# Understanding How FDA Regulates Stem Cell and Exosome Products A plain-language, source-cited public education resource on the federal law, FDA pathways, and manufacturing standards that govern mesenchymal stem cell (MSC) and MSC-derived exosome products in the United States — plus a summary of the current peer-reviewed research for three specific conditions. ## 1 351(a) vs. 361 Pathways The single most important regulatory distinction in this field — and the one most often blurred in marketing. ## 2 Why 361 Products Are Restricted Structural, homologous, non-systemic use only — and why that is not the same thing as an approved drug. ## 3 The Federal Right to Try Act What the 2018 federal law actually covers, and the narrow conditions that must be met. ## 4 State Law (6-State Survey) Why state statutes cannot legalize an FDA-unapproved biologic, and what a representative sample of states have tried anyway. Partial survey, not all 50 states. ## 5 ISO 5 Cleanrooms & cGMP What cleanroom classification and manufacturing-quality regulation actually require. ## 6 RUO Labeling & Release Testing Why "Research Use Only" is not a legal safe harbor, and what release testing is actually expected. ## 7 TBI Research Summary 20 recent PubMed-indexed studies on MSC/exosome approaches to traumatic and acquired brain injury. ## 8 COPD Research Summary 20 recent PubMed-indexed studies on MSC/exosome approaches to COPD. ## 9 Knee OA Research Summary 20 recent PubMed-indexed studies on MSC/exosome approaches to knee osteoarthritis. ## 10 Full Legal Disclaimer Complete terms of use, scope limitations, and no-guarantee language for this entire site. ## Why this site exists Regenerative medicine — including mesenchymal stem cell (MSC) therapy and MSC-derived exosome products — is one of the fastest-growing and most misunderstood areas of FDA regulation. Marketing claims from clinics and product sellers frequently blur three separate legal questions: (1) whether a product is even lawful to sell or administer under federal law, (2) whether a state statute changes that answer (it generally does not), and (3) whether "Research Use Only," "FDA-registered," or "Right to Try" language means what a reasonable consumer would assume it means (it usually does not). This site was built as a plain-language, source-cited public education reference on those questions. It was drafted by a regulatory compliance professional with an FDA/CBER background — not a licensed physician and not a licensed attorney — and every regulatory or scientific claim is cited to a primary source (the U.S. Code, the Code of Federal Regulations, FDA guidance, FDA enforcement letters, or peer-reviewed literature indexed on PubMed) or is explicitly flagged where a primary source could not be confirmed. ## What this site is not This site does not sell, market, or recommend any specific product, clinic, treatment, or provider. It does not diagnose or recommend treatment for traumatic brain injury, COPD, knee osteoarthritis, or any other condition. Where it summarizes peer-reviewed research on a condition, that summary is provided to describe the current state of the published scientific literature — it is not a claim that any product is safe or effective for treating that condition, and it is not a substitute for a conversation with a licensed physician. ## Sources cited in this section - U.S. Food & Drug Administration, Center for Biologics Evaluation and Research (CBER) — public guidance and enforcement materials cited throughout this site, primarily at fda.gov . - National Library of Medicine, PubMed — peer-reviewed literature searches cited on the condition-specific pages. This website is an independent public-education resource about how the U.S. Food and Drug Administration (FDA) regulates regenerative medicine products, including mesenchymal stem cell (MSC) and exosome products. It is published for general informational and educational purposes only and does not constitute, and should not be relied upon as, medical advice, legal advice, or a recommendation to pursue, avoid, or forgo any specific treatment, product, or provider. Nothing on this site creates a physician-patient relationship or an attorney-client relationship. The individual(s) responsible for this site are not licensed physicians and are not licensed attorneys, and no content here should be read as an opinion offered in either professional capacity. No claim is made, express or implied, that any product, therapy, or treatment discussed or referenced on this site is safe, effective, or FDA-approved for any use unless the text explicitly states that FDA has approved or licensed that specific product for that specific use. As of the most recent update to this site, FDA has not approved or licensed any exosome product for any use, and FDA has stated publicly that it has not approved any stem cell-based product for any use outside of hematopoietic stem cell products for certain specified indications. See the full disclaimer page for complete terms, including limitations on outcomes, no guarantee language, and how to report a correction. Always consult a licensed physician before making any medical decision, and consult a licensed attorney in your jurisdiction before making any decision with legal consequences. If you believe you are experiencing a medical emergency, call 911 or your local emergency number.