Brands & technologies · Cellulose composite fiber

SeaCell™

Cellulose composite fiber · understand the name behind the label.

Reviewed 2026-09-22. Evidence level: verified. Open the interactive profile.

Key figures

Generic fiber
lyocell containing ground seaweed
Base technology
Zimmer AG lyocell process (NMMO solvent)
Active variant
silver loaded by metal sorption (SeaCell Active)
Clinical study
37 atopic dermatitis patients, 8 weeks, less S. aureus colonization than with cotton
Public specifications
limited; seaweed share and species not published

Approximate values under the stated conditions.

Overview

A branded cellulose fiber incorporating seaweed material. It should not be described as a fabric made entirely from seaweed.

Feel and behavior

Depends on the specified fiber grade, yarn and fabric construction.

Where you find it

See the linked underlying material and the producer’s product-specific documentation.

Source and geography

SeaCell is a lyocell fiber into which ground seaweed is incorporated, so its generic fiber is lyocell and most of its mass is wood-pulp cellulose. Published accounts from 2006 describe it as developed on the lyocell process of Zimmer AG, a German engineering company in Frankfurt, and a clinical study of the silver-activated variant, SeaCell Active, credits SeaCell GmbH of Rudolstadt, Germany. The brand's current official page is hosted by smartfiber. Seaweed species, loading levels and present-day production partners could not be verified from public sources, so buyers should request them.

Advantages

  • It inherits lyocell's softness, drape, moisture handling and closed-loop solvent spinning.
  • Seaweed is a renewable additive that requires no irrigation or fertilizer.
  • It is suitable for next-to-skin knits and blends.
  • The fiber remains cellulose-based, so its microfibers are expected to be less persistent than synthetic ones.

Drawbacks

  • The seaweed share is small and inconsistently reported, making claims hard to evaluate.
  • Evidence that seaweed in the fiber benefits skin after washing is limited.
  • It is more expensive than plain lyocell for similar performance.
  • Wild seaweed harvesting needs management to avoid local ecological effects.

Worth knowing

  • The seaweed in SeaCell is reported to be knotted wrack (Ascophyllum nodosum) from Icelandic fjords, a brown alga of North Atlantic rocky shores.
  • Published figures for SeaCell's seaweed content disagree by several-fold, from about 4% by weight to about 19%.

Types, grades and fabrics

Types and grades

SeaCell is essentially one fiber concept: lyocell with powdered seaweed incorporated during spinning, sold as staple fiber for spinning into yarn. Producer and secondary sources name the seaweed as knotted wrack (Ascophyllum nodosum), a brown alga harvested in Icelandic fjords. Published figures for the seaweed share are inconsistent, ranging from about 4% by weight to figures near 19%, and one description gives a volume ratio of 69% cellulose, 15% water and 16% seaweed; buyers should ask smartfiber for the current specification. A variant named SeaCell LT appears in producer literature. In finished fabrics, SeaCell is typically a minority blend component, so the seaweed share of the garment is lower still.

Fabrics and products

SeaCell yarns, usually blended with other fibers, are used mainly in underwear, sleepwear, loungewear, T-shirts and other next-to-skin knits. Hand-knitting yarn companies have offered SeaCell blends for sweaters and shawls. Knit mills use it in fine-gauge jersey for its lyocell softness and drape. Because the base fiber is lyocell, fabrics behave like lyocell blends, with a smooth hand and good moisture uptake.

Buying and care

How to judge quality

The label should say lyocell (or rayon in the US), with SeaCell as a trademark. Ask for the SeaCell percentage in the garment and the seaweed share in the fiber; retail copy that calls a product 'seaweed fabric' or 'made from seaweed' overstates the content. Skin-benefit claims (vitamins, minerals, antioxidants) should be backed by test data showing effects from the actual fabric after washing; such evidence is limited. Judge the fabric as for lyocell: smooth even surface, no white fibrillation marks at seams, and good recovery in knits. Genuine SeaCell supply can be confirmed with smartfiber.

Care in detail

Care as for lyocell blends: machine wash at 30 C on a gentle cycle, inside out, with mild liquid detergent, and avoid overloading to limit fibrillation. Skip bleach and optical brighteners. Line dry or tumble on low and remove promptly; dry flat for knits to hold shape. Iron on a medium setting (about 150 C) while slightly damp if needed. Store dry, as cellulose can mildew. The producer's own care guidance should be followed if it claims that seaweed components persist through washing, since harsh detergents or hot washes would be expected to reduce any surface additive.

Care at a glance

Follow the finished product’s care label. A trademark does not specify the care needs of every blend or construction.

Environmental and social footprint

SeaCell's footprint is mostly that of lyocell: wood pulp sourcing, energy for dissolution and spinning, and NMMO solvent recovery. The seaweed, reported as Ascophyllum nodosum from Iceland, is a wild-harvested resource; its sustainability depends on harvest rates and regeneration, and no independent assessment specific to SeaCell's supply was found for this entry. Producer claims of skin benefits are separate from environmental claims and are not supported by independent studies located here. At end of life, the cellulose matrix should behave like other regenerated cellulose; a 2019 study (Zambrano and colleagues) found rayon microfibers biodegraded in aerobic aquatic tests while polyester persisted. Blends with synthetic fibers change that outcome.

Tradeoffs

Producer claims apply to defined products and comparisons. This atlas does not independently certify performance, sourcing or environmental claims.

A useful question to ask: Which exact grade, composition and current producer documentation apply to this product?

Science

Manufactured cellulose family

Regenerated cellulose or a cellulose derivative, depending on the fiber.

Structure and chemistry

The matrix is lyocell: cellulose II, highly oriented and crystalline, with a smooth, round cross-section. Seaweed material is dispersed within the fiber rather than chemically bonded to the cellulose. Researchers at Jena described a particular property of the SeaCell fiber as its capacity to bind and absorb substances; in SeaCell Active, silver is taken up by the fully formed cellulose fiber through metal sorption during an activation step. How much seaweed remains accessible at the surface after washing, and what it contributes chemically, is not quantified in public data.

From source to yarn

As Zimmer AG described it, cellulose is dissolved in the lyocell system of cellulose, water and N-methylmorpholine N-oxide, a process able to handle diverse pulp types after suitable pretreatment. Seaweed is incorporated during fiber production, and filaments are formed by the dry-jet wet lyocell route, washed and finished. For SeaCell Active, a further activation step charges the fiber with metal ions, silver in the published studies, to make it antibacterial. The developer stated that neither the seaweed nor the activation impaired lyocell's textile properties. Plant-specific solvent recovery and seaweed content should come from current producer data.

Performance in use

In use SeaCell behaves as lyocell: absorbent, strong when wet compared with viscose, prone to wet fibrillation and charring rather than melting. Evidence for added function concerns the silver-activated form. Laboratory studies showed dose-dependent activity of SeaCell Active against Candida species, Staphylococcus aureus and Escherichia coli, and a randomized, single-blinded study in 37 people with atopic dermatitis found less S. aureus colonization with silver-loaded seaweed-fiber T-shirts than with cotton over eight weeks. Claims that plain seaweed content benefits skin rest on producer statements rather than such trials.

How it is identified

Burn tests are indicative only and show cellulose behavior: rapid burning, a paper-like smell and soft ash. Microscopy may show dispersed particles in otherwise smooth, round lyocell fibers, and elemental analysis can detect silver in the Active grade, but no standard test identifies the brand. In safety testing, no silver release from the fibers was detected, and none was found in the skin's outer layer or in serum. Retail phrases such as 'seaweed fabric' overstate the seaweed share, since the fiber is mainly cellulose from wood.

History

Timeline

  1. 2006A Zimmer AG author described the production of a lyocell fiber containing seaweed and its silver-loaded antimicrobial variant. [1]
  2. 2008Dermatologists reported antifungal and antibacterial activity of the silver-loaded seaweed fiber in laboratory tests. [2]
  3. 2010A randomized, single-blinded study in 37 people with atopic dermatitis reported less Staphylococcus aureus colonization with the silver-loaded fiber than with cotton over 8 weeks. [3]

SeaCell is part of the development of functionalized cellulose fibers. Product formulation and evidence matter more than transferring general seaweed benefits to a textile.

The deeper record

SeaCell appears in the scientific literature by 2006, when solvent-spun cellulose had made it practical to add functional particles to the spinning dope without viscose chemistry. That year a Zimmer AG author described the seaweed fiber and its silver-activated version, and dermatologists at Friedrich Schiller University Jena published in vitro antifungal and antibacterial tests, followed by a patch test in 111 volunteers showing no sensitization and a 2010 trial in atopic dermatitis. The brand is now presented on smartfiber's website. Launch dates, ownership transfers and current production volumes could not be verified from primary sources.

Labeling and law

SeaCell is a trademark, not a generic fiber name. In the United States the fiber is labeled lyocell (or rayon) under the Textile Fiber Products Identification Act and 16 CFR 303.7, and in the EU it is lyocell under Regulation (EU) No 1007/2011; additives do not create a new generic name. Antibacterial or skin-benefit statements are separate claims needing substantiation for the specific product, and silver-treated textiles may fall under additional chemical or biocide rules depending on jurisdiction. Any certification should be checked on the certificate for the specific yarn or fabric.

This describes what rules and standards cover. It is not legal advice; jurisdiction, product form and current rule text control.

Frequently asked

Is SeaCell made from seaweed?

Only partly. It is lyocell, made from wood pulp, with powdered seaweed incorporated into the fiber. Reported seaweed shares vary from a few percent to under a fifth, and garments usually blend SeaCell with other fibers, so the seaweed content is modest.

Does SeaCell benefit the skin?

The producer promotes seaweed's minerals and antioxidants, but independent evidence that these transfer from a washed textile to skin in useful amounts is limited. Treat skin-benefit claims as unproven unless backed by tests on the actual fabric.

What seaweed is in SeaCell?

Sources describe knotted wrack, Ascophyllum nodosum, a brown alga harvested in Icelandic fjords, milled to a powder and added to the lyocell spinning solution. Confirm the current specification with the producer.

Sources

Cite this page

Chaos. (2026). SeaCell™. In Fibers of Earth: An independent textile atlas. https://www.hendrickresearch.com/fibers/materials/seacell/