Unverified (grey market)

Vialox (pentapeptide-3)

Also called pentapeptide-3, Vialox, GPRPA-NH2, Gly-Pro-Arg-Pro-Ala-NH2, glycyl-L-prolyl-L-arginyl-L-prolyl-L-alaninamide

Vialox (pentapeptide-3) is a five-amino-acid peptide modeled on a snake venom toxin and sold in creams as a 'Botox-like' wrinkle relaxer. The claimed muscle-relaxing effect comes almost entirely from the ingredient maker's own data. It is now also sold online in vials, but there are no studies of injecting it.

UnverifiedSold online, but not an approved drug and with no published human trials. What it really contains is not verified.

New · under editorial review. Added October 31, 2026 by our automated research, with every claim sourced. A person has not checked this page yet; treat it with extra care. How we research

Drawn from its published sequence: 5 residues, one bead each.

At a glance

Type: Peptide
Size: 5 amino acids, C-terminal amide
Sequence: GPRPA-NH2
Formula: C21H37N9O5
Molecular weight: 495.6 g/mol
CAS number: 135679-88-8
Origin: Synthetic; based on a peptide from the venom of the pit viper Tropidolaemus wagleri [1][3][4]. Note: the EU CosIng entry for 'pentapeptide-3' describes a peptide containing alanine, arginine, isoleucine, glycine and proline; isoleucine is not in GPRPA, so the official INCI definition may not match the Vialox sequence [2].
Evidence: Unverified
US FDA status: Not an FDA-approved drug and not a substitute for approved botulinum toxin products. Cosmetic ingredients do not need FDA approval before sale ⁹, but products claiming to remove wrinkles or change skin structure are treated as drugs ¹⁰.

Overview

How it works

Claimed: blocks the acetylcholine receptor on muscle, so nerve signals cannot make the muscle contract, relaxing expression lines ³. Shown: a 2020 review says no independent studies describe its anti-wrinkle action and that the only data come from the manufacturer ³. A 2026 systematic review lists the Vialox data (a 49% wrinkle reduction and 71% less muscle contraction) as manufacturer data with high risk of bias ⁶. Computer modeling studies from 2026 predicted binding to other targets (such as SIRT-1 and MMPs) but these are predictions, not proof ⁵. Whether enough peptide passes through skin to reach muscle has not been shown in the sources found.

What research shows

Manufacturer data (as summarized in a 2026 systematic review): 28-day cream test reported 49% wrinkle reduction and a 71% drop in muscle contraction in a lab test; number of people not reported; rated high risk of bias; no adverse events reported ⁶.
2020 review: no independent studies of its anti-wrinkle effect; only manufacturer in vitro and in vivo claims ³.
Cell and computer study (2026): no toxicity to skin cells (HaCaT) up to 1 mg/mL; docking predicted binding to SIRT-1 and MMPs ⁵.
Cell and computer study (2026): docking and cell assays explored possible anticancer activity; early lab work only ⁴.
No peer-reviewed controlled human trials and no injection studies were found.

What is claimed online

These are claims made where it is sold or discussed. They are not established facts, and some are contradicted by the evidence above.

Claimed: a topical alternative to Botox that relaxes facial muscles. Evidence: only manufacturer data, rated high risk of bias; no independent trials ⁶³.
Claimed: 49% wrinkle reduction in 28 days. Evidence: a manufacturer figure; study size not reported ⁶.
Claimed: anti-aging or anticancer actions through other targets. Evidence: computer predictions and cell tests only ⁵⁴.
Claimed: injection works faster or stronger. Evidence: no injection studies exist.

Doses studied in people

There is no published human data for injecting pentapeptide-3, and no peer-reviewed human trial of the cream; the only human figures are manufacturer claims.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Safety

No Cosmetic Ingredient Review safety assessment of pentapeptide-3 was found.
Topical use: no adverse events were reported in the manufacturer data summarized in a 2026 review, but that data is limited and high risk of bias ⁶.
It is designed to block acetylcholine receptors on muscle ³; what injecting such a compound could do (for example, unwanted muscle weakness) has never been studied.
FDA has not assessed injectable forms. For other injectable peptides, FDA has flagged possible immune reactions from aggregation and peptide impurities ¹².
Vials sold online as research peptides have unknown identity, purity, sterility and strength ¹⁴¹⁵.
Long-term safety is unknown.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA: Not an FDA-approved drug and not a substitute for approved botulinum toxin products. Cosmetic ingredients do not need FDA approval before sale ⁹, but products claiming to remove wrinkles or change skin structure are treated as drugs ¹⁰.
Compounding: Not named on FDA's 503A bulk drug substance category lists (updated May 14, 2026) or on FDA's Category 2 safety-risk page (current as of April 22, 2026) ¹¹¹².
Sports (WADA): Not named on the WADA 2026 Prohibited List. WADA's S0 class covers pharmacological substances with no government approval for human therapeutic use ¹³.
Other: 'Pentapeptide-3' is listed in the EU CosIng database as an active cosmetic ingredient (function: skin conditioning), though its stated amino acid make-up differs from GPRPA ².

Rules change often. See Legal status of peptides for how these categories work.

History

Developed as a cosmetic 'neurotransmitter-inhibiting' peptide modeled on a viper venom peptide ⁴³. The name is easy to confuse with 'palmitoyl pentapeptide-3', an older name for Matrixyl (palmitoyl pentapeptide-4), which is a different peptide ⁸⁷.

Common questions

Is Vialox like Botox?

It is claimed to block the muscle's acetylcholine receptor, but the only evidence comes from the manufacturer and is rated high risk of bias ³⁶.

Is Vialox the same as palmitoyl pentapeptide-3?

No. Palmitoyl pentapeptide-3 is an older name for Matrixyl (Pal-KTTKS), a different peptide ⁸.

Is it safe to inject?

Injection has never been studied, and online vials have unknown purity and sterility ¹⁴.

Is it approved or banned in sport?

It is not an approved drug ⁹, and it is not named on the WADA 2026 list ¹³.

Related compounds

Cosmetic & skinEarly human dataFlashcard

Argireline (acetyl hexapeptide-8)

acetyl hexapeptide-8 · acetyl hexapeptide-3 (older INCI name)

Argireline is a short lab-made peptide used in anti-wrinkle creams and serums.

Cosmetic & skinEarly human dataNewFlashcard

Leuphasyl (pentapeptide-18)

Pentapeptide-18 · [D-Ala2]-Leu-enkephalin

Leuphasyl is the trade name of pentapeptide-18, a small lab-made peptide used in anti-wrinkle creams and serums.

Cosmetic & skinPreclinical onlyFlashcard

SNAP-8 (acetyl octapeptide-3)

Acetyl octapeptide-3 · Acetyl glutamyl heptapeptide-3

SNAP-8 is a short lab-made peptide used in anti-wrinkle creams and serums.

Cosmetic & skinEarly human dataNewFlashcard

Palmitoyl pentapeptide-4 (Matrixyl)

Matrixyl · Pal-KTTKS

Palmitoyl pentapeptide-4, sold under the trade name Matrixyl, is a skin-care ingredient made of five amino acids joined to a fatty acid.

Sources

Last reviewed 2026-10-31 · How we research · Found an error? See our corrections policy.