Myristoyl Pentapeptide-17_Dosage, benefits & legal status
Also known as SymPeptide 226EL, myristoyl pentapeptide 17, lash peptide
The lash-serum peptide, used where people want to avoid prostaglandins.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Myristoyl Pentapeptide-17?
Plain language first. The technical label stays, but it never stands alone.Overview
The peptide in most lash serums that avoid prostaglandins. Slower and safer than the prescription drops, and nobody selling it can agree on what it is actually made of.
Myristoyl pentapeptide-17, a topical lipopeptide marketed as SymPeptide 226EL, COSING reference 85279, used at roughly 0.001 to 0.1 percent in periocular leave-on products. Claimed activity is upregulation of keratin gene expression in the follicle. Published sequences are inconsistent and no independent single-ingredient trial has been published.
What it's used for
A topical peptide used in lash and brow serums for longer, thicker-looking hair.
How does Myristoyl Pentapeptide-17 work?
What it does in the body, and where.This peptide is the reason many lash serums can advertise results without using a prostaglandin.
- 01The fatty acid is there to get it through skinMyristic acid is a fourteen-carbon fatty acid attached to the front of the peptide. The oily tail helps it cross the outer layer of skin, which a bare peptide struggles to do.
- 02The claimed action is on keratinKeratin is the structural protein a hair is made of. More of it is proposed to mean a thicker, stronger shaft rather than more hairs.
- 03The real comparison is prostaglandin analoguesBimatoprost and its relatives work, and they carry documented risks including permanent iris darkening and orbital fat loss. Peptide serums are slower and much gentler, and the honest trade is a smaller result for a smaller risk.
Where this compound is thought to act.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Longer and thicker-looking lashes and brows, applied to the lash lineOTC / supplement
- Supporting keratin production in the hair shaftEarly research
- Scalp hair productsnone
- Paired with myristoyl hexapeptide-16 or biotinoyl tripeptide-1 in multi-peptide serumsnone
How much, and do you cycle it?
The range, and whether you take breaks.Serum, per product, daily. Not cycledCommunity practice
Used daily as part of a routine. The effect depends on continued use and returns to baseline when you stop, so there is nothing to cycle off.
How long does it stay in the body?
The half-life, and where the figure comes from.Not measured, and not the right questionNo figure
This is a topical cosmetic ingredient. A blood half-life measures how fast something leaves the bloodstream, and these are not intended to reach it in meaningful amounts. What matters for a topical is how much penetrates the skin and how long it stays in the tissue, which is a different measurement and one that is rarely published.
You can compare this against the whole library to see where it sits.
What does it cost?
Typical dose and cost, in plain numbers.Myristoyl Pentapeptide-17 is not injected
It is taken on the skin (topical). Applied as a topical product at the concentration the manufacturer sets. There is no injected dose.
How do you store it?
Before mixing, and after.Room temperature, out of light. Cap it tight after each use.
Myristoyl Pentapeptide-17 ships as a cream, gel, or serum. Keep it at room temperature away from sun and heat unless the label says otherwise. Refrigerating an emulsion can split the texture. Watch for color, smell, or separation changes and stop using it if any appear.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- A known allergy to this ingredient or to others in the same product
- Broken, cracked, or actively irritated skin
- Use inside the eye or on the waterline, since lash products are meant for the skin above the lash line only
- Anyone who wants established safety data, because none exists for this compound in humans
Stop and get help
- A rash that spreads beyond where you applied it
- Swelling of the face, lips, or eyelids, or any trouble breathing
- Burning that does not settle after rinsing it off
- Redness, itching or swelling of the eyelid
- Any change in vision
- Anything unusual, since there is no known safety profile to compare it against
Common effects
- Very safe on the skin.
- Beyond the above, unknown. There is no reliable human data on what this compound commonly causes
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Myristoyl Pentapeptide-17 approved?
And where the numbers on this page come from.Not as a medicine. Myristoyl Pentapeptide-17 is sold without a prescription as a supplement or cosmetic ingredient, which is a different thing from being approved as a drug.
- Approval statusOTC / supplement
- RouteOn the skin (topical)
- CheckedAugust 2026
What has happened recently
Regulated as a cosmetic ingredient, not a drug. Cosmetic ingredients are not reviewed for effectiveness before sale in the US, so a product may legally claim an appearance benefit without a trial behind it.
You can compare this against the whole library, or read how to check a seller.
- DoseFrom product labeling and published use.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Reviewed24 August 2026
What else is like Myristoyl Pentapeptide-17?
Others in Skin and cosmetic, side by side.If you're weighing Myristoyl Pentapeptide-17, it's worth reading Oligopeptide-1 (EGF), Melanotan III, and GHK-Cu in the same class.
The lash-serum peptide, used where people want to avoid prostaglandins.
- Dose
- Serum, per product
- How often
- Daily
Epidermal growth factor under a cosmetic name, and the only real protein on this shelf.
- Dose
- Serum, per product
- How often
- Daily
A name sold on the research market with no molecule publicly attached to it.
- Dose
- Research only
- How often
- Not established
A copper skincare peptide for smoother, firmer, younger-looking skin.
- Dose
- Topical serum, 1-2 pumps
- How often
- Daily
10What these words mean
Show glossary +
What these words mean
- 503A and 503B
- The two kinds of compounding pharmacy in US law. A 503A pharmacy prepares medicine for one named patient. A 503B outsourcing facility makes larger batches under stricter manufacturing rules.
- Agonist
- Something that switches a receptor on. The opposite is an antagonist. It blocks the receptor instead.
- Amino acid
- The building blocks that link together in a chain to make a peptide or a protein. The order they sit in is what makes one peptide different from another.
- Amylin
- A hormone released alongside insulin that slows the stomach emptying and reduces appetite. Several weight loss compounds copy it.
- Analog
- A compound built to copy a natural one with small deliberate changes, usually so it lasts longer or holds onto its target more tightly.
- Animal study
- Research done in rats, mice or other animals. Most findings do not repeat in people, so an animal result is a reason to keep looking. It is not a reason to act.
- Antibody
- A large immune protein, far bigger than a peptide, engineered to lock onto one specific target. These are made by drug companies and are not sold as research powders.
- Bacteriostatic water
- Sterile water with a tiny amount of preservative, used to mix powdered peptides.
- Banned in drug-tested sport
- Prohibited by the World Anti-Doping Agency (WADA); using it can disqualify a competing athlete.
- Bioavailability
- How much of a dose actually reaches your bloodstream. Most peptides survive stomach acid badly, so most of them are injected instead of swallowed.
- Bioregulator
- Very short peptides from a Russian research tradition, usually two to four amino acids long, sold for supporting a specific organ. Human evidence is thin and most of it is published in Russian.
- Blend
- One vial holding more than one compound, mixed together by the seller. Working out a dose means working out each ingredient separately, because they are rarely present in equal amounts.
- Boxed warning
- The most serious warning the FDA puts on a drug label, printed inside a black border. It flags a risk considered severe enough to sit above everything else on the label.
- Bulks list
- The FDA's list of ingredients that compounding pharmacies are allowed to use. A substance can sit under review on it for years without anything being decided either way.
- Certificate of analysis (COA)
- A lab report on a batch of product. It only means something if it names the batch you actually received, comes from an independent lab, and can be checked with that lab.
- Clinical trial
- A study that gives a treatment to people under a written plan and measures what happens. It is the only kind of evidence that can show something works in humans.
- Compounding
- A licensed pharmacy preparing a medicine to order. Being allowed to compound something is not the same as the FDA approving it, and the two get mixed up constantly.
- Concentration
- How strong the mixed peptide is, in milligrams per milliliter (mg/mL). More water makes it weaker; less water makes it stronger.
- Cycle
- A stretch of time using a compound followed by a break. Most cycling patterns come from community practice. Very few have been tested.
- DAC
- Short for Drug Affinity Complex. An attachment added to a peptide so it grabs onto a blood protein and stays in the body for days instead of minutes.
- Dead space
- The small amount of liquid left sitting inside the needle and hub after you inject. On very small doses it can be a real share of what you meant to take.
- Dilute
- Adding more liquid to make a mix weaker. The amount of peptide in the vial does not change. It is just spread through more water, so each draw is bigger.
- Endpoint
- The result a trial said in advance that it would measure. A study can be reported as positive and still have missed the endpoint it set out to hit.
- FDA approved
- Reviewed by the FDA and cleared for a specific use, in a specific form, at a specific dose. Approval for one use is not approval for another, and approval in another country is not approval here.
- Fragment
- A short piece cut out of a larger natural protein. A fragment can behave very differently from the whole protein it came from, so evidence about one does not transfer to the other.
- Ghrelin
- The hunger hormone. Some growth hormone compounds work by copying it, so they can make you noticeably hungrier.
- GHRH
- A natural signal telling the pituitary gland to release growth hormone. Several compounds copy it.
- GHRP
- A second, separate signal that also triggers growth hormone release, through a different door than GHRH. This is why the two types are often used together.
- GLP-1
- A natural gut hormone that lowers appetite and blood sugar. Drugs that copy it, like semaglutide, are used for weight loss.
- Growth hormone secretagogue
- A compound that nudges your body to release more of its own growth hormone, rather than injecting the hormone itself.
- Half-life
- How long a compound stays active in your body. A longer half-life means you inject less often.
- HPLC
- A lab method that separates out everything in a sample so the amounts can be measured. It shows how much of the main ingredient is there. It does not confirm that the main ingredient is the right molecule.
- In vitro
- Done in a dish or a test tube, on cells outside a living body. It is the earliest kind of evidence there is.
- Injection site
- The spot on the body where you inject. Moving it around gives the skin and fat underneath time to recover between doses.
- Intramuscular (IM)
- An injection into a muscle, using a longer needle.
- Intravenous (IV)
- An injection into a vein. It needs training and equipment and is not something to do at home.
- Investigational
- Still being tested in clinical trials and not yet approved or legally sold for general use.
- Lyophilized
- Freeze-dried into a powder so it keeps longer. That is the white cake or dust in the bottom of an unmixed vial.
- Mass spectrometry
- A lab method that weighs molecules to confirm what they are. HPLC answers how much is in the sample. This answers what it is.
- mcg and mg
- Units of dose. 1 milligram (mg) equals 1,000 micrograms (mcg).
- Myostatin
- A natural brake on muscle growth. Several compounds are built to block it, though human results have been far smaller than the animal work suggested.
- Off-label
- A doctor prescribing an approved drug for something other than its approved use. This is legal and common, and it is different from a compound having no approval at all.
- Orphan drug designation
- A status given to treatments for rare conditions to make them worth developing. It is an incentive, not an approval, and a compound can hold it while being approved for nothing.
- PCAC
- The FDA advisory committee that reviews compounding ingredients. It recommends. It does not approve, and the FDA does not have to follow what it says.
- Peer review
- Other scientists checking a paper before a journal publishes it. It filters out some bad work. It does not make a finding true.
- Peptide vs small molecule
- A peptide is a short chain of amino acids. A few items here (like MK-677 or methylene blue) are small molecules, not true peptides, but people use them the same way.
- Placebo
- A dummy treatment given for comparison. Without one it is very hard to tell a real effect apart from expectation and time passing.
- Purity
- The share of a sample that is the intended compound, usually given as a percentage. A high purity number on the wrong molecule is still the wrong molecule.
- Randomized
- Deciding by chance who gets which treatment, so the two groups are comparable. Studies that skip this are much easier to read the wrong way.
- Receptor
- A docking point on a cell that a compound attaches to. If a cell has no matching receptor, the compound does nothing to it.
- Reconstitution
- Mixing a powdered peptide with liquid (bacteriostatic water) so it can be drawn into a syringe.
- Research only
- No approved dose or use in people. Sold for research and not reviewed by the FDA for safety or quality.
- Stack
- Using more than one compound at the same time. Almost no combinations have been tested together in people, so a stack is usually built on guesswork.
- Sterile water
- Water with nothing added to stop bacteria growing. It works for a single dose, but a vial mixed with it should not be kept and used again.
- Subcutaneous
- An injection just under the skin, into the fat layer, usually with a short, thin insulin needle.
- Titrate
- Starting at a low dose and increasing it slowly over time so your body adjusts and side effects stay mild.
- Trial phases
- The stages of human testing. Phase 1 checks safety in a small group, phase 2 looks for an effect, and phase 3 tests it against a comparison in a large group.
- Units (on the syringe)
- The marks on an insulin syringe. 100 units equals 1 mL. They measure how much liquid you draw, not the dose in milligrams.
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Last reviewed 24 August 2026
Peptide Decoding is published by Decoded Sciences LLC. We take no payment from vendors for coverage, inclusion or ranking, and our affiliate relationships are disclosed in full.