Jellyfish are used for far more than you might expect. They’re eaten as food across Asia and Latin America, harvested for collagen in medicine and skincare, turned into biodegradable absorbent materials, applied as fertilizer, and have even contributed one of the most important tools in modern biology. The global jellyfish market reached $348 million in 2024, and that figure only counts the food trade.
Food: A Low-Calorie, High-Protein Staple
Jellyfish have been eaten in China, Japan, and Southeast Asia for over a thousand years, prized mainly for their crunchy texture rather than strong flavor. The most commonly consumed species belong to the Rhizostomae group, and they’re typically preserved through a weeks-long process of salting with sodium chloride and alum, then desalted and rehydrated before serving. You’ll find them sliced thin in cold salads, tossed with sesame oil and soy sauce, or lightly cooked in stir-fries.
Nutritionally, ready-to-eat jellyfish is roughly 95% water, with about 4 to 5% protein and almost no fat. That translates to around 12 calories per 100 grams for cannonball jellyfish, making it one of the lowest-calorie animal proteins available. On a dry-weight basis, the protein content is more impressive. One commercially important species has protein levels above 38% of its dry weight in the bell and over 53% in the oral arms. China, Mexico, and Indonesia lead global consumption, and South Korea is the largest exporter by volume, shipping around 13,000 tons in 2024.
One safety consideration worth knowing: the alum used in traditional processing contains aluminum. China caps the allowable aluminum residue at 100 milligrams per kilogram of dry weight, and international food safety bodies set a tolerable weekly intake of 2 milligrams per kilogram of body weight. Proper desalting before eating reduces aluminum levels significantly.
Green Fluorescent Protein Changed Biology
The single most influential jellyfish contribution to science came from the crystal jelly, a species found off the Pacific coast of North America. Scientists isolated a glowing protein from it that fluoresces bright green under ultraviolet light. This protein, known as GFP, earned its discoverers the 2008 Nobel Prize in Chemistry and became one of the most widely used tools in cell biology.
GFP works like a biological highlighter. Researchers attach its gene to any protein or cell type they want to track, and the target glows green under the right light. In cancer research, this has been transformative. Scientists can label cancer stem cells with green fluorescent protein and non-stem cancer cells with a red version, then watch both populations behave simultaneously inside a living organism. Newer techniques link fluorescent proteins to cell-cycle markers so that cells change color from red to green as they shift from resting to dividing, letting researchers see exactly when and where tumor cells become active. This color-coding can distinguish individual tumor cells from healthy tissue at single-cell resolution.
Collagen for Medicine and Skincare
Jellyfish are a rich source of collagen, the structural protein that holds skin, bones, and cartilage together. What makes jellyfish collagen particularly appealing is what it lacks. Collagen from cows carries a small risk of transmitting diseases like mad cow disease. Collagen from pigs raises concerns for people with religious dietary restrictions. Jellyfish collagen sidesteps both problems entirely, making it a safer and more broadly acceptable alternative.
In regenerative medicine, jellyfish collagen scaffolds have shown real promise. When used as a framework for bone repair, these scaffolds promoted greater new bone formation and attracted more immune cells involved in healing compared to control groups. Researchers have also tested jellyfish-derived scaffolds for cartilage repair, exploring their ability to encourage cartilage cells to grow and differentiate. One limitation is that jellyfish collagen is less thermally stable than bovine collagen, meaning it breaks down at lower temperatures, which researchers must account for in medical applications.
In skincare, jellyfish collagen and its broken-down form (collagen hydrolysate) have demonstrated measurable effects on UV-damaged skin. In animal studies, both forms increased skin moisture retention in a dose-dependent way, meaning higher concentrations worked better. They also repaired damaged collagen and elastin fibers in sun-exposed skin and restored the natural ratio of the two main collagen types found in healthy skin. At higher concentrations, the collagen distribution returned to levels seen in undamaged skin. These properties make jellyfish extracts attractive ingredients for anti-aging and hydration products.
Biodegradable Absorbent Materials
Jellyfish bodies are roughly 95% water, and the flesh that holds all that water turns out to have remarkable absorbent properties. A company founded by a Tel Aviv University scientist developed a material called “hydromash” by breaking down jellyfish tissue and adding antibacterial nanoparticles. The resulting material can be used in diapers, tampons, pads, and medical bandages.
The key advantage over conventional absorbent products is environmental. Standard disposable diapers use petroleum-based superabsorbent polymers that take hundreds of years to decompose. Hydromash biodegrades in about 30 days. Given that jellyfish populations are booming in many oceans due to warming waters and overfishing of their predators, turning a marine nuisance into a useful product has obvious appeal.
Fertilizer for Coastal Agriculture
When jellyfish wash ashore in large numbers, they’re increasingly being studied as a potential organic fertilizer rather than just a disposal problem. Jellyfish contain meaningful amounts of nitrogen, phosphorus, and potassium, the three nutrients plants need most. Their nitrogen content is comparable to conventional animal manures, and they have a narrow carbon-to-nitrogen ratio, which means soil microbes can break them down quickly and release nutrients to plants faster than most organic fertilizers.
There are tradeoffs. Jellyfish contain less potassium than standard manures (six to ten times less) and about half the calcium. Oven-dried jellyfish can also introduce significant sodium into the soil, which is a concern for salt-sensitive crops in coastal areas. Phosphorus and magnesium levels are reasonable, with magnesium actually running up to twice as high as in typical animal-based fertilizers. The approach works best as a supplemental nutrient source rather than a complete replacement for conventional fertilizers.
Space Research and Gravity Sensing
NASA sent thousands of jellyfish polyps into orbit aboard the Space Shuttle to study how gravity affects development. Jellyfish use small calcium crystal structures to sense which way is up, much like the balance organs in the human inner ear. This made them a useful model for understanding how microgravity might affect human balance and spatial orientation.
The jellyfish that developed in space looked nearly identical to their Earth-grown counterparts, with no significant differences in body structure or arm number. But their behavior told a different story. About 18% of space-developed jellyfish showed pulsing abnormalities, compared to just 3% of those raised on Earth. These movement problems pointed to disrupted development of their gravity-sensing organs, their neuromuscular system, or the connections between the two. The findings offered early evidence that animals developing in microgravity can look normal but have subtle functional deficits, a concern directly relevant to long-duration human spaceflight.