Tesamorelin’s side-effect record is better than most peptides’, because it went through placebo-controlled trials to reach FDA approval. The limit is who was in them. Nearly every participant had HIV and excess belly fat, the one use on the Egrifta label [1].
What the drug did for that belly fat is covered in the Egrifta trials, and the doses the trials used are in tesamorelin dosage. This page reads the same record for harm. Tesamorelin is covered under the weight goal, as the brand product only.
That matters for safety. Egrifta’s approval was deemed a biologics license in 2020 [7], and the FDA states that such products are not eligible for the exemptions that allow pharmacies to compound drugs [8]. Every figure below comes from the brand product, and none describes a compounded version.
The label’s adverse-reaction table
The label pools the first 26 weeks of the controlled trials: 543 people on tesamorelin and 263 on placebo [1]. The table below lists the reactions that were more common on the drug and reached 4% of the tesamorelin group.
| Reaction | Tesamorelin (n=543) | Placebo (n=263) |
|---|---|---|
| Injection site reaction (grouped term) | 17% | 6% |
| Joint pain (arthralgia) | 13% | 11% |
| Pain in arm or leg | 6% | 5% |
| Muscle pain (myalgia) | 6% | 2% |
| Swelling of the legs or feet | 6% | 2% |
| Tingling (paresthesia) | 5% | 2% |
| Reduced sensation (hypoesthesia) | 4% | 2% |
| Rash | 4% | 2% |
Most gaps in that table are small, a few percentage points. The two that stand out are injection-site reactions and the cluster of muscle pain, swelling and tingling.
Injection-site reactions
The label’s warnings section gives a broader count than the table. It states that injection-site reactions occurred in 25% of people on tesamorelin and 14% on placebo during the first 26 weeks [1]. They included redness, itching, pain, irritation and bruising.
The pattern held in the later liver-fat trial of 61 people with HIV. The tesamorelin group had more local injection-site complaints than the placebo group, and none was judged serious [6]. How injection sites are chosen and rotated is covered in peptide injection sites.
Swelling, joint pain and tingling
The label groups several reactions under fluid retention, which it links to the rise in growth hormone [1]. It lists swelling, joint pain and carpal tunnel syndrome, and states they are either short-lived or resolve when the drug is stopped.
Carpal tunnel syndrome appeared in 1% of the tesamorelin group and in none on placebo. Muscle pain and leg swelling were each three times as common on the drug, at 6% against 2%.
Blood sugar
The glucose finding is the one the label treats most carefully. Mean HbA1c at the start was 5.3% in both groups [1]. By week 26, 5% of the tesamorelin group had an HbA1c of 6.5% or higher, the diabetes range, against 1% on placebo. The hazard ratio was 3.3, with a confidence interval of 1.4 to 9.6.
Individual trials found less. The 52-week extension of the first phase 3 trial reported glucose changes that were not clinically significant [2]. In 53 people who already had type 2 diabetes, 12 weeks of 1 mg or 2 mg daily did not change insulin response or HbA1c against placebo [3].
A 2024 analysis of 38 people from the liver-fat trial, all on newer integrase-inhibitor regimens, found a similar rate of high blood sugar on tesamorelin and placebo over 12 months [4]. The label still says to check glucose before and during treatment, and to consider stopping in anyone who develops diabetes without a clear benefit.
IGF-1 above the normal range
Tesamorelin works by raising growth hormone and, through it, IGF-1. The label reports how often that rise overshot [1]. After 26 weeks, 47% of people had IGF-1 more than 2 standard deviations above the mean, and 36% more than 3. Among those still on the drug at 52 weeks, the figures were 34% and 23%.
The label states that the effects of a prolonged IGF-1 rise are unknown. It advises monitoring, and considering stopping when levels stay high and the fat response is weak.
Allergic reactions and antibodies
Allergic reactions occurred in 4% of people on tesamorelin in the trials, including itching, redness, flushing, hives and rash [1]. Antibodies to the drug were common: 50% of people developed them by 26 weeks, and 85% of those with an allergic reaction had them.
The label reports that people with and without antibodies lost similar amounts of visceral fat. About 60% of the antibodies also recognized the body’s own growth-hormone-releasing hormone, and the long-term meaning of that has not been studied.
The one trial outside HIV that counted side effects
A 20-week trial gave 1 mg nightly to 152 adults aged 55 to 87, testing memory and thinking [5]. Adverse events were reported by 68% on tesamorelin and 36% on placebo, and the authors describe them as mild. In participants with mild cognitive impairment, fasting insulin rose 35%, within the normal range.
That single trial is the whole safety record in people without HIV or diabetes. For a related molecule with an even thinner record, see sermorelin side effects.