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Observationalskin

Eyeseryl

An anti-puffiness tetrapeptide for under-eye bags that works on fluid retention and capillary leak rather than on wrinkles or pigment.

Also known as Acetyl Tetrapeptide-5, Ac-beta-Ala-His-Ser-His, Eyeseryl

Observational — Human data without randomisation. Suggestive, and easily confounded.

Efficacy data are Lipotec's own uncontrolled in-vivo panels on small numbers of subjects. The carbonic anhydrase and anti-glycation mechanisms are plausible but not independently verified in periorbital skin.

How it works

Under-eye puffiness is mostly a fluid problem, not a collagen problem: lax orbital septum, poor lymphatic drainage and leaky capillaries let interstitial fluid pool where the skin is thinnest on the body. Acetyl tetrapeptide-5 is described as inhibiting carbonic anhydrase, which shifts local fluid handling, and as reducing protein glycation, which improves capillary elasticity and reduces permeability. Both effects would reduce oedema rather than remove fat herniation, which is why it does nothing for true fat-pad bags. It carries a beta-alanine at the N-terminus, making it a structural cousin of carnosine's anti-glycation chemistry.

Targets: Carbonic anhydrase, Protein glycation, Capillary permeability, Periorbital lymphatic drainage

Dosing

ProtocolDoseFrequencyRoute
Under-eye gel or serumMorning application matters most, since fluid pooling peaks after a night lying flat.—twice dailytopical
  • · Trade solution used at 2-10% of the formula. From raw powder, 0.05-0.1% w/w in a light aqueous gel. Pat gently on the orbital rim; do not drag the thin skin.

Cycling

Continuous use; puffiness returns when you stop because the underlying fluid dynamics are unchanged.

Work out your exact syringe units →

Pharmacology

Half-life
Not established.
Onset
Supplier panels report visible reduction in puffiness within 15 days of twice-daily use.
Routes
topical
Molecule
Synthetic acetylated tetrapeptide
Sequence length
4 amino acids
Molecular weight
492.5 Da

Handling

Diluent
Distilled or deionised water
Typical mix
20 or 50 mL
Vial sizes
50, 100, 200 mg
Lyophilised
Sealed, cool and dry; freezer for long-term.
Reconstituted
Refrigerated and preserved — an unpreserved eye product is a genuine infection risk.

Mixing

Water soluble.

Side effects

  • commonStinging if it migrates into the eye— Apply on the orbital bone, not the lash line.
  • uncommonContact irritation on thin periorbital skin

Do not use if

  • Puffiness caused by herniated orbital fat pads, thyroid eye disease or renal or cardiac oedema — a topical peptide will do nothing for any of those, and two of them need a doctor.

Combining it

  • synergyhaloxyl — The standard eye-contour pairing — one targets puffiness, the other targets pigment.
  • synergycaffeine — Vasoconstriction plus fluid handling; nearly every eye product combines them.

What to monitor

  • · Morning photographs at a fixed time after waking, since puffiness varies enormously through the day.

Legal status

Cosmetic ingredient (INCI Acetyl Tetrapeptide-5) approved worldwide.

References

  • Lubrizol/Lipotec Eyeseryl technical dossier (other)

Mechanism in depth

Under-eye puffiness is a fluid dynamics problem and it is worth being precise about which kind, because the answer determines whether any topical can help. There are three distinct causes that look similar in a mirror. First, fat pad herniation — the orbital septum weakens and periorbital fat pushes forward. Nothing topical touches that; it needs a blepharoplasty. Second, tear trough anatomy — a bony and ligamentous groove that casts a shadow. Also untouchable topically. Third, genuine oedema — interstitial fluid pooling from leaky capillaries and sluggish lymphatic drainage in tissue that has almost no structural support. Only the third is addressable, and that is what Eyeseryl claims. The proposed mechanisms are carbonic anhydrase inhibition, which shifts local bicarbonate and fluid handling in the same broad way acetazolamide reduces fluid accumulation systemically, and reduced protein glycation, which improves capillary wall elasticity and reduces permeability. The beta-alanyl-histidine element at the N-terminus is essentially the carnosine motif, and carnosine's best-established biochemistry is precisely anti-glycation — it acts as a sacrificial carbonyl scavenger, intercepting reactive aldehydes before they cross-link proteins. So the anti-glycation arm has real chemistry behind it even if the specific tetrapeptide has not been tested. The carbonic anhydrase arm has histidines, which is what you would want for a zinc-metalloenzyme interaction, but no published inhibition constant.

What usually goes wrong

The dominant failure is diagnostic. If your under-eye bags are fat pad herniation, this will do nothing over any timescale, and twelve weeks is a long time to find that out. A quick test: true oedema is worst on waking and improves through the day, and it changes with salt and alcohol intake. Fat pads do not move. Thyroid eye disease, renal disease and heart failure all cause periorbital oedema and all need a doctor rather than a serum — new, persistent, bilateral puffiness in someone who did not have it before is worth taking seriously. Second failure: unpreserved product near the eye. An aqueous peptide gel with no preservative applied to the orbital rim twice a day is a genuine infection risk, not a theoretical one. Third: application technique. Pat on the orbital bone, do not drag the lid skin, and keep it off the lash line.

Pharmacokinetics

Crosses blood-brain barrier
no
Metabolism
N-terminal acetylation blocks aminopeptidase attack. The beta-alanine at position 1 is the same residue that makes carnosine resistant to most peptidases, which is presumably deliberate.
Elimination
No meaningful systemic exposure. Worth noting that systemic carbonic anhydrase inhibitors such as acetazolamide have real side effects — paraesthesia, metabolic acidosis, taste disturbance — and none of those apply here because nothing is getting into the circulation.

Receptor targets

  • Carbonic anhydrase — No inhibition constant published for acetyl tetrapeptide-5

    Claimed shift in local fluid handling reducing periorbital oedema.

  • Protein glycation / advanced glycation end-product formation — Not a binding interaction; carbonyl scavenging

    Improved capillary wall elasticity and reduced permeability. The beta-alanyl-histidine motif gives this arm genuine chemical plausibility.

Trials

  • D'Arcangelis et al. in vitro, ex vivo, instrumental and clinical evaluation of a topical cream on the signs of periorbital ageing (Int J Cosmet Sci) Multi-stage in vitro, ex vivo and clinical evaluation · 2025

    Signs of periorbital ageing assessed instrumentally and clinically. Included in this record because it is one of very few indexed studies on periorbital peptide formulations; it is a multi-ingredient cream and does not isolate acetyl tetrapeptide-5.

What to expect, and when

Day 15: the supplier's claimed point of visible reduction with twice-daily use, which is unusually fast for this class and is consistent with a fluid mechanism rather than a structural one. Week 4-8: whatever plateau you reach. Discontinuation: puffiness returns quickly because the underlying fluid dynamics are unchanged.

Stacking and comparisons

Caffeine is the standard partner and the combination is sensible: caffeine is a vasoconstrictor and a mild diuretic locally, so it reduces the capillary leak that Eyeseryl is trying to counteract downstream. Haloxyl is the other conventional partner, targeting pigment rather than fluid, and the two together cover the two treatable causes of a dark, puffy under-eye. What actually outperforms all of this for morning puffiness is boring and free: sleeping with the head elevated, reducing evening sodium and alcohol, and a cold compress for five minutes on waking. Say that plainly to anyone spending money on eye serums. Do not stack retinoids in the same step — periorbital skin tolerates them poorly and the irritation will look like more puffiness, not less.

Against caffeine, caffeine is cheaper, better characterised and probably does more of the work in any product containing both. Against Haloxyl, different target entirely — fluid versus pigment — so they are complements not alternatives. Against a cold compress and head elevation, honestly a close contest for morning puffiness, and one of the two is free.

Rough cost

$12–$60/month. Raw acetyl tetrapeptide-5 runs roughly $30-70 per gram. Finished eye products $15-60 a month. Market observation, not a sourced pricing study.

Genuinely uncertain

  • No published carbonic anhydrase inhibition constant exists for acetyl tetrapeptide-5.
  • The anti-glycation claim is plausible from the beta-alanyl-histidine motif but has not been demonstrated for this specific tetrapeptide.
  • No independent human trial exists. The 15-day figure is from uncontrolled Lipotec panels.
  • Whether enough peptide reaches periorbital capillaries and lymphatics to alter fluid handling has never been measured.
  • The molecular weight of 492.5 Da in the Core record is plausible for the acetylated tetrapeptide but is unconfirmed against a primary source.

Papers