Understanding FDA Regulations for Adipose Tissue: Section 361 vs. 351 HCT/P Pathways Explained

If you have ever wondered how the FDA regulates adipose tissue banking, you are not alone. The regulatory framework that governs how fat tissue is collected, processed, and stored in the United States is complex, and understanding it is essential for making informed decisions. This guide breaks down the two primary regulatory pathways, Section 361 and Section 351, explains the four criteria that determine how adipose tissue products are classified, and shows you why these distinctions matter for both patients and healthcare providers. By the end, you will have a clear understanding of how FDA regulations shape the landscape of adipose tissue banking and regenerative medicine.

TLDR: The FDA regulates adipose tissue products under two pathways. Section 361 covers minimally manipulated tissue used for homologous purposes, requiring registration but no clinical trials. Section 351 applies when tissue undergoes more than minimal manipulation or is used non-homologously, requiring full drug and biologic approval. Federal courts have ruled that enzymatically processed stromal vascular fraction (SVF) qualifies as a drug under federal law. Understanding these pathways helps patients and providers distinguish compliant tissue banking from unapproved treatments.

Important Disclaimer: This content is for educational purposes only and does not constitute legal or medical advice. Save My Fat does not provide FDA-approved treatments or cures for any disease. Banking adipose tissue does not guarantee eligibility, access, or clinical benefit from any future therapy, clinical trial, or medical program. For specific regulatory questions, consult qualified legal counsel specializing in FDA regulations. Patients must consult their own licensed healthcare professionals regarding all medical decisions.

You have likely seen clinics advertising “stem cell treatments” for everything from knee pain to chronic disease. At the same time, tissue banking services preserve adipose tissue for potential future use. The natural question: How does the FDA regulate all of this, and what separates a compliant service from one operating outside the rules? Getting this distinction right matters. Clinics that misclassify their products face FDA warning letters, injunctions, and criminal prosecution. Patients who do not understand these pathways risk unapproved treatments that lack evidence of safety or efficacy.

This guide walks you through the FDA’s regulatory framework for adipose tissue in plain language. You will learn what HCT/Ps are, how the four criteria for Section 361 status work, what triggers the Section 351 biologics pathway, and how federal court rulings have shaped current enforcement. Whether you are a patient exploring adipose tissue banking or a provider evaluating compliance, this guide gives you the regulatory foundation you need.

What Are HCT/Ps and Who Regulates Them?

Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps) are biological materials intended for implantation, transplantation, infusion, or transfer into a human recipient. The FDA regulates these products under 21 CFR Part 1271 to minimize the risk of communicable disease transmission and protect patient safety.

HCT/Ps include a wide range of materials: bone, skin, corneas, heart valves, reproductive cells, and adipose tissue. The level of FDA oversight depends on how the tissue is processed and what it is used for. Products that meet all four regulatory criteria face lighter requirements. Products that fail any criterion are regulated as drugs and biological products, requiring clinical trials and marketing approval before use.

This two-tier system creates a clear regulatory boundary. On one side, minimally processed tissue products can operate under registration and listing requirements alone. On the other side, more extensively processed products must go through the full drug approval pipeline. Understanding where adipose tissue falls on this spectrum is essential for patients and providers alike.

The Four Criteria for Section 361 HCT/P Status

Section 361 of the Public Health Service Act establishes a streamlined regulatory pathway for tissue products that meet all four criteria outlined in 21 CFR 1271.10(a). If a product satisfies every criterion, it is regulated solely as an HCT/P and does not require premarket approval, clinical trials, or a Biologics License Application (BLA). If it fails even one criterion, the product falls under Section 351 and must follow the full biologics approval pathway.

All four criteria must be met simultaneously. Failing any single criterion moves the product into the Section 351 biologics pathway, which requires an Investigational New Drug (IND) application and a BLA before the product can be legally marketed for disease treatment. This all-or-nothing framework is the foundation of FDA’s approach to tissue product regulation.

Section 351 Biologics: What Triggers Full FDA Oversight

When an adipose tissue product fails to meet one or more of the four Section 361 criteria, the FDA classifies it as a drug and biological product under Section 351 of the Public Health Service Act. This classification carries significantly higher regulatory requirements.

Products regulated under Section 351 must demonstrate safety and efficacy through rigorous clinical trials before they can be marketed to patients. This pathway exists to protect patients from unproven treatments and to ensure that any product making therapeutic claims has the evidence to support those claims.

Most adipose-derived products currently offered by clinics for disease treatment, including stromal vascular fraction (SVF) injections for arthritis, neurological conditions, or chronic pain, fall under Section 351 because they involve more than minimal manipulation, non-homologous use, or both. For a deeper look at what research is currently underway, visit the emerging research page.

Minimal Manipulation: Defined and Applied to Adipose Tissue

The FDA defines minimal manipulation differently depending on whether the tissue is structural or cellular. Under 21 CFR 1271.3(f), structural tissues must retain their original relevant characteristics after processing. For cells and nonstructural tissues, processing must not alter the relevant biological characteristics.

The FDA’s guidance document, Regulatory Considerations for Human Cells, Tissues, and Cellular and Tissue-Based Products: Minimal Manipulation and Homologous Use, clarified a critical point: the FDA classifies adipose tissue as a structural tissue. This means processing must preserve the tissue’s structural properties, including its cushioning, support, and volume characteristics.

Enzymatic digestion with collagenase fundamentally alters the structural characteristics of adipose tissue by breaking it down into a cell suspension. The resulting product, the stromal vascular fraction, is structurally and functionally different from intact adipose tissue. The FDA has consistently held that this process exceeds minimal manipulation.

For patients considering tissue banking, this distinction is significant. Services that preserve intact adipose tissue through cryopreservation without enzymatic processing operate under a fundamentally different regulatory framework than clinics that isolate SVF or culture-expand cells for injection. Learn more about how stem cell banking works and the processing standards involved.

Homologous Use: Defined and Applied to Adipose Tissue

Homologous use means the tissue performs the same basic function in the recipient as it did in the donor. Under 21 CFR 1271.10(a)(2), the product must repair, reconstruct, replace, or supplement a recipient’s tissues with an HCT/P performing the same basic function.

Adipose tissue naturally provides cushioning, structural support, and energy storage. Using it to restore soft tissue volume is homologous. Using adipose-derived cells to treat arthritis, neurological conditions, or heart disease is non-homologous because fat does not naturally perform those functions.

Non-homologous use automatically triggers Section 351, regardless of processing method. This is why clinics marketing adipose-derived injections for arthritis or back pain face FDA enforcement. The FDA’s consumer alert on regenerative medicine warns that most such products are not FDA-approved. For information about research being conducted, visit the stem cell research areas page.

How Adipose Tissue Is Classified Under FDA Regulations

The same starting material, a patient’s own fat tissue, can fall under either regulatory pathway depending on how it is processed and what it is used for.

This framework explains why tissue banking services and treatment clinics operate under different regulatory requirements. A service that cryopreserves intact adipose tissue follows a different pathway than a clinic that enzymatically digests tissue and injects cells to treat disease.

Tissue banking services like Save My Fat focus on preservation for future opportunities, not disease treatment. This approach positions patients to potentially access future FDA-regulated clinical research, Expanded Access programs, or approved therapies without crossing regulatory boundaries. Banking tissue today does not guarantee eligibility, access, or clinical benefit from any future therapy. Visit the Save My Fat disclaimer page for complete details.

Enzymatic Digestion and SVF: The Definitive Regulatory Status

The stromal vascular fraction (SVF) is the mixed cell population obtained when adipose tissue undergoes enzymatic digestion, typically using collagenase. SVF contains adipose-derived stem cells (ADSCs), endothelial cells, pericytes, immune cells, and other cell types. While SVF has attracted significant research interest, its regulatory status in the United States is clearly defined through both FDA guidance and federal court precedent.

The FDA has consistently classified enzymatically processed SVF as more than minimally manipulated. The guidance documents finalized in November 2017 and updated in July 2020 confirmed this position. Multiple FDA warning letters have cited clinics for marketing SVF products without required IND applications and BLA approvals.

Federal Court Rulings

Three federal appellate courts have addressed the legal status of SVF:

In United States v. Regenerative Sciences, LLC (D.C. Circuit, 2014), the court held that a stem cell mixture constitutes a “drug” under the Federal Food, Drug, and Cosmetic Act (FDCA). In United States v. U.S. Stem Cell Clinic, LLC (Eleventh Circuit, 2021), the court reached the same conclusion. In United States v. California Stem Cell Treatment Center, Inc. (Ninth Circuit, September 27, 2024), the court unanimously ruled that SVF produced through enzymatic digestion meets the statutory definition of a “drug,” that the enzymatic process creates a fundamentally different product from intact adipose tissue, and that the “same surgical procedure” exception does not apply.

On October 14, 2025, the U.S. Supreme Court declined to hear the appeal. Three circuits now agree on this classification.

This means that clinics offering same-day SVF injections using enzymatic processing are operating outside current FDA regulations unless they have an active IND for clinical research. Common violations that trigger FDA enforcement include marketing SVF for disease treatment without an IND, misclassifying Section 351 products as Section 361 HCT/Ps, and making disease treatment claims without clinical evidence. These violations carry consequences ranging from warning letters to injunctions and criminal prosecution. The FTC also monitors health product advertising for deceptive claims.

Patients should verify whether any SVF-based treatment they are considering is being conducted under an IRB-approved clinical trial with an FDA-authorized IND. You can search for registered trials at ClinicalTrials.gov.

What This Means for Patients and Providers

For Patients

Before pursuing any adipose tissue service:

1. Ask whether the service involves enzymatic digestion or cell culture expansion. If yes, request the IND number and verify it on ClinicalTrials.gov.
2. Determine whether the intended use is homologous or non-homologous. Clinics promising to treat arthritis or chronic disease with adipose-derived cells should have FDA authorization.
3. Verify the facility’s FDA registration and cGTP compliance.
4. Consult your physician about any regenerative medicine option before proceeding.
5. Report suspicious claims to the FDA.

For Providers

Misclassifying a Section 351 product as a Section 361 HCT/P exposes practices to enforcement action. Key steps include verifying minimal manipulation standards, confirming homologous use, maintaining proper establishment registration, and following applicable cGTP or cGMP requirements. The Reagan-Udall Foundation Navigator provides resources for navigating FDA pathways. Providers interested in partnering with a compliant tissue banking service can visit the Save My Fat providers page.

Frequently Asked Questions

Q: How does the FDA regulate adipose tissue banking? A: The FDA regulates adipose tissue products under 21 CFR Part 1271. Products meeting all four criteria in Section 1271.10(a) may be regulated under the streamlined Section 361 pathway. Products failing any criterion are regulated as drugs and biologics under Section 351, requiring clinical trials and marketing approval.

Q: What does “minimal manipulation” mean for adipose tissue? A: The FDA classifies adipose tissue as structural tissue, so minimal manipulation means processing that preserves its cushioning, support, and volume properties. Washing, centrifuging, and cryopreserving intact tissue generally qualifies. Enzymatic digestion, cell culture expansion, and cell selection are considered more than minimal manipulation.

Q: Does enzymatic digestion make adipose tissue a drug? A: Yes. Three federal appellate courts have ruled that SVF produced through enzymatic digestion meets the legal definition of a “drug” under the FDCA. The U.S. Supreme Court declined to hear the appeal in October 2025, leaving these rulings as established precedent.

Q: Is adipose tissue banking itself a drug or device? A: No. Tissue banking that collects, minimally processes, and cryopreserves intact tissue is not classified as a drug or device. It may fall under Section 361 HCT/P regulations. Products derived from banked tissue that undergo more than minimal manipulation or non-homologous use would be regulated under Section 351. Learn more about how stem cell banking works.

Q: Do I need FDA approval for autologous use of my own tissue? A: Autologous use does not automatically exempt a product from FDA regulation. The product must still meet all four criteria. Autologous SVF injections for disease treatment still require FDA authorization because they involve more than minimal manipulation and non-homologous use.

Q: What is the “same surgical procedure” exception? A: This exception under 21 CFR 1271.15(b) exempts certain HCT/Ps removed and reimplanted during the same procedure. Federal courts have ruled it does not apply to SVF processing because the removed fat tissue and the reimplanted SVF are fundamentally different products.

Q: Why does regulation matter to me as a patient? A: Unapproved products have not demonstrated safety or efficacy through clinical trials. Patients who receive unregulated treatments risk adverse events, financial loss, and delayed access to proven care. Regulatory knowledge helps you distinguish compliant services from clinics making unsubstantiated claims.

Q: Can banked tissue be used in future clinical trials? A: Banked tissue may potentially be used in future FDA-regulated research, Expanded Access programs, or approved therapies. However, banking does not guarantee participation or access. Eligibility depends on trial criteria, physician guidance, and regulatory status at the time. Explore current stem cell research areas for context.

Q: How can I verify if a clinic is FDA-compliant? A: Check the clinic’s FDA establishment registration, ask for IND or BLA numbers, search ClinicalTrials.gov for registered studies, and review FDA warning letters for enforcement history. Compliant services will be transparent and will not make disease-cure claims.

Q: Does Save My Fat offer family eligibility for banked tissue? A: Save My Fat’s service may allow first-degree family members to access banked tissue under certain guidelines. Any future use must comply with FDA regulations at that time. Banking does not guarantee future access or clinical benefit for any individual.

Key Takeaways

FDA Regulatory Framework

• The FDA regulates adipose tissue under Section 361 (HCT/P) and Section 351 (biologics)
• All four criteria must be met for Section 361: minimal manipulation, homologous use, no combination with other articles, and no systemic effect (or autologous use)
• Failing any single criterion triggers the full Section 351 drug approval pathway

Minimal Manipulation and Homologous Use

• The FDA classifies adipose tissue as structural tissue
• Enzymatic digestion, cell culture, and cell selection exceed minimal manipulation
• Non-homologous use (treating arthritis, neurological conditions) triggers Section 351 regardless of processing

SVF Court Precedent

• Three federal appellate circuits classify enzymatically processed SVF as a drug
• The U.S. Supreme Court declined review in October 2025, establishing binding precedent
• The same surgical procedure exception does not apply to SVF

Patient Safety

• Verify regulatory compliance before pursuing any adipose tissue service
• Consult your physician and check ClinicalTrials.gov for treatment claims
• Banking tissue does not guarantee future treatment access or clinical benefit
• Tissue banking and treatment clinics operate under fundamentally different regulatory requirements

Ready to Learn More About Compliant Adipose Tissue Banking?

You now understand how the FDA regulates adipose tissue, what separates Section 361 from Section 351, and why these distinctions matter. Save My Fat helps individuals preserve adipose tissue through validated cryopreservation protocols for potential future use in FDA-regulated clinical research, Expanded Access programs, or approved therapies.

We focus on education, regulatory compliance, and honest communication about what tissue banking can and cannot do. Here is what we provide:

• Comprehensive consultation about tissue banking and realistic expectations
• Validated cryopreservation protocols for long-term tissue preservation
• Educational resources about FDA pathways and patient safety
• Family eligibility information for first-degree relatives

Important: Banking adipose tissue does not guarantee eligibility, access, or clinical benefit from any future therapy. All medical decisions must be made with your licensed healthcare provider.

Ready to learn more?

Contact Us: https://savemyfat.com/contact-us/

Providers: https://savemyfat.com/providers/

Save My Fat Adipose Tissue Banking for Future Regenerative Medicine Opportunities

Last updated: February 18, 2026