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  1. Warning Letters

WARNING LETTER

R3 Medical Companies MARCS-CMS 726330 —

Delivery Method:
Via UPS and EMAIL
Reference #:
CBER 26-726330
Product:
Biologics
Recipient:
Recipient Name
David L. Greene, M.D.
Recipient Title
Chief Executive Officer
R3 Medical Companies

10045 E. Dynamite Blvd., Suite 260
Scottsdale, AZ 85262
United States

dgreene@bello.bio
dgreene@regensuppliers.com
Issuing Office:
Center for Biologics Evaluation and Research (CBER)

United States

WARNING LETTER

August 14, 2026

CBER 26-726330

Dear Dr. Greene:

The United States Food and Drug Administration (FDA) inspected your facilities, Bello Bio, LLC (herein referred to as “Bello”) and Regen Suppliers, LLC (herein referred to as “Regen”) co-located at 10045 E. Dynamite Blvd., Suite 260, Scottsdale, AZ 85262, between November 17, 2025, and December 16, 2025.1,2 During the inspections, FDA documented that Bello contract manufactures and labels umbilical cord derived products, ReBellaWJ, ReBellaXO, and ReBellaXOL, for private label distribution by Regen.3,4 Regen approves, labels, stores, and distributes the aforementioned products as well as an umbilical cord blood derived product, ReBellaCB, contract manufactured under private label by (b)(4) ReBellaWJ, ReBellaXO, and ReBellaXOL will herein be referred to as “your umbilical cord derived products.” These three products, together with ReBellaCB, will be referred to collectively as “your products.”

This letter is to advise you that your products are unapproved new drugs in violation of section 505(a) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. § 355(a). Your products are also unlicensed biological products in violation of section 351(a)(1) of the Public Health Service Act (PHS Act), 42 U.S.C. § 262(a)(1). A biological product for which a biologics license application (BLA) has been approved under section 351(a) of the PHS Act is not required to have an approved application under section 505 of the FD&C Act, 21 U.S.C. § 355; 42 U.S.C. § 262(j). Otherwise, with certain exceptions not applicable here, a new drug may not be introduced or delivered for introduction into interstate commerce without an approved application from FDA in effect, as described in section 505(a) of the FD&C Act. Your introduction or delivery for introduction of your products into interstate commerce, or the causing thereof, is prohibited under section 301(d) of the FD&C Act, 21 U.S.C. § 331(d).

This warning letter also summarizes significant violations of current good manufacturing practice (CGMP) requirements, including violations of section 501(a)(2)(B) of the FD&C Act, 21 U.S.C. § 351(a)(2)(B), and 21 CFR parts 210 and 211, in the manufacture of your products. Because your methods, facilities, or controls for manufacturing, processing, packing, or holding drugs do not conform to CGMP, your products are adulterated within the meaning of section 501(a)(2)(B) of the FD&C Act, 21 U.S.C. § 351(a)(2)(B). Your introduction or delivery for introduction of your products into interstate commerce, or the causing thereof, is a prohibited act under section 301(a) of the FD&C Act, 21 U.S.C. § 331(a).

Unapproved New Drug and Unlicensed Biological Product Violations

Based on information and records reviewed by FDA, including, but not limited to, your YouTube channel, @R3StemCell www.youtube.com/@R3StemCell, TikTok @R3StemCell www.tiktok.com/@r3stemcell, Instagram @R3stemcellofficial, www.instagram.com/r3stemcellofficial, Facebook page R3 Stem Cell www.facebook.com/r3stemcelltherapyofficial, and websites, www.r3stemcell.com, www.bello.bio, and www.regensuppliers.com5, (last visited August 2026), your products are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease or conditions in humans, and/or are intended to affect the structure or function of the body. For example:

  • ReBellaWJ:
    o R3 Stem Cell, LLC website (www.r3stemcell.com/):
     In a November 15, 2020, blog post entitled “What is Umbilical Cord Wharton’s Jelly?” (https://r3stemcell.com/what-is-umbilical-cord-whartons-jelly/):
    • “One of the major effects is the reduction of inflammation. Chronic inflammation has been shown to be present in the body and is a known precursor to many medical conditions including organ failure, arthritis, several types of cancer and more. The biologic’s cells are able to systemically reduce this inflammation…”
    • “…The top wharton’s jelly stem cell product being offered is ReBellaWJ…To find out more information and to place an order, visit and call Regen Suppliers at (888) 568-6909.”
     Under a title of “What conditions benefit from their use?” on Umbilical Cord Stem Cell Therapy tab: “In the research literature and from our provider’s experience, there are benefits being shown for: Neurologic Conditions…Heart/Kidney/Lung Failure (e.g. Cardiomyopathy, COPD)…Autism…Cerebral Palsy…Diabetes…Lyme Disease...SI Joint Pain...Erectile Dysfunction..”
    o R3 Anti-Aging website (https://r3antiaging.com):
     Under the “Umbilical Cord Allograft” tab within your “Regenerative Therapies” page: “R3 Anti-Aging and Medspa in Scottsdale and Nashville offers umbilical cord allograft therapy for patients who have joint or soft tissue pain...In addition, the umbilical cord tissue contains a significant amount of growth factors, exosomes, mesenchymal stem cells and cytokines as well. These facilitate one's body to amp up the repair and regeneration activities to reduce pain from joint degeneration, tendonitis, bursitis...and neuropathy.”
  • ReBellaXO and ReBellaXOL:
    o Regen website (https://www.regensuppliers.com):
     Until recently, within the “ReBellaXO 1.0mL - B” product page: “ReBellaXO an exosome allograft derived from Wharton's Jelly MSCs... For your procedures involving IV's, joints, soft tissue, hair, facial or sexual rejuvenation, ReBellaXO represents your most cost effective and safe option for fitting regenerative biologics into your patient care!”
     Until recently, under the “About” tab: “ReBellaXOL Lyophilized Exosomes… produces collagenesis, anti-scar, pro-angiogenesis, & anti-apoptosis. BelloXO intensely stimulates regeneration…”
    o R3 Stem Cell, LLC website (www.r3stemcell.com/):
     Under the Exosome Therapy tab: “Can exosomes help with neurodegenerative conditions? Research has shown that exosomes can penetrate the blood-brain barrier and stimulate neuronal differentiation, growth of neurons, and reduce inflammatory processes within the brain tissue. This may result in future benefit to neurodegenerative conditions such as Alzheimer’s, Parkinson’s, Post Stroke and other issues.”
    o R3 Anti-Aging website (https://r3antiaging.com):
     The "Exosome therapy" page within your "Treatments" tab under "Regenerative Therapies,"
    • “Exosome Therapy for Joint Pain… Exosome therapy is getting great results for joint pain relief:… Rebuilding cartilage: Exosomes help fix damaged cartilage… Reducing inflammation: They calm the swelling in your joints.”
    • Listing “Wound Healing” and “Anti-Inflammation” in a chart titled “Benefits of Exosome Therapy”
  • ReBellaCB:
    o Until recently, the product page for ReBellaCB on your Regen website, (www.regensuppliers.com), states, “REBELLACB is an Umbilical Cord Blood Stem Cell Allograft” and links to an R3 Stem Cell YouTube video, https://www.youtube.com/watch?v=sZeux0WXsUU&feature=youtu.be, titled “Is Umbilical Cord Blood Safe for Regenerative Procedures?” with the video description stating, “For years now, umbilical cord blood has been used increasingly for non-malignant conditions such as arthritis, neurological conditions, autism, diabetes, liver/kidney failure and much more. Umbilical cord tissue has a ton of hematopoietic and mesenchymal stem cells along with cytokines, growth factors, and exosomes. All of this makes it very effective for these conditions.”
  • ReBellaCB and ReBellaXO:
    o In a video posted on your R3 Stem Cell YouTube Channel on March 5, 2026 (https://www.youtube.com/watch?v=L0QlPvhdjds) titled “Elite Football Player Talks to His Stem Cells (844) GET-STEM,” an employee is seen showing vials of ReBellaCB and ReBellaXO to a patient and states: “These are your stem cells. There’s 30 million in each vial... This is ReBellaXO. These are your exosomes… Those are very anti-inflammatory...” [0.00-0.24] so should help a lot…” The video description states, “When receiving stem cell therapy to help with injuries, athletes should talk to their cells.”

Therefore, your products are drugs as defined in section 201(g)(1) of the FD&C Act, 21 U.S.C. § 321(g)(1), and biological products as defined in section 351(i) of the PHS Act, 42 U.S.C. § 262(i).

Your ReBellaWJ, ReBellaXO, ReBellaXOL, and ReBellaCB products are also human cells, tissues, or cellular or tissue-based products (HCT/Ps) as defined in 21 CFR 1271.3(d) and are subject to regulation under 21 CFR part 1271, issued under the authority of section 361 of the PHS Act, 42 U.S.C. § 264. HCT/Ps that do not meet all the criteria in 21 CFR 1271.10(a) are not regulated solely under section 361 of the PHS Act and the regulations in 21 CFR part 1271. Unless an exception in 21 CFR 1271.15 applies, such products are regulated as drugs, devices, and/or biological products under the FD&C Act and/or the PHS Act and are subject to additional regulation, including applicable premarket review. Based on a review of relevant materials, your firm does not qualify for any exception in 21 CFR 1271.15, and your products fail to meet all criteria in 21 CFR 1271.10(a).

For example, your ReBellaWJ, ReBellaXO, ReBellaXOL and ReBellaCB products fail to meet the criterion that the HCT/Ps be “intended for homologous use only.” Homologous use means that the “labeling, advertising, or other indications of the manufacturer’s objective intent” demonstrate that the HCT/P is intended to perform “the same basic function or functions in the recipient as in the donor” (21 CFR 1271.3(c) and 1271.10(a)(2)). Your products are not intended solely to perform the same basic function or functions of the HCT/P in the recipient as in the donor (e.g., serving as a conduit for umbilical cord or forming and replenishing the lymphohematopoietic system for umbilical cord blood). Rather, your products are intended for use in the treatment of various diseases and conditions, such as, but not limited to, arthritis and inflammation, which is not a basic function of umbilical cord or umbilical cord blood in the donor.

Moreover, your ReBellaCB product fails to meet the criterion in 21 CFR 1271.10(a)(4) because it is manufactured from allogeneic umbilical cord blood, is dependent on the metabolic activity of living cells for its primary function, and is not for autologous use, allogeneic use in a first-degree or second-degree blood relative, or reproductive use.

Therefore, these HCT/Ps are not regulated solely under section 361 of the PHS Act, 42 U.S.C. § 264, and the regulations in 21 CFR part 1271.6 See 21 CFR 1271.20. In addition to being regulated under section 361 of the PHS Act and 21 CFR part 1271, your products are regulated as drugs as defined in section 201(g)(1) of the FD&C Act, 21 U.S.C. § 321(g)(1), and biological products as defined in section 351(i) of the PHS Act, 42 U.S.C. § 262(i), as stated above.

Subject to certain exceptions not applicable here, to lawfully introduce or deliver for introduction into interstate commerce a drug that is a biological product, a valid BLA must be in effect under section 351(a)(1) of the PHS Act, 42 U.S.C. § 262(a)(1). Such licenses are issued only after showing that the product is safe, pure, and potent. Your products are not the subject of an approved BLA.

CGMP Violations

FDA’s inspections of your Bello and Regen facilities documented evidence of significant CGMP violations. At the conclusion of the inspections, FDA investigators issued a Form FDA-483, List of Inspectional Observations (Form FDA-483), to each of Bello and Regen. FDA also identified additional significant violations upon further review of the evidence collected during the inspection, as set forth below.

The CGMP violations applicable to your Bello facility pertaining to your umbilical cord derived products include, but are not limited to, the following:

1. Failure to establish and follow appropriate written procedures designed to prevent microbiological contamination of drug products purporting to be sterile, including procedures for validation of all aseptic and sterilization processes, as required by 21 CFR 211.113(b). For example, your firm has not validated the aseptic processes used to manufacture your umbilical cord derived products. Your umbilical cord derived products purport to be sterile and are expected to be sterile.

2. Failure to establish written procedures for production and process control designed to assure that the drug products have the identity, strength, quality, and purity that they are purported or represented to possess, as required by 21 CFR 211.100(a). For example, your firm has not validated the manufacturing processes for your umbilical cord derived products with respect to identity, strength, quality, and purity.

3. Failure to establish laboratory controls that include scientifically sound and appropriate specifications, standards, and test procedures designed to assure that components, drug product containers, closures, in-process materials, labeling, and drug products conform to appropriate standards of identity, strength, quality, and purity, as required by 21 CFR 211.160(b). For example, samples of your umbilical cord derived products are frozen and thawed prior to sterility testing. Freezing samples has the potential to destroy or compromise any microbial content in the samples before testing, if present; therefore, any contamination that was present prior to freezing may not be reliably detected.

4. Aseptic processing areas are deficient regarding the system for cleaning and disinfecting the room and equipment to produce aseptic conditions, as required by 21 CFR 211.42(c)(10)(v). For example, you have not validated your processes for cleaning and disinfecting the ISO (b)(4) biological safety cabinet (BSC) where your products are exposed to the environment during aseptic processing.

5. Failure to establish and follow a written testing program designed to assess the stability characteristics of drug products and to use results of such stability testing to determine appropriate storage conditions and expiration dates, as required by 21 CFR 211.166(a). For example, your firm assigns a 24-month expiration date to your products without supporting stability testing data.

The CGMP violations applicable to your Bello and Regen facilities pertaining to your products include, but are not limited to, the following:7

6. The responsibilities and procedures applicable to the quality control unit are not in writing and fully followed, as required by 21 CFR 211.22(d). For example, at the time of the inspection, written procedures describing the responsibilities of the quality unit had not been established, including but not limited to, procedures for the approval or rejection of drug products (21 CFR 211.22(a)) and the handling of all written and oral complaints regarding a drug product (21 CFR 211.198(a)).

Responses to the Form FDA-483

We have reviewed your responses to the Form FDA-483s issued to each of your Bello and Regen facilities dated January 08, 2026 and January 06, 2026, as well as your correspondence dated November 20, 2025, in detail. While you represented that you have implemented or plan to implement certain corrective actions, the described corrective actions are not adequate to remedy the violations noted above. For example, your responses do not address your continued distribution of your products or specific plans for disposition of the remaining inventory manufactured under the violative conditions outlined above. We note that certain corrective actions cannot be evaluated because they lack supporting documentation.

Further, for your previously distributed products, you do not describe actions you have taken or plan to take that adequately address the impact of the above-noted deficiencies on your distributed products that are still within expiry and were manufactured under the above-described violative conditions.

We acknowledge your commitment to temporarily suspend manufacturing operations until you have made corrections to the observations listed on the Form FDA-483 issued to each of your Bello and Regen facilities. However, this does not resolve the violations outlined in this letter because your responses do not adequately address your failure to have an Investigational New Drug (IND) in effect to study your products addressed in this letter or your lack of an approved BLA to lawfully market your products.

FDA has previously provided notice to you, David Greene, in a letter dated May 28, 2019, that based on a review of your website for R3 Stem Cell, LLC (www.r3stemcell.com) at that time, your firm appeared to offer “regenerative stem cell therapies” while promoting these stem cell therapies for numerous diseases or conditions, such as amyotrophic lateral sclerosis (ALS), diabetes, kidney failure, Lyme disease, Parkinson’s disease, and stroke. Based on that review, R3 Stem Cell, LLC did not appear to qualify for any exception under 21 CFR 1271.15; the “regenerative stem cell therapies” were intended for nonhomologous uses and thus would be regulated as drugs as defined in section 201(g) of the FD&C Act [21 U.S.C. 321(g)] and biological products as defined in section 351(i) of the PHS Act [42 U.S.C. 262(i)]. However, our review of your current websites and various social media accounts, which are also linked to your websites, indicates umbilical stem cell therapy and exosome therapy continue to be offered by R3 Stem Cell, LLC for treatment of various diseases and conditions, as described above.

Additional Concerns

In addition to the violations described above, we have the following concerns:

  • FDA’s review of information and records collected during the inspections documented Bello also manufactures the following umbilical cord derived8 products: BelloWJ, BelloXO, and BelloXOL. Your response dated January 08, 2026 asserts that Bello is a manufacturer of HCT/Ps and is subject only to current good tissue practice (CGTP) requirements of 21 CFR Part 1271 and is regulated solely under section 361 of the PHS Act); however, review of the evidence collected shows these products do not appear to meet the relevant criteria to be regulated solely under section 361 of the PHS Act, for the reasons discussed above. These products appear to be drugs and/or biological products, which are subject to premarket review and approval requirements.
  • FDA review of Bello’s manufacturing records revealed that (b)(4) is a component of the (b)(4) used during Bello’s manufacturing process of products derived from umbilical cord tissue; however, there did not appear to be evidence that testing for (b)(4) had been performed prior to the release of these products, as required by (b)(4).
  • Bello determines donor eligibility upon review of relevant medical records per your contract agreement with (b)(4). The “Donor Eligibility Criteria” documents (effective date 08/15/2023) submitted with your January 8, 2026, response and also collected during the inspection do not include “qualifiers/comments” for Transmissible Spongiform Encephalopathy (TSE). In accordance with 21 CFR 1271.75(a)(1)(iv), all donors of cells or tissues, except as provided under 1271.90, must be screened by reviewing the donor’s relevant medical records for risk factors for, and clinical evidence of, relevant communicable disease agents and diseases, including human transmissible spongiform encephalopathy, including Creutzfeldt-Jakob disease. Additionally, FDA Guidance for Industry: Eligibility Determination for Donors of Human Cells, Tissues, and Cellular and Tissue-Based Products (August 2007)9 recommends screening donors for TSE, including Creutzfeldt-Jakob disease (CJD) and variant CJD (vCJD), by asking if donors have been diagnosed with dementia or any degenerative or demyelinating diseases of the central nervous system or other neurological disease of unknown etiology. For additional information and recommendations intended to assist establishments with complying with all requirements in 21 CFR part 1271, subpart C, please refer to the guidance.

Conclusion

Neither this letter nor the observations noted on the Form FDA-483s for both Bello and Regen, which were discussed with you at the conclusion of the inspections, are intended to be all-inclusive lists of deficiencies that may exist in connection with your products. You are responsible for investigating and determining the causes of any violations and for preventing their recurrence or the occurrence of other violations. It is your responsibility to ensure full compliance with the FD&C Act, PHS Act, and all applicable regulations.

This letter notifies you of our concerns and provides you an opportunity to address them. Failure to adequately address these matters may result in action without further notice including, without limitation, seizure and/or injunction.

Please submit your response in writing within fifteen (15) working days from your receipt of this letter, outlining the specific steps you have taken or plan to take to address any violations and prevent their recurrence. Include any documentation necessary to show that the matters have been addressed. If you cannot address these matters within fifteen (15) working days, please explain the reason for your delay and the timeframe for completion. If you do not believe your products are in violation of the FD&C Act, PHS Act, or applicable regulations, include your reasoning and any supporting information for our consideration.

Send your electronic response and any questions regarding this letter to CBER’s Office of Compliance and Biologics Quality, Division of Case Management at CBERDCMRecommendations@fda.hhs.gov.

Sincerely,
/S/

Vincent Amatrudo
Acting Director
Office of Compliance and Biologics Quality
Center for Biologics Evaluation and Research

Cc: (b)(4)

________________________

1 During the inspections, you informed FDA that R3 Medical Companies is the parent company of these companies co-located at the same business address: Bello, Regen, R3 Stem Cell, LLC and R3 Anti-Aging Scottsdale LLC. You bear primary responsibility for the business operations at each of the aforementioned entities.

2 Greene Technologies, LLC, for which you are the co-owner and majority holder, along with Ms. Deborah Greene, invests in the referenced entities and other R3 Anti-Aging LLC clinics located at 5020 Thoroughbred Lane, Brentwood, TN 37027 and 9301 Wilshire Boulevard Penthouse, Beverly Hills, CA 90210. The referenced entities function together with Bello as the manufacturer and Regen as the private label distributor to the three R3 Anti-Aging clinics, healthcare professionals, and other clinics as direct-to-customers and through R3 Stem Cell’s partnership program, R3 Alliance Partner. We note you are also the current Chief Executive Officer (CEO) of R3 Anti-Aging & MedSpa Nashville, LLC (located at 5020 Thoroughbred Lane, Brentwood, TN 37027) and R3 Anti-Aging Beverly Hills, LLC (located at 9301 Wilshire Boulevard Penthouse, Beverly Hills, CA 90210).

3 Regen markets ReBellaXO and ReBellaXOL as exosome products; however, products manufactured by Bello use the same starting material and manufacturing process (with the exception of an added lyophilization step for ReBellaXOL), which does not appear would isolate exosomes.

4 ReBellaXOL was also labeled as ReBellaGF by Bello at the time of the inspections.

5 As of August 14, 2026, it appears that the Regen Suppliers website www.regensuppliers.com is no longer accessible with a “404, Not Found.” message displayed.

6 Because your products fail to meet at least one criterion in 21 CFR 1271.10(a), this letter does not evaluate all other criteria in 21 CFR 1271.10(a) for each product.

7 Although products are contract manufactured for Regen, Regen’s activities, as described above, constitute manufacturing under 21 CFR 210.3(b)(12). Regen is therefore subject to CGMP requirements.

8 Bello markets BelloXO and BelloXOL as exosome products; however, it does not appear that the manufacturing process would isolate exosomes.

9 See https://www.fda.gov/regulatory-information/search-fda-guidance-documents/eligibility-determination-donors-human-cells-tissues-and-cellular-and-tissue-based-products.

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