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By Alice Henshaw, Aesthetic Specialist and Founder of SKIN|CYCLES
When I first started treating patients at my Harley Street clinic, I noticed something that frustrated me. Patients would leave their appointments with beautifully treated skin, only to return weeks later with the same concerns creeping back. The treatments were working. The problem was everything that happened between appointments.
The serums and creams available to my patients at the time were well-marketed but poorly designed. Peptides that degraded before they could reach the dermis. Antioxidants that oxidised in the bottle. Active ingredients that irritated more than they repaired. I kept asking myself: why can we deliver extraordinary results in clinic, but the at-home products meant to maintain those results are so far behind?
That question led me to spend three years working alongside dermatological scientists to develop something that did not yet exist in cosmeceutical skincare: a multi-peptide complex that could genuinely replicate the biological mechanisms we relied on in clinical settings. The result was TGHA⁴®, and it became the foundation of every product in the SKIN|CYCLES range.
This article is the full scientific story behind TGHA⁴®: what each component does at a cellular level, why we chose these four actives together, how liposomal encapsulation changes the game for peptide delivery, and what you can realistically expect to see over weeks and months of use.
Here is a truth that the skincare industry is uncomfortable with: most peptide serums do not work anywhere near as well as they should. Not because peptides are ineffective. The problem is delivery.
Peptides are short chains of amino acids that act as cellular messengers. When they reach the right cells, they can trigger collagen production, relax expression lines, reduce inflammation, and accelerate repair. A study in the American Journal of Clinical Dermatology demonstrated that topical Acetyl Hexapeptide-8 produced a 49% reduction in wrinkle depth after four weeks. Another review in the International Journal of Molecular Sciences confirmed that multi-peptide formulations showed significant wrinkle improvement within two weeks.
But there is a catch, and it is a significant one. Peptides are hydrophilic molecules with relatively large molecular weights. The outermost layer of your skin, the stratum corneum, is designed to be a lipophilic barrier. It keeps things out. That includes most of the peptides sitting in your serum. Research published in Cosmetics journal found that without an advanced delivery system, peptide absorption through the stratum corneum remains extremely limited, regardless of the concentration used.
This is the core problem that TGHA⁴® was built to solve. We did not simply choose good ingredients. We engineered a way to get them where they need to go, and we selected four specific actives that target ageing through four distinct biological pathways. Let me walk you through each one.
If you have ever looked into Botox, you already understand the principle behind Argireline. Botulinum toxin works by blocking the release of acetylcholine at the neuromuscular junction, which prevents the muscle contractions that form expression lines around the eyes, forehead, and between the brows.
Argireline operates through a similar mechanism. It is a synthetic hexapeptide designed to mimic the N-terminal end of the SNAP-25 protein. It interferes with the same signalling pathway that Botox targets, but topically and without the potency risks of a neurotoxin. A randomised, placebo-controlled clinical trial on 60 subjects found that the Argireline group showed total anti-wrinkle efficacy of 48.9%, while the placebo group showed 0%.
What makes Argireline particularly valuable in a multi-peptide complex is that it addresses a cause of ageing that collagen-stimulating peptides cannot touch on their own. Fine lines around the eyes and forehead are not just a structural collagen problem. They are driven by repeated muscle movement. You need something that calms that movement alongside something that rebuilds the structural matrix beneath it.
That is exactly what the next peptide in TGHA⁴® does.
While Argireline works on expression-driven lines, Acetyl Tetrapeptide-5 addresses something different entirely: the structural degradation of the dermal matrix that happens with chronological ageing and environmental exposure.
This tetrapeptide has been shown to reduce the accumulation of advanced glycation end-products (AGEs) in the skin. Glycation is a process where sugar molecules bond to proteins like collagen and elastin, making them stiff, brittle, and unable to function properly. It is one of the key drivers behind loss of skin elasticity, and it accelerates noticeably after the age of 35.
Acetyl Tetrapeptide-5 also works to improve microcirculation in the delicate tissue around the eyes, which is why it is a core ingredient in our Eye Matrix Mask and Revive Eyes formulations. Improved blood flow means better nutrient delivery to skin cells and more efficient removal of the waste products that contribute to dark circles and puffiness.
What I find particularly interesting about this peptide from a clinical perspective is that it targets glycation, a mechanism of ageing that most skincare products ignore completely. The industry is obsessed with collagen stimulation, which matters enormously, but if the collagen your skin produces is immediately damaged by glycation, you are fighting a losing battle.
Your skin's fibroblasts are the cells responsible for producing collagen, elastin, and the glycosaminoglycans that keep your skin plump and hydrated. As you age, fibroblast activity slows. The cells do not disappear, but they become less responsive, producing fewer structural proteins and doing so more slowly.
Palmitoyl Hexapeptide-12 is a signal peptide that communicates directly with fibroblasts, telling them to increase their output. The "palmitoyl" attachment refers to a fatty acid chain added to improve its affinity with the lipid-rich layers of the skin, making it more compatible with cell membranes and better able to reach the dermal layer where fibroblasts reside.
In our formulations, Palmitoyl Hexapeptide-12 serves as the primary collagen synthesis accelerator. You will find it at meaningful concentrations across the TGHA⁴® range, including in the Collagen Renewal Complex and the Bio-Cellulose Mask, where it is delivered through the mask's active transportation technology for immediate skin-cell penetration.
The research supporting signal peptides for collagen stimulation is substantial. Published work has confirmed that peptide complexes stimulating basement membrane proteins can produce significant wrinkle improvement in as little as two weeks, with the most pronounced effects on glabellar frown lines and nasolabial folds.
The fourth component of TGHA⁴® is not a peptide at all. It is a tripeptide antioxidant called Glutathione, and its inclusion was one of the most deliberate formulation decisions we made.
Glutathione is often called the body's "master antioxidant" because it plays a central role in neutralising reactive oxygen species (ROS), the unstable molecules generated by UV exposure, pollution, stress, and normal metabolic processes. These free radicals are directly responsible for the oxidative damage that breaks down collagen and elastin in the skin.
From a formulation perspective, Glutathione serves two critical purposes in TGHA⁴®. First, it provides direct antioxidant protection to skin cells, helping to prevent the environmental damage that accelerates ageing. Research has shown that Glutathione inhibits matrix metalloproteinases (MMPs), the enzymes responsible for breaking down collagen in the dermis. By suppressing MMP activity, it preserves the structural proteins that the other peptides in the complex are working to build.
Second, Glutathione helps protect the other active ingredients in the formula from oxidative degradation. Peptides are inherently unstable molecules, susceptible to breakdown from light, heat, and oxidation. Having a potent antioxidant as part of the complex provides an additional layer of ingredient stability that supports long-term efficacy.
This is why you will find Glutathione throughout the SKIN|CYCLES range, from the Bio-Balance moisturiser to the Lasting Lips balm, where it also contributes to visible brightening and tone evening.
This is the part that matters most, and it is the piece that most skincare brands either do not understand or choose to overlook.
Skin ageing is not a single process. It is the result of multiple biological mechanisms happening simultaneously. A single peptide, no matter how well-studied, can only target one of these pathways. TGHA⁴® was designed to address four at once:
Argireline calms the neuromuscular signals that drive expression lines. Acetyl Tetrapeptide-5 protects structural proteins from glycation damage and improves microcirculation. Palmitoyl Hexapeptide-12 activates fibroblasts to ramp up collagen and elastin synthesis. Glutathione neutralises the oxidative stress that degrades everything the other three are building.
When I explain this to patients at my clinic, I use an analogy. Imagine you are trying to fill a bathtub. Most skincare products focus on turning the tap on (stimulating collagen production). But if the plug is out (oxidative damage is breaking collagen down), the tub has cracks (glycation is damaging structural proteins), and someone keeps splashing water out (expression lines are deepening), turning the tap on harder will only get you so far. You need to address all four problems simultaneously.
This approach mirrors what we do in clinical aesthetics. A good treatment plan never relies on a single modality. We combine neurotoxins for dynamic lines, dermal stimulators for collagen production, antioxidant support for protection, and targeted treatments for specific concerns. TGHA⁴® translates that multi-modal philosophy into a daily topical formula.
Having four excellent active ingredients means nothing if they cannot reach the cells they are meant to influence. This brings us to what I believe is the most important and most misunderstood aspect of TGHA⁴®: liposomal encapsulation.
A liposome is a microscopic vesicle made from phospholipids, the same type of molecules that form the membranes of your skin cells. These tiny spheres have a lipid bilayer structure with an aqueous core, which means they can carry both water-soluble ingredients (like peptides and Glutathione) and oil-soluble compounds simultaneously.
Your stratum corneum is fundamentally lipophilic. It is designed to repel water-based molecules. Since most peptides are hydrophilic, they struggle to pass through this barrier when applied in conventional serum or cream formulations. They sit on the surface, evaporate or break down, and never reach the deeper layers where they could actually make a difference.
Liposomes bypass this problem because their phospholipid structure is biocompatible with the stratum corneum. They can fuse with or pass between skin cells, carrying their encapsulated payload deeper into the skin. The liposome looks like a natural part of the skin barrier, so it is allowed through. Once it reaches the target layer, it breaks down and releases its contents directly where they are needed.
Controlled release. Instead of dumping all the active ingredient onto the skin surface at once, liposomes release their contents gradually over hours. This means sustained, consistent delivery of peptides throughout the day or night, which better mimics the continuous treatment of a clinical procedure.
Reduced irritation. When potent actives hit the skin at full concentration, they can trigger redness or sensitivity. The controlled-release mechanism prevents this spike, which is one of the reasons TGHA⁴® products are suitable for all skin types, including sensitive skin.
Improved stability. Peptides are notoriously unstable. Exposure to oxygen, UV light, and temperature changes can degrade them before they reach your skin. The liposomal bilayer acts as a protective shell, shielding encapsulated actives from environmental degradation.
When we developed the TGHA⁴® formulation with our team of dermatological scientists in Germany, these delivery benefits were not an afterthought. They were the starting point. We worked backwards from the question: "How do we get these actives to behave as if they were being delivered directly to the dermis?"
Here is something that rarely gets attention in skincare content but makes an enormous difference to real-world results: product stability.
Peptides are vulnerable to hydrolysis (breakdown by water), oxidation (breakdown by oxygen exposure), and thermal degradation (breakdown from temperature fluctuations). Every time you open a jar-packaged peptide cream, you expose the contents to air. Every time it sits in a warm bathroom, the active ingredients degrade. You could be applying an expensive moisturiser base with minimal active benefit and never know it.
TGHA⁴® addresses this at two levels. The liposomal encapsulation provides molecular-level protection, keeping each peptide shielded within its phospholipid shell until it is released on or within the skin. And Glutathione plays a quiet but vital role as well. As a potent reducing agent, it scavenges the free radicals that would otherwise attack the peptide bonds in Argireline, Acetyl Tetrapeptide-5, and Palmitoyl Hexapeptide-12, acting as an internal preservative for the complex itself.
This is the kind of formulation detail that separates cosmeceutical-grade skincare from what you find on most shelves. It is not enough to list impressive ingredients. You have to ensure they remain active and available when they meet the skin.
I run an aesthetics clinic and administer injectable treatments regularly. So I want to be clear: TGHA⁴® is not Botox, and it is not a dermal filler. It does not produce the immediate, dramatic results of an injectable neurotoxin or a hyaluronic acid filler.
What it does is target the same underlying biological mechanisms through a different route. Botulinum toxin blocks acetylcholine release at the neuromuscular junction; Argireline inhibits SNARE complex formation at the same junction, producing a milder, gradual version of the same muscle-relaxing effect. Dermal stimulators activate fibroblasts to increase collagen output; Palmitoyl Hexapeptide-12 does the same thing topically. Antioxidant infusions administered during clinical facials protect against oxidative damage; Glutathione provides that protection daily.
The real value of TGHA⁴® is not as a replacement for clinical treatments. It is the bridge between them. My patients get the best results when they combine in-clinic procedures with a consistent, scientifically sound at-home routine. That is precisely what SKIN|CYCLES was built to provide.
For those who choose not to pursue clinical treatments at all, TGHA⁴® offers a meaningful alternative that works on the same biological principles, delivered through the most advanced topical technology we could develop.
One of the things I always tell my patients is that real skin transformation follows the natural timeline of cellular renewal. Here is what TGHA⁴® users typically experience:
Weeks 1 to 2: Hydration and initial comfort. The liposomal delivery system begins improving moisture retention almost immediately. Most users notice their skin feels softer, more supple, and less reactive. This is the phospholipid barrier support at work, reinforcing the stratum corneum while beginning to deliver actives deeper.
Weeks 2 to 4: Surface texture refinement. As the peptides begin reaching their target cells consistently, early changes in skin texture become visible. Fine surface lines, particularly around the eyes and mouth, may start to appear softer. Skin tone often becomes more even as Glutathione's brightening and MMP-inhibiting effects take hold.
Weeks 4 to 6: Visible smoothing of expression lines. Argireline's neuromuscular effects become increasingly apparent with consistent use. The areas most affected by repetitive movement, crow's feet, forehead lines, and the "eleven" lines between the brows, typically show the most noticeable improvement in this window.
Weeks 6 to 8: Firmness and elasticity gains. This is where Palmitoyl Hexapeptide-12's collagen-stimulating effects start to show visually. Collagen synthesis is a slow biological process; your fibroblasts need time to produce new fibres and for those fibres to organise into functional tissue. Many users report that their skin feels firmer, more resilient, and has a "bounce" that was not there before.
Weeks 8 to 12 and beyond: Cumulative transformation. All four mechanisms are now working in concert. New collagen is being produced and protected from glycation and oxidative damage, expression lines continue to soften, and overall tone and radiance improve. This is where the multi-pathway approach truly distinguishes itself from single-ingredient products.
I always encourage a minimum commitment of 12 weeks for any serious anti-ageing routine. That aligns with two full skin cell turnover cycles and gives the collagen remodelling process enough time to produce meaningful structural change.
Every product in the SKIN|CYCLES range is built around TGHA⁴® technology, but some are particularly worth highlighting for those focused on anti-ageing results:
Bio-Balance is our daily moisturiser that delivers the full TGHA⁴® complex alongside hydrating and skin-balancing ingredients. It is the foundation of a TGHA⁴® routine.
Collagen Renewal Complex pairs TGHA⁴® with marine collagen and dual retinol for those who want to intensify their collagen-building results.
Revive Eyes is specifically formulated for the delicate periorbital area, where Acetyl Tetrapeptide-5's anti-glycation and microcirculation benefits are most impactful.
ExoYouth Radiance Cream and ExoYouth Sleep Mask combine TGHA⁴® with growth factor peptides (Oligopeptide-1) for an intensive regenerative approach to overnight renewal.
Eye Matrix Mask delivers the TGHA⁴® complex through a hydrogel matrix that keeps the actives in direct contact with the under-eye area for 20 minutes of concentrated treatment.
For a complete anti-ageing protocol, I recommend pairing TGHA⁴® products with our supporting actives, including 5D HA for multi-weight hyaluronic acid hydration and Luminesce-C for Vitamin C antioxidant support.
Explore the full TGHA⁴® collection
When I founded SKIN|CYCLES, I made a commitment that science would lead every decision. Not trends, not marketing, not what competitors were doing. That philosophy is what led to TGHA⁴®: a complex that took years to develop because we refused to cut corners on the formulation science.
Every ingredient earns its place. Every delivery mechanism is chosen for function, not for label appeal. And the liposomal encapsulation technology that ties it all together is not a buzzword we borrowed from another brand. It is the core engineering principle that makes TGHA⁴® different from conventional peptide skincare.
My goal from the beginning has been to give people access to results that were previously only available in a clinical setting. Not a perfect replication, but a genuine bridge between professional treatments and daily skincare. TGHA⁴® is that bridge, and every product we create is designed to bring you closer to the skin you had always assumed was only achievable with needles and appointments.
The science is real. The results are cumulative. And the best time to start is always now.
RN · NMP · Founder of SKIN|CYCLES & Harley Street Injectables
Alice is the founder of SKIN|CYCLES, a cosmeceutical skincare range formulated around the proprietary TGHA4® peptide complex and sold at Harrods, Liberty and Harvey Nichols. She is also the founder and medical director of Harley Street Injectables, the largest clinic on Harley Street dedicated exclusively to non-surgical aesthetic treatments. A qualified nurse prescriber registered in the UK, Australia and New Zealand, Alice is a Key Opinion Leader for Allergan Aesthetics, was named Best Aesthetic Injector in London by the GHP Awards, and has been featured in Vogue, Tatler, Vanity Fair, and the Tatler Cosmetic Surgery Guide.
To explore the SKIN|CYCLES range, visit skincycles.com. To book a consultation at Harley Street Injectables, visit harleystreetinjectables.com or call +44(0) 3455 485 658.
