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The Hidden Supply Chain Risk in Vaccines: Why Sustainably Sourced Squalene Matters

Ingredient security is no longer a background consideration for vaccine formulators and manufacturers. It is now critical high-quality ingredients are sourced from proven partners, that can provide a secure and consistent supply to support the vaccines of tomorrow and equally be prepared to deliver a resilient supply through future pandemics. 

There has been growing momentum to not just focus on the intricate parts of the vaccine development supply chain, but to go straight to the source of the ingredients. Where are they coming from? Is the source unlimited in supply, without having a negative impact on ecosystems and the environment? Squalene is a clear example of innovators asking questions at the right time. 

Squalene is a well-established component in emulsion adjuvant systems; it plays an important role in vaccine formulation. Squalene is used to help strengthen the body’s response to the vaccine antigen, supporting protection against diseases like seasonal influenza and emerging pandemic flu strains. Beyond influenza, squalene containing adjuvant systems continue to be explored in clinical development across other disease areas. 

Traditionally, squalene has been sourced from deep-sea shark liver, a practice that raises sustainability and ethical concerns. The latest amendment to CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) Appendix II includes all gulper sharks (Centrophoridae spp.), a family of species historically used for squalene because some have very large livers with high squalene concentrations. Regulation of responsibly sourced shark-derived squalene is tightening, with increased monitoring requirements expected to become effective during 2027. This regulatory change reflects the objective of protecting these species and helping ensure that international trade does not compromise their survival in the wild. Countries that do not adopt the Appendix II amendment would still need to comply with CITES requirements for export purposes. As a result, there is a high likelihood that this will place additional pressure on an already constrained supply chain, affecting both availability and pricing.

A broader conversation has begun. By switching from shark-derived squalene to Croda Pharma’s Sustainably Sourced Squalene, vaccine formulators and manufacturers can access a non-animal-derived, secure, consistent, and high-purity source. This fermentation-based source offers the flexibility to scale up rapidly in response to market demand. Fermentation-derived squalene is not subject to CITES regulation.

To explore this further, we spoke directly to our experts to share their perspectives on the future of Sustainably Sourced Squalene. From sustainable sourcing and manufacturing scale-up to quality assurance. Hear from Dr. Rasmus Münter (Lead Research Scientist), George Grimsey Jones (Sector Sustainability Specialist), Rebecca Murray (Operations Manager – Leek U.K.), Helen Albans (Regulatory Submissions Manager), Davina Nagington (Quality Control Manager, Leek U.K.). 

Why is the industry shifting toward sustainable alternatives to traditional squalene sources?

Ethical concerns about sourcing have been a major driver of research into alternative sources. The vaccine industry has also contributed, driven by growing sustainability goals and a stronger focus on environmentally responsible production.  

This is part of a broader global trend in societies toward increased focus on wildlife protection, a trend that has gained momentum over recent decades. Studies demonstrate that shark and ray populations play a vital role in maintaining healthy marine ecosystems. Many shark species used for squalene also reproduce slowly and have long lifespans, which makes them especially vulnerable to depletion and population collapse. Squalene is used not only in pharmaceuticals but also in personal care products. The demand has historically contributed to unsustainable fishing practices and biodiversity loss.

As a result, all gulper sharks (Centrophoridae spp.) have recently been included in CITES Appendix II. International trade in materials derived from these species will therefore be subject to stricter controls, including documentation demonstrating compliance with CITES requirements. This is expected to make traditional deep-sea shark-derived squalene more difficult to source, with likely implications for cost, availability, and lead times.

George Grimsey Jones

George Grimsey Jones, Sector Sustainability Specialist

Squalene remains important for seasonal and pandemic influenza vaccines, creating a need for secure and scalable supply chains to ensure production of life saving vaccines. A scalable viable alternative has demonstrated to be equivalent, if not superior, to shark derived squalene, satisfying the stringent requirements from the vaccine industry. Vaccine manufacturers can now transition to a secure, viable, and sustainably sourced squalene – great news!
Dr. Rasmus Münter

Dr. Rasmus Münter, Lead Research Scientist

What challenges do vaccine manufacturers face today when sourcing squalene?

Vaccine manufacturers can face different challenges with different sources of squalene. Traditional sources of squalene are the incumbent, but their insecurity of supply and ecological impacts are increasingly seen as unacceptable risks, particularly considering the long development and intended use cycles of vaccines. Newer sources of squalene provide a more secure long-term supply chain, while avoiding the ecological impacts and risks of shark-derived squalene. However, not all alternatives to shark-derived squalene are the same. Scalability is a vital issue for vaccine supply chains seeking to support an increasing number of vaccines while being prepared to respond to outbreaks and even pandemics. This is why new sources of squalene must be capable of scaling with secure supply, consistent quality, and minimal environmental impact. New sources of squalene are often plant derived, creating demand for land and agriculture. It’s therefore vital that the most efficient routes to squalene are used to minimise these demands and impacts. Harnessing synthetic biotechnology ensures efficient production of squalene from biobased carbon sources, minimising environmental impacts and demands for land and agriculture while transitioning away from shark derived material.
George Grimsey Jones

George Grimsey Jones, Sector Sustainability Specialist

What does “sustainably sourced squalene” mean in practice?

In practice, sustainably sourced squalene refers to a fermentation-based production process, developed by our partner Amyris, a pioneer in synthetic biology, rather than extraction from plant sources. During this proprietary process, engineered yeast converts sugar into squalene through a controlled metabolic pathway. The resulting crude material is then purified through downstream processing to achieve a highly refined pharmaceutical-grade product. This approach combines established fermentation technology with cutting-edge targeted strain engineering and purification expertise to deliver consistent quality at scale. 

The material is characterised by high purity of ≥99%, in line with the stringent requirements of vaccine manufacturers. It also demonstrates strong stability, can be shipped at ambient temperature, and has proven compatibility in emulsion adjuvant systems. Together, these attributes make it a practical and reliable option for vaccine applications.
Dr. Rasmus Münter

Dr. Rasmus Münter, Lead Research Scientist

To substantiate the sustainability profile of this resource-efficient production route, a comprehensive life cycle assessment has been conducted, including carbon emissions and land use. This provides an evidence base for the environmental advantages of fermentation-derived squalene compared with traditional sourcing models.
George Grimsey Jones

George Grimsey Jones, Sector Sustainability Specialist

How does Sustainably Sourced Squalene compare to the well-established and proven shark-derived squalene?

Our Sustainably Sourced Squalene is molecularly identical to squalene from traditional shark sources. Alongside the benefits to security and sustainability of supply, our squalene is also produced to an even higher purity than traditional sources. While shark-derived sources are the well-established incumbent, the equivalence and increased purity of our squalene give Croda Pharma and our customers confidence in it. 

Croda is committed to being climate, nature, and people positive, and Sustainably Sourced Squalene has clear alignment with all three. This is an ongoing journey. We also have various programs and embedded processes working to continuously improve the sustainability of our operations and supply chains.
George Grimsey Jones

George Grimsey Jones, Sector Sustainability Specialist

Why is supply chain security so important for vaccine adjuvants and pharmaceutical excipients?

High quality adjuvants and excipients are critical to the performance of the final drug product. Consistent and reliable sourcing of these ingredients is needed to prevent disruption to production schedules, which can be critical to a vaccine project’s success. This becomes increasingly important in complex global supply chain networks, where having confidence in your supplier’s ability to deliver is key.
Rebecca Murray

Rebecca Murray, Operations Manager – Leek U.K

How does Croda Pharma ensure continuity of supply during periods of high global demand?

Collaboration is key at Croda, and we maintain close relationships with our suppliers and our partner Amyris Inc.. Through utilising forecasting and order data, our operations teams can coordinate production planning to meet demands. This is further complimented by flexible production assets, meaning we have versatility in manufacturing scale. To support local supply, Croda operates on a global footprint with warehousing infrastructure across all regions. Croda’s Sustainably Sourced Squalene has also demonstrated excellent temperature stability, meaning it does not require refrigerated or frozen shipment. This provides a further opportunity for flexibility, with all this translating to Croda Pharma being a consistent and reliable source of supply.
Rebecca Murray

Rebecca Murray, Operations Manager – Leek U.K

Why does purity matter so much in vaccine and injectable applications?

Purity requirements for vaccines and injectable products are stringent because these products bypass many of the body’s natural defences and are administered directly into systemic circulation or tissues. Doses are small but highly impactful, as there is no dilution or metabolism before systemic exposure. This is why injectable standards enforce much stricter impurity limits than for oral products. 

Global regulatory agencies expect injectable excipients to be of high purity (≥99%) and well characterised including full impurity profiling. Vaccines are specifically designed to stimulate the immune system, so any impurity has a heightened risk of unexpected molecules being recognised as antigens that can lead to adverse patient reactions such as hypersensitivity, autoimmune responses and increased reactogenicity (pain, inflammation and fever). 

High purity excipients ensure consistent adjuvant performance through known composition. Squalene is used in emulsions (e.g., oil-in-water systems) where the exact composition can affect droplet size, stability of the emulsion and interaction with immune cells. 

Impurities can disrupt emulsion structure, affect biodistribution and lead to inconsistent immune responses between batches. High purity ensures reproducibility, which directly impacts on vaccine potency and consistency which is essential for clinical trial comparability, manufacturing validation and positive patient outcomes.
Helen Albans

Helen Albans, Regulatory Submissions Manager

What additional quality testing or controls are in place beyond standard pharmacopeia requirements?

The standard European Pharmacopoeia sets out a GC assay method which has known limitations and is not sufficient to demonstrate the high purity required for vaccine applications.  We have developed our own GC methods, which include a purity method to demonstrate ≥99% purity, plus a separate method to quantify impurities present. We’ve proven alignment of the monograph and Croda methods, demonstrating that Croda Squalene exceeds the minimum purity requirements outlined in the monograph.
Davina Nagington

Davina Nagington, Quality Control Manager, Leek U.K

What role does manufacturing expertise play in maintaining product integrity and quality at scale?

Croda Leek has over forty years of experience in the manufacture and purification of lipid products. Our highly knowledgeable and skilled team operate to the highest of standards and have experience in manufacturing from kilogram to tonne scale. Our operational teams work closely with in-house technical colleagues, meaning product quality is monitored throughout the production process. The site is also supported by our numerous quality standards, including ISO 9001 and EXCiPACT certification. All of this contributes to established systems with a proven track record of delivering high quality products.
Davina Nagington

Davina Nagington, Quality Control Manager, Leek U.K

Why do you believe the technology and manufacturing process of Sustainably Sourced Squalene represent the future for squalene supply for vaccines?

The reasons for moving away from animal-derived squalene are clear. Ethical considerations and tightening regulations to preserve biodiversity in marine ecosystems make the transition to alternative sources increasingly compelling. At the same time, global health depends on access to secure, reliable sources that meet stringent regulatory requirements. 

This aligns with Croda’s sustainability ambitions, including its Commitment to be Climate, Nature and People Positive by 2030. Developing a viable alternative to animal-derived squalene is a natural extension of that commitment and supports customers in addressing both sustainability and supply challenges.
George Grimsey Jones

George Grimsey Jones, Sector Sustainability Specialist

Our Sustainably Sourced Squalene meets the key requirements of the vaccine industry, from product quality to global supply and distribution. Although it represents only one component in vaccine formulation, it plays an important role in supporting reliable access to life-saving vaccines. Even in the absence of a current legal or regulatory obligation, a transition to alternative sources strengthens resilience. What if supply was disrupted in the future, whether driven by a regulatory ban or depletion of shark populations?
Dr. Rasmus Münter

Dr. Rasmus Münter, Lead Research Scientist

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Published on:
Thursday 9th July 2026

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