Material Dossier -- 2026

Reishi™

The cultivation plant that grew this sheet closed in October 2025 and the original grown-mycelium route is no longer running, so confirm what is on offer, and from which entity, before designing it into a range. Capacity, not performance, was always the constraint.

Material Category: Mycelium leather

Composition by Mass

Declared Material Matrix

Fine Mycelium™ (grown mycelium sheet)

Supplier-stated public specification. MycoWorks announced on 11 September 2025 that next-generation Reishi™ is 'grown and made with one hundred percent mycelium', eliminating the cotton insert used in earlier sheets; its earlier retail SKUs were published by MycoWorks as '60% mycelium, 40% cotton'. The 100% figure describes the grown sheet as supplied to partner tanneries — MycoWorks publishes no by-weight share for the tanning, dyeing and finishing inputs applied afterwards, so no split between grown structure and finishing system is stated here. Not independently verified by Material Primer.

100.0%
Plant-Based
Declared Total 100.0%
Technical Data Sheet

Specifications

Technical specifications for Reishi™
Property Value Unit Standard Ref
Commercial status Producer closed its cultivation plant in Oct 2025 — verify before specifying
Availability Not confirmed for new programmes
Process Grown, then tanned in conventional leather finishing
Typical thickness 0.8–1.6 mm
Hand Supplier and its tannery partners describe the hand as close to calf skin; subjective, not independently verified supplier statement — no test method
Application Guidance -- Verified Boundaries

Where This Material Works -- and Where It Must Not

Suitable For

Listed for reference. Premium small leather goods and limited runs where the material story is part of the product — but only if current supply can be confirmed first; see Known limits.

Not Suitable For

Not for volume programmes, and not for any programme that needs multi-season supply continuity. Any offer of Reishi™ stock should be verified against the current producing entity before purchase.

Known Limits

Documented Constraints & Untested Conditions

Capacity, not performance, was always the constraint — and it has now bound. In October 2025 MycoWorks announced the closure of its Union, South Carolina cultivation plant (opened 2023) and a shift away from growing its own mycelium toward sourcing third-party mycelium and applying its Rei-Tan™ tanning process through partner tanneries. Reishi™ as produced by the original Fine Mycelium™ route is no longer being made. There are further reports that the company was subsequently wound up and its intellectual property sold; Material Primer has not verified those reports, and has not been able to confirm current status with the producer directly. Confirm what is actually on offer, and by which entity, before designing this into a range.

No independent test record on file. Material Primer has not bench-tested this product. The figures above are the supplier’s own published specification. Treat them as a starting point for your own testing, not as verified performance.

Verification Boundary -- What This Page Does Not Claim

This dossier compiles the supplier's published specification, the stated scope of certificates held, and referenced standards. It does not represent independent laboratory testing, production batch monitoring, or transaction data. Suitability judgements derive from the documents above, not from bench tests.

Dossier v20260822