Tesamorelin

Tesamorelin (brand names Egrifta, Egrifta SV, Egrifta WR) is a 44-amino-acid synthetic copy of growth hormone-releasing hormone with one small chemical tweak at its front end that lets it survive longer in the bloodstream. Given by subcutaneous injection, it stimulates the pituitary gland to release its normal pulses of growth hormone, which raises IGF-1 and preferentially reduces visceral (deep belly) fat. The FDA approved it in 2010 for a specific problem — the lipodystrophy that occurs in some people with HIV on antiretroviral therapy. Everything else the drug is used or marketed for — general weight loss, NAFLD, bodybuilding, anti-aging, cognitive enhancement — is off-label, and the supporting human data are typically limited to one or two small trials run by a single academic group with drug supplied by the manufacturer.

Tesamorelin acetate (TH9507; C221H366N72O67S · xC2H4O2, x≈7; free-base MW 5,135.9 Da) is a stabilized analog of hGRF(1-44)-NH2 in which the N-terminal tyrosine is N-acylated with a trans-3-hexenoyl group, conferring DPP-4 resistance and extending subcutaneous plasma half-life to roughly 8–11 minutes (bioavailability <4%). It acts as a full agonist at the pituitary GHRH receptor (GHRHR), stimulating synthesis and pulsatile release of endogenous GH with consequent hepatic IGF-1/IGFBP-3 elevation; downstream GH signaling drives lipolysis of visceral adipose tissue through hormone-sensitive lipase activation while sparing subcutaneous depots disproportionately. Originally developed by Theratechnologies (Montreal) as TH9507; FDA-approved November 10, 2010 (NDA 022505) for HIV-associated lipodystrophy; reformulated as Egrifta SV (2019) and Egrifta WR (sBLA approved March 25, 2025, 11.6 mg/vial, weekly reconstitution). Since March 23, 2020 the approved NDA has been deemed a BLA under the BPCIA transition provision, placing tesamorelin outside the scope of 503A compounding.

• Arthralgia
• Injection site erythema and pruritus (~25% vs 14% placebo)
• Pain in extremity
• Peripheral edema
• Myalgia
• Paresthesia / hypoesthesia
• Rash / urticaria
• Hypersensitivity reactions (~4% of patients: pruritus, erythema, urticaria)
• New-onset HbA1c ≥6.5% (5% tesamorelin vs 1% placebo; hazard ratio 3.3, 95% CI 1.4–9.6)
• Fluid retention (edema, arthralgia, occasional carpal tunnel syndrome)

• Disruption of the hypothalamic-pituitary axis (hypophysectomy, hypopituitarism, pituitary tumor or surgery, head irradiation, or head trauma)
• Active malignancy — do not initiate; discontinue if recurrent or new
• Pregnancy — rat offspring hydrocephaly and delayed skull ossification observed at clinically relevant exposures
• Known hypersensitivity to tesamorelin or mannitol

• GH elevation may decrease CYP450 activity, potentially lowering exposures of drugs metabolized by these enzymes (steroids, sex steroids, anticonvulsants, cyclosporine).
• Ritonavir AUC decreased ~9% in interaction studies.
• Patients on glucocorticoid replacement may require dose adjustment because GH inhibits 11β-HSD-1 conversion of cortisone to cortisol.
• Insulin and oral antidiabetics may need monitoring given glucose intolerance risk.

No. Egrifta SV and Egrifta WR are the only FDA-approved tesamorelin products, with pharmaceutical excipients (histidine, mannitol, sucrose, polysorbate 20), CMC-controlled impurity specifications, and sterility/endotoxin release testing. Since the BPCIA transition in March 2020, tesamorelin has been a biologic and is categorically ineligible for 503A compounding. Any product sold as "compounded tesamorelin" in the US is operating outside the FDA compounding regulatory pathway.

The honest answer is we don't know for certain. Tesamorelin raises IGF-1, a growth factor epidemiologically associated with several cancer types. In Phase 3 trials, 12 of 550 tesamorelin patients vs 3 of 266 placebo patients developed malignancies, but between-trial rates were inconsistent (one trial favored placebo, the other favored tesamorelin) and investigators attributed only one case in each arm as drug-related. Lifetime rodent carcinogenicity studies were never conducted. The FDA label contraindicates active malignancy and requires discontinuation if recurrence is detected. Short-term data are reassuring but do not establish long-term safety.

Tesamorelin is the only peptide in this class with Phase 3 RCT evidence for visceral fat reduction (~15–18% VAT in HIV lipodystrophy). CJC-1295 (with or without DAC) and ipamorelin have no Phase 3 RCT evidence in any indication. Mechanistically they differ: tesamorelin and CJC-1295 are GHRH analogs; ipamorelin is a ghrelin-receptor agonist acting through a separate pathway. No head-to-head trial exists, so any "X beats Y for fat loss" claim is extrapolation.

This is off-label. The FDA label explicitly states the drug is "not indicated for weight loss management (weight-neutral)." No RCT has been published in healthy athletes or bodybuilders. The only non-HIV visceral-fat RCT (Makimura 2012, n=60) enrolled obese adults specifically selected for reduced GH secretion and was not designed to support general obesity use. Extrapolating from HIV lipodystrophy or from GH-deficient obese adults to typical healthy users is a leap the trials do not support.

Egrifta is a specialty biologic with a small patient population, no generic, cold-chain distribution, and a single manufacturer (Theratechnologies / Belrose Pharma). Published cash pricing shows Egrifta WR around $41,680 list on GoodRx; Egrifta SV listed at multiple thousands per 30-day supply. Commercial-insurance and patient-assistance programs typically reduce out-of-pocket to the $50–500/month range for patients with the approved indication.

The FDA label does not specify cycling; it describes continuous daily dosing studied for 26 and 52 weeks. "Cycling" is a community/clinic convention based on theoretical receptor desensitization and has not been tested head-to-head in an RCT. In the extension-phase trials, VAT re-accumulated in patients switched to placebo, which directly argues that the registrational evidence supports continuous therapy, not cycles.

Label says once daily; does not mandate time. Off-label protocols commonly use bedtime to align with the endogenous nocturnal GH pulse, but no head-to-head AM vs PM trial has been published. The bedtime convention is physiologically plausible extrapolation, not trial evidence.

Phase 3 trials used 26 weeks as the primary endpoint, at which point ~69% of tesamorelin recipients achieved ≥8% VAT reduction vs 33% of placebo. Partial effect may be detectable at 8–12 weeks; the registrational effect size is at 6 months; and the effect reverses after discontinuation.