What is ferulic acid?
Since over a hundred years ago, scientists discovered it in a plant called "Artemisia," and since then, there's been no stopping it, as it's been found in various plants and foods.
Ferulic acid is one of the most classic phenolic acid compounds, characterized by the presence of both phenolic and acidic structures in its chemical makeup. It is precisely this unique chemical structure that determines its distinct character and efficacy.
Firstly, the basic structure of ferulic acid consists of a phenolic group and an unsaturated side chain (remember, double solid lines represent unsaturated bonds). As we discussed earlier, "unsaturated" itself is synonymous with reduction, which explains its potent antioxidant activity.
Secondly, when one molecule of ferulic acid encounters another molecule of ferulic acid with a free radical, it may result in the formation of a whole new compound - curcumin. Doesn't that excite you? Finally, a familiar component! It's quite heartwarming to see something you've heard of, isn't it?
And everyone is surely familiar with the anti-inflammatory and antioxidant properties of curcumin.
Thirdly, the true chemical name of ferulic acid is 4-hydroxy-3-methoxycinnamic acid. The term "methoxycinnamic acid" indicates that it is a derivative of cinnamic acid. As the name suggests, cinnamic acid is an organic acid found in cinnamon bark. If you've done some research on sunscreen ingredients, you might recall seeing an ingredient called "ethylhexyl methoxycinnamate" often listed as the second ingredient in the ingredient list of many chemical and physical combination sunscreens.
Molecular structure of Ethylhexyl methoxycinnamate
Cinnamic acid derivatives exert their sunscreen properties by efficiently absorbing UVB ultraviolet radiation through their conjugated double bonds. Since ferulic acid shares a similar structure, it can also play a comparable role in absorbing UV radiation and providing sunscreen protection.
Of course, despite its potency, ferulic acid does have some drawbacks. For instance, it may decompose under high temperatures and extreme conditions, and its solubility in water solutions might be lower. However, it's fortunate that it blends well with various polyols, making it relatively easy to incorporate into antioxidant formulations.
Effects of Ferulic Acid
Antioxidant effect
Ferulic acid exhibits multiple mechanisms in antioxidant action, such as inhibiting the generation of reactive oxygen species (ROS) and scavenging excessive free radicals. Additionally, it can chelate protonated metal ions and prevent lipid peroxidation.
In various in vitro and in vivo experiments, ferulic acid has been shown to significantly increase the activity of a range of antioxidant factors, including total antioxidant capacity (TAC), superoxide dismutase (SOD), and catalase (CAT) activity.
As early as 2006, a review analysis indicated that ferulic acid, as an excellent antioxidant, had been increasingly utilized in the treatment of various diseases. Moreover, in skincare products, the use of ferulic acid as an antioxidant has long been widely recognized.
Ferulic acid's antioxidant effects also manifest in significantly improving skin barrier protection when taken orally. For example, daily oral intake of 200mg of ferulic acid can substantially reduce transepidermal water loss and enhance stratum corneum hydration after two weeks.
While ferulic acid might not be as famous for its antioxidant properties as vitamin C, it possesses unique advantages. For instance, once it enters the skin or bloodstream, ferulic acid tends to stay active for a longer duration. For example, in situations where there is a high generation of oxygen free radicals within the body, when highly active vitamin C has already been depleted, ferulic acid might still be able to continue fighting until the last moment, showcasing its prowess in a "war of attrition."
Resisting ultraviolet radiation and radiation protection
Due to its structural similarity to cinnamic acid derivatives, ferulic acid naturally exhibits sunscreen effects, as research indicates it can directly absorb ultraviolet radiation in the 290-320nm range.
More importantly, as a naturally occurring sunscreen agent with antioxidant properties, ferulic acid is safer compared to other sunscreen ingredients like benzophenone derivatives. It is less likely to induce potential phototoxicity due to the excessive generation of free radicals, thus boasting a high safety profile.
A study in 2018 demonstrated that combining 1% ferulic acid with other sunscreen ingredients such as 5% ethylhexyl triazone (a UVA sunscreen agent) and 10% Bis-ethylhexyloxyphenol methoxyphenyl triazine (a UVA and UVB sunscreen agent) increased the SPF and PA values by 37% and 26%, respectively.
In recent years, due to the emissions of nuclear pollution, the potential hazards of ionizing radiation have become increasingly concerning to the public. However, one lesser-known fact is that even exposure to very low doses of ionizing radiation in environments where radiation levels slightly exceed the standard or are near the threshold can cause oxidative damage to organs and tissues, as well as DNA breakage. The milder effects include chronic inflammation, while the more severe consequences include tumors and cancer.
Several studies have indicated that ferulic acid can mitigate apoptosis in skin and tissue cells caused by various forms of ionizing radiation by promoting the Nrf2 signaling pathway.
Anti-inflammatory effects
Due to its potent antioxidant properties, it's no surprise that ferulic acid also exhibits anti-inflammatory effects. After all, many inflammatory signaling pathways are strongly associated with antioxidants. Numerous experiments have directly compared ferulic acid with various nonsteroidal anti-inflammatory drugs (NSAIDs) and glucocorticoid medications.
For instance, ferulic acid can suppress the gene expression of cyclooxygenase-2 (COX-2), leading to anti-inflammatory effects similar to those of NSAIDs.
In terms of intervening with pro-inflammatory factors in vitro, ferulic acid's effectiveness rivals that of the glucocorticoid medication dexamethasone. This indicates its significant anti-inflammatory potential.
Ferulic acid can lower the levels of most inflammatory mediators, such as the well-known prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-α), among others. It also reduces the synthesis and expression of inflammatory bodies in skin cells, significantly decreasing the damage caused by external extreme conditions to the skin.
Ferulic acid a certain degree of whitening effect
Ferulic acid does exhibit a certain degree of whitening effect, but it's not the most outstanding in this aspect. To avoid misrepresentation, I've collected some recent literature on the topic, and while there is research on ferulic acid's whitening effects, it's not extensive, and the quality varies.
A study conducted by a research team at Kyungpook National University in South Korea in 2018 demonstrated that ferulic acid can inhibit melanin synthesis and tyrosinase activity at the cellular level.
I'm not sure if you all remember, but we previously discussed the MITF gene, known as the microphthalmia-associated transcription factor in English. In terms of lightening and brightening skin, it's an incredibly crucial regulatory factor. Being at the top of the melanin synthesis pathway means controlling it can be more effective than many traditional methods of intervening with tyrosinase. That's why in recent years, more and more studies have shifted their focus to the MITF gene.
Regarding ferulic acid, research results have shown that in addition to inhibiting tyrosinase, it can also suppress the expression of MITF at the protein level.
There are many ways to intervene with MITF, and one method we previously developed is using small interfering RNA (siRNA) material called UNISOUL RNAiW, which can significantly reduce MITF expression at the transcriptional level. To enhance the stability and efficiency of siRNA delivery, we also encapsulated it in lipid nanoparticles for improved transfection.
Representative Product Review
Due to its inherent characteristics, ferulic acid is destined to be one of the best supporting ingredients in skincare products. Especially when compared to the frontline stars like vitamin C (VC), vitamin A (VA), and peptides, it may feel a bit overshadowed. Therefore, it's rare to find products named primarily after ferulic acid in skincare.
In skincare products, ferulic acid is effective at concentrations greater than 0.1%. In products aimed at efficacy, the concentration typically falls between 0.1% to 1%. If the concentration is too low, such as when it appears in trace amounts, it's likely just for marketing purposes. On the other hand, if the concentration is too high, it may increase skin irritation and could affect the texture and formulation of the product.
Dr Dennis Gross Skincare Skincare Ferulic and Retinol Anti-Ageing Moisturiser
The addition of ferulic acid at a concentration of 0.3-0.4% falls within the clinically effective range. By also incorporating approximately 0.1-0.2% of retinol and adenosine, the anti-aging effects of the face cream are solidified. Another commendable aspect is the inclusion of various whitening botanical extracts, such as gallic acid, ellagic acid, arbutin (in extract form), and Glycyrrhiza glabra extract, which work synergistically to inhibit tyrosinase activity.
One of the most remarkable features of this product is its base texture. The combination of silicone oil with a significant amount of cyclomethicone provides a luxurious sensation, although it may not be suitable for everyone's preferences. Unfortunately, it contains all the silicone types, including D4, D5, and D6, which are of concern to some users, so those who are sensitive to them may want to avoid it.
Kiehl's Ferulic Brew Facial Treatment Essence
Once again, we have a product from the Kiehl's brand that evokes mixed feelings. The combination of water and oil may make it feel deeply moisturizing for some with dry skin, but those with combination or oily skin might find it entirely unsuitable. Despite being named after ferulic acid, its concentration only reaches the effective dosage of 0.1%. However, it benefits from the permeation-enhancing effects of lactic acid and salicylic acid, which improve absorption.
Additionally, with around 1% of vitamin E and vitamin C derivatives, some fans wonder if this could be considered a similar formulation to SkinCeuticals' CEF combination. Many bloggers have hailed it as a potent antioxidant, but opinions vary. A downside is the low concentration of vitamin C, especially as it's in the form of AA2G, but it still offers some brightening and whitening effects.
When you consider that it's just a toner, providing good hydration and moisture retention alongside some antioxidant and absorption-boosting effects, it suddenly seems much more appealing compared to many other toners on the market.
Of course, that's if you're not too concerned about the price.
UNILIPO VITAMIN C SERUM
UNILIPO, the first efficacious serum officially launched in 2019, might have had a hint of resemblance to the Skinceuticals CEF formula in its earlier formulations. However, with the upgraded 3.0 version, in my opinion, it has become a complete antioxidant "monster."
Over the course of five years, from version 1.0 to the current 3.0, one can only imagine the transformations this product has undergone.
A good product is never just a simple assembly of active ingredients, but if it's meant to be a potent product, it must meet the minimum requirements for active ingredient concentration. Besides 10% Ethyl Ascorbic Acid (VC), 5% VC-IP, 1% vitamin E, and 0.5% ferulic acid, this product also contains 3% water-soluble ions of milk thistle and 2% Pterostilbene lipid microspheres.
In addition to these, there are many other components you may not be aware of, such as 0.4% Carnosine + Decarboxy Carnosine, 1% Daily Smooth, 0.8% Trehalose, 0.5% Panthenol, and so on, all working together to maximize the antioxidant effects of the entire vitamin C serum.
SKINCEUTICALS C E FERULIC
Since we're discussing the classic combination of CEF, Skinceuticals' CEF serum is a product that cannot be overlooked. We've already delved into the details of vitamin C in previous articles, so you can refer back to those for more information.
In this serum, ferulic acid is added at a concentration of 0.5%, alongside 15% L-ascorbic acid and 1% vitamin E. This classic combination not only delivers potent efficacy without causing irritation but also enhances the penetration and absorption of vitamin C more effectively. With such potent active ingredients, the serum performs well in terms of gentleness and permeation enhancement, showcasing its remarkable efficacy.
Perhaps the only drawbacks are its texture and price, although the latter might not be considered a true drawback. Texture can be subjective and difficult to please everyone. Additionally, many brands have introduced their own versions of CEF serums, claiming to be "equivalents" to Skinceuticals', but most of them only compete on price. It's important to note that "equivalent" doesn't necessarily mean comparable in terms of efficacy, and the concept of equivalence in this context is somewhat misleading.
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