Pinnacle Professional Research dba Pinnacle Peptides
FDA issued a warning letter to Pinnacle Professional Research dba Pinnacle Peptides (Greensboro, NC) in December 2025 after reviewing their website and finding three SARM products — S4 Andarine, LGD-4033, and MK-2866 — marketed with drug-intended-use claims including treatment of cancer, osteoporosis, muscle wasting, and diabetes. Despite 'FOR RESEARCH ONLY / NOT FOR HUMAN USE' disclaimers, FDA determined the website copy established human drug intent, rendering the products unapproved new drugs in violation of FD&C Act sections 301(d) and 505(a). The letter demands a written corrective-action response within 15 working days and warns that failure to comply may result in seizure or injunction.
Flagged claims (15)
Andarine . . . is a non-steroidal selective androgen receptor modulator (SARM) . . . anabolic activity is similar to that of testosterone's . . . for musculoskeletal disorders and benign prostatic hyperplasia [and] found to improve fertility and sexual health in men and women.
FOR RESEARCH ONLY
Cancer . . . Andarine might have the ability to inhibit tumor growth. The androgen receptor has been shown to be associated with the development of pancreatic cancer. Hence, SARMs might prove effective in treating pancreatic cancer.
Insulin Sensitivity . . . antidiabetic effect
[MK-2866] binds with androgen receptors in specific tissues such as muscles. This triggers the cascade of intracellular signaling, resulting in protein synthesis within muscle cells that promotes muscle growth and repair.
One study investigated the effect of ostarine on cachexia in cancer patients. . . . [R]esults indicated a significant increase in lean body mass in patients who took ostarine as compared to the control group.
MK-2866 . . . belongs to the class selective androgen receptor modulator (SARM). . . . [I]t increases muscle mass and growth, improves insulin sensitivity and prevents bone loss. It has also been shown to treat breast cancer.
[A]ndarine shows anticarcinogenic effects on lung cancer by inhibiting cell growth and proliferation and promoting apoptosis.
Osteoporosis . . . Ligandrol binds to the androgen receptors in bone cells and stimulates the activity of osteoblasts. Osteoblasts are the bone cells mainly responsible for the formation of bone and mineral deposition.
Literature supports the evidence that S4 can boost muscle mass and increase strength.
As ligandrol has been shown to improve bone mineral density, it might also speed up the healing of fractured bones.
NOT FOR HUMAN USE
Hormonal decline with age is associated with the loss of muscle health and function. . . . [L]igandrol can counteract these changes and boost muscle strength and mass.
LGD-4033 . . . belongs to the class selective androgen receptor modulator (SARM). . . . [I]t exerts anabolic effects on muscles and bones without causing side effects associated with steroids.
Andarine positively impacts bone mineral density and might offer a promising treatment for osteoporosis.
Required actions (3)
Please notify FDA in writing, within fifteen working days of receipt of this letter, of the specific steps you have taken to correct any violations. Include an explanation of each step being taken to prevent the recurrence of violations, as well as copies of related documentation.
Failure to adequately address this matter may lead to regulatory or legal action including, without limitation, seizure and injunction.
Failure to adequately address this matter may lead to regulatory or legal action including, without limitation, seizure and injunction.
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