Claim Check: "No Side Effects"

The claim

"No side effects" is a common line in peptide marketing. This page checks what it says, what evidence exists and where it stops. It is information only. It does not say any compound is safe or unsafe for a person, and it is not medical advice.

Evidence labels used: approved medicine, insufficient evidence, evidence of harm, marketing claim, Proper evidence not found.

What the claim says

The claim says that using a peptide causes no unwanted effects. For that to be true, researchers would need large, well-run studies that look for harm, in the right people, for long enough, with the exact product. For most unapproved peptides those studies do not exist, so the claim is a marketing claim.

Approved peptide medicines list side effects

Peptide medicines that regulators approved have labeled risks, which shows that peptides as a class do not come without effects.

• The tesamorelin label lists hypersensitivity reactions, edema-related reactions such as joint pain and carpal tunnel syndrome, high blood sugar and injection site reactions among the most commonly reported adverse reactions, and says the effects of prolonged IGF-1 elevation are unknown. [1]
• The semaglutide label lists most common adverse reactions of at least 5% including nausea, diarrhea, vomiting, constipation and abdominal pain, and carries a boxed warning about thyroid C-cell tumors seen in rodents, with human relevance not determined. [2]

These risks belong to these two products. They are not a list for all peptides.

Growth hormone studies

In a systematic review of trials in healthy older adults, growth hormone was linked to more swelling, joint pain, carpal tunnel syndrome and gynecomastia, with somewhat more diabetes or impaired fasting glucose. [3] That review studied growth hormone itself, not the releasing peptides sold to raise it, so it cannot be transferred to those compounds. It does show why "raises growth hormone" and "has no side effects" are different claims.

Unapproved compounds: what is known and unknown

FDA's compounding safety page says it has identified serious adverse events associated with CJC-1295, including increased heart rate and a systemic vasodilatory reaction. [4] For GHRP-6 it cites a potential effect on cortisol and increased blood glucose through reduced insulin sensitivity. [4] For Melanotan II it cites published case reports of serious events including melanoma and priapism. [4] For thymosin beta-4 fragment (TB-500) it says it has found no human exposure data. [4] The page was current as of 04/22/2026 when we read it, and some of these compounds appear in its section for nominations later withdrawn. That is a record of FDA's safety review, not an approval.

For BPC-157, a 2026 systematic review found three human studies (30 people in total). They reported symptom improvement in most participants without treatment-related adverse events but were judged to be of poor quality, with very low certainty. [5] One of them infused the compound into two adults at a private clinic. It reported no side effects. [6] A separate review noted no clinical safety data in its searched literature and warned of possible effects from unregulated manufacturing and contamination. [7] "No adverse events reported" in two or twelve people is insufficient evidence, not proof of safety.

Product quality adds risk that is separate from the compound

Test purchases of semaglutide from illegal online sellers found endotoxin in all samples. [8] FDA has also received an adverse-event report of redness, swelling and a lump at the injection site with a product labeled as compounded tirzepatide from a pharmacy that did not actually compound it. [9] Adverse events with compounded versions are likely underreported, according to FDA. [9]

Bottom line

"No side effects" is a marketing claim. Approved peptides have labeled side effects, several unapproved compounds have FDA safety concerns, and for many there is Proper evidence not found on human safety.

Related guides

See peptide safety and adverse events, BPC-157 research, growth-hormone-releasing peptides, and side effects, allergic reactions and reporting.