What is tesamorelin? What it does, benefits and what the evidence shows

Tesamorelin is a synthetic growth hormone-releasing hormone (GHRH) analogue. The FDA first approved it in 2010 under the brand name Egrifta, made by Theratechnologies, for exactly one indication: reducing excess abdominal fat in HIV-infected adults with lipodystrophy. Newer formulations are sold as Egrifta SV and Egrifta WR. That's the only use with FDA backing. Everything else it's used for — general visceral fat loss in people without HIV, liver fat, cognitive effects, bodybuilding and anti-aging protocols — is off-label, and the evidence behind those uses ranges from a genuine, published human trial to nothing beyond marketing copy. This isn't medical advice.

What tesamorelin is and how it works

Tesamorelin works upstream of growth hormone itself: it's a GHRH analogue, meaning it stimulates the pituitary gland to release the body's own growth hormone, rather than supplying growth hormone directly. DailyMed's listing for EGRIFTA SV describes it as a "growth hormone-releasing factor (GHRF) analog" indicated for the "reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy" (DailyMed, EGRIFTA SV label). A peer-reviewed post-hoc analysis of the pivotal phase III trial describes the same mechanism plainly: tesamorelin is "a synthetic growth hormone-releasing hormone" that works by stimulating growth hormone secretion, which in turn reduces visceral fat accumulation, and confirms tesamorelin is "approved by the Food and Drug Administration (FDA) for reduction of" visceral adipose tissue in this population (post-hoc analysis, PMC). It was first approved in 2010 and reformulated as EGRIFTA SV later; Theratechnologies is the manufacturer. In grey-market listings it's typically sold on its own as a research chemical labeled "for research use only," separate from and unaffiliated with the approved product, its manufacturer, or its FDA-reviewed manufacturing process.

What people use it for

The approved use and the liver-fat and dorsocervical-fat findings above all come from trials in people with HIV — the same population the drug is approved for, just measuring different outcomes within it. The cognitive trial is a different story: it was run in people without HIV, entirely outside the approved indication, which is exactly why it's graded as early human data rather than approved use.

What the research actually shows

The approved use: visceral fat in HIV-associated lipodystrophy

The pivotal phase III program behind tesamorelin's approval was placebo-controlled and specifically measured visceral adipose tissue (VAT) by CT scan. A post-hoc analysis of that trial, splitting participants by whether they also had dorsocervical fat accumulation (sometimes called a "buffalo hump"), looked at 337 HIV-positive participants over 26 weeks and found VAT decreased by roughly 50 cm² in treatment responders in both the group with dorsocervical fat and the group without (both p<0.001), with no significant difference between the two groups — the authors concluded tesamorelin "is equally effective... regardless of the presence of dorsocervical fat" (PMC). That's the core, FDA-reviewed evidence: a real, statistically significant reduction in a specific fat depot, in a specific population, measured by imaging rather than self-report.

Liver fat: a related but separate finding, same population

A double-blind, placebo-controlled trial in 50 antiretroviral-treated people with HIV and abdominal fat accumulation, run for six months at Massachusetts General Hospital, found that tesamorelin reduced visceral fat (a mean change of -34 cm² versus +8 cm² with placebo; treatment effect -42 cm², p=.005) and liver fat (a median change of -2.0% versus +0.9% in lipid-to-water percentage; p=.003) (Stanley et al., JAMA, 2014). The authors called it a preliminary study with modest liver-fat reductions. A larger 12-month placebo-controlled trial enrolling 61 people with HIV and fatty liver disease later reported a 4.1 percentage-point greater fall in liver fat with tesamorelin than with placebo (Stanley et al., Lancet HIV, 2019). This is genuine human trial evidence, but it's still within the HIV population the drug is approved for — it isn't evidence that tesamorelin reduces liver fat in the general population, and liver-fat reduction itself isn't part of the FDA-approved indication.

Cognitive function: a real trial, but outside the approved population

The most interesting off-label evidence is a randomized, double-blind, placebo-controlled trial that enrolled 152 adults aged 55 to 87 (66 with mild cognitive impairment), none of whom had HIV; 137 completed it (76 healthy, 61 with MCI), and treatment ran for 20 weeks. The trial, published in Archives of Neurology in 2012 (now JAMA Neurology), found favorable effects on executive function (p=.005) across measures including task-switching accuracy and a Stroop color-word test, with a smaller, borderline effect on verbal memory (p=.08), and reported no significant difference in benefit between the healthy and MCI groups (Baker et al., Archives of Neurology, 2012). That's a genuine, peer-reviewed, controlled human trial — it just isn't the trial that got tesamorelin approved, it ran in a different population than the label covers, it lasted only 20 weeks, and it's one trial, not a replicated body of evidence. We graded it "early human data" rather than "human trials" for that reason: it's a real signal, not an established, repeated finding. A 2025 trial in a different population found no clear cognitive benefit: in 73 virally suppressed people with HIV and abdominal obesity, six months of tesamorelin did not change cognition significantly more than standard care, though the trial was open-label, underpowered and had no placebo arm (Ellis et al., J Infect Dis, 2025).

What has no trial evidence at all

We could not find a published human trial designed to test tesamorelin for general fat loss or body recomposition in people without HIV, for muscle growth, for athletic recovery, or for broad "anti-aging" effects. The closest signal is a secondary result in the cognition trial above, where percent body fat fell 7.4% in the older adults given tesamorelin (Baker et al., Archives of Neurology, 2012); that is not the same as a trial built to test fat loss. Those uses appear widely in grey-market marketing and biohacking forums, built on the logical leap that a drug which raises growth hormone and IGF-1, and which reduces one specific fat depot in one specific clinical population, should do similar things more broadly. That may or may not turn out to be true, but as of this writing it hasn't been tested and published, so we're not going to state it as though it has.

It's worth being specific about why that leap doesn't hold automatically. The visceral-fat trial evidence is specific to a population with HIV-associated lipodystrophy, a condition with its own distinct fat-redistribution pattern tied to the disease and its treatment; a healthy person's abdominal fat did not go through the same process, and nothing in the approved trial data says tesamorelin acts on it the same way. Raising growth hormone and IGF-1 is a real, measured effect of the drug, but "raises a hormone associated with growth" is not the same claim as "builds muscle" or "reverses aging," and we found no trial connecting tesamorelin to either of those outcomes in any population, on or off label.

Side effects and risks

For the approved use, DailyMed's label lists important limitations directly: tesamorelin's "long-term cardiovascular safety... has not been established," it is "not indicated for weight loss management" (it has a weight-neutral effect on the body overall, redistributing where fat sits rather than reducing total weight), and there's no data showing it improves adherence to antiretroviral therapy in people with HIV (DailyMed). The label also flags increased IGF-1 levels, fluid retention, glucose intolerance and diabetes risk, and a general caution around growth hormone-axis drugs and malignancy, since growth hormone can support the growth of existing tumor tissue — none of that is unique to tesamorelin, but it's part of why prescribing it involves screening and monitoring.

None of that monitoring exists when tesamorelin is bought as a research-labeled vial. Off-label users in bodybuilding and anti-aging contexts are, by definition, using it outside the population and duration the safety data describes, without the screening a prescriber for the approved indication would normally do. The cognitive trial adds its own separate unknown: it ran for only 20 weeks, so nothing published tells us whether the benefit persists, grows, or fades with longer use, or what happens after stopping. On top of the drug's own risk profile, a grey-market vial adds a separate, unrelated risk: whether it actually contains tesamorelin at the purity and amount the label claims, which is a manufacturing and vendor-integrity question, not a pharmacology one.

What the lab tests show

Today, VendorVerify's database includes 32 tesamorelin vials from 12 vendors, drawn from 24 lab reports dated November 2024 through July 2026; as of September 29, 2026, those reports came from 3 labs. 32 of the 32 tested vials have a purity result; 29 (91%) came in at 99% or higher, median purity was 99.27%, and 1 measured under 95%. As of September 29, 2026, only 12 (38%) reached 99.5% or higher — noticeably fewer than the very high-purity GLP-1 compounds in our data. On dose versus label, 30 vials had both a label amount and a measured amount; the median ran 5.4% over label and 11 landed within ±5% (17 were within ±10% as of September 29, 2026). 4 vials measured more than 10% under label, and of those, 3 measured more than 20% under; 1 measured more than 20% over.

As of September 29, 2026, four of the 32 vials (12.5%) failed by our definition, and all four came from a single vendor, which we don't name; 11 of the 12 vendors with tesamorelin results have no failed vial on file. Ranking is thin here: only 2 of the 12 vendors have five or more tesamorelin lab reports, and none currently has enough to be ranked on this specific compound — a genuinely honest headline given rising search interest in tesamorelin generally. Endotoxin testing is rarer still for this compound: only 2 results in our data, one below the lab's detection limit and one in the 2–10 EU range, which is too little to draw any pattern from either way.

Here's how the ranked picture looks right now for this compound. It flags any vendor with more than 5% failed vials, and being ranked isn't automatically good; with this little data, the table may be short or empty.

For the full, continuously updated breakdown, see the tesamorelin results page and our companion article, tesamorelin test results.

Buying smarter

Check a vendor's tesamorelin-specific record at /peptides/tesamorelin rather than judging by their reputation on other compounds — the single vendor behind all four tesamorelin failures in our data, as of September 29, 2026, illustrates why a peptide-specific check matters. Verify any certificate of analysis against the issuing lab rather than trusting a PDF on sight; our guides on reading a peptide COA and spotting fake ones cover what to look for. If you want your own answer, how to get a peptide tested walks through ordering identity, purity and quantity testing independently. If your report comes back bad, stop using that batch, tell anyone else who bought from the same run, bring the report to the vendor, and submit it to VendorVerify. For background on this market generally, see what are gray market peptides.

Approved-use and clinical-trial figures above are cited individually to DailyMed, PMC, JAMA and Archives of Neurology. Database figures without a date update automatically from VendorVerify's lab results; dated figures are snapshots. This isn't medical advice.