The Antiviral Power of Carrageenan found in Natures Farmer Sea, Sea Moss

By Lillian Jessop (B. Marine Science, Dip. Health Science)

At Natures Farmer Sea, we carefully select the highest-quality sea moss, focusing on two species: Kappaphycus alvarezii and Chondrus crispus. These seaweeds are naturally rich in carrageenan—a sulfated polysaccharide that has been extensively studied for its antiviral properties.

Over the last two decades, researchers have conducted clinical trials and laboratory studies demonstrating carrageenan’s natural antiviral potential, particularly in fighting respiratory infections, human papillomavirus (HPV) and even COVID-19 (Figueroa et al., 2021; Ludwig et al., 2013; Chahla, et al., 2021; Laurie et al., 2023). Unlike pharmaceutical antiviral drugs that target the virus after an infection, carrageenan acts as a first line of defence, physically blocking viruses from attaching to human cells (Ludwig et al., 2013).

In this blog, we’ll explore the science behind carrageenan’s antiviral properties, its applications in medicine and food, and how incorporating sea moss into your daily routine may support immune health.

How Does Carrageenan Fight Viruses?

To cause infection, viruses must first attach to host cells using specific receptors on the cell surface. Carrageenan disrupts this process by binding to the virus itself, preventing it from docking onto human cells and stopping infection before it begins (Ludwig et al., 2013).

This mechanism is particularly effective against viruses that require heparan sulfate proteoglycans (HSPGs) for cell entry, such as:

• Human papillomavirus (HPV) (Laurie et al., 2023)

• SARS-CoV-2 (COVID-19) (Figueroa et al., 2021)

• Common cold viruses (Ludwig et al., 2013)

Carrageenan essentially acts as a protective shield, making it much harder for these viruses to infect cells and spread (Halley et al., 2023).

Carrageenan and Respiratory Viruses

Common respiratory viruses, including influenza, rhinovirus, and coronaviruses, are highly contagious and spread easily through airborne droplets. Scientists have investigated whether carrageenan nasal sprays could help protect against these infections.

Clinical Evidence

• A randomised controlled trial (RCT) with 211 patients found that those using a carrageenan nasal spray recovered 2.1 days faster than those using a placebo (Ludwig et al., 2013).

• Another study showed that carrageenan reduced viral loads in patients’ nasal fluids, suggesting a direct antiviral effect at the site of infection (Ludwig et al., 2013).

• A feasibility study found that regular use of a prophylactic carrageenan nasal spray resulted in consistent reductions in upper respiratory tract infection (URTI) symptoms, making it a potential immune support option (Halley et al., 2023).

These findings suggest that nasal sprays containing carrageenan could be a safe and effective tool for preventing and managing respiratory infections.

Carrageenan and COVID-19

During the COVID-19 pandemic, researchers looked at carrageenan-based nasal sprays as potential preventive treatments.

• A clinical trial in Argentina found that healthcare workers using a carrageenan nasal spray were 79.8% less likely to contract COVID-19 compared to those using a placebo (Figueroa et al., 2021).

• Another study combining carrageenan with ivermectin showed a significant reduction in SARS-CoV-2 infection rates, highlighting its potential as a protective barrier against airborne viruses (Carvallo et al., 2021).

• In vitro studies confirmed that carrageenan inhibits SARS-CoV-2 infection in cell cultures, further validating its antiviral action (Sattari et al., 2021).

While more research is needed, these findings indicate that carrageenan could play a vital role in future pandemic preparedness strategies.

Carrageenan and HPV 

Beyond respiratory infections, carrageenan has shown remarkable potential in preventing human papillomavirus (HPV), which is linked to genital warts and cervical cancer.

Key Studies on Carrageenan and HPV

• A double-blind RCT on HPV infections in men found that carrageenan-based lubricants significantly increased viral clearance, making it a potential preventive agent (Laurie et al., 2023).

• A study on anogenital HPV lesions found that carrageenan-based topical treatments significantly reduced recurrence rates after three months (Chahla, et al., 2021)

• The LIMIT-HPV trial demonstrated that carrageenan-based gels could reduce HPV prevalence, especially in at-risk groups (Laurie et al., 2020).

These studies suggest that carrageenan may serve as a natural, safe, and effective method to help prevent HPV infections.

Carrageenan as an Antiviral Food Ingredient

Emerging research suggests that consuming carrageenan-rich foods may also support immune health.

Recent studies indicate that dietary carrageenan may play a role in immune modulation and inflammation reduction, both of which are essential for viral resistance and recovery.

A controlled clinical trial investigating carrageenan supplementation in patients with cardiovascular disease found that it had a moderate immunomodulatory effect, without causing overactivation of the immune system. The study showed a statistically significant reduction in chronic inflammation markers, including a 15.9% decrease in leukocytes, 8.62% reduction in fibrinogen, and a 13.03% drop in C-reactive protein—all of which are key indicators of immune system health (Sokolova et al., 2014).

The same study reported that carrageenan supplementation led to a significant reduction in cholesterol levels, which is relevant since metabolic health plays a crucial role in immune function and overall resilience against infections (Sokolova et al., 2014).

Additionally, other studies have linked carrageenan-rich diets to lower inflammation levels, which could contribute to improved immune defences against viral infections (Sattari et al., 2021).

Although most research on carrageenan’s direct antiviral effects has focused on nasal sprays and topical applications, these findings suggest that regular consumption of sea moss and carrageenan-containing foods could support immune function, reduce inflammation, and promote overall health.

Summary

Extensive scientific research highlights carrageenan’s powerful antiviral properties, with demonstrated effectiveness against respiratory viruses, HPV, and COVID-19. Whether applied as a nasal spray, topical treatment, or consumed as a functional food ingredient, carrageenan consistently shows remarkable immune-supporting benefits.

By integrating sea moss into your daily routine, you may be naturally reinforcing your body's defences—supporting immunity, promoting overall wellness, and harnessing the power of nature for stronger, healthier living.

Lillian Jessop is a seaweed scientist with a Bachelor of Marine Science and a Diploma in Naturopathy. She is passionate about harnessing seaweed’s potential for both environmental sustainability and human health. Guided by the belief that nature holds the answers, Lilly combines scientific research with traditional wisdom to explore seaweed’s role in nutrition, wellness, and ecosystem restoration.

References

Carvallo, H. & Hirsch, R. (2021). Study of the Efficacy and Safety of Topical Ivermectin + Iota-Carrageenan in the Prophylaxis against COVID-19 in Health Personnel. Journal of Biomedical Research and Clinical Investigation, 2(1). DOI: 10.31546/2633-8653.1007.

Chahla, R.E., Ruiz, L.M., Ortega, E.S., RN, M.F.M., … & Bruna, M.P. (2021). Intensive Treatment With Ivermectin and Iota-Carrageenan as Pre-exposure Prophylaxis for COVID-19 in Health Care Workers from Tucuman, Argentina. American Journal of Therapeutics, 28(5). doi: 10.1097/MJT.0000000000001433

Figueroa, J. M., Kombardo, M.E., Dogliotti, A., Flynn, L.P., … &  Uchitel, O. (2021). Efficacy of a nasal spray containing iota-carrageenan in the postexposure prophylaxis of COVID-19 in hospital personnel dedicated to patient care with COVID-19 disease. International Journal of General Medicine, 14, 6277–6286. DOI: 10.2147/IJGM.S328486.

Halley, C., Honeywill, C., Kang, L., Pierse, N., … & Crane, K. (2023). Preventing upper respiratory tract infections with prophylactic nasal carrageenan: A feasibility study. Future Microbiology, 18, 1319–1328. DOI: 10.2217/fmb-2021-0122.

Laurie, C., El-Zein, M., Tota, J., Tellier, P.P., Coutlee, F., … & Pokomandy, A.D. (2020). Lubricant Investigation in Men to Inhibit Transmission of HPV Infection (LIMIT-HPV): Design and methods for a randomized controlled trial. BMJ Open, 10. DOI: 10.1136/bmjopen-2019-035113.

Ludwig, M., Enzenhofer, E., Schneider, S., Rauch, M., … & Mueller, C.A. (2013). Efficacy of a carrageenan nasal spray in patients with common cold: A randomized controlled trial. Respiratory Research, 14, 124. DOI: 10.1186/1465-9921-14-124.

Sattari, A., Ramazani, A., & Aghahosseini, H. (2021). Repositioning therapeutics for COVID-19: Virtual screening of the potent synthetic and natural compounds as SARS-CoV-2 3CLpro inhibitors. Journal of the Iranian Chemical Society, 18, 2807–2827. https://doi.org/10.1007/s13738-021-02235-7

Sokolova, E.V., Bogdanovich, L.N., Ivanova, T.B., Byankina, A.O., … & Yermak, I.M. (2014). Effect of carrageenan food supplement on patients with cardiovascular disease results in normalization of lipid profile and moderate modulation of immunity system markers. PharmaNutrition, 2(2), 33-37. https://doi-org.ezproxy.scu.edu.au/10.1016/j.phanu.2014.02.001