Pentapeptide-18: evidence, FDA status and research

It is a cream ingredient sold as a Botox alternative for expression lines. Two small studies of 20 people each had no comparison group, so the proof is weak.

Sold for

Pentapeptide-18 is sold as a topical alternative to botulinum toxin that softens expression lines, usually paired with acetyl hexapeptide-8 (Argireline).

Studies say

Two small uncontrolled studies in 20 volunteers each report shorter or fewer wrinkles after weeks of use, one of them with retinol in the same cream, which is grade C support at best.

Why grade C. The human evidence is two small uncontrolled studies: a 20-volunteer, two-month test of pentapeptide-18 creams at three strengths, in which only the strongest reduced measured wrinkle length, and an eight-week test in 20 women of a cream that also contained retinol. Neither had a vehicle or placebo control, and the manufacturer has not published its own trial data. Uncontrolled series put it at C for expression lines. ¹³

FDA. Pentapeptide-18 is a cosmetic ingredient, sold under the trade name Leuphasyl. Cosmetic ingredients in the United States are not reviewed or approved by the FDA before sale, so there is no FDA approval to cite for or against it. ²

Written from 3 cited sources. Fact-checked 2026-10-27: 10 claims checked, 5 corrected. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for: Softening expression lines
Can a US doctor prescribe it?: No prescription; it is a cosmetic ingredient.
Properly tested in people?: Not properly: animal or lab studies, or small uncontrolled human reports. Two reports of 20 people each.

Evidence checklist

Randomised controlled trial Maker's test only; no peer-reviewed trialno
Human study over 100 people No independent human studyno
More than one research group Only manufacturer datano
Clinical outcomes, not surrogate markers No clinical outcomeno
Human safety data beyond case reports No formal safety studyno

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Pentapeptide-18 is a lab-made chain of five amino acids. Lipotec (now part of Lubrizol) designed it and markets it as Leuphasyl. It goes into creams and serums for expression lines around the eyes and forehead. It is usually sold with acetyl hexapeptide-8, the ingredient better known as Argireline. ²

It is used in cosmetics, not in drugs. So pentapeptide-18 has never gone through a drug approval process anywhere. Published papers group it with the neurotransmitter-inhibiting peptides, alongside acetyl hexapeptide-8. ¹³

How it works

The maker describes pentapeptide-18 as an enkephalin mimic. Enkephalins are small opioid peptides that the body makes. They bind receptors on nerve endings. This reduces the release of acetylcholine, the chemical signal that tells a muscle to contract. The claim is that a topical peptide can reach those nerve endings. It would then dampen the signal enough to relax the small muscles behind expression lines. No published work shows whether a water-soluble peptide on the skin reaches the neuromuscular junction in meaningful amounts. ¹²

What human research shows

A 2014 study came from a Romanian pharmacy faculty. It applied creams with three concentrations of pentapeptide-18 to the forehead and eye area of 20 volunteers for two months. A 2D skin imaging device tracked wrinkles. Only the strongest cream produced a clear change. Wrinkle length fell by an average of 34.7% between the eyebrows and 28.4% around the eyes. The study had no cream-only comparison and did not measure wrinkle depth. So it cannot separate the peptide from the cream base or from measurement drift. ¹

A 2024 Polish study put pentapeptide-18 and retinol together into lipid nanoparticles in a night cream. It tested the cream for eight weeks in 20 women with signs of skin aging. It reported fewer wrinkles and better hydration. Retinol has its own evidence for wrinkles. So the study says little about pentapeptide-18 alone. Supplier data on the ingredient sit behind a login on trade listings. No journal has published them. ³²

Study	Model	Finding
Dragomirescu 2014, Leuphasyl creams	Humans, n=20 volunteers, three concentrations, two months, no control	Only the strongest cream reduced measured wrinkle length, by 34.7% between the eyebrows and 28.4% around the eyes. ¹
Pawłowska 2024, retinol plus pentapeptide-18 cream	Humans, n=20 women, eight weeks, no placebo, combined with retinol	Fewer wrinkles and better hydration were reported, but the effect cannot be attributed to the peptide. ³

Safety

The 2014 study reported no side effects in its 20 volunteers. The 2024 study reported that the nanoparticle form reduced the irritation retinol usually causes. Cosmetic peptides of this type are used at low concentrations. But no formal safety study of pentapeptide-18 alone exists. Two short studies of 20 people cannot detect uncommon reactions. ¹³

Questions for your clinician

Is there any independent trial of this ingredient?
What does the maker's own test actually show?
Are there wrinkle treatments with controlled data?

Questions people ask

Is pentapeptide-18 the same as Argireline?

No. Argireline is acetyl hexapeptide-8, a peptide of six amino acids. It targets a different step in the release of acetylcholine. Pentapeptide-18 has five amino acids. It is described as working one step earlier. The two are often sold together on the theory that their effects add up. ¹²

Does pentapeptide-18 need FDA approval?

No. The FDA does not approve cosmetic ingredients in the United States before they are sold. It can act against a cosmetic that is unsafe or makes drug claims. But there is no approval to look up for pentapeptide-18. ²

What does the research actually show?

Very little. Two small studies report fewer or shorter wrinkles after two months. Each had 20 people and no placebo or plain-cream comparison. One of them combined the peptide with retinol. No one has published a controlled trial of pentapeptide-18. The maker has not published its data. ¹³

Citations

Dragomirescu 2014, Cosmetics (MDPI): the efficiency and safety of Leuphasyl, a botox-like peptide mdpi.com
SpecialChem: Lubrizol Leuphasyl (pentapeptide-18) product listing specialchem.com
Pawłowska 2024, Life: retinol and pentapeptide-18 loaded lipid nanocarriers in anti-acne and anti-aging creams doi.org