Tesamorelin vs HGH: how they differ and which is approved

The short answer: tesamorelin is a signal that makes the pituitary release more of the body's own growth hormone, while HGH (somatropin) is growth hormone itself. [1] [2] Both are FDA approved, but for different things: tesamorelin only for excess abdominal fat in adults with HIV lipodystrophy, and somatropin for growth hormone deficiency and several growth disorders.

This post compares them on mechanism, evidence, approvals, and legal access. It does not give dosing advice; label doses for approved uses are on each product's prescribing information.

How do tesamorelin and HGH work?

Tesamorelin is an analog of growth hormone releasing hormone. It binds the same pituitary receptor as the natural hormone, which triggers the synthesis and pulsed release of the body's own growth hormone. [1] Because it depends on the pituitary, its label rules it out for people whose hypothalamic pituitary axis has been disrupted by pituitary surgery, tumor, head radiation, or head injury. [1]

Somatropin is recombinant human growth hormone, a 191 amino acid protein identical in sequence to the pituitary hormone. [2] It replaces the hormone directly, which is why it is the treatment for people whose pituitary cannot make enough.

What is each one approved for?

Egrifta WR is indicated to reduce excess abdominal fat in adults with HIV who have lipodystrophy. Its label says it is not indicated for weight loss management because it is weight neutral, and that long term cardiovascular safety has not been established. [1]

Somatropin is approved for growth failure in children due to growth hormone deficiency, Prader-Willi syndrome, Turner syndrome, being born small for gestational age, and idiopathic short stature, and for adults with growth hormone deficiency that began in childhood or adulthood. [2] One somatropin brand, Serostim, is approved for HIV-associated wasting, to increase lean body mass, body weight, and physical endurance. [3]

So in HIV care the two answer different problems: somatropin for wasting, tesamorelin for excess belly fat. See the HIV lipodystrophy page and the muscle wasting page.

What does the evidence show for belly fat?

Tesamorelin. In two phase 3 trials pooled across 806 adults with HIV, visceral fat fell 15.4% relative to placebo at 26 weeks, triglycerides fell, and glucose measures did not change meaningfully. [4] In the extension phase, visceral fat rose again in people switched to placebo. [1] A 12 month trial in 61 people with HIV and fatty liver cut liver fat by an absolute 4.1 percentage points. [6] Outside HIV, a 12 month trial in 60 adults with abdominal obesity and low growth hormone output found a similar visceral fat drop with no change in glucose. [7] See the fatty liver disease page for how that result compares.

Somatropin. It was tested for the same HIV fat problem. In a randomized trial of 325 people, 12 weeks of daily somatropin cut visceral fat by 32.6 square centimeters versus almost no change on placebo, but it also reduced limb fat. [5] In the tesamorelin phase 3 trials, by contrast, abdominal fat under the skin did not change. [4] The Serostim label calls HIV lipodystrophy an unapproved indication and reports dose dependent glucose intolerance in those trials. [3]

No trial has compared tesamorelin and somatropin head to head, so these results come from different trials and cannot be ranked directly.

How do the side effects compare?

Because both raise growth hormone and IGF-1, the labels share several warnings. Both list fluid retention, which shows up as swelling, joint pain, and carpal tunnel syndrome; both warn about glucose intolerance or diabetes; both call for care around cancer; and both warn of increased deaths in people with acute critical illness. [1] [2]

Tesamorelin's label adds IGF-1 monitoring: after 26 weeks, 47% of patients had IGF-1 more than 2 standard deviations above normal. [1] Somatropin's label adds warnings about raised pressure inside the skull and a higher risk of a second tumor in childhood cancer survivors. [2]

Is either legal for anti-aging or fat loss?

Neither is approved for anti-aging, and the evidence for growth hormone in healthy older adults runs against it. A systematic review found small body composition changes, more swelling, joint pain, and carpal tunnel syndrome, and a trend toward diabetes, and concluded that growth hormone cannot be recommended as an anti-aging therapy. [8]

The legal lines differ. Federal law makes it a crime to knowingly distribute HGH for any use other than treating a disease or recognized condition that FDA has authorized, on a physician's order. [11] No equivalent statute covers tesamorelin, so a clinician may prescribe Egrifta WR off-label, though the evidence outside HIV is limited to the one trial above. [7]

Neither can be lawfully compounded. Tesamorelin and somatropin were both deemed biologics on March 23, 2020, and FDA states that biological products are not eligible for the 503A or 503B compounding exemptions. [9] [10] Compounded "tesamorelin" or "HGH" from a clinic has no lawful basis. The tesamorelin cost page lists dated prices for the brand product, and the tesamorelin regulatory tracker logs status changes.

Both are banned in sport under WADA section S2, at all times. [12]

How does tesamorelin compare with other growth hormone peptides?

See sermorelin vs tesamorelin, tesamorelin vs CJC-1295, and tesamorelin vs MK-677. For the older GHRH fragment against growth hormone, read sermorelin vs HGH, and for safety of the long acting analog, CJC-1295 side effects. Our tesamorelin prescription guide covers who qualifies.

Talk to a clinician first

Choosing between them is a diagnosis question, not a preference: an HIV specialist or endocrinologist can test for growth hormone deficiency or assess abdominal fat and decide which, if either, fits. The growth hormone deficiency page explains how deficiency is confirmed.