This article presents a concise overview of innovations in vitamin C formulation, highlighting solutions for stability and taste challenges, market trends and the science behind creating effective, consumer-friendly dosage forms.
Vitamin C (ascorbic acid) has long been a staple in both pharmaceutical and dietary supplement formulations. Its well-documented benefits – ranging from immune support and antioxidant protection to collagen synthesis and iron absorption – have made it a go-to ingredient for decades. Yet, today, the vitamin C market is transforming. Driven by evolving consumer expectations, technological innovation and competitive differentiation, manufacturers must ensure that their vitamin C-containing products deliver patient-friendly dosage formats. At the same time, maintaining stability throughout their whole shelf-life is critical.
A Growing Market with Evolving Needs
As a flagship ingredient in both pharmaceutical and nutraceutical applications, the global vitamin C market is projected to show steady growth from $2.37 billion in 2025 to more than $4 billion by 2034 (at a compound annual growth rate [CAGR] of 6%). Fuelling that growth are factors such as the lingering impact of the COVID-19 pandemic, the rise of functional foods/supplements and growing consumer awareness of preventive healthcare. Notably, Asia-Pacific and North America remain the largest markets, with the former dominating production and the latter driving innovation and premium product demand.(1)
Beyond the Basic Tablet
Today’s informed consumers are not just looking for active ingredients; they also want smarter and more enjoyable ways to take them. Efficacy, convenience and sensory appeal have become key drivers in product choice, prompting pharmaceutical and nutraceutical developers to rethink traditional formats. This shift has led to a growing demand for alternative oral dosage forms with vitamin C that align with modern lifestyles. These include gummies and chewables, effervescent and orally disintegrating tablets, as well as powder sachets and stickpacks.(2)
Developing oral formats with vitamin C poses some challenges due to its chemical and physical properties. Dr Michael Black, Senior Sales Manager Pharma at BENEO, states: “From instability under environmental stress to poor compressibility and demanding sensory attributes, the challenges associated with incorporating vitamin C into oral dosage forms are multifaceted and often interdependent. Whatever the delivery format, stability, consumer-friendly design and taste masking remain central to successful vitamin C product development.”
From instability under environmental stress to poor compressibility and demanding sensory attributes, the challenges associated with incorporating vitamin C into oral dosage forms are multifaceted and often interdependent
Dr Michael Black, Senior Sales Manager Pharma at BENEO
Introducing Isomalt
To address these formulation requirements, the use of multifunctional excipients has gained in popularity. Producers increasingly look for a broad spectrum of benefits, including ease of processing, high compressibility and flowability, stability enhancement and taste improvement. A prime example is isomalt, a water-soluble sugar alcohol derived from beet sugar.
Isomalt is a mixture of two disaccharide alcohols and is the only sugar alcohol derived from sucrose. It consists of 6-O-α-D-glucopyranosyl-D-sorbitol (GPS) and 6-O-α-D-glucopyranosyl-D-mannitol dihydrate (GPM). Monographs of isomalt are described in current editions of the Ph. Eur., BP, JP and USP-NF.
Isomalt has a lower hygroscopicity than most polyols and sugars and absorbs almost no moisture at room temperature and/or at relatively high humidity levels. Isomalt prevents compressed tablets from becoming sticky or moist, for example, so even non-wrapped items can be packaged together to increase their overall shelf-life. It helps to stabilise sensitive ingredients during processing and storage too. Studies show that isomalt may protect proteins during freeze-drying and outperforms sucrose when it comes to maintaining enzyme activity.(3)
Isomalt is produced through a two-step process involving enzymatic sucrose treatment and hydrogenation. This gives it a molecular structure that delivers a sweetness close to sugar but with only half the calories. Dr Michael Black explains: “Unlike sugar, isomalt doesn’t lower the buccal pH or feed bacteria that produce tooth-decaying acids. This makes it a preferred excipient when developing tooth-friendly products.”
Processing Challenges
From a chemical viewpoint, vitamin C is notoriously unstable. It degrades rapidly when exposed to moisture, oxygen, heat and light, leading to a loss of potency and a reduced shelf-life. This degradation is particularly problematic in high-dose formulations and products with long distribution chains.
For example, moisture sensitivity is especially critical in effervescent tablets and chewables wherein hygroscopic excipients can accelerate degradation. This requires stringent humidity control throughout production and storage. Isomalt, because of its low hygroscopic nature, resists moisture absorption and supports the long-term stability of vitamin C formulations.
In addition to moisture sensitivity, heat stress is another critical issue. Exposure to elevated temperatures during manufacturing can degrade vitamin C, making temperature control essential to preserve its efficacy. Isomalt offers a distinct technological advantage here as it can be compressed at low forces with minimal heat generation.
In its crystalline form, ascorbic acid has poor flow and compressibility properties, making it difficult to process using direct compression techniques. This can lead to inconsistent tablet weights, capping and lamination. However, agglomerated spherical isomalt, with its uniform particle size distribution, provides excellent flow and mixing properties. This not only simplifies the tableting process but also reduces or eliminates the need for additional glidants.
Sticking (material adhering to punch faces) and picking (material pulling away from embossed areas) are common issues in vitamin C tablet production, especially with high-dose or sugar-rich formulations. Acting as a highly compactable filler-binder, agglomerated isomalt shifts the balance toward stronger cohesive forces within the tablet and away from adhesive forces between the tablet and tooling, thus reducing sticking.
Additionally, vitamin C is known to interact with other formulation components, which can compromise both stability and efficacy. Selecting inert and compatible excipients is therefore crucial. In this regard, agglomerated isomalt is advantageous as it remains non-reactive with other ingredients to preserve the formulation’s overall integrity.
Stability Test: Isomalt versus Sorbitol in Tablets Containing Ascorbic Acid
To examine the stability qualities of isomalt, BENEO conducted a study comparing ascorbic acid tablets with either agglomerated isomalt (direct compression grade: galenIQ™ from BENEO) or sorbitol as an excipient. Both excipients were used in coated and uncoated tablets containing a mixture of the excipient and ascorbic acid at a ratio of 3:1 as well as in placebo tablets (99.5% isomalt or sorbitol). The tablets were stored for 14 days at 25 °C and 80% relative humidity. Their stability was subsequently assessed (based on initial tablet weight) to monitor moisture uptake (Figure 1).
Figure 1: Increase in ascorbic acid tablet weight derived from moisture uptake after 14 days of storage.
Dr Michael Black comments: “Test results have shown that direct compression grade isomalt demonstrated excellent stability under high humidity conditions. Whereas the sorbitol tablets completely dissolved after 2 days of storage (Figure 2), those with isomalt showed significantly lower moisture uptake. This confirms isomalt’s very low hygroscopicity.”
Test results have shown that direct compression grade isomalt demonstrated excellent stability under high humidity conditions.
Dr. Michael Black
Figure 2: Results of dissolution test on placebo tablets containing either agglomerated isomalt (left) or sorbitol (right) after two days of storage.
Taste Matters: Enhancing Palatability
Incorporating vitamin C into patient-friendly oral dosage forms presents another challenge: taste. Ascorbic acid is naturally sour, slightly bitter and often accompanied by a metallic aftertaste. These sensory characteristics can be particularly off-putting for sensitive patient groups such as children and older adults. In the context of pharmaceutical development – when patient compliance and product appeal are critical – taste is a decisive factor in both initial acceptance and long-term adherence, especially for self-administered supplements.
The sourness of vitamin C stems from its acidic nature, whereas its bitterness is often amplified when combined with other actives. Traditional approaches to mitigate these sensory drawbacks often include the use of flavouring agents or coatings to mask the taste of vitamin C.
Modern formulation solutions increasingly turn to excipients with favourable sensory profiles. Sweeteners such as sucrose, mannitol and isomalt are selected not only for their functional properties but also for their ability to improve mouthfeel and mask unpleasant flavours. Being an integral part of our food since primaeval times, sucrose serves as the benchmark for sweetness perception.(4) Because of concerns about sugar intake, tooth health and suitability for diabetic populations, however, sugar alcohols have become the preferred alternative.
Isomalt stands out for its unique sensory advantages. Its ability to improve palatability has been demonstrated in a comparative sensory study. In a blind-test, a professional sensory panel compared the sensorial properties of sucrose, mannitol and isomalt (BENEO’s galenIQ™ 720 and 721) under standardised test conditions (1.6 g, dry). Each sample was assessed according to multiple descriptive attributes (sweetness, mouthfeel and aftertaste, for example), using a 10-point intensity scale (0 = not discernible and 10 = very discernible).
The results were then plotted as a spider chart (Figure 3) that showed that galenIQ™’s profile was very similar to sugar, particularly in terms of taste, flavour, mouthfeel and aftertaste. Additionally, both tested isomalt grades were perceived to be significantly more sugar-like when compared with mannitol.
Figure 3: Spider chart comparison of the sensory profiles of different sweeteners (sucrose, mannitol and isomalt [720 and 721]).
![Figure 3: Spider chart comparison of the sensory profiles of different sweeteners (sucrose, mannitol and isomalt [720 and 721]).](http://www.all4nutra.com/wp-content/uploads/2025/12/Spider-chart-comparison.png)
Conclusion
The formulation of stable, palatable oral vitamin C products is no longer just a technical challenge; it‘s a critical driver of consumer acceptance, product differentiation and market success. Advances in excipient technology, particularly the use of multifunctional ingredients such as isomalt, have enabled manufacturers to overcome long-standing hurdles such as moisture sensitivity, heat-induced degradation, poor compressibility and an unpleasant taste.
Dr Michael Black states: “By improving stability, manufacturability and sensory appeal simultaneously, isomalt empowers the development of diverse dosage forms – from chewables and effervescents to swallowable tablets – that meet the evolving expectations of today’s health-conscious consumers.”
As the global vitamin C market continues to grow and diversify, leveraging such innovative formulation strategies ensures that products are not only effective but also enjoyable and convenient, ultimately supporting better compliance and long-term health outcomes.
References
- Vitamin C Market Size to Hit Around USD 4.01 Billion by 2034
- https://www.accio.com/business/vitamin-c-supplement-trends.
- https://pubmed.ncbi.nlm.nih.gov/29341910/.
- https://www.behrs.de/titel/handbuch-suessungsmittel/5.
- Luhn, et al., “Evaluation of Isomalt, Maltitol, Mannitol and Sucrose as Bitterness Suppressors in a Liquid Preparation Containing Quinine Hydrochloride,” PharmaChem September/October 8–10 (2014).
Dr Maj-Britt Cepok
Head of Pharma, BENEO GmbH
About the author:
Dr Maj-Britt Cepok,
Head of Pharma, BENEO GmbH
Dr. Maj-Britt Cepok is a thought leader in the pharmaceutical industry with over 20 years of experience. She holds a degree in Food Chemistry and a PhD in Analytical Chemistry. Drawing on extensive expertise from both the food and pharmaceutical sectors, she specializes in the development of solid dosage forms and the profiling of taste characteristics.
As Head of Pharma at BENEO, she spearheads global sales initiatives and drives strategic growth for galenIQ™, an innovative excipient shaping the future of pharmaceutical and nutraceutical applications. Her leadership encompasses international market strategies, excipient technology, and the advancement of solutions that address the evolving needs of the pharmaceutical and nutraceutical industries.
