Route comparison

Oral vs injectable

Oral is the practical preference for most users. The key question is not whether oral is superior, but whether an intact Lys-Glu dipeptide can reach relevant cells after intestinal transport.

Verdict

Oral is the reasonable practical route

For a dipeptide like Lys-Glu, the PEPT1 transporter is the logical absorption path. Enteric coating aims to release in the small intestine. The missing piece is a human pharmacokinetic study measuring intact KE in blood after an oral dose.

Human bioavailability gap

No published human KE percentage

We did not recover a published human study reporting the percentage of intact Lys-Glu absorbed after oral Vilon. Animal work on peroral Vilon and digestive enzymes is suggestive but not conclusive for humans.

[KHAVINSON-2001-ORAL]

PEPT1 transport

How a dipeptide crosses the intestine

PEPT1 is the major proton-coupled transporter for di- and tripeptides in the small intestine. A Lys-Glu dipeptide fits the size class, but transporter affinity and intestinal stability for KE specifically are not well characterized in humans.

Enteric coating aims to release the capsule in the duodenum or jejunum, where PEPT1 is abundant, rather than in the stomach, where acid hydrolysis and luminal peptidase activity could cleave the peptide bond. Gastric acid is not the only or proven limiting mechanism.

[PEPT1-MEREDITH-2009]

Route matrix

Oral enteric capsules vs injectable research forms

Feature	Enteric oral	Injectable research
Practical route	Swallow capsules. No needles, no reconstitution.	Subcutaneous injection after sterile reconstitution.
Absorption logic	PEPT1 handles di-/tripeptides in the small intestine. Enteric coating aims to release there rather than in the stomach.	Bypasses GI entirely; reaches plasma directly, but still requires tissue uptake.
Vilon evidence	Peroral Vilon altered digestive enzyme activity in rats. No human intact-KE bioavailability data.	Animal and in vitro research; no human pharmacokinetic profile for Vilon specifically.
Sterility	Manufactured as a dietary supplement; cGMP and third-party testing, but not a drug product.	Requires sterile handling and research-grade sourcing. Higher infection and dosing risk if done improperly.
Best for	People who want a practical, non-invasive research option with a clear product label.	Researchers comfortable with sterile technique and looking for direct plasma exposure in animal models.

Practical route

Enteric oralSwallow capsules. No needles, no reconstitution.

Injectable researchSubcutaneous injection after sterile reconstitution.

Absorption logic

Enteric oralPEPT1 handles di-/tripeptides in the small intestine. Enteric coating aims to release there rather than in the stomach.

Injectable researchBypasses GI entirely; reaches plasma directly, but still requires tissue uptake.

Vilon evidence

Enteric oralPeroral Vilon altered digestive enzyme activity in rats. No human intact-KE bioavailability data.

Injectable researchAnimal and in vitro research; no human pharmacokinetic profile for Vilon specifically.

Sterility

Enteric oralManufactured as a dietary supplement; cGMP and third-party testing, but not a drug product.

Injectable researchRequires sterile handling and research-grade sourcing. Higher infection and dosing risk if done improperly.

Best for

Enteric oralPeople who want a practical, non-invasive research option with a clear product label.

Injectable researchResearchers comfortable with sterile technique and looking for direct plasma exposure in animal models.

Decision tree

Which route makes sense?

Choose oral if

You prefer a non-invasive route.
You want a labeled, cGMP-manufactured product.
You accept the bioavailability uncertainty of a dipeptide.

Consider injectable only if

You are running a controlled research protocol.
You have sterile technique and equipment.
You need to bypass gastrointestinal digestion entirely.

Avoid

Any source that claims proven 100% oral absorption.
Unsterile home injection of research powders.
Using oral and injectable forms simultaneously without supervision.

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