The topic is short and compact
In cosmetics, niacinamide is predominantly used at concentrations of 4 to 5%; a 2% concentration showed no significant effect on pigment spots compared to the active-ingredient-free base.
A stated concentration does not prove efficacy: according to Regulation (EU) No 655/2013, efficacy claims require evidence that relates specifically to the actual product.
The pH value affects absorption: in one study, niacinamide penetrated human skin about twice as effectively at pH 7.4 compared to pH 5.0.
Stability and preservation are tested in the final packaging; the packaging material should therefore be determined before stability testing begins.
Ascorbic acid creates a pH conflict because vitamin C only penetrates the skin to any significant degree below pH 4; derivatives like ascorbyl glucoside defuse this.
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What concentration of niacinamide makes sense in a serum?
For most serum concepts, a range of 4 to 5% is the most technically and argumentatively robust choice. The review by Boo (2021) notes that niacinamide in cosmetics is predominantly formulated at 4 to 5%, and the skin studies described there work with 2 to 5%. The concentration is therefore primarily a decision regarding which marketing claims the product can carry later on.
Concentration | What the study data shows | Implications for product claims |
|---|---|---|
2% | In a Japanese study group, sebum production decreased after the application of 2% niacinamide (Joshi et al. 2023); for hyperpigmentation, 2% was not significantly better than the vehicle control. | Nourishing and mattifying concepts; no claims regarding hyperpigmentation without proprietary product data. |
4 to 5% | 5% reduced hyperpigmentation over eight weeks compared to the vehicle control; in facial studies, 5% was applied over twelve weeks. | Broadest range of claims: skin appearance, skin barrier, even skin tone. |
10% | Boo primarily describes skin compatibility for 10%: during an application with 10%, subjects reported neither stinging nor flushing. | Positioning as a high-dose product; the concentration itself does not prove a stronger effect. |
Boo describes the brightening effect as dose-dependent and reversible: after discontinuation, the effect of a 5% product gradually diminished. Claims such as "permanent" are not supported by these data. Niacinamide is considered well tolerated at the usual concentrations below 5%. Those positioning a 10% product should have the skin compatibility tested on the finished product rather than relying on raw material data.
Regarding the skin barrier, primarily laboratory data is available: in cultured keratinocytes, niacinamide increased the synthesis of ceramides and barrier proteins, and Joshi et al. describe reduced transepidermal water loss after topical application. For a barrier claim on your own product, this serves as justification for the choice of active ingredient, not as product proof.
What claims does a niacinamide serum make?
Every claim on a label, website, or in retail requires substantiation that is relevant to the specific product. Article 20(1) of Regulation (EC) No 1223/2009 prohibits text and illustrations that imply characteristics or functions which the product does not possess. The common criteria of Regulation (EU) No 655/2013 require adequate and verifiable evidence that takes into account the state of the art; studies must be relevant to the product and the claimed benefit.
Raw material data is not proof of product efficacy
The studies from the previous section demonstrate what niacinamide achieved in a specific base at a specific concentration. A serum with a different base, a different pH, or additional active ingredients may behave differently. Boo explicitly points out for multi-active products that the contribution of niacinamide can hardly be assessed in such cases. Pursuant to Article 11(2)(d) of the Cosmetics Regulation, proof of the claimed effect belongs in the product information file where justified by the nature or effect of the cosmetic product.
Lower burden of proof: descriptive details regarding ingredient and concentration, as well as sensory claims assessed in an in-use test.
Product study required: claims regarding a visibly more even skin tone, reduced skin shine, or a strengthened skin barrier, each with measurement methods and study durations appropriate to the claim.
Non-cosmetic: claims regarding the treatment of acne, rosacea, or melasma generally fall outside the scope of a cosmetic product and do not belong on a serum.
Which formulations are permissible and what evidence they require is explored in depth in the article Cosmetic Advertising Claims in the EU.
What is the right pH level for a niacinamide serum?
There is no fixed target pH, but the pH value influences how much niacinamide penetrates into the skin. In a study by Sjöberg et al. (2026) using 5% niacinamide, permeation through human skin approximately doubled at pH 7.4 compared to pH 5.0; the authors attribute this to reversible changes in skin lipids. The saturation solubility was around 46% by weight at both pH values. Even a serum containing 10% niacinamide is therefore well below saturation; the concentration poses no solubility issue in the aqueous phase.
For formulation development, this implies a trade-off: leave-on serums are usually formulated to be slightly acidic and skin-friendly, yet a higher pH improved absorption in this model. The authors emphasize the importance of pH control in topical formulations. The pH value should therefore be included in the bulk product specification with tight tolerances and measured for every batch prior to filling.
Why nicotinic acid is a testing parameter
Unlike nicotinic acid, niacinamide does not cause flushing, as Boo notes. Sjöberg et al. also demonstrated that skin flora bacteria enzymatically convert niacinamide to nicotinic acid, albeit to a very minor extent (less than 0.05% of the applied amount). This affects the skin, not the bulk product. For development, it is nevertheless advisable to analytically track the nicotinic acid content during stability testing rather than assuming it is uncritical.
Can niacinamide be combined with vitamin C and other active ingredients?
Yes, but every combination shifts the requirements regarding pH value, stability, and evidence. The conflict with vitamin C is primarily a pH conflict: according to Pullar et al. (2017), ascorbic acid only penetrates the skin to any notable extent at a pH value below 4 and must be protected against oxidation. A serum intended to carry both active ingredients in a single phase thus works against the pH range in which niacinamide was better absorbed in the study by Sjöberg et al.
Vitamin C derivatives: According to Pullar et al., ascorbyl glucoside is considered more stable and can penetrate the skin, although how quickly it is converted into ascorbic acid there is unknown; Boo describes a gel with 2% ascorbyl glucoside and 3.5% niacinamide. Derivatives alleviate the pH conflict, but alter the evidence base, as studies using ascorbic acid cannot be transferred directly.
Tranexamic acid and N-acetylglucosamine: In Boo's overview, combinations with both substances are described for anti-hyperpigmentation concepts. Here, too, the evidence must relate to the combination in the product.
Hyaluronic acid and humectants: can generally be formulated in the same pH range and primarily alter viscosity and skin feel. Stickiness and absorption behavior are evaluated during sampling on the actual sample.
A combination serum therefore requires an early decision as to which active ingredient carries the primary claim. The pH window, preservation system, and testing plan are aligned with this active ingredient; the second active ingredient is selected so that it remains stable within this window.
How to formulate a serum with ascorbic acid as the main active ingredient is described in the article Vitamin C Serum produzieren lassen.
How is the stability of a niacinamide serum tested?
The final formulation in its intended final packaging is tested, as information on stability is a mandatory part of the safety report. Annex I Part A point 2 of Regulation (EC) No 1223/2009 requires information on the stability of the cosmetic product under reasonably foreseeable storage conditions, and pursuant to Art. 10(1), a safety report must be available prior to placing on the market. The scope of testing depends less on the active ingredient than on the formulation, combination partners, and packaging material.
Typical Scope of Testing
Accelerated storage: The Cosmetics Europe guidelines on stability testing specify standard conditions of 37 °C, 40 °C, or 45 °C over one, two, or three months, depending on the product type.
Test parameters: pH value, color, odor, viscosity, and appearance; for niacinamide, additionally the active ingredient content and nicotinic acid content.
Temperature fluctuations: According to the guidelines, freeze-thaw cycles reveal certain weaknesses faster than storage at a constant temperature, such as clouding or precipitation in gel serums.
Preservation: Aqueous products are susceptible to microbial contamination. The efficacy of the preservation system is tested using the preservative challenge test according to ISO 11930; Halla et al. (2018) describe this challenge test as the method adopted by international regulations.
Accelerated data are a projection. Cosmetics Europe recommends confirming them after launch through the regular testing of retain samples at room temperature. The testing process leading up to the safety report is described in the article Stability and Safety Testing for Cosmetics.
Which packaging is suitable for a niacinamide serum?
Packaging determines dosing, hygiene, and the scope of testing for a niacinamide serum. Cosmetics Europe recommends testing stability in packaging made of the exact same materials as on the market, testing each type if there are multiple packaging types, and testing the smallest container if there are multiple package sizes.
Glass bottle with pipette: classic serum format with metered drop dispensing. The bottle is opened with each use; Halla et al. classify bottles and jars as more susceptible to contamination than closed systems. The bulb of the pipette is in direct contact with the formulation and must be included in the compatibility testing between product and packaging.
Pump dispenser: narrow opening and defined dose. The viscosity of the formulation must match the pump stroke, which is tested during sampling for very fluid serums and for gels.
Airless dispenser: according to Halla et al., less accessible to contamination; sensible for low-preservative concepts or sensitive combination partners, usually at a higher unit cost for the packaging material.
Packaging components have their own delivery lead times and minimum order quantities from suppliers. If packaging is determined only after formulation approval, stability testing in the final packaging begins correspondingly later, and the timeline shifts by the duration of the storage testing.
The timeline depends primarily on whether an already tested formulation is adapted or a new one is developed. A serum in the white-label model, meaning based on a market-ready, tested Labtree formulation, is generally ready for delivery within 2 to 3 months with standard packaging; the formulation remains the property of Labtree. In the private-label model, the formulation is newly developed according to the brand's requirements, usually taking 3 to 6 months to reach market maturity; formulation rights or exclusivity can be contractually transferred to the brand.
As a B2B cosmetics developer and cosmetics manufacturer, Labtree covers formulation development, in-house laboratory work, sampling, manufacturability testing, and cosmetics production, transforming a serum concept into laboratory samples, a manufacturable formulation, and the finished packaged product. Samples of pre-qualified formulations typically ship from the sample warehouse within 24 hours. The minimum order quantity is generally 1,500 units per product, depending on the product type, fill size, and packaging.
Cost Drivers
Concentration and combination active ingredients: Higher niacinamide proportions and partners such as tranexamic acid or vitamin C derivatives increase raw material costs per unit.
Packaging materials: Glass with a dropper and airless systems generally cost more per unit than a standard pump dispenser and come with their own supplier minimum order quantities.
Scope of testing: Any efficacy claim beyond descriptive statements requires a product study; the number of test subjects, duration, and measurement method determine the costs and schedule.
Variants: Multiple concentrations or container sizes each require separate stability tests and their own minimum order quantities.
The differences between the two models are described in the article White Label Cosmetics: Advantages and Limits; the process from conceptualization to production is shown on the page Having cosmetics developed.
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FAQ
What percentage of niacinamide should a serum contain?
For most concepts, 4 to 5% makes sense because the active ingredient is predominantly used this way in cosmetics, 5% reduced pigmentation spots in a controlled study, and niacinamide is considered well tolerated at typical concentrations below 5%. 2% is suitable for gentle, mattifying concepts. Higher concentrations are primarily a positioning decision.
Does a serum with 10% niacinamide make sense?
As a positioning claim it can make sense, but concentration alone does not prove a stronger effect. The skin compatibility should be tested on the finished product, and every efficacy claim requires evidence for the product. Technically, the concentration is uncritical because the solubility of niacinamide in water is far higher.
Can a niacinamide serum be advertised as 'anti-pigmentation'?
A claim regarding a more even complexion is cosmetically possible, but requires evidence that is relevant to the product, such as an application study measuring skin tone. Studies conducted with the raw ingredient in a different base do not replace this proof. Details are described in the magazine article "Cosmetic Advertising Claims in the EU".
Does a niacinamide serum need to be preserved?
Water-based serums are susceptible to microbial contamination and require an effective preservative system. Its efficacy is evaluated using the preservative efficacy test in accordance with ISO 11930. While airless systems reduce the risk of contamination during use, they generally do not eliminate the need for testing.
Who owns the formulation of a niacinamide serum?
In the white-label model, the formulation remains with the manufacturer, meaning at Labtree it remains the property of Labtree; the brand customizes it. In the private-label model, the formulation is newly developed for the brand, and rights or exclusivity are contractually agreed upon. The magazine article "Confidentiality with the contract manufacturer: NDA and formulation ownership" explores this topic in greater depth.
What is the minimum order quantity for a niacinamide serum at Labtree?
The minimum order quantity is generally 1,500 units per product. The exact quantity depends on the type of product, filling size, and packaging. Special packaging materials may also have their own minimum order quantities set by the suppliers.
How long does it take to develop a niacinamide serum?
With Labtree's white-label model using standard packaging, it usually takes 2 to 3 months, while a new private-label development typically takes 3 to 6 months. The timeline is mainly extended by late packaging decisions, additional product studies for efficacy claims, and multiple variants.
