Why we're obsessed with red seaweed

The marine ingredient with antiviral research behind it

10/28/20253 min read

Let's talk about red seaweed or carrageenan as it's officially called. Not the food additive you've vaguely heard of, we're talking about a derivative from red seaweed that's been showing promising potential in clinical research for it's antiviral effect.

What is carrageenan?

Carrageenan is a naturally-occurring seaweed that’s been used safely in food and pharmaceutical products for decades. But it's the antiviral research from recent years that got our attention.

Because when it comes to what goes inside your body, the science matters. And the science on carrageenan?

It's f*cking fascinating

The clinical research

Between 2013 and 2023, researchers at McGill University conducted comprehensive clinical trials on carrageenan's potential to reduce sexually transmitted infections.

The CATCH study: HPV

The Carrageenan-gel Against Transmission of Cervical HPV (CATCH) study was a phase IIB randomised, double-blind, placebo-controlled trial with 461 sexually active women.

The interim analysis demonstrated a 36% protective effect of carrageenan against incident HPV infections. The final analysis, published in 2023, confirmed these findings; women using carrageenan-based gel had significantly fewer new HPV infections compared to placebo.

Researchers noted that carrageenan demonstrated potent anti-HPV activity in vitro and in animal models, and suggested that carrageenan-based gels could complement HPV vaccination in protecting against HPV-related diseases.

HSV-2 (genital herpes) research

The genital herpes research is equally compelling. Early studies from 1997 showed that vaginal formulations of carrageenan were highly effective in protecting mice from HSV-2 infection. At doses that infected half of control animals, 1% carrageenan solutions prevented infection in almost all treated animals. Even at 0.05% concentration, carrageenan protected the large majority of mice.

More recent studies showed that carrageenan in combination with other compounds demonstrated potent antiviral activity against both HSV-2 and HPV at clinically relevant concentrations.

The safety profile

Carrageenan has been used in food, cosmetics, and pharmaceuticals for decades with an excellent safety record. It's generally recognised as safe (GRAS) by the FDA.

Clinical trials have shown that carrageenan-containing gels are safe and well-tolerated for vaginal use. The CATCH study participants used carrageenan-based gel regularly for up to 12 months with no significant adverse effects reported.

Multiple safety studies over the years have confirmed minimal toxicity and good biocompatibility.

Individual responses vary

It's worth noting that everyone's body responds differently to ingredients. While carrageenan has shown excellent safety and tolerability in clinical trials, individual experiences can vary. Some people may find certain formulations work better for them than others, this is completely normal and reflects the unique nature of each person's vaginal microbiome and chemistry.

Finding what works best for your body is a personal journey.

Why this matters

Research findings on carrageenan's clinical efficacy suggest it could be an important area for future research, potentially complementing existing prevention strategies like vaccination and barrier methods.

Researchers have noted that future work should explore carrageenan's addition to other prevention methods, assess impact on various infections, and continue research into multi-purpose prevention technology.

The science is still evolving. Clinical trials are continuing. More data is being published.

The future

Carrageenan represents an exciting intersection of seaweed, clinical research, and sexual health innovation. Decades of research, from initial in vitro studies to randomised controlled trials, have demonstrated its potential as a biologically active ingredient.

This blog post discusses published scientific research. It does not make health claims about any vögeln products.