Tesamorelin vs MK-677: evidence, cost, and legality

Which is better, tesamorelin or MK-677 (ibutamoren)?

Both have a human RCT evidence grade, but tesamorelin's trials produced an approvable outcome (visceral fat reduction in 806 patients) and an FDA label, while MK-677's largest trial (2 years, 65 older adults) found lean mass gain with no functional benefit and worsening glucose, and a later trial was terminated for a possible congestive heart failure signal. On regulation the gap is wider: tesamorelin is FDA approved and available by prescription as Egrifta WR, MK-677 is unapproved and sits in Category 2 for both 503A and 503B, leaving no lawful access path. [1] [2] [3] [4] [8] [9] [11]

How do tesamorelin and MK-677 (ibutamoren) compare?

Tesamorelin and MK-677 (ibutamoren) compared by dimension
Dimension	TesamorelinFavored	MK-677 (ibutamoren)
Mechanism [3] [6]	Stabilized 44 amino acid GHRH analog. Binds pituitary GHRH receptors to increase pulsatile GH release with feedback loops intact; the hexenoyl modification resists dipeptidyl peptidase cleavage.	Oral non peptide agonist of the ghrelin receptor (GHS-R1a). Amplifies GH pulse amplitude without changing frequency, raises IGF-1 for a full day after one dose, and as a ghrelin mimetic increases hunger.
Trial evidence [1] [2] [4] [5] [7] [8]	Two multicenter double blind placebo controlled phase 3 trials pooled (806 patients, 26 weeks plus extension) and a 12 month NIH funded randomized trial in 61 patients with HIV associated fatty liver.	A 2 year randomized trial in 65 healthy older adults, an 8 week trial in 24 obese men, a 12 month trial in 563 Alzheimer patients showing no benefit, and a phase 2b hip fracture trial terminated early.
Effect on fat and lean mass [1] [2] [4] [5]	Visceral adipose tissue fell 24 cm2 versus a 2 cm2 rise on placebo at 26 weeks (treatment effect minus 15.4%), with no change in abdominal subcutaneous fat; hepatic fat fraction fell an absolute 4.1 points over 12 months. Fat returns after stopping.	Fat free mass rose about 1.1 kg over 2 years and about 3 kg over 8 weeks in obese men, with increased energy expenditure but no significant fat loss and no improvement in strength or function.
Glucose effects [1] [3] [4]	Glucose parameters did not differ meaningfully from placebo in the pooled phase 3 trials or the fatty liver trial, but the label warns of glucose intolerance and new diabetes in some patients and advises monitoring.	Fasting glucose rose about 0.3 mmol/L and insulin sensitivity fell over 2 years; higher glucose is a consistent finding across trials.
Route and dosing frequency [4] [12] [13]	Subcutaneous injection into the abdomen once daily: Egrifta WR 1.28 mg or Egrifta SV 1.4 mg on the FDA label; the original Egrifta used 2 mg.	Oral capsule or tablet once daily; trials used 25 mg.
Safety signals [3] [4] [8] [9]	Arthralgia (about 13%), injection site reactions, peripheral edema, paresthesia, hypersensitivity; label requires IGF-1 monitoring and lists contraindications for active malignancy, pituitary disruption, and pregnancy.	Increased appetite, edema, muscle and joint pain, transient cortisol and prolactin rise, and a possible congestive heart failure signal that halted the hip fracture trial and is FDA's stated Category 2 rationale.
Regulatory status [3] [9] [10] [12] [15]	FDA approved as Egrifta on November 10, 2010 for excess abdominal fat in HIV lipodystrophy; Egrifta SV approved 2019 and Egrifta WR in 2025. Egrifta became a biologic on March 23, 2020, and biologics are not eligible for 503A or 503B compounding, so Egrifta WR by prescription is the only lawful product; use for fat loss without HIV is off-label.	Never approved. Placed in 503B Category 2 on December 29, 2022 and 503A Category 2 on September 29, 2023; still in both as of April 22, 2026, so no pharmacy or outsourcing facility can lawfully compound it, and FDA has warned that supplements containing it are misbranded.
WADA status [11]	Prohibited at all times under section S2, which names tesamorelin among GHRH analogues.	Prohibited at all times under section S2, which names ibutamoren among GH secretagogues.
Typical cost [9] [12] [14] [15]	Egrifta WR has no published list price; one retail cash listing put a 28 day kit at about 10,709 USD (checked 2026-09-22). Compounded tesamorelin has no lawful price because tesamorelin is a biologic; dated prices are on the tesamorelin cost page.	No licensed channel. Products sold as research chemicals or supplements are not lawful for human use and are not verified for identity or purity.

Evidence grade and regulatory status

Pulled from each peptide’s own record, so it stays in step with the peptide pages.

Tesamorelin and MK-677 (ibutamoren): grade, status, and cost
Attribute	Tesamorelin	MK-677 (ibutamoren)
Class	Synthetic 44 amino acid analog of human growth hormone releasing hormone with an N-terminal trans-3-hexenoic acid modification that resists enzymatic degradation	Oral non peptide growth hormone secretagogue (small molecule ghrelin receptor agonist)
What it is	FDA approved lab-made growth hormone releasing hormone (Egrifta, 2010) that cuts deep belly fat about 15% in HIV lipodystrophy and cut liver fat in a trial.	Oral ghrelin mimetic with real RCTs: raises IGF-1 and lean mass modestly, raises glucose and appetite, a heart failure signal stopped development. Not approved.
Evidence	Evidence: Human RCT evidence	Evidence: Human RCT evidence
FDA status	Regulatory: FDA approved	Regulatory: Not eligible for compounding
Compounding	FDA approved as Egrifta (tesamorelin for injection) on November 10, 2010, for reduction of excess abdominal fat in HIV infected adults with lipodystrophy; Egrifta SV, a 2 mg vial formulation, was approved in 2019, and Egrifta WR, an 11.6 mg vial formulation, in March 2025. Tesamorelin is a 44 amino acid protein, and on March 23, 2020 FDA deemed the Egrifta application (022505) to be a biologics license. FDA states that biological products are not eligible for the 503A or 503B compounding exemptions, so compounded tesamorelin sold by telehealth and anti-aging clinics has no lawful basis, and Egrifta WR by prescription is the only lawful product. A clinician may prescribe Egrifta WR off-label, but use for fat loss in people without HIV has only limited trial support.	Not FDA approved for any use. FDA placed ibutamoren mesylate in 503B Category 2 on December 29, 2022 and in 503A Category 2 on September 29, 2023, citing the potential for congestive heart failure based on the terminated hip fracture trial. As of the FDA page current to April 22, 2026, it remains in both categories, so no licensed pharmacy or outsourcing facility can lawfully compound it. It was not among the substances withdrawn from Category 2 in April 2026. It is widely sold online as a research chemical or mislabeled supplement.
WADA	WADA: WADA prohibited	WADA: WADA prohibited
Routes	Subcutaneous injection into the abdomen once daily (Egrifta WR, Egrifta SV), No oral, sublingual, or nasal form is FDA approved or tested in a published trial	Oral capsule or tablet, once daily (all trials and as sold)
Typical cost	Egrifta WR has no published list price; a retail cash listing put one 28 day kit at about 10,709 USD, and a manufacturer co-pay program helps eligible commercially insured patients with the approved HIV indication. Compounded tesamorelin has no lawful price, because tesamorelin is a biologic and biologics cannot be compounded. Prices checked 2026-09-22.	Not available through licensed US channels. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity.
Last verified	Sep 23, 2026	Sep 23, 2026

Has tesamorelin been tested directly against MK-677 (ibutamoren)?

No published trial has compared tesamorelin and MK-677 (ibutamoren) directly. The dimensions above come from separate studies and labels, and cross-trial comparisons are less reliable than a direct trial.

What do tesamorelin and MK-677 (ibutamoren) cost?

Typical cost of Tesamorelin and MK-677 (ibutamoren)
Dimension	Tesamorelin	MK-677 (ibutamoren)
Typical cost	$10,709 per month	Not available through licensed US channels. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity.
Price detail	Tesamorelin price by channel	Price index in progress

Where a price index exists, the range is the cash price per month across branded, compounded, and telehealth channels, without insurance. The cost pages give each channel separately with its sources. Otherwise the typical cost from the peptide record is shown. Legal access depends on your state: see peptide legality by state.

Frequently asked questions

Which is better for losing belly fat, tesamorelin or MK-677?

Tesamorelin, and it is not close. It reduced visceral fat by 15.4% relative to placebo in 806 HIV patients with lipodystrophy and reduced liver fat by 37% in a 12 month trial. MK-677 increased lean mass and energy expenditure but produced no significant fat loss in its trials. Note that tesamorelin's evidence is in HIV lipodystrophy; its use for fat loss in people without HIV is off-label and untested. [1] [2] [4] [5]

Is MK-677 safer because it is oral?

No. The route is more convenient, but the trials showed higher fasting glucose, reduced insulin sensitivity, edema, and increased appetite, and a hip fracture trial was stopped early for a possible congestive heart failure signal. That signal is the reason FDA placed ibutamoren in Category 2 for both 503A and 503B compounding. [4] [8] [9]

Can either be prescribed in the United States?

Tesamorelin can, by prescription: Egrifta WR and Egrifta SV are FDA approved for HIV lipodystrophy. Compounded tesamorelin is not lawful, because tesamorelin became a biologic in 2020 and biologics cannot be compounded. MK-677 cannot: it is unapproved, in Category 2 for both compounding pathways, and may not lawfully be sold as a supplement. [3] [9] [10] [12] [15]

Do both raise IGF-1?

Yes, by different routes. Tesamorelin raised IGF-1 by about 108 ng/mL in the phase 3 trials and the label calls for monitoring and discontinuation if persistently elevated. MK-677 raised IGF-1 by roughly 50 to 60% into the young adult range in older adults. Both carry the theoretical tumor growth concern that comes with sustained IGF-1 elevation. [1] [3] [4] [6]

Are they allowed in sport?

No. Both are prohibited at all times under WADA section S2: tesamorelin as a GHRH analogue and ibutamoren as a growth hormone secretagogue. [11]

Conditions studied

From the blog

Tesamorelin vs HGH: how they differ and which is approved
Tesamorelin (Egrifta) signals the pituitary to release growth hormone and is approved for HIV-associated belly fat; HGH (somatropin) is the hormone itself, approved for other conditions.
Does tesamorelin build muscle? What the trials show
Tesamorelin raised lean body mass about 1.2 kg in HIV trials and slightly increased trunk muscle area, but no trial tested strength or muscle growth, and it is prohibited in sport.
Peptides for men, ranked by human evidence
hCG, GLP-1 drugs, teriparatide, and tesamorelin have human trials and a lawful route. PT-141 is off-label for men, and kisspeptin and melanotan II have no lawful path. Ranking, legality, and WADA.

Sources

Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.

Cite this page

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APA style: PeptideAgent. (2026, September 23). Tesamorelin vs MK-677 (ibutamoren): evidence, cost, and legality. https://peptideagent.ai/compare/tesamorelin-vs-mk-677
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Tesamorelin vs MK-677 (ibutamoren)

The short answer