The topic is short and compact
Triterpenoids are a class of compounds, not a raw material: betulin, ursolic acid, oleanolic acid, and Centella triterpenoids differ in solubility and the extent of scientific research.
Data on the barrier and collagen predominantly comes from cell cultures, animal testing, and small studies with combination products.
Free triterpenic acids have log P values of 5.8 to 6.7 and easily crystallize out in water-rich formulations; the carrier system and microscopy are decisive.
Birch bark extract is an active ingredient in an EU medicine for wound healing; healing claims are inadmissible for cosmetics and are particularly close to the threshold of medicinal products here.
According to Regulation (EU) No. 655/2013, properties of an ingredient must not be presented as properties of the final product; barrier and strength claims require evidence based on the finished product.
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What are triterpenoids and which groups are relevant for skincare?
Triterpenoids are a large class of substances composed of six isoprene units. For skincare, the pentacyclic representatives are particularly relevant—that is, molecules with five rings. The review by Ghiulai et al. (2020) distinguishes three main groups among them:
Lupane type: Betulin and betulinic acid from birch bark, as well as lupeol, which also occurs in fruits and vegetables.
Oleanane type: Oleanolic acid, which has been identified in more than 120 plant species, and glycyrrhizin from licorice. Marigold also contains oleanane derivatives.
Ursane type: Asiatic acid, asiaticoside, and madecassoside from Centella asiatica.
In addition, there are tetracyclic triterpenoids, such as the ginsenosides from ginseng. A second distinction is important for the formulation: Free triterpenic acids such as ursolic or asiatic acid behave differently from their glycosides like asiaticoside, where sugar residues are attached to the basic scaffold. The glycosides are generally more polar, whereas the free acids and alcohols are decidedly lipophilic.
For a brand, this implies: "Triterpenoids" is not a raw material designation, but a class of substances. The briefing, the raw material specification, and later the product information file must state which substance or which extract is meant, which plant it comes from, and in what concentration it is used. Only then can the available research, solubility, and claims be properly assigned.
Where do cosmetic triterpenoids come from and how much does their content vary?
Cosmetic triterpenoids come onto the market as plant extracts, enriched fractions, or isolated pure substances. The choice determines the content, range of variation, and declaration.
Source | Typical triterpenoids | Relevance to formulation |
|---|---|---|
Birch bark | Betulin, betulinic acid, lupeol, oleanolic acid | very lipophilic, can be used as a dry extract in oils |
Centella asiatica | Asiaticoside, madecassoside, asiatic and madecassic acid | Glycosides and free acids with varying solubility |
Licorice | Glycyrrhizin and its aglycone glycyrrhetinic acid | Content strongly depends on the extraction process and fraction |
Marigold | Oleanane derivatives | mostly used as a whole extract, inquire with the supplier about the content of reference substances |
How widely the content fluctuates is illustrated by Centella asiatica. According to the review by Bylka et al. (2013), triterpene saponins account for 1 to 8 percent of the constituents, depending on the origin of the plant. The European Pharmacopoeia requires at least 6.0 percent total triterpenoid derivatives, calculated as asiaticoside, for the herbal drug. In contrast, the finished products mentioned in the review, such as Madecassol, contain a standardized fraction of 40 percent asiaticoside and 60 percent asiatic and madecassic acid.
For procurement, this means: An extract with the same INCI name can have a very different active ingredient content depending on the supplier. It is advisable to agree on a specification with content details of the reference substances, analytical method, and permissible variation per batch. Without this information, neither the usage concentration is reproducible nor can a subsequent advertising claim be substantiated.
What do studies show regarding skin barrier and firmness?
The state of research is mechanistically interesting, but is predominantly based on cell culture and animal data as well as on small studies with combination products. For the two positioning fields, it looks like this:
Skin barrier
Matsubara et al. (2017) tested 19 triterpenoids for the inhibition of the protease kallikrein 5 (KLK5), which is involved in the desquamation of the stratum corneum and can be excessively active in rosacea and atopic dermatitis. Ursolic acid and oleanolic acid inhibited KLK5 at 10 µM in the enzyme assay by approximately 55 and 52 percent, respectively. In human keratinocytes, ursolic acid reduced the processing of the antimicrobial peptide LL-37 at non-cytotoxic concentrations. The authors also refer to earlier work in which ursolic and oleanolic acids improved barrier recovery in the tape-stripping model. These are indications of a mechanism, not proof of efficacy for a finished product.
Firmness and elasticity
For Centella asiatica, the review by Bylka et al. describes the induction of type I collagen synthesis by asiaticoside in human dermal fibroblasts. The cited clinical study on photoaged skin included 20 women between the ages of 45 and 60 who used a preparation containing 0.1 percent madecassoside and 5 percent vitamin C for six months; firmness, elasticity, and skin hydration improved significantly. The effect can therefore not be attributed to the triterpenoid alone. For the clinical studies on cellulite cited there, the same review notes that most lacked a control group.
The raw material data support the selection of the active ingredient and the product's hypothesis. Which claims the finished product can support is ultimately determined only by testing on the finished product. Why barrier topics are in particular demand for sensitive skin is described in the magazine article on the skin barrier as a lifestyle topic.
Why are triterpenoids difficult to formulate?
The central formulation problem is solubility. The review by Furtado et al. (2017) reports octanol-water partition coefficients (log P) between 5.8 and 6.7 for betulinic, oleanolic, ursolic, and asiatic acid. These substances are markedly lipophilic and hardly soluble in water. In a purely aqueous serum or gel, free triterpene acids therefore do not remain dissolved, but exist as particles or crystallize out during storage.
Typical formulation problems
Recrystallization: An active ingredient dissolved warm during manufacturing can crystallize out again upon cooling or during temperature changes. This manifests as graininess, turbidity, or visible crystals under the microscope.
Viscosity change: Betulin can co-determine the texture of an oil phase. In the oleogel study by Pârvănescu et al. (2021), 0.3 percent betulin or lupeol with 15 percent glyceryl dibehenate as a gelling agent was incorporated at 45 °C into sunflower and olive oil in a 2:1 ratio. The betulin oleogel was about 1.5 times as viscous as the lupeol oleogel; the authors interpret betulin as an additional gelling agent.
Carrier system: Anhydrous oleogels, emulsions with a sufficiently large oil phase, solubilizers, or encapsulated systems are the usual routes. Each route changes the sensory profile, preservation requirements, and packaging choice.
Extract color and odor: Whole extracts bring accompanying substances that affect the color and odor of the bulk product and can vary from batch to batch.
Distribution in the skin also depends on the carrier. In the ex vivo experiment on porcine skin, approximately three times the amount of betulin or lupeol from the oleogels of Pârvănescu et al. remained in the skin at the end of the permeation experiment compared to the amount that penetrated through it. Why the carrier system determines whether a claim holds up is explored in depth in the magazine article on carrier systems and penetration.
Which tests does a triterpenoid formulation require?
Before being placed on the market, every cosmetic product must undergo a safety assessment. According to Art. 10 of Regulation (EC) No 1223/2009, the responsible person shall ensure that a safety report in accordance with Annex I is available. Annex I requires, among other things, information on the stability of the cosmetic product under reasonably foreseeable storage conditions and the results of the preservation challenge test. For triterpenoid formulations, this results in specific test points:
Stability storage in the final container: Storage at elevated temperature, room temperature, and temperature cycling, with monitoring of appearance, odor, pH value, and viscosity.
Microscopy: Inspect samples for crystal formation at fixed intervals. For lipophilic triterpenoids, this is the most critical early indicator of an unstable formulation.
Assay determination: It is recommended to analytically determine the content of the marker substance at the beginning and end of storage if the product is advertised with the active ingredient.
Preservation challenge test according to ISO 11930: for water-containing formulations with the final formulation, since solubilizers and extracts can alter the efficacy of the preservative system.
skin compatibility: Plant extracts are not automatically well tolerated. Bylka et al. report local allergic reactions and burning sensations with Centella preparations, as well as eczema after three months of topical application.
Stability storage can only begin with the final formulation in the final packaging and is therefore usually the longest phase in the schedule. The article Stability and Safety Testing for Cosmetics describes which tests must be completed before launch.
Which advertising claims are substantiated for triterpenoid products?
According to Art. 2(1)(a) of Regulation (EC) No 1223/2009, a cosmetic product serves to clean, protect, keep in good condition, or change the appearance of the skin. Claims regarding barrier function and firmness must remain within this framework. Pursuant to Art. 20(1), labeling and advertising must not imply characteristics or functions that the product does not possess.
The common criteria set out in the Annex to Regulation (EU) No 655/2013 are particularly relevant for active ingredient products. Under the truthfulness criterion, claims about the properties of an ingredient must not imply that the finished product has the same properties when it does not. Under the evidential support criterion, claims must be supported by adequate and verifiable evidence, and under the fairness criterion, presentations of efficacy must not exceed the available evidence.
Birch bark extract illustrates a clear boundary. It is the active ingredient of the medicinal product Filsuvez, which has been authorized across the EU since June 21, 2022, for the treatment of wounds associated with dystrophic and junctional epidermolysis bullosa. According to the EMA, the extract contains triterpenes such as betulin, betulinic acid, lupeol, and oleanolic acid. Claims regarding wound healing or the treatment of skin diseases fall outside the scope of cosmetic purposes; with a raw material that is simultaneously an active pharmaceutical ingredient, such wording very quickly shifts the product into the medicinal realm.
Generally substantiated with evidence on the finished product | Risky or impermissible |
|---|---|
“supports the natural skin barrier” | “repairs damaged skin”, “heals” |
“skin feels firmer” (with user study) | “builds up collagen” without product data |
“with Centella asiatica extract” (specifically included) | “soothes rosacea”, “against neurodermatitis/atopic dermatitis” |
The rules for advertising claims and the required evidence are summarized in the article Cosmetic Advertising Claims in the EU.
Labtree is a B2B cosmetics developer and cosmetics manufacturer from Hamburg with its own laboratory and production facilities in Germany. Formulation development, in-house laboratory work, sampling, manufacturability testing, and cosmetics production are all managed under one roof, turning a triterpenoid concept into laboratory samples, a manufacturable formulation, and the finished serum or cream.
The process follows the steps of conceptualization, sampling, customization, prototyping, and production. For a triterpenoid project, it is advisable to define the raw material, source, use concentration, and delivery system during conceptualization to match the intended product claim. Samples of pre-qualified formulations typically ship from the sample warehouse within 24 hours, allowing texture and skin feel to be evaluated early on using a physical sample.
White Label: A tested Labtree formulation is adapted for the brand and is typically deliverable within 2 to 3 months with standard packaging. The formulation remains with Labtree.
Private Label: New development tailored to the brand's requirements, typically taking 3 to 6 months to reach market readiness. Formulation rights or exclusivity can be contractually transferred to the brand.
Minimum Order Quantity: typically 1,500 units per product, depending on product type, filling volume, and packaging.
Safety assessment and regulatory documentation, including the Product Information File, are part of the services; however, compliance or specific test results are not guaranteed in advance. The project process is detailed on the page Have cosmetics developed.
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FAQ
What is the difference between triterpenes and triterpenoids?
Triterpenes are hydrocarbons composed of six isoprene units with 30 carbon atoms. Triterpenoids also include oxygenated derivatives such as ursolic acid, betulin, or asiatic acid. In scientific literature and raw material documentation, both terms are often used interchangeably.
Is Centella asiatica a triterpenoid active ingredient?
Yes. The key active ingredients in Centella asiatica are mainly the triterpenoids asiaticoside, madecassoside, asiatic acid, and madecassic acid. Their concentration varies depending on the plant's origin, which is why the raw material specification should indicate the content of these marker substances.
Can a cosmetic product containing birch bark extract claim wound healing properties?
No. Birch bark extract is an active ingredient in a medicinal product approved in the EU for wound treatment, and according to Art. 2 Para. 1 Point a of Regulation (EC) No. 1223/2009, a cosmetic product is intended for purposes such as cleaning, protecting, keeping in good condition, or changing the appearance, not for treatment. Claims regarding healing or treating skin diseases place the product into the medicinal product category.
Can triterpenoids be incorporated into a water-based serum?
Free triterpenic acids and betulin are highly lipophilic and barely dissolve in water. Therefore, aqueous serums require solubilizers, encapsulation, or an emulsion with an oil phase; alternatively, more polar glycosides such as madecassoside are used. In any case, stability must be checked microscopically for crystal formation.
Are triterpenoids suitable for natural cosmetics positioning?
As plant-based raw materials, they are well suited for natural positioning. A natural or natural origin index is calculated according to ISO 16128 for the entire formulation, which includes solubilizers, emulsifiers, and preservatives. For a seal, the criteria of the respective standard also apply.
How long does it take to develop a triterpenoid product?
The timeline is primarily determined by raw material procurement with full specifications, resolving the solubility problem, and stability storage in the final container. Because triterpenoid formulations are usually developed from scratch or significantly adapted, stability storage with the final formulation in the final packaging material is typically the longest phase. The influencing factors are described in the magazine article "Cosmetics Development: Realistic Timelines and Which Factors Determine Them".
