US Chem Labs
FDA issued a warning letter to US Chem Labs (Miami, FL, United States) on Feb 7, 2024, citing 21 CFR 201.5. Subject: CGMP, Finished Pharmaceuticals, Adulterated.
From the letter: “your website offers “Semaglutide,” “Tirzepatide” and “Thymalin” products for sale in the United States.”
At a glance
What a reviewer notes before reading: findings, citations, the response deadline and what the letter warns of.
- Violations
- 13 findings · 1 issue type
- Cited
- 21 CFR 201.5
- Response due
- 15 working days after receipt of this letter
- FDA asks for
- 5 actions
- Named as possible actions
- Seizure, injunction
- Issued by
- Center for Drug Evaluation and Research
- Published status
- No close-out recorded
AI assisted findings
Model-assisted reading of each issue. Open one to see the FDA text it comes from, and check it against the full letter.
01Labeling, claims & marketingThe firm offered unapproved new drugs for sale in interstate commerce.
your website offers “Semaglutide,” “Tirzepatide” and “Thymalin” products for sale in the United States. As described below, your “Semaglutide,” “Tirzepatide” and “Thymalin” products are unapproved new drugs introduced or delivered for introduction into interstate commerce in violation of sections 505(a) and 301(d) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 355(a) and 301(d).
02Labeling, claims & marketingThe firm introduced misbranded drugs into interstate commerce.
your “Semaglutide,” “Tirzepatide” and “Thymalin” products are misbranded drugs under section 502 of the FD&C Act, 21 U.S.C. 352, introduced or delivered for introduction into interstate commerce in violation of section 301(a) of the FD&C Act, 21 U.S.C. 331(a).
03Labeling, claims & marketingThe firm marketed products as research chemicals despite evidence of human drug use.
Despite statements on your product labeling marketing your products as “research chemicals only” and “not for human consumption,” evidence obtained from your website establishes that your products are intended to be drugs for human use.
04Labeling, claims & marketingThe firm's products are drugs because they are intended to treat or cure diseases.
Your products are drugs as defined by section 201(g)(1) of the FD&C Act 21, U.S.C. 321(g)(1) because they are intended to prevent, treat, or cure disease conditions and/or affect the structure or function of the body.
05Labeling, claims & marketingThe firm's website made drug claims for semaglutide, including weight loss and diabetes treatment.
From your website www.uschemlabs.com: Semaglutide “What is Semaglutide?” “It's a carefully researched medication with approval from the U.S. Food and Drug Administration (FDA) that was discovered to be a ‘missing link’ for weight loss by accident.
06Labeling, claims & marketingThe firm's website made drug claims for tirzepatide, including weight loss and glucose control.
Tirzepatide is a GLP-1 receptor agonist, it can promote feelings of fullness and reduce food intake, which may lead to weight loss as a secondary effect.
07Labeling, claims & marketingThe firm's website made drug claims for thymalin, including immune and endocrine regulation.
Thymalin is biologically regulating your thymus to produce more peptides that will help regulate your immune system and endocrine system.
08Labeling, claims & marketingThe firm's products are not generally recognized as safe and effective, making them new drugs.
Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are not generally recognized as safe and effective for the above referenced uses and, therefore, are “new drugs” under section 201(p) of the FD&C Act, 21 U.S.C. 321(p).
09Labeling, claims & marketingThe firm's products lack approved applications from FDA.
No approved applications pursuant to section 505 of the FD&C Act, 21 U.S.C. 355 are in effect for these products.
10Labeling, claims & marketingThe firm marketed thymalin for children without FDA evaluation for safety and effectiveness.
In addition, FDA is particularly concerned that you market your “Thymalin” product for use in children. Your product has not been evaluated by FDA for safety, effectiveness, and quality.
11Labeling, claims & marketing · 21 C.F.R. 201.5The firm's products lack adequate directions for their intended uses.
Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are also misbranded under section 502(f)(1) of the FD&C Act, 21 U.S.C. 352(f)(1), in that their labeling fails to bear adequate directions for their intended use(s).
12Labeling, claims & marketingThe firm's products are for conditions not amenable to self-diagnosis, so adequate directions cannot be written.
Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are indicated for conditions that are not amenable to self-diagnosis and treatment by a layperson, therefore adequate directions cannot be written such that a layperson can use the products safely for their intended uses.
13Labeling, claims & marketingThe firm's products are prescription drugs due to toxicity or potential harmful effects.
your “Semaglutide,” “Tirzepatide” and “Thymalin” products are also prescription drugs as defined in section 503(b)(1)(A) of the FD&C Act, 21 U.S.C. 353(b)(1)(A), in light of their toxicity or potential for harmful effects, methods of use, or collateral measures necessary for their use.
What FDA requested
- Provide specific steps taken to address violations
- Include explanation of each step to prevent recurrence
- Submit copies of related documentation
- State reason for delay if corrective actions incomplete
- Provide reasoning and supporting info if products not in violation
FDA Warning Letter
37 paragraphs · 7 sectionsText as published on FDA.gov, retrieved Sep 8, 2026. Layout added for reading; the wording is FDA’s. View on FDA.gov (opens in a new tab)
RE: 669074
1Introduction
3 paragraphs
This letter is to advise you that the United States Food and Drug Administration (FDA) reviewed your website at the Internet address www.uschemlabs.com in October 2023 and has observed that your website offers “Semaglutide,” “Tirzepatide” and “Thymalin” products for sale in the United States. As described below, your “Semaglutide,” “Tirzepatide” and “Thymalin” products are unapproved new drugs introduced or delivered for introduction into interstate commerce in violation of sections 505(a) and 301(d) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 355(a) and 301(d). Furthermore, your “Semaglutide,” “Tirzepatide” and “Thymalin” products are misbranded drugs under section 502 of the FD&C Act, 21 U.S.C. 352, introduced or delivered for introduction into interstate commerce in violation of section 301(a) of the FD&C Act, 21 U.S.C. 331(a).
Despite statements on your product labeling marketing your products as “research chemicals only” and “not for human consumption,” evidence obtained from your website establishes that your products are intended to be drugs for human use. Your products are drugs as defined by section 201(g)(1) of the FD&C Act 21, U.S.C. 321(g)(1) because they are intended to prevent, treat, or cure disease conditions and/or affect the structure or function of the body. Examples of claims observed on your website that establish the intended use of your products as drugs intended for human use include, but may not be limited to, the following:
From your website www.uschemlabs.com:
2Semaglutide
5 paragraphs
“What is Semaglutide?”
“It's a carefully researched medication with approval from the U.S. Food and Drug Administration (FDA) that was discovered to be a ‘missing link’ for weight loss by accident.
Semaglutide first gained FDA approval as a treatment for type 2 diabetes. When used as part of a lifestyle update, semaglutide injections have been shown to help control blood sugar levels in people living with type 2 diabetes. Additionally, semaglutide is used to help reduce the risk of stroke, heart attack, and heart disease in people with type 2 diabetes. However, this medication has received heavy attention for other reasons recently.
Semaglutide injections are quickly becoming famous for weight loss. When used as part of an individualized plan that includes calorie adjustments and exercise, semaglutide can help overweight adults to lose significant amounts of weight. The treatment is especially promising for people seeking to shed pounds quickly due to obesity-related health risks tied to high blood pressure, high cholesterol, and diabetes. The best part is that nobody has to feel hungry when losing weight with semaglutide.
Injections mimic the body's own natural hunger-suppressing hormones that are triggered when the stomach is full. Is semaglutide the ultimate hack for losing weight without feeling deprived? Take a look at what everyone struggling with weight loss needs to know about what is shaping up to be the most promising injectable medication for weight loss ever.”
3Tirzepatide
2 paragraphs
“What is Tirzepatide? Tirzepatide is a GLP-1 receptor agonist, it can promote feelings of fullness and reduce food intake, which may lead to weight loss as a secondary effect.”
“Benefits of Tirzepatide • Improved glucose control: Tirzepatide to US Chem Labs’ tirzepatide product page has been shown to be effective in early clinical trials in improving blood glucose control in people with type 2 diabetes. • Weight loss: In clinical trials, people with type 2 diabetes treated with Tirzepatide have reported modest reductions in body weight compared to those treated with placebo. • Once-daily dosing: Tirzepatide can be taken as a once-daily injection, which is more convenient than multiple injections or doses per day required by some other medications for type 2 diabetes. • Low risk of side effects: Tirzepatide has been shown to be well-tolerated with a low risk of side effects in clinical trials. • Delayed or prevented need for insulin injections: Tirzepatide has the potential to delay or prevent the need for insulin injections in people with type 2 diabetes. • Improved quality of life: By controlling blood glucose levels and reducing the need for multiple injections or doses of medication, Tirzepatide has the potential to improve the quality of life for people with type 2 diabetes.”
4Thymalin
6 paragraphs
“What is Thymalin?”
Thymalin is biologically regulating your thymus to produce more peptides that will help regulate your immune system and endocrine system. The thymus has the task of creating T-lymphocytes or T-cells. These cells are a vital white blood cell when it comes to the immune system. Not only does it support the immune system. It also supports the cardiovascular, endocrine, and nervous systems. Studies have been done on both humans and animals to test the effectiveness and determine its overall effects to the user.
To date, there have been no known negative effects reported through these studies.
Benefits • Improve Cardiovascular System • Support Endocrine & Immune System
Uses • Immunodeficiency in adults and children (from 6 months to 14 years) with infectious purulent and septic processes. • Acute and chronic viral and bacterial infections. • Regenerative processes disorders. • Immunosuppression and hematopoiesis after chemotherapy or radiation therapy in cancer patients. • Neuroendocrine effects.
Thymalin is natural thymic peptide that has been isolated from calf thymus and acts as an immunocorrector or immunostimulant. Restores impaired immune system (regulates the number and ratio of T- and B-lymphocytes and their subpopulations, stimulates cellular immunity reactions, enhances phagocytosis, stimulates regeneration and blood formation in the event of their oppression, and also improves the course of cellular metabolism.”
5Unapproved New Drugs
2 paragraphs
Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are not generally recognized as safe and effective for the above referenced uses and, therefore, are “new drugs” under section 201(p) of the FD&C Act, 21 U.S.C. 321(p). Subject to certain exceptions not applicable here, new drugs may not be legally introduced or delivered for introduction into interstate commerce without an approved application from FDA in effect, as described in sections 301(d) and 505(a) of the FD&C Act, 21 U.S.C. 331(d) and 355(a). No approved applications pursuant to section 505 of the FD&C Act, 21 U.S.C. 355 are in effect for these products. Accordingly, the introduction or delivery for introduction into interstate commerce of these products violates sections 301(d) and 505(a) of the FD&C Act, 21 U.S.C. 331(d) and 355(a).
In addition, FDA is particularly concerned that you market your “Thymalin” product for use in children. Your product has not been evaluated by FDA for safety, effectiveness, and quality. The use of untested drugs can have unpredictable and unintended consequences, especially in vulnerable populations such as children and infants who may be at greater risk for adverse reactions associated with certain drug products due to differences in the ability of children to absorb, metabolize, distribute, or excrete such drug products or their metabolites.
6Misbranded Drugs
2 paragraphs
Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are also misbranded under section 502(f)(1) of the FD&C Act, 21 U.S.C. 352(f)(1), in that their labeling fails to bear adequate directions for their intended use(s). “Adequate directions for use” means directions under which a layman can use a drug safely and for the purposes for which it is intended, 21 C.F.R. 201.5. Prescription drugs, as defined in section 503(b)(1)(A) of the FD&C Act, 21 U.S.C. 353(b)(1)(A), include those that, because of their toxicity or other potentiality for harmful effect, or the method of their use, or the collateral measures necessary for their use, are not safe for use except under supervision of a practitioner licensed by law to administer them. Your “Semaglutide,” “Tirzepatide” and “Thymalin” products are indicated for conditions that are not amenable to self-diagnosis and treatment by a layperson, therefore adequate directions cannot be written such that a layperson can use the products safely for their intended uses. In addition, your “Semaglutide,” “Tirzepatide” and “Thymalin” products are also prescription drugs as defined in section 503(b)(1)(A) of the FD&C Act, 21 U.S.C. 353(b)(1)(A), in light of their toxicity or potential for harmful effects, methods of use, or collateral measures necessary for their use. For these reasons, your “Semaglutide,” “Tirzepatide” and “Thymalin” products are misbranded under section 502(f)(1) of the FD&C Act.
The introduction, delivery for introduction, or causing the introduction or delivery for introduction into interstate commerce of these misbranded drugs is a prohibited act under section 301(a) of the FD&C Act, 21 U.S.C. 331(a).
7Conclusion
4 paragraphs
This letter is not intended to be an all-inclusive statement of violations 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 that your firm complies with all requirements of federal law, including FDA regulations.
This letter notifies you of our concerns and provides you an opportunity to address them. Failure to adequately address this matter may result in legal action including, without limitation, seizure and injunction.
Please notify FDA in writing, within 15 working days of receipt of this letter, of the specific steps you have taken to address any violations. Include an explanation of each step being taken to prevent the recurrence of violations, as well as copies of related documentation. If you cannot complete corrective actions within 15 working days, state the reason for the delay and the time within which you will do so. If you believe that your products are not in violation of the FD&C Act, include your reasoning and any supporting information for our consideration.
Your response should be sent to U.S. Food and Drug Administration, CDER/OC/Office of Unapproved Drugs and Labeling Compliance by email to FDAADVISORY@fda.hhs.gov.
Citations and trends
Each 21 CFR section, ISO 13485 clause and issue type in this letter, how often it appears across all letters, and its trend by the year FDA issued the letters. 2026 runs to Nov 3, 2026, compared with the same dates last year. Select a row or a bar to see those letters in Letters. As cited in this historical letter, not a statement of current requirements.
Regulations
Issue types
Record details
- Issuing center
- Center for Drug Evaluation and Research
- Issuing office
- Center for Drug Evaluation and Research
- Location
- Miami, FL, United States
- Letter posted date
- Feb 13, 2024
- Letter issue date
- Feb 7, 2024
- Addressed to
- Not recorded
- Inspection dates
- Not recorded
- Response window
- 15 working days after receipt of this letter
Read the source clause
Please notify FDA in writing, within 15 working days of receipt of this letter, of the specific steps you have taken to address any violations.
- Record length
- 1,614 words · 4 recorded redactions
- Published status
- No published close-out
- Original letter
- View on FDA.gov (opens in a new tab)
- Dataset last checked
- Nov 11, 2026 · How this is built
A response window is not a calculated due date. Source excerpts are selected passages. Finding interpretations and categories are model-assisted. Verify the original letter before relying on a finding.