A formulator’s perspective
Let’s address the elephant in the lab: the skincare industry’s fixation on percentages is, at best, a wild oversimplification and at worst, what could be perceived as a marketing ploy that can undermine formulation science.
For those of us in R&D, innovation and manufacturing, the real conversation should centre on how ingredients work together and not just how much is thrown into a formulation.
The allure of high numbers
In today’s digitally savvy skincare market, consumers and marketing teams are increasingly drawn to products boasting high percentages of active ingredients such as 10% niacinamide or 2% salicylic acid.
Vogue Business reported a 229% rise in ingredient-based searches like retinol and vitamin C.
This trend reflects a desire for transparency and efficacy. While this shift towards ingredient awareness is positive, consumers are keen on understanding skincare science.
Focusing only on percentages can be misleading, more isn’t always better (often riskier) and percentages alone rarely predict product performance or safety.
This is why ingredient percentages shouldn’t be the sole factor guiding formulation choices.
Consumer trends
A 2023 Mintel report found that 68% of UK skincare buyers actively seek percentage disclosures, a trend fuelled by social media.
Ingredient-focused searches in South Korea have also surged. Cosmetics Business reports a 168% increase in weekly searches for ‘Korean skincare’, driven largely by terms like kojic acid with buyers prioritise high percentages on labels.
While some brands disclose ingredient percentages to promote transparency, others may use this information as a marketing narrative by inflating numbers such as 20% vitamin C or 10% glycolic acid, even when those concentrations are unnecessary or unstable.
Clinical strength claims
Terms like clinical or medical-grade or 10% potency imply medical efficacy, yet most clinical studies cited by brands are in-house trials with questionable methodology. 78% of in-house studies lack placebo controls (Cosmetics & Toiletries, 2023).
For instance, a “10% tranexamic acid” claim may reference a single-arm study (no placebo) on 30 participants, hardly robust evidence (Cosmetics & Toiletries, 2022).
Yet independent research (Journal of Cosmetic Dermatology, 2021) shows that tranexamic acid’s efficacy plateaus at 2–5% in topical formulations.
The greenwashing of percentages
There are brands which claim to be “clean” and are known to market “10% lactic acid” as “natural,” while omitting synthetic stabilisers that are essential for shelf life.
60% of “clean” brands use synthetic stabilisers (pentylene glycol) despite marketing claims, with environmental groups funded by organic brands also fueling this narrative (The Eco Well, 2023).
Regulatory realities (where % matters)
A higher concentration doesn’t always mean better results and can cause irritation.
There are many compliance steps brands must follow when sourcing raw materials, including obtaining certificates of analysis and safety data sheets, ingredient usage guidelines and conducting third-party safety assessments before a product can be sold.
The EU’s Regulation (EC) No 1223/2009 governs cosmetic products with strict rules on ingredient limits and safety assessments, to ensure products sold to the market are safe to use on our skin.
For example, alpha-arbutin is limited to 2% and kojic acid at 1% in face products from April 2025 onward. These aren’t arbitrary numbers, data on skin tolerance, long-term exposure and cumulative risk back them.
Salicylic acid in the US is an over-the-counter (OTC) acne ingredient with a 2% FDA monograph limit (21 CFR 333.310).
South Korea’s KFDA regulations sets a 3% tranexamic acid limit for particular claims (Notification 2021-64).
These regulations highlight that the efficacy of an ingredient isn’t solely dependent on its concentration. Factors such as formulation, pH levels and ingredient synergy are key to a product’s performance.
More isn’t always better
The effectiveness of an active ingredient doesn’t necessarily increase with its concentration. Higher percentages can sometimes lead to skin irritation without providing additional benefits.
It’s essential to recognise that the optimal concentration varies depending on the ingredient and individual skin types.
The role of formulation
The percentage of ingredients is just one piece of the efficacy puzzle. The overall performance can depend on factors such as pH levels, delivery systems and the presence of complementary ingredients.
A well-formulated product considers these interactions to maximise benefits and minimise potential adverse effects.
The limits of penetration and bioavailability
A 10% active sounds impressive on a label, but if the formulation lacks the right method of delivering the ingredient into the skin, most of it will sit on the skin’s surface.
The International Journal of Pharmaceutics (2020) showed that some active ingredients require optimised delivery systems to achieve skin penetration.
Delivery systems with 0.3% retinol have shown to outperform 1% basic emulsions (Journal of Controlled Release 2021) with a reduced risk of irritation.
Again, non-delivery systems containing retinol in lower concentrations (0.25-0.5%) can still yield noticeable improvements in fine lines and pigmentation with minimal side effects.
pH and stability
For actives like Alpha Hydroxy Acids (AHAs), Beta Hydroxy Acids (BHAs) and vitamin C, pH is the critical factor and not just a percentage.
A 10% glycolic acid at pH 5 is practically inert, while a 5% formula at pH 3.5 delivers superior exfoliation.
Vitamin C (ascorbic acid) is most effective at a pH below 3.5 and an oxidisable active, above 10% it is unstable.
Yet most brands omit pH disclosure, leaving consumers (and even retailers) none the wiser.
The EU’s Cosmetic Regulation (EC 1223/2009) requires pH data to exist in technical documents (though not public-facing), a loophole that is often misunderstood.
Also, there is no requirement to test/document pH in South Korean regulations unless product is classified as functional (e.g., whitening).
Synergy over strength
A well-formulated 2% salicylic acid with other ingredients outperforms a 4% salicylic acid toner because it leverages multi-mechanistic exfoliation.
Similarly, vitamin C works best when paired with other ingredients designed to stabilise the molecule and enhance antioxidant efficacy and prevent oxidation.
Niacinamide paired with barrier-repairing ingredients outperforms standalone 10% formulation.
Brand marketing often relies on isolated high-percentage actives (e.g., 10% niacinamide), but their minimalist formulations often lack the supporting ingredients needed for optimal performance.
A formulator’s quick guide
☑️ Delivery systems or advanced formulation methods
☑️ pH optimisation
☑️ Stabilisation
☑️ Synergistic pairing of ingredients
A call to action for the industry
As formulators and R&D leaders, we must push back against the percentage obsession by:
-Educating retailers and consumers on why 10% isn’t inherently better than 5%.
-Considering patents and delivery systems over isolated actives
-Third party substantiated claims and robust scientific evidence
-Demanding regulatory clarity on pH and stability claims.
The future of skincare isn’t in labels with percentages, it’s in intelligent formulation. Let’s lead with science, not marketing temptations.
While knowing the percentage of active ingredients can provide insight, it’s not the definitive measure of a product’s efficacy.
A thoughtful approach that considers formulation, ingredient synergy, robust scientific evidence and individual skin needs is crucial for achieving desired skincare outcomes. Remember, more isn’t always better, it’s about finding the right balance for your skin.
For more formulation insights, connect with me on LinkedIn and at in-cosmetics Korea in Seoul and in-cosmetics Asia in Bangkok, 2025. Let’s elevate the conversation beyond percentages.
References:
Vogue Business (2023), Ingredients before brands: The new beauty consumer priority?
Mintel (2023) Transparency trends in UK skincare buying habits.
Cosmetics & Toiletries (2023), Industry survey on clinical claims.
Cosmetics & Toiletries (2022), Tranexamic acid in skincare: Misused metrics.
Journal of Cosmetic Dermatology (2021) Efficacy of topical tranexamic acid.
The Eco Well (2023) A critical look at the ‘clean’ beauty movement.
International Journal of Pharmaceutics (2020) Penetration enhancers in topical delivery.
British Journal of Dermatology (2020) Niacinamide: Efficacy in skin barrier support.
Journal of Investigative Dermatology (2005) Stabilisation of ascorbic acid with ferulic acid and vitamin E.
Journal of Controlled Release (2021) Liposomal retinol delivery in skincare.
Almeman, A. A. (2024), Evaluating the Efficacy and Safety of Alpha-Hydroxy Acids in Dermatological Practice: A Comprehensive Clinical and Legal Review. Clinical, Cosmetic and Investigational Dermatology, 17, 1661–1685. https://doi.org/10.2147/CCID.S453243
European Commission (2009), Cosmetic Regulation (EC) No 1223/2009.
U.S. Food & Drug Administration. (n.d.). 21 CFR 333.310: OTC acne treatments monograph.
Korea Food and Drug Administration (2021), KFDA Notification 2021-64: Whitening ingredient concentration limits.
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