Side-by-Side Comparison · 2026

Endomorphin vs Enkephalins

Endomorphin vs Enkephalins — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Endomorphin
Endogenous Opioid

Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and Endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) are tetrapeptides discovered in 1997 by Zadina et al. as the most selective and potent endogenous agonists of the mu-opioid receptor (MOR)....

Calculate Endomorphin dose →
Enkephalins
Endogenous Opioid

Enkephalins are the smallest endogenous opioid peptides, consisting of just five amino acids. They exist as two forms: Leu-enkephalin (YGGFL) and Met-enkephalin (YGGFM), differing only in the C-terminal residue....

Calculate Enkephalins dose →
Key Parameters
Parameter Endomorphin Enkephalins
Category Endogenous Opioid Endogenous Opioid
Research Research Research
Half-Life Seconds to minutes (rapidly degraded) < 1 min (plasma, rapidly degraded by enkephalinases)
Typical Dose 1-100 nmol/kg (animal) Research variable
Frequency Variable Variable
Route Intrathecal, Intracerebroventricular, Subcutaneous Intrathecal, Intravenous (research); oral Met-enkephalin (LDN adjacent)
FDA Status Not approved Not approved

Calculate doses for both

Use ASCEND's free reconstitution calculator to get exact syringe draw amounts for your vial.

Calculate Endomorphin Calculate Enkephalins
Frequently Asked Questions
What is the difference between Endomorphin and Enkephalins?
Endomorphin: Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and Endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) are tetrapeptides discovered in 1997 by Zadina et al. as the most selective and potent endogenous agonists of the mu-opioid ... Enkephalins: Enkephalins are the smallest endogenous opioid peptides, consisting of just five amino acids. They exist as two forms: Leu-enkephalin (YGGFL) and Met-enkephalin (YGGFM), differing only in the C-termin...
Which has a longer half-life, Endomorphin or Enkephalins?
Endomorphin half-life: Seconds to minutes (rapidly degraded). Enkephalins half-life: < 1 min (plasma, rapidly degraded by enkephalinases).
Can you stack Endomorphin and Enkephalins?
Endomorphin and Enkephalins are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.