Types of Retinoids: What’s the Difference and How Do They Affect the Skin?
Skincare can be confusing—especially when it comes to retinoids. With so many different products and percentages available, it can feel almost impossible to choose the best one for you. To make matters worse, you often have to distinguish between different types of retinoids, as each one affects the skin in a slightly different way. Like I said, it can be confusing stuff to sort through!
Luckily, after spending over 30 years as an esthetician and product formulator, I have a lot of experience with retinoids. In this post, I will discuss the various types of retinoids and the pros and cons of each. I will also talk a little bit about the history of retinoids and how they work to achieve more smooth, youthful-looking skin. My hope is that it also brings you some much-needed clarity and helps you become a smarter, more informed skincare consumer. Let’s go!
The History of Retinoids
First, I want to give some background on retinoids, what they are, and how they came to be so widely used in the skincare industry.
Retinoids are a class of compounds derived from vitamin A. They have been researched since the early 20th century, which was when the structure of vitamin A was first discovered. Back then, most of the research had to do with using vitamin A to address specific skin conditions. It wasn’t until 1969 that research showed retinoic acid was beneficial for treating acne. Retinoic acid, or tretinoin, is the most active form of vitamin A (but more on that later).
In 1971, the FDA approved tretinoin for topical use in the treatment of acne. Soon after, Johnson & Johnson created the first prescription-only tretinoin cream. To this day, it’s still only available by prescription since it needs to be used carefully and specifically to manage potential side effects. You’ll often see tretinoin creams at only 0.1% or less. Only a tiny bit is needed because the body can readily accept it.
After that, in the ’80s, patients and doctors started noticing that tretinoin was providing powerful anti-aging benefits. With time, they noticed that the appearance of sun damage was greatly improved, and skin looked younger and smoother overall. This eventually led to tretinoin being used for anti-aging purposes as well.
My Personal Experience
In the late ’80s, I was an 18-year-old esthetician in Boston. I had just got my first job at a full-service salon, which offered skin services along with hair and nail services. One of the salon’s regular clients was a man named Dr. Thomas Fitzpatrick. At the time, he was the Chief of Dermatology at Mass General Hospital.
I’ll never forget the day he showed me his hands. He held out both of his hands and said, “Renée, can you see the difference in my hands?” One hand looked so much younger than the other; it had fewer wrinkles, fewer brown spots, and less uneven texture. It was all thanks to tretinoin.
Dr. Fitzpatrick would demonstrate how to apply tretinoin to his patients by taking a pea-size amount (which was what he recommended for applying to the entire face) and rubbing it on one of his hands. He would do this, day in and day out. To his surprise, he began to notice that one hand looked much younger than the other! This realization was what led Dr. Fitzpatrick to become one of the doctors instrumental in getting the FDA to recognize Retin-A as a cream that could help reduce wrinkles.
My Clients’ Experience
When the story broke on the TV news that there was a prescription that could be beneficial for wrinkles, everybody ran to the dermatologist. Here’s the thing, though. Back then, there wasn’t an awareness of how to use it. People began slathering it on like it was some sort of face cream when it really needs to be used sparingly and specifically to manage side effects.
Lo and behold, they were experiencing side effects like skin dryness, peeling, and even cracking. As an esthetician, my schedule suddenly became super busy. Clients were calling in and telling me, “Renée, my skin is so dry! Help me!” As I was talking to one client when she came in for her facial treatment, her nasolabial fold (laugh lines) cracked and started bleeding right in front of my eyes. It was crazy.
Now, what happened next was most of the people that were experiencing the harsh side effects decided to give up on it. However, I had a few clients that stuck with it, and I saw their skin transform. It took a while to see the improvement, but within 6-9 months, I really saw it starting to change for the better. Their pores looked smaller, pigmentation was disappearing, and there were fewer visible lines and wrinkles. Really, it was reversing the look of sun damage. It was incredible and I became a believer.
How Retinoids Affect the Skin
Remember how I said retinoids are derived from vitamin A? Well, our bodies can’t make vitamins, so we must get them externally. We can get vitamin A either through topical application or through the ingestion of beta carotene-rich foods like carrots, sweet potatoes, and spinach. When broken down, vitamin A and its metabolites are very beneficial. They can affect everything from vision to inflammation to the proliferation of cells.
Proliferation means growth. Retinoids increase cellular turnover in the skin, meaning they grow faster, which is going to make the skin a little bit thicker. They also make the outermost cells shed, which is why some people think it’s exfoliating, even though that’s really a secondary effect. This makes the stratum corneum (the outermost layer of skin) more compact, which gives a nice anti-aging benefit.
Retinoids also stimulate the skin to produce more glycosaminoglycans, which are compounds that have sugars in them. This helps aid in the moisturization of the skin and helps support collagen production. Finally, retinoids are antioxidants, so they help prevent a lot of oxidative stress. Retinoids are truly amazing and do so many great things for the skin!
Just remember that using retinoids is a marathon, not a sprint. They must be used consistently and carefully to achieve results and manage side effects. Check out my beginner’s guide to retinol and retinoids to learn more.
The Different Types of Retinoids
1. Retinoic Acid (Tretinoin)
Our skin can only use vitamin A in the form of retinoic acid. Since tretinoin IS retinoic acid (Retin-A is a brand name), it’s already in its most active form, which means it doesn’t have to go through any conversions to become retinoic acid. That explains why it’s so effective and why it has the potential to be so irritating. It’s a very tiny molecule that penetrates very readily and is easily accepted by the skin. The other retinoids have larger molecules and require more conversions. The more conversions it requires, the “weaker” a retinoid is.
As I said, tretinoin is only available by prescription, and it must be used carefully and consistently for the best results. I only suggest getting a prescription if you’ve been using other, milder retinoids for some time and you’re now looking to address the appearance of more serious sun damage.
I always compare it to running. If somebody wants to compete in a marathon, and they have never run before, they shouldn’t start running 10 miles a day (using prescription retinoids). They should slowly ease into it (start with milder forms first).
Read the beginner’s guide to retinol and retinoids.
2. Retinaldehyde (Retinal)
Retinaldehyde has a small molecular size and only takes one conversion to become retinoic acid, so it’s considered to be the “strongest” of all non-prescription retinoids. As such, it can be irritating, especially to people who have never used retinoids before. That’s why I recommend starting with something gentler and then working your way up to retinaldehyde.
Retinol itself is not necessarily functional within the skin, because it has to be converted to retinoic acid. This is actually a two-step process that occurs in the cell. It first gets converted to retinaldehyde and then it’s converted to retinoic acid. Even though it requires two conversions, it’s still very effective, which is why it’s found in so many cosmetic formulations.
Retinol is notoriously unstable. The “ol” in “retinol” means it has a hydroxy group on it that really wants to react with something. When this happens, let’s say in a jar or bottle, it’s degrading and will never get converted to retinoic acid in the skin. It reacts with temperature, air, water, and light. That’s why formulations with retinol should be manufactured in airless packaging.
It’s also important to avoid light. Retinol formulas shouldn’t be packaged in transparent containers, because it’s not photostable. That’s also why it’s not recommended to wear retinol during the day. UV rays can decompose retinol prematurely on the skin and create photosensitivity and phototoxicity, which is not good. That’s also why wearing SPF every day is so important!
I have been using retinol since I was 35. At the time, I had given up on a prescription retinoid, because it was causing eczema on my eyelids. I was testing my own retinol formula, and I remember waking up one day and noticing a pulsing sensation in my skin. I experienced the same thing when I used the prescription retinoid. That’s when I knew it was the real deal. I called it the Advanced Resurfacing Serum, and I’ve been using it ever since!
Read 4 things to look for in a retinol product.
What About Encapsulated Retinol?
Take a look at retinol products online or at the store, and you’ll see many of them list “encapsulated retinol” as an ingredient. This means that the retinol was put inside of an encapsulate, like a liposome or oil, to protect it from light and air exposure. Since retinol is notoriously unstable, hiding it inside of a shell gives customers some certainty that it’s stable when it’s time to apply it.
The downside of encapsulated retinol is that it’s expensive, so it might not be used at high levels. More importantly, though, there’s often very little retinol inside the encapsulates. So, really, you’re not getting very much retinol to your skin. Also, you need to ensure that the encapsulates will actually break open and release the retinol. Some of them break open from the force of rubbing the product onto the skin. Others disintegrate due to a change in pH when it comes into contact with the skin. Each one is a little different.
4. Retinyl Esters
This category of retinoids is considered to be the “weakest,” but it’s also the least irritating, which makes it perfect for people who have sensitive skin or are just starting out with retinoids. They are made up of larger molecules that require a three-step conversion to become retinoic acid.
Most skincare brands formulate with this type of retinoid since they’re much more stable than retinol. Some common retinyl esters include retinyl acetate, retinyl linoleate, and retinyl palmitate. The last one is probably the most popular because it was one of the earlier retinyl esters created.
The drawback of using a retinyl ester is the three-step conversion. There are discussions going on in the scientific community about whether or not this conversion is actually happening at any great level. Let’s say it’s included at 1.0% in a formula. Not all of that 1.0% is getting converted to retinol. Even less of the retinol is getting converted to retinaldehyde, and even then, not all of the retinaldehyde will become retinoic acid. At the end of the day, only a small portion is getting converted. Because of this, it may have less anti-wrinkle activity compared to retinol.
The Bottom Line
Without a doubt, retinoids are powerful skincare ingredients, and I’ve seen their effects firsthand on my clients’ skin and my own skin. At the end of the day, it’s up to you to decide which type of retinoid is best for you. The goal shouldn’t necessarily be to work your way up all the way to tretinoin. Many people stick with non-prescription retinoids, and over time, see amazing results.
Once you start using retinoids, it’s a long game. Make a commitment to use them consistently, otherwise, you won’t see the best results. I, for one, have been using retinoids since I was 35. I’m now 52, and my skin looks all the better for it!
Next, find out whether or not you should wear retinol in the summer.
Celebrity Esthetician & Skincare Expert
As an esthetician trained in cosmetic chemistry, Renée Rouleau has spent 30 years researching skin, educating her audience, and building an award-winning line of products. Trusted by celebrities, editors, bloggers, and skincare obsessives around the globe, her vast real-world knowledge and constant research are why Marie Claire calls her “the most passionate skin practitioner we know.”