The Skincare Series:
4. Retinoids

Retinoids have been used since 1970 as an acne treatment. Since then, every year that passes seems to find a new use for them. They are applied in creams or can be taken as tablets. Its benefits are legion:

  • Reduce sebaceous gland size and secretions.
  • Reduces the number of bacteria in the skin.
  • Suppresses keratinization, which keeps dead skin cells from clumping and causing clogged pores.
  • Reduces inflammation.
  • Decreases sun damage (photoaging) such as wrinkles, dark spots and roughness.
  • Taken orally, retinoids can treat rosacea and psoriasis and can slow the progress of some skin cancers.

In short, retinoids are the absolute gold standard for skincare. There is some complexity to them, and we will try to sort it all out for you here.

Retinoic Acid

There are many different retinoids, but your skin can only use the active form, known as retinoic acid. This chemical binds to the retinoid receptors in our bodies. That's where it does all the magic of normalizing cellular renewal and repair processes.

The most potent retinoids are pure retinoic acid. With one exception (we'll discuss this all more below), they are available only by prescription. There are two reasons for this. The primary one is that many studies have found that super-high oral dosages of retinoic acid can cause birth defects in rats. This has been extrapolated to humans even though the doses are lower, and probably most of the human applications are topical, not oral. Many people think this is an over-reaction, but no one wants to take the chance of causing birth defects.

The second reason is that pure retinoic acid can also be extremely irritating to the skin.

Many people think the only retinoids worth taking are the prescription versions. There are good reasons for starting with the over-the-counter ones. Aside from avoiding any risk of birth defects if you are pregnant, OTC retinoids are milder and have fewer side effects. You can slowly work your way up to more potent retinoids, eventually moving to prescription versions if you want. OTC retinoids do work, probably as well as the prescription ones, but they do take much longer. I know this from personal experience.

OTC Retinoids

Over-the-counter (OTC) or non-prescription retinoids are weaker because they must first be converted by enzymes in your skin to retinoic acid. The actual amount of retinoic acid you get after the conversion is different for everyone. A typical estimate is anywhere from 0.5-2%. There are several conversion steps, and some of the original gets lost at each step along the way:

Retinol Conversion Steps As you will see, it is possible to offer products that start later in the process and therefore become stronger.

Retinol Esters

Retinol esters are the weakest form because they must be converted three times before they turn into retinoic acid. If you have really sensitive skin, these might be the right choice for you. The most effective ester is Retinyl propionate. Retinyl palmitate is regarded as the next best choice. However, they are only mildly effective.

I've never used these, and I don't have any product recommendations. There are products available. If you are interested in retinol esters, I suggest you do some label reading at your drugstore.


Retinol is the most popular over the counter retinoid. Since it is already at stage two of the process, it only goes through two conversions before it turns into retinoic acid. More retinol can be converted to the active form, and therefore it is more effective. Retinol has been shown to induce precisely the same kind of skin changes as retinoic acid. However, it takes longer to do it. It is estimated to be anywhere from 10 to 20 times less potent than retinoic acid.

It is significantly more drying and irritating than the esters. Starting slow and working up in application and concentration is the key to getting your skin to tolerate retinol.

Retinol creams are easy to find. They are everywhere. The Ordinary has the following concentrations and amounts:

Obviously, as the concentrations increase, the risk of irritation also increases.

The Ordinary's retinol products are mixed with Squalane. You might not have heard of Squalane; I certainly never had. It is a plant-derived oil that is very hydrating. Personally, I find it a bit oily on my skin and wouldn't want to wear it in public. But since I only use retinol at night, I don't think it is a problem.

One important note about The Ordinary's Retinol formulations: Retinol is actually a pretty unstable molecule and degrades quickly. One of the reasons The Ordinary's products are cheaper than other companies is because they don't include some of the stabilizers that you do find in more expensive products. The Ordinary has recommended that you keep their Retinol products refrigerated.

NOTE TO EU READERS: At the moment, you can get retinol in the E.U. from any source. However, the Scientific Committee on Consumer Safety published an opinion (April 20, 2016) recommending that cosmetics should contain only 0.3% Retinol. If this is or becomes an issue, consider the Retinoic Acid Esters described below.

Retinoic Acid Esters

Please note that these are not the same as Retinol Esters. These are significantly stronger. This is a new generation of over-the-counter retinoids. There is not a lot of data on them yet, but they show great promise. One type is retinyl retinoate. This breaks down into both retinoic acid and retinol, which makes it active within one step. Studies have shown (at least so far) that retinyl retinoate supports collagen synthesis eight times more than retinol. It is also more effective for treating wrinkles and works on mild to moderate acne by fighting bacteria and reducing sebum production. It is well-tolerated and less irritating than other retinoids.

The other type of retinoic acid ester is hydroxypinacolone retinoate (HPR) which is often called "granactive retinoid" by cosmetic companies. Granactive retinoid is a complex that includes the active ingredient HPR in a 1:10 ratio with a solvent (dimethyl isosorbide). This means that you need to divide the percentage of granactive retinoid by 10 to get the actual concentration of HPR.

HPR binds directly to retinoid receptors, so its activity is similar to pure retinoic acid. It is fascinating to me that not only is it less irritating than prescription retinoic acid products, it is less irritating than 0.5% retinol (the lowest retinol that would be effective!). Right now, all the research comes from the manufacturer, who finds that HPR significantly reduces wrinkles, age spots, and sun damage. Another study found it has more significant levels of gene expression than retinol.

Obviously, with all the studies coming from the manufacturer, some bias is undoubtedly possible, and a bit of skepticism is called for.

The Ordinary Has two Granactive Retinoid products:

This second product is quite interesting since it contains not only a 2% concentration of HPR but also some pure retinol in a capsule delivery system.

Unfortunately, there are no studies. It is impossible to even compare these products to retinol because the molecules are different. I am looking forward to trying both of these products.

Generally speaking, they are regarded as much less irritating than Retinol and obviously less irritating than Retinoic Acid.

Granactive Retinoid is more stable than Retinol so you might not need to store these products in the refrigerator. However, note that the 2% emulsion contains Retinol, so you should probably refrigerate that product.

NOTE: You can get HPR over the counter in the U.S., U.K., and Australia, but Canada considers it a drug.


Adapalene at a 0.1% concentration was previously prescription only but is now available over the counter. It binds directly to some (but not all) of the retinoid receptors in our skin and does not need to be converted. It is highly effective at treating acne. Some studies show it is better than Tretinoin (see below) and better tolerated. It is not clear whether or not it will demonstrate the anti-aging effects of the other retinoids.

OTC Adaplene is found as Differin, ProactivMD Adapalene, and La Roche-Posay Effaclar Adaplene. These are all gels.



If you want stronger Adapalene at 0.3% concentration, you will need a prescription. Effects are the same as above.

No concentration of Adapalene is available OTC in the UK, Canada and Australia.


This is famously known as Retin-A. Since it is pure retinoic acid, it is approximately 20 times more potent than retinol.

It has a significant ability to reduce lines and wrinkles by restoring collagen formation and inhibiting collagen degradation. It tightens loose skin, smooths rough skin, fades brown spots and melasma, and reduces sallowness. It also treats acne via anti-keratinization (mentioned earlier).

Since it is so much stronger, it is also much harder on your skin. Irritation, dryness, peeling, redness, and even swelling are not uncommon. There's also the risk that tretinoin-induced inflammation can lead to hyperpigmentation.


This is the most potent topical retinoid. Like Adapalene, it only binds to some of our receptors where it is immediately active (no conversion required).

It is best known as the brand name Tazorac, which is a prescription medication for psoriasis and acne. It works better than Tretinoin for these conditions, although there's controversy about whether it is better or worse than Adapalene.

It also reduces wrinkles, fades pigmentation, shrinks pore size and thickens the epidermis.

It has similar side effects to Tretinoin and is definitely more irritating than Adapalene.


Trifarotene is the newest retinoid (the first new one in 20 years). It only became available in the U.S. last year. It targets only one retinoid receptor (the most common one found on our skin). It is, therefore, gentler than the other prescription retinoids. So far, it is being advertised as an acne medication. I can't find any mention of any of the different effects of the other retinoids.

It is definitely less irritating than Tretinoin and Adapalene, so if you have acne and have had trouble with these retinoids, give this one a try.


This is also known as Accutane, and you take it orally. It is used to treat severe acne that has not responded to other medications. It does work, but it is linked to many serious side effects, including cheilitis, tiredness, eczema, headaches, joint pain, bone disorders, and anemia. Users are also at higher risk for depression, suicide, and inflammatory bowel disease.

I'm not sure this one is worth the risk.

This brings us to the end of our drug/acid survey. In the next and final installment, we'll talk about how to start using them to get more beautiful skin! Don't miss it! Meanwhile, if you have comments or questions, please send the nice ones to me! To do that, you can