Why We Use CO₂ Extracts in Some Formulas
The extraction changes the material. The formula determines whether that difference is useful.
By Eric R. Cêch | Edited by Anita Felice
CO₂ extraction is used far beyond essential oils.
Food, flavor, cosmetic, fragrance, and nutraceutical manufacturers use it to work with spices, herbs, berries, seeds, flowers, and resins.
The reason is not simply that CO₂ is a modern extraction technology.
It can give us a different part of the plant to formulate with.
For Ananda, that distinction matters most when we are building topical formulas.
What CO₂ Gives the Formulator
Steam distillation is designed to recover volatile aromatic compounds.
CO₂ extraction can reach further into the oil-soluble portion of a plant. Depending on the botanical and the extraction conditions, the resulting material may contain terpenes alongside heavier constituents such as:
- sesquiterpene lactones
- triterpenes
- gingerols and related pungent compounds
- diterpenes
- carotenoids
- tocopherols
- phytosterols
- fatty acids
- waxes and resinous compounds
That does not make the extract automatically better.
It gives the formulator different molecules to work with.
And in an oil-based topical formula, that can be particularly useful.
Oil-Soluble Matters on Skin
The outermost layer of skin, the stratum corneum, is lipid-rich.
Oil-soluble molecules can have an affinity for that environment, but this does not mean that every CO₂ extract automatically penetrates skin more deeply or absorbs better.
Skin delivery depends on the particular molecule, its concentration, the carrier oils and other ingredients around it, and the finished formulation itself.
That distinction is important.
We do not choose CO₂ because we believe that "CO₂ penetrates better."
We choose it when the extraction gives us oil-soluble constituents we specifically want available in a topical formula.
Research with Arnica illustrates the difference.
Investigators studying Arnica's sesquiterpene lactones found that the compounds could enter and move through the stratum corneum. More interestingly, penetration was greater when the lactones were delivered as part of Arnica plant preparations than when the isolated compounds were tested alone. The authors concluded that the plant preparation itself influenced delivery. (PubMed)
That does not prove a universal advantage for whole botanical extracts.
It does demonstrate something important for formulation:
The molecule does not act in isolation from the material carrying it.
Arnica: The Extract and the Formula Both Matter
Arnica gives us an unusually useful body of research because its topical constituents have actually been followed into the skin.
A separate study examined sesquiterpenes from a supercritical CO₂ Arnica extract using human stratum corneum and epidermis in Franz diffusion cells. The compounds could be studied moving through the skin model, while the addition of penetration enhancers changed how much permeated. (PubMed)
Another study formulated the same type of supercritical CO₂ Arnica extract into six different semisolid bases.
The extract did not behave identically in every one.
Different bases produced different release and skin-deposition results. (PubMed)
That tells us something more useful than "Arnica CO₂ absorbs."
It tells us:
The extract matters. The vehicle matters. The complete formula matters.
That is how we approach topical formulation.
Why We Use Arnica CO₂ in First Reach™
First Reach™ begins with Arnica CO₂, but Arnica is not working alone.
The formula also contains CO₂ extracts of:
- Calendula
- Turmeric
- Ginger
These were chosen because their oil-soluble fractions give us a broader constituent profile than volatile oils alone.
Arnica CO₂ provides a concentrated sesquiterpene-lactone-containing botanical fraction.
Calendula CO₂ contributes a different family of lipophilic compounds: triterpenoids, including faradiol esters.
In experimental research, fractionation of Calendula CO₂ extract identified those triterpenoids as important contributors to its topical anti-inflammatory activity, with activity related to faradiol monoester content. (PubMed)
Ginger and Turmeric add still different groups of oil-soluble compounds.
This is the reason for using several extracts rather than asking one botanical to do everything.
One plant gives us one constituent profile. A formula lets us compose several.
A Formula Is More Than a List of Actives
Botanical extracts are chemically complex.
A CO₂ extract may contain dozens of compounds rather than one purified active ingredient. When several botanical extracts are combined, the finished formula contains several constituent families at once.
Those compounds can contribute in different ways.
Some effects may be additive.
Some constituents may act at different points within the same biological process.
Others may affect solubility, stability, skin partitioning, or the behavior of neighboring compounds.
And occasionally researchers observe effects from a whole botanical preparation that differ from an isolated constituent.
The Arnica penetration study is a useful example: isolated sesquiterpene lactones showed comparatively little permeation, while the compounds behaved differently when delivered within plant preparations. (PubMed)
That supports the possibility of a matrix effect.
It does not prove that every multi-ingredient formula is synergistic, and we should not use "synergy" as a blanket claim.
Instead, Ananda formulates for a combined and complementary constituent profile and looks for evidence when particular interactions have actually been studied.
That distinction matters.
Athlete Magic™: Three CO₂ Extracts, Three Different Contributions
In Athlete Magic™, we use CO₂ extracts of:
- Frankincense Carterii
- Ginger
- German Chamomile
They are not three variations on the same idea.
Frankincense Carterii CO₂
Frankincense is a resin.
CO₂ extraction reaches further into that resinous material than steam distillation alone, giving us a fuller lipophilic and aromatic fraction.
That broader resin profile is why we choose the CO₂ material here.
Ginger CO₂
Steam-distilled Ginger primarily gives us its volatile aromatic fraction.
Ginger CO₂ can retain heavier compounds such as gingerols and related pungent constituents that are not represented in the same way in the distilled oil.
That makes the CO₂ material a different ingredient for topical formulation—not simply a stronger Ginger essential oil.
German Chamomile CO₂
German Chamomile demonstrates the extraction question particularly clearly.
The flower naturally contains matricin. During steam distillation, heat converts matricin to chamazulene, producing the familiar deep-blue essential oil.
Supercritical CO₂ extraction preserves a different constituent balance.
Researchers directly comparing extraction methods measured α-bisabolol, matricin, and chamazulene and showed that extraction conditions materially changed the final Chamomile profile. (ScienceDirect)
So in Athlete Magic™, we are not merely deciding that Chamomile belongs.
We are deciding which Chamomile belongs.
Together, Frankincense Carterii CO₂, Ginger CO₂, and German Chamomile CO₂ bring three chemically different botanical fractions into the same composition.
That is the formulation logic.
Sun Radiance™: When the Useful Material Is Not the Aroma
CO₂ extraction has another role in Sun Radiance™.
The formula contains:
- Rosehip Seed CO₂
- Carrot Root CO₂
- Sea Buckthorn CO₂
- Rosemary Antioxidant CO₂
Here, we are not primarily interested in volatile fragrance molecules.
We are working with lipid-soluble botanical fractions.
Sea Buckthorn CO₂
Research on supercritical CO₂ extraction of Sea Buckthorn has identified fractions containing:
- carotenoids including β-carotene, zeaxanthin, and lycopene
- α-, β-, and δ-tocopherols
- phytosterols
- palmitoleic, linoleic, linolenic, oleic, and other fatty acids
Extraction pressure materially altered the resulting phytochemical profile. (PubMed Central)
This is precisely why "Sea Buckthorn" alone is not enough information.
The extraction determines which part of the berry we are putting into the formula.
Rosehip Seed CO₂
Rosehip Seed provides another oil-rich material.
A study of supercritical CO₂ extraction found the resulting seed oil particularly rich in linoleic and linolenic acids, followed by palmitic and stearic acids, with extraction conditions affecting both yield and fatty-acid composition. (ScienceDirect)
Again, this is not about extracting an essential oil.
We are choosing an oil-soluble botanical material for an oil-based skin formula.
Rosemary Antioxidant CO₂
Rosemary CO₂ serves a different role again.
Supercritical extraction can concentrate Rosemary's antioxidant diterpenes, particularly carnosic acid and carnosol. Research has demonstrated that extracts enriched in those compounds can slow oxidation in vegetable oils, with performance depending on both extract concentration and the oil being protected. (PubMed)
In Sun Radiance™, Rosemary Antioxidant CO₂ is therefore not there primarily as an aromatic Rosemary ingredient.
It is selected for the antioxidant fraction.
This is formulation at the level of the material rather than the plant name.
Ever Youthful™ and The Standard™
The same reasoning appears in our facial oils.
Ever Youthful™ uses Rosehip CO₂ and Carrot CO₂.
The Standard™ uses Rosehip Seed CO₂ and Carrot Root CO₂.
These are oil-based formulas, and the CO₂ materials are selected for the lipid-soluble botanical fractions they bring to that environment.
Rosehip gives us a fatty-acid-rich seed fraction rather than a volatile essential oil. Research on Rosehip CO₂ confirms substantial unsaturated fatty-acid content and shows that extraction conditions influence the material obtained. (ScienceDirect)
Carrot Root CO₂ similarly belongs to the formulation for its oil-soluble botanical fraction rather than because we need a distilled Carrot aroma.
The distinction is simple:
We select the form that contains the part of the plant we want to formulate with.
Why Several Botanical Extracts?
There is a temptation in botanical marketing to point to one celebrated molecule and make it responsible for the entire formula.
Plants rarely work that neatly.
Arnica does not contain only sesquiterpene lactones.
Calendula does not contain only faradiol esters.
Sea Buckthorn is not simply β-carotene.
Rosemary is not simply carnosic acid.
Each extract arrives as a constituent profile.
A finished formula brings several of those profiles together.
That allows us to formulate across different chemical families rather than maximizing a single ingredient.
The result may include complementary, additive, and—in specific circumstances—synergistic biological effects.
But the important distinction is that synergy has to be demonstrated; it should not be assumed simply because several plants are combined.
What we can formulate deliberately is the composition:
one material for its resinous fraction;
another for its sesquiterpene lactones;
another for its triterpenes;
another for its carotenoids and lipids;
another for antioxidant diterpenes.
Then we ask whether the materials make sense together for the purpose of the finished formula.
That is the difference between adding botanicals and formulating with them.
Extraction Is Only One Decision
CO₂ extraction is not the end of the formulation question.
A concentrated CO₂ extract may contain exactly the constituents we want, but topical performance still depends on:
- concentration
- solubility
- carrier oils
- other extracts in the composition
- release from the finished vehicle
- affinity for skin lipids
- stability
- irritation and sensitization potential
- how long and where the compounds remain within the skin
The Arnica research makes this especially clear: changing the formulation around the same extract changed release and skin deposition. (PubMed)
So we do not formulate from an extraction label.
We formulate from the material that extraction produced.
The Ananda View
CO₂ extraction gives us access to materials that can be difficult—or impossible—to obtain through steam distillation.
But access is not the same as judgment.
The important questions come afterward:
What did the extraction recover?
Which constituents does that give us?
Are those the constituents we want for this particular formula?
How will that extract behave in the oil system around it?
What do the other materials contribute alongside it?
That is why CO₂ appears in Athlete Magic™, First Reach™, Sun Radiance™, Ever Youthful™, and The Standard™ for different reasons.
There is no single "CO₂ benefit" repeated across every formula.
In one, we want a broader resin profile.
In another, sesquiterpene lactones and triterpenes.
In another, carotenoids, phytosterols, fatty acids, and tocopherols.
In another, an antioxidant diterpene fraction that helps protect the oil system itself.
The extraction gives us the material.
Formulation determines where that material belongs.
References
Arnica — Skin Delivery and Formulation
Wagner S, Suter A, Merfort I. Skin penetration studies of Arnica preparations and of their sesquiterpene lactones. Planta Medica. 2004;70(10):897–903. DOI: 10.1055/s-2004-832613. The study compared isolated sesquiterpene lactones with Arnica plant preparations and found greater permeation from the preparations, supporting the importance of the botanical matrix in topical delivery.
pubmed.ncbi.nlm.nih.gov/15490315
Bilia AR, Bergonzi MC, Mazzi G, Vincieri FF. Evaluation of skin permeability of sesquiterpenes of an innovative supercritical carbon dioxide Arnica extract by HPLC/DAD/MS. Pharmazie. 2005. PMID: 15700776. A supercritical CO₂ Arnica extract was evaluated using human stratum corneum and epidermis in a modified Franz diffusion-cell system; permeation was affected by the formulation environment and penetration enhancers.
pubmed.ncbi.nlm.nih.gov/15700776
Bilia AR, Bergonzi MC, Mazzi G, Vincieri FF. Development and stability of semisolid preparations based on a supercritical CO₂ Arnica extract. Journal of Pharmaceutical and Biomedical Analysis. 2006;41(2):449–454. DOI: 10.1016/j.jpba.2005.12.024. Different vehicles containing the same CO₂ extract produced different release and skin-deposition behavior.
pubmed.ncbi.nlm.nih.gov/16457981
Calendula
Della Loggia R, Tubaro A, Sosa S, Becker H, Saar S, Isaac O. The role of triterpenoids in the topical anti-inflammatory activity of Calendula officinalis flowers. Planta Medica. 1994. DOI: 10.1055/s-2006-959562. Fractionation of Calendula CO₂ extract identified triterpenoids, particularly faradiol monoesters, as important contributors to the measured activity.
pubmed.ncbi.nlm.nih.gov/7809203
German Chamomile
Kotnik P, Škerget M, Knez Ž. Supercritical fluid extraction of chamomile flower heads: Comparison with conventional extraction, kinetics and scale-up. Journal of Supercritical Fluids. 2007;43(2):192–198. DOI: 10.1016/j.supflu.2007.02.005. The study compared supercritical CO₂ extraction with steam distillation and other methods and measured α-bisabolol, matricin, and chamazulene directly.
sciencedirect.com/science/article/abs/pii/S0896844607000496
Sea Buckthorn
Mihalcea L, et al. CO₂ Supercritical Fluid Extraction of Oleoresins from Sea Buckthorn Pomace: Evidence of Advanced Bioactive Profile and Selected Functionality. Molecules. 2021. The extracts contained carotenoids, tocopherols, phytosterols, and substantial fatty-acid fractions; pressure significantly affected the resulting profiles.
pmc.ncbi.nlm.nih.gov/articles/PMC8615056
Rosehip Seed
Machmudah S, Kawahito Y, Sasaki M, Goto M. Supercritical CO₂ extraction of rosehip seed oil: Fatty acids composition and process optimization. Journal of Supercritical Fluids. 2007;41(3):421–428. DOI: 10.1016/j.supflu.2006.12.011. Rosehip CO₂ seed oil contained predominantly linoleic and linolenic acids, and extraction conditions affected its composition.
sciencedirect.com/science/article/pii/S0896844606004062
Rosemary Antioxidant CO₂
Vicente G, Martín D, García-Risco MR, Fornari T, Reglero G. Supercritical carbon dioxide extraction of antioxidants from rosemary leaves for use in edible vegetable oils. Journal of Oleo Science. 2012;61(12):689–697. DOI: 10.5650/jos.61.689. Extracts enriched in carnosic acid and carnosol increased oxidative stability in vegetable oils, with the effect dependent on extract concentration and the particular oil.
pubmed.ncbi.nlm.nih.gov/23196869
Yeşil-Celiktas O, et al. Relevance of phenolic diterpene constituents to antioxidant activity of supercritical CO₂ extract from the leaves of rosemary. Natural Product Research. DOI: 10.1080/14786410701591754. The work characterized carnosic acid and carnosol among the principal antioxidant constituents of supercritical Rosemary extracts.
pubmed.ncbi.nlm.nih.gov/17999341
Further Reading from the Ananda Apothecary™ Library
CO₂ Extracts vs. Essential Oils: When Does the Difference Matter? →
Eric R. Cêch's deeper discussion of the botanicals for which CO₂ extraction substantially changes the material—and those for which steam distillation remains the preferred expression.
Why CO₂ Extracts Make a Difference →
A shorter introduction to the difference between the material obtained through steam distillation and the broader oil-soluble fractions made possible through CO₂ extraction.
Research discussed here includes laboratory, ex-vivo, in-vitro, and formulation studies. Findings from individual extracts or experimental models should not be interpreted as demonstrating identical clinical effects from a finished Ananda formulation. Botanical composition, concentration, carrier system, and finished formulation all affect topical performance.
For educational purposes only. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.
