Tocopherol vs. Tocopheryl Acetate

Q.  Can you talk about the differences between the different types of Vitamin E? 

A. I'd be happy to!

There are two forms of vitamin E: tocopherol and tocopheryl acetate.  Tocopherol is naturally-occurring, while tocopheryl acetate is synthetic.  Both are used in cosmetics as antioxidants, keeping oils from turning rancid, and for their reported benefits on skin (healing, anti-aging).  

The term "vitamin E" actually refers not just to one molecule, but a family of molecules that are chemically similar.  That's why sometimes you'll see the words "mixed tocopherols" on a vitamin E label. There are multiple forms of tocopherol, including alpha and gamma, and a sub-family of compounds called tocotrienols.  All of these compounds have the same chemical formula (same amount and ratio of atoms) just in slightly different arrangements (called isoforms.)  To simplify, instead of listing out each and every isoform, we refer to these compounds collectively, as "vitamin E."  The most predominant molecule in the vitamin E family is alpha-tocopherol, and most of the time, when one says "tocopherol," they are referring to alpha-tocopherol.  (As I will be doing for the purposes of this discussion.)

Tocopheryl acetate is the ester of tocopherol.  On a molecular level it is an tocopherol molecule with an acetate group added.  It is more stable than tocopherol, typically giving products a longer shelf-life.  In order for the body to absorb and use vitamin E, it must somehow remove the acetate group. Thus, many claim that tocopherol is more bioavailable to skin and for internal use because it can be absorbed without additional metabolism. (Source)

(Alpha) Tocopherol

(Alpha) Tocopheryl Acetate [Note the acetate group on the far left of the molecule

Interestingly, both tocopherol and tocopheryl acetate can be made synthetically.  So, while tocopherol is usually touted as "natural tocopherol," it may still be synthetic.

Tocopheryl acetate requires more steps and ingredients for production:

Dichloromethane-->Sodium chloride-->Xylene-->Zinc chloride-->Isopropyl ether-->PASSION FLOWER OIL-->SOYBEAN OIL-->SODIUM SULFATE DECAHYDRATE-->Isophytol-->Trimethylhydroquinone-->Vitamin E-->(POLYOL) (Source)

Whereas synthetically-produced tocopherol requires fewer steps:

Acetic anhydride-->Isophytol-->Trimethylhydroquinone (Source)

You'll notice, though, that both of these processes use a chemical called trimethylhydroquinone. This is one of the biggest problems that the Cosmetics Database has with both forms of vitamin E, because the finished products can contain traces of hydroquinone.  Hydroquinone is in a class of chemicals called aromatic organic compounds.  This means not just that it's aromatic in the sense of it being fragrant, but it contains a benzene ring.  If you're a reader of this blog, you'll know that I view most compounds with simple benzene rings with caution for their possible xenoestrogenic effects.  Animal studies have found hydroquinone to alter immune function and to increase the "incidence of renal tubule cell tumors and leukemia in F344 rats." (Source)  While the Cosmetics Industry Review board states that cosmetic use is unlikely to cause these effects, they do recommend its use at less than 1% in a product, and state that it should not be used in leave-on products.  So, if one were cautious about what they put on their skin, hydroquinone and hydroquinone-contaminated vitamin E would be an ingredient that I would recommend avoiding. 

What to look for

Now that we know that even "natural tocopherol" can be a synthetic compound and laced with hydroquinone, does this mean that all vitamin E should be avoided?  No.  There are safe forms of vitamin E.  Unfortunately, you're not able to tell the difference just by looking at a label. You have to dig deeper and ask the manufacturer of the product you're using.

The best form of vitamin E when considering contamination concerns, is vacuum-distilled.  This means that they'll take an oil with naturally-occurring vitamin E and basically suck the vitamin E out.  Vitamin E has a different evaporation point than the fatty acids in the oil.  So, under certain pressures the vitamin E separates from the oil, evaporates up through a tube, and is thus completely extracted. 

The oils most frequently used for vitamin E production are corn, soy, and rapeseed/canola.  Unfortunately, in the US, 90% or so of these oils are from genetically-modified crops.  So, if you want to take it a step further, ask if the vitamin E in the product is certified non-GMO.  Certified organic products cannot contain any genetically modified material, so the USDA organic seal on a product would ensure that the vitamin E used is non-GMO. 

Is Vitamin E Safe and Beneficial?

Contamination concerns aside, the Cosmetics Database still gives tocopherol a little flag for "cancer," albeit the risk is low.  (See the listing here)   

The Database gives vitamin E a mark for cancer based on a 1985 study where vitamin E mixed with soybean oil were injected in to mice and tumors formed.  (Whether the soy was GMO or the vitamin E vacuum-distilled or synthetic, the study doesn't specify.)  Either ingredient injected separately did not cause this effect, but for some reason, the ingredients created these tumors when mixed together. The study was repeated again in 1991, researchers found that tocopherol acetate alone caused tumors to form when injected, but tocopherol alone did not. 

The particular tumors that were formed in this study are called fibrosarcomas.  Fibrosarcomas are cancers of the connective tissue, and typically form under the skin at sites where vaccines have been administered.  The exact mechanism whereby these tumors form is still unknown, but it is believed that an inflammatory response occurs at injection site and triggers the cell mutation.  (Source)  Ingestion or topical application of vitamin E do not cause these tumors; it is unique to areas where multiple injections have been made, and these tumorigenic effects have not been proven to apply to humans. 

So, is vitamin E safe?  The answer is yes.  It's not just safe, but highly beneficial and a vital nutrient the body cannot live without.  One thing that I see as a flaw with The Cosmetics Database is that they don't factor in any positive information when scoring ingredients.  An ingredient could be the cure for cancer, but if it caused an allergic reaction in a test study in 1945, it would still get a negative score.

Ingestion and topical application of vitamin E has proven to be a powerful force against cancer.  This study found vitamin E to help reduce lung tumors in animals.  This study found vitamin E to be anti-inflammatory in the lungs and colon.  This study found vitamin E to have a potential role in breast cancer prevention.  Applied topically, vitamin E also shows strong anti-oxidant and anti-inflammatory properties.  This study found reduced inflammation and incidence of skin cancer in mice treated topically with vitamin E.  This study confirmed this potential in humans.  Additionally, very recent studies have found that tocotrienols may have the most health-promoting benefits. (Source) Tocotrienols are not found in tocopheryl acetate, and can be found in the highest concentration in solvent-free, vacuum-distilled vitamin E.

What about soy?

Most vacuum-distilled vitamin E is extracted from soybean oil.   There are many people who avoid soy based on hormonal concerns, thyroid issues, and allergies.  Only in cases of extreme soy allergy would I suggest avoiding a soy-extracted vitamin E.  Vitamin E extracted from soy does not contain any of the isoflavone phytoestrogens, so it is not a concern for the thyroid or hormonal balance.  (Isoflavones are largely insoluble in water and in oil, and are not found in soybean oil [Source].  The vaccuum extraction of the vitamin E from the oil further insures no isoflavone content in the finished vitamin E product, as isoflavones have a largely differing evaporation point than the mixed tocopherols. [Source][Source])  Naturally-extracted vitamin E is highly purified, and also lacks the most of the compounds that trigger allergies associated with soy.


Linear Sulfonate

Q. I just bought a natural cleaner and it contains LINEAR SULFONATE. Do you know anything about this? I have seen it compared to SLS's but maybe as a better option? I just want to make sure that it is not as equally carcinogenic - or that it is not bad!


A.  Thanks for your question, Tiffany! 

It turns out that "Linear Sulfonate" is not just one chemical, but a blend of several chemicals all in the same family.  I'm assuming the product you're looking at is Biokleen, as they claim on their website "Linear Sulfonate is a propriety blend of vegetable based surfactants."  While their blend is proprietary (read: not disclosed), we can take an educated guess at what this "Linear Sulfonate" is. 

There is a group of surfactants (detergents) that are called Linear Alkylate Sulfonates.  Traditionally, a blend of compounds are sold under the name Linear Alkylbenzene Sulfonate (commonly abbreviated LAS).

  • Decylbenzene sulfonic acid, sodium salt
  • Dodecylbenzene sulfonic acid, sodium salt
  • Tridecylbenzene sulfonic acid, sodium salt
  • Undecylbenzene sulfonic acid, sodium salt
  • C10-16 Monoalkylbenzene sulfonic acid, sodium salt
  • C10-13 Alkylbenzene sulfonic acid, sodium salt
  • C10-14 Alkyl deriv benzene sulfonic acid, sodium salt
  • C10-14 Monoalkylbenzene sulfonic acid, sodium salt
  • C10-13 Alkyl deriv benzene sulfonic acid, sodium salt

This blend of chemicals commonly known as LAS is likely what this "Linear Sulfonate" listing refers to. 


LAS can be acutely toxic when ingested or applied to skin at very high amounts.  It is most toxic when inhaled in powder form, with mortality occurring at a particle concentration of 310 mg/m3.  This concentration would likely only happen in an industrial setting, however, not posing a risk in household use as you would use it in a dishwasher or laundry soap.


At low concentrations (up to 2.5%), LAS typically does not exhibit skin irritancy, but at 5% it's moderately irritating and severely irritating at a 50% concentration.  Eye irritation can occur as well, but is easily reversed by flushing with water.  This study found it to be less absorbable by skin than SLS. (Source)


Not found to be a carcinogen or mutagen.

Reproductive Toxicity

Not found to be a genotoxin or estrogen mimicker.  However, in high amounts, it was found to increase the estrogenic effects of other pollutants in aquatic life. (Source)

It is found to be highly toxic to acquatic life, but is also highly biodegradable. (Source)

So, all in all, as long as you're not exposed to high amounts of LAS, I would consider it to be relatively safe as used in a laundry detergent or dishwasher soap.  Because of its irritancy and potential for moderate toxicity, however, I would avoid it in a personal care product. 



Linalool is a component of many essential oils, including orange, lavender, rose, rosewood, and coriander.  The main problem the Cosmetics Database has with linalool is the risk of skin irritation and allergic reactions.  Just like limonene, linalool is not a skin allergen in its pure form.  However, when it's oxidized, it can cause allergic reactions/sensitivity at high concentrations.  (Source

Also, like limonene, pure linalool has anti-cancer effects.  One study found that "...linalool exhibited comparable IC(50) values to the commercial drug vinblastine on the ACHN cell line" in killing liver cancer cells.  (Source)

This study found that linalool "may improve the therapeutic index of anthracyclines in the management of breast cancer, especially in MDR tumors."  In other words, it aided breast cancer drugs in killing breast cancer cells that had grown resistant to the drugs.  (Source)

Linalool also shows promise against leukemia. Among the substances tested "linalool showed the strongest activity against histiocytic lymphoma cells U937 (IC50: 3.51 microg/ml, SI: 592.6) and Burkitt lymphoma cells P3HR1 (IC50: 4.21 microg/ml, SI: 494.1)."  (Source)

So, again, we get back to the point that the Cosmetics Database doesn't give an accurate or full picture of linalool because it doesn't factor in the positive information.  Yes, oxidized linalool can cause skin reactions, but as long as the essential oil or linalool extractive is pure and fresh, it is not just safe, but beneficial.



Q. I love having essential oils in my bath & body products. I think they are a great alternative to synthetic fragrances due to phthalates, etc. I know that some essential oils contain naturally occurring components such a limonene and linalool. EWG's Skin Deep database rates these components poorly. I'm guessing it's because some people can have skin sensitivities to them. I'm not one of those people so I don't mind essential oils that naturally contain them. My issue with it is that when companies choose to list these components they sometimes get a poorer rating on their products posted on the database. Is it because the components have synthetic versions too? I feel like essential oils are unnecessarily being given a bad name. Can you please shed some light on this subject and help people to understand whether these components are good or bad?



A.  Hi Victoria--I think that's a wonderful question!

First, let's look at limonene, one of the major constituents of orange essential oils.  Limonene is typically not made synthetically because it is so cheaply and easily sourced from the orange industry. But on a molecular level, synthetic and natural limonene are identical.  It's possible that synthetic limonene can contain traces of contaminants, but for the most part, synthetic and natural act the same. 

The Cosmetics Database gives orange essential oil a "0-1" score, depending on the variety of orange.  But limonene, the major constituent gets a scary-looking "6."  Now, wouldn't it make sense that orange essential oil should score similarly, given that orange essential oil is 90 percent or more limonene? 

The discrepancy lies within how the Cosmetics Database works.  The Database is basically a collection of databases, gathering its information from about 50 other data sources.  Most of these databases pertain to workplace safety.  Limonene is much more widely used in industrial applications because it's cheaper than buying whole orange oil, so it shows up a lot more in these industrial databases.  But whole orange oil isn't used as much in industrial applications, so there is a lot less data, and thus, a lower score. 

So, does that mean that orange essential oil should score higher, like limonene, since orange essential oil is 90% limonene?  Is orange or any oil that contains limonene oil dangerous?

Let's look at the score for limonene in the Cosmetics Database. 

The biggest problem that the Database has with limonene is "allergies/immunotoxicity" and "irritation, (skin, eyes, lungs)."

One of the biggest source databases for the Cosmetics Database is HAZMAP, an occupational safety database, which, in turn, draws its information from the National Library of Medicine.  So, let's look at some actual source data. 

It turns out that the vast majority of the problems with limonene happen when the compound is oxidized, or turned rancid.  "Studies in guinea pigs revealed that air oxidized d-limonene, but not d-limonene itself, induced contact allergy." (Source)  In the 1960s, various citrus oils were studied for their tumor promoting effects.  Undiluted citrus oils were applied to skin that had been treated with a cancer initiator.  The citrus oils promoted the growth of the tumors (some malignant, some benign).  A few years later, it was discovered that only oxidized limonene promoted tumor growth.  (Source

In fact, the Cosmetics Database states that, "Upon storage and exposure to sunlight and air, limonene degrades to various oxidation products which act as skin and respiratory irritants and sensitizers."  So, it does acknowledge that it's not limonene itself that's problematic, but the compounds it turns in to when it turns rancid. 

And, in fact, several new studies have found limonene and citrus oils to have anti-tumor effects, preventing the growth of many types of tumors in animals treated with cancer initiators.  Here are just a few statements from different studies:

"D-limonene, which comprises >90% of orange peel oil, has chemopreventive activity against rodent mammary, skin, liver, lung and forestomach cancers." (Source)

D-limonene and other monoterpenes '"act through multiple mechanisms in the chemoprevention of mammary and other cancers." (Source)

"These results suggest that the monoterpenoid d-limonene might be a chemopreventive agent for colonic carcinogenesis in rats." (Source)

D-Limonene and other monoterpenes "are effective, nontoxic dietary antitumor agents which act through a variety of mechanisms of action and hold promise as a novel class of antitumor drugs for human cancer." (Source)

Robert Tisserand, one of the foremost researchers in the field of essential oils study states that, "Although even oxidised citrus oils are very unlikely to present a hazard in aromatherapy, this research very much underlines the importance of using relatively fresh essential oils, which have not oxidised."  [Essential Oil Safety, Tisserand, 1995]

So, how can you tell if the orange oil or limonene in the products you're using are oxidized or not?

The use of oxidized orange essential oil in a personal care product is likely not to pose any significant threat because the negative effects primarily apply to being exposed to full-strength limonene over extended periods of time.  But, if you want to play it safe, there are some simple things you can do to ensure the freshness of the product.  One thing to look for is the addition of rosemary extract or vitamin E.  Both ingredients are powerful antioxidants that help to keep the orange oil/limonene fresh.  Second, would be the smell.  If it smells like a fresh orange, lemon, or lime, it's likely fresh. Third, follow the manufacturer's shelf-life dates.  And fourth, if there's a question, ask the manufacturer about the freshness of the ingredient.  (A personal note: As a certified organic processing facility, at any time, anyone can ask us about any ingredient--from your ordering records we can tell you any certifying agency of the ingredient, the lot number of the ingredient, and the date of manufacturing/harvest for that ingredient, and the manufacturing date and batch number of our product.  We order our ingredients frequently and in small amounts, and make our batches in small amounts to ensure freshness.  Typically, when you order from us, the product you order has been made in the last two weeks.  We are very careful to store all our essential oils away from sunlight and heat, so we can give you the freshest products possible.)

I hope that begins to answer your question, Victoria.  As I've said many times before, the Cosmetics Database is a great place to start, but it can be incorrect or incomplete.  Because it only factors in negative information and doesn't consider issues of freshness, you don't get a full picture of the ingredient.  With its promise for being a treatment or prevention method for cancer, limonene is not only safe when used in a pesonal care product, its benefits are far-reaching. 

Tomorrow we'll take an in-depth look in to the second compound you mentioned, linalool.  



Q:  What about soy lecithin in lotion? Soy acts as estrogen in the body, right? Is it safe for external use? Thanks so much!


A.  That's a great question, Kelly! The active weakly estrogenic compounds in soy are called isoflavones. The jury's still out on isoflavones, as some studies have found them to be helpful in preventing breast cancer, but other studies have found them to contribute to estrogen dominance.  That aside--there are no isoflavones in lecithin.  The fats are pressed from the seed to create soybean oil, which is just comprised of fatty acids, no isoflavones) and then the lecithin is further extracted from the oil.  Lecithin exhibits no estrogenic effects, and is actually a vital nutrient in the body, present in our cells' membranes.