-2%

Salicylic acid is great in an wash, toner, and a peel. Salicylic acid is good for razor bumps (ingrown hairs) KP (bumps often on the back of the arms) as well as acne and blackheads.

My picks:

Just Breathe Clarifying serum (niacinamide, salicylic acid, zinc):

Obagi Clenziderm 2% toner (a favorite I have used in-office for years)

Obagi Clenziderm 2% Salicylic Wash

Cereve SA wash (this can be used on the arms too!)


Hyluronic acid has been perhaps the most buzzed about ingredient of the past few years. You may have heard of hyaluronic acid (HA) in skincare but did you know that it is naturally found in our body? HA is an incredibly important component when it comes to healthy, vibrant, youthful skin. When you think of a child's face you might picture that supple, bouncy youthful skin. This is partially due to ample amounts of HA (ok and collagen and elastin). As we age we want to re-hydrate the surface as much as possible and encourage natural HA proiduction on the inside as well.

The molecular sizes of different hyaluronic acids vary from bigger molecules that stay on top of the skin’s surface to smaller ones that can go in deeper into the epidermis. Many toners and serums use this powerhouse humectant in their formulas making it an easy active to get in to your skincare routine.

Type: Hydrator

Best for: Dehydrated skin and using as a 'slip agent' when microneedling with a pen.

Results after: Depending on dehydration levels and the product you choose, you may see a difference right away.

When to use: Look for products that contain HA - that way it's easy to fit in twice a day

Do/don’t mix with: HA mixes with just about everything

Clinical proof: STRONG

What to look for: I recommend HA for slip when microneedling. But not just any HA - Dr. Lance Setterfield, one of the leading authorities on microneedling, recommends that we only use high molecular weight HA while microneedling for collagen induction (CIT) at depths of .5mm or over. This is because of the anti-inflammatory nature of high molecular weight HA. To understand this more please visit my microneedling playlist. Outside of microneedling, I like a 'mixed weight' HA.

My picks:

High molecular weight hyaluronic acid (best type to use while microneedlng)

Cos de BAHA

Timeless 100% pure Hyluronic acid

Mixed molecular weight hyluronic acid

NIOD Multi Molecular Hyaluronic Complex


Azelaic acid is in a class of acids called dicarboxylic acids. Azelaic acid has long been used by dermatologists to treat rosacea as its suitable for all skin types and can help to reduce sensitivity. Azelaic acid is antibacterial - reducing the growth of bacterial in the hair follicle. Azelaic acid is also quite anti-inflammatory. This combo makes it an incredible acne fighter. Because azelaic acid is also a pigment inhibitor it is helpful to use post-acne to combat PIH (dark marks left after a trauma or blemish).

If you have rosacea and you haven't investigated azelaic acid I urge you to check it out!

Typically percentages of 15-20% are quite effective. If you feel you need the higher percentages you may want to consult a dermatologist to determine the right azelaic acid product for you.

Type: Exfoliant, antibacterial, pigment inhibitor

Best for: Acne, hyper-pigmention, PIH and rosacea

Results after: You'll want to give a full three months to evaluate

When to use: Gentle enough that it can be used in both your morning and evening routine.

Do/don’t mix with: Like niacinimide, azelaic acid is easy to combine with most any ingredient.

Clinical proof: SOLID

What to look for: Happily, Azelaic acid is a relatively inexpensive ingredient that can be found in a range of products. I recommend that you ease your way into using it if you have dry or sensitive skin. You might also consider 'buffering' it by layering it on top of a moisturizer.

Of course, as with most ingredients like this the prescription strength is more potent and does require a visit to your dermatologist :)

My picks: PENN

Finnacea prescription 20% Azelaic Acid (through a derm)


Beta glucan is a humectant that, much like hyaluronic acid, attracts water to the top layers of skin. Beta glucan is an ingredient that soothes irritated skin and helps to calm redness. Beta glucan is a polysaccharide (a sugar) derived from yeast or oats typically and is your skin's best friend if you struggle with skin barrier issues (redness, dehydration, itchiness, flakiness or acne). The anti-aging benefits of BG are readily apparent as lines and wrinkles get slightly diminished with even the first use (hello hydration! hello calm skin!). You can learn more in 5 Superstar Products I'm LOVING - the Beta Glucan bit starts at minute 4:30.

Type: Hydrator, antioxidant, antibacterial and antiviral

Best for: Calms redness, supports skin barrier, smooths skin

Results after: Like hyluronic acid, you'll see an initial increase in hydration

When to use: Morning, evening - or both!

Do/don’t mix with: Mix with what you like - it works well with all other ingredients.

Clinical proof: SOLID

What to look for:

My picks:

IUNIK Beta-Glucan Power Moisture Serum


There are many types of signal peptides that take messages throughout our body. For example, when our collagen breaks down, signal peptides send a message telling our body to make more collagen to replace what’s been lost. Applying signal peptides topically entices our skin into thinking it needs to make more collagen. Perhaps the most widely known signal Peptide is Matrixyl™️ 3000 which is actually a combination of two peptides. Matrixyl™️ 3000 promotes the production of collagen and elastin by nourishing our supplies of fibroblasts and glycosaminoglycan. Sounds good, doesn't it? The interesting thing is that the studies back it up. One study showed that after two months of treatment with Matrixyl™️ 3000, the area occupied by deep wrinkles was reduced by 45%, and the skin’s tonicity increased by nearly 20%.

Type: Peptide

Best for: Antiaging

Results after: Signaling peptides require a commitment - I'd recommend three months before you evaluate effectiveness

When to use: Morning or night

Do/don’t mix with: Care must be taken when mixing peptides with strong antioxidants. I avoid using my peptides along with vitamin c in the form of L-ascorbic acid but some practitioners allow for their layering without issue.

Clinical proof: STRONG

What to look for: Look for the ™️ when buying MATRIXYL and also the concentration

My picks:

Timeless MATRIXYL™️ 3000 SERUM


I love Copper Peptides. There, I said it! Since falling down the CP rabbit hole a few years ago, I've been fascinating by the role they have not only in collagen synthesis but also the creation of other crucial skin-identical ingredients such as elastin and glycosaminoglycans. It also plays a crucial protective role by stimulating the antioxidant enzyme superoxide dismutase (see above for more on SOD!) Copper Peptides are shown to tighten skin and improve elasticity, density, and firmness. They can reduce fine lines as well as deeper wrinkles. It can improve skin clarity and even reduce hyperpigmentation. It's a star.

Type: Peptide

Best for: Wrinkles, sagging,

Results after: Beginning at three months, but this is a long term relationship💕!

When to use: I like to use copper peptides in the morning, alternating with Vitamin C.

Do/don’t mix with: L-ascorbic acid

Clinical proof: STRONG

What to look for: First and second generation. First gen is best for anti-aging, second gen is best for scar revision and remodeling. See my copper peptides video for even more info!

My picks: NIOD CAIS: US

Dr Pickart's Super CP serum (second generation copper peptides)

The Ordinary Buffet+Copper Peptides:


Tranexamic acid is all about helping to manage hyper-pigmentation and is one of my favorite ingredients to manage melasma, PIH and other pigment issues. Tranexamic acid works 2 ways-both as a tyrosinase inhibitor (like hydroquinone) and by blocking the transfer of melanin from the melanosomes to melanocytes (like niacinamide). Brilliant! Tranexamic acid also calms the helps restore the skin's barrier. This is a superstar in the fight against hyperpigmentation.

Type: Pigment inhibitor, skin brightener

Best for: Fades discoloration, brightens skin, reduces the appearance of acne scars

Results after: Weeks to months. Everyone will respond differently to TA

When to use: I recommend that people start with a few times a week and see how the skin adapts. If all is well after the first 2 weeks (no dryness) then you can up to using it more often until you can tolerate it up to morning and night. If that is not tolerable, once a day is fine.

Do/don’t mix with: Tranexamic acid plays well with others but as always watch for irritation. Avoid use with retinoids (at the same time) to avoid irritation.

Clinical proof: STRONG - studies have shown that 3% TA is as effective as 4% hydroquinone!

What to look for: You know my opinion on pigmentation-busting ingredients - best to buy a cocktail because they work at different levels. I like TA combined with kojic acid, niacinimide and other ingredients that help attack the problem in their own ways.

My picks:

Skinceuticals discoloration Defense:

Dearskin Tranexamic Acid Serum (only available in 2 pack)


DMAE is a derivative of the B vitamin, choline which in turn is a building block for another chemical, acetylcholine. Acetylcholine a chemical that functions as a neurotransmitter—a chemical message released by nerve cells to send signals to other cells. As we age, acetylcholine breaks down and is less available to help the muscles on our face hold taught and toned. Because the skin on our face is attached to the muscles on our face, less-than-toned muscles create a sagging effect overall. In comes DMEA! DMAE helps acetylchloline to fire off to the muscles like it did when we were younger, encouraging more tone in both the muscles and skin. DMAE, when topically applied, is proven to help engage acetylcholine which help muscles contract. Additionally, DMAE has been shown to help increase skin thickness and luminosity.

Type: Neurotransmitter precursor

Best for: Sagging and laxity

Results after: I've noticed both immediate effects and as well as long term lifting.

When to use: I use DMAE in the ... PENN

Do/don’t mix with:

Clinical proof: SOLID

What to look for: Don't use too much; when high percentages are used they may contribute to a REDUCTION in fibroblasts. This is a case where more is NOT better.

My picks:

Printable versions of the graphics can be downloaded here

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Disclaimer: This post is not intended to provide diagnosis, treatment or medical advice. Content provided on this blog is for informational and entertainment purposes only. Please consult with a physician or other healthcare professional regarding any medical or skin related diagnosis or treatment options. Information on this website should not be considered as a substitute for advice from a healthcare/skin professional. The statements made about specific products throughout this website are not to diagnose, treat, cure or prevent disease. It is important that you check labels to determine if a product is right for you. Before starting any treatment at home consult a health care or skin care professional to determine if it’s right for you.

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Feb 13, 2023

Love this! I'm personally wondering how does one know if a product has antioxidants that are too strong to be used with (copper) peptides. NIOD SOD isn't too strong, so is green tea okay? Feeling like a total noob with this one. Does anyone know?


David William
David William
Sep 26, 2022

Can you use a copper peptide and tranexamic acid in the same routine?


Ray Watson
Ray Watson
May 02, 2022

Dermalmd lightening serum smells amazing, it is PERFECT for my oily skin. I apply it daily before sleeping, it has given me lighter skin tone one or two drops are enough and it has made my skin smooth and less oily plus the added coolness! worth it.


Feb 16, 2021

Hi Penn, When looking at active ingredients in serums such as AHA's/BHA's, is there a cheat sheet for optimal % the ingredient you should be looking for in a product? I mean, even the same ball park. Does it depend on the condition you are trying to treat? Like me, anti-aging, dry skin, broken capillaries on my cheeks, hyperpigmentation.

I also get confused it the product has multiple active ingredients in them. I am using your Active Topical Ingredients guide. This is a tremendous help as to what while with each of my skin issues.


Katherine Sweet
Katherine Sweet
Nov 18, 2020

Hi Penn! I just discovered you and am basically spending every waking minute I can watching and reading your posts so I can catch up. This post is a particularly genius treasure trove. Thank you so much! I'm 45, a mom to a 6-yr-old and with a full-time job, and my face is falling! While I actually like some of the definition that's appearing, I DO NOT like the emergence of jowels, eye sockets/circles, and the downturn of my mouth. I'm about to invest - thanks to you - in a micro-needling pen, microcurrent device, and switch up my skincare, holding onto my beloved tretinoin (I'm 10 years in), vitamin-c, and various NIOD products. Thanks again for putting all this…

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