Medik8 Liquid Peptides Versus Dr. Diamond's Metacine Instafacial Plasma

Medik8 Liquid Peptides Versus Dr. Diamond's Metacine Instafacial Plasma

This anti-aging serum is formulated around Carnosine and Palmitoyl Tripeptide-5 to soften the look of wrinkles and refine skin texture.

This anti-aging serum is formulated around Nicotiana Benthamiana Hexapeptide-40 Sh-Oligopeptide-1 and Sh-Oligopeptide-1 to soften the look of wrinkles and strengthen the skin barrier.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Glycerin

Butylene Glycol

Inulin

Sodium Hyaluronate

Panthenol

Alpha-Glucan Oligosaccharide

Carnosine

Carbomer

Polysorbate 20

Caprylyl Glycol

Phenoxyethanol

Hydroxypropyl Cyclodextrin

Dunaliella Salina Extract

Ethylhexylglycerin

Citric Acid

Palmitoyl Tripeptide-5

Sodium Benzoate

Acetyl Hexapeptide-8

Tetrapeptide-21

Pentapeptide-18

Palmitoyl Tripeptide-1

Pantolactone

Palmitoyl Tripeptide-38

Palmitoyl Tetrapeptide-7

Glyceryl Caprylate

Lactic Acid/Glycolic Acid Copolymer

Polyvinyl Alcohol

Phenylpropanol

Copper Palmitoyl Heptapeptide-14

Heptapeptide-15 Palmitate

Potassium Sorbate

Xanthan Gum

Water, Glycerin, Butylene Glycol, Inulin, Sodium Hyaluronate, Panthenol, Alpha-Glucan Oligosaccharide, Carnosine, Carbomer, Polysorbate 20, Caprylyl Glycol, Phenoxyethanol, Hydroxypropyl Cyclodextrin, Dunaliella Salina Extract, Ethylhexylglycerin, Citric Acid, Palmitoyl Tripeptide-5, Sodium Benzoate, Acetyl Hexapeptide-8, Tetrapeptide-21, Pentapeptide-18, Palmitoyl Tripeptide-1, Pantolactone, Palmitoyl Tripeptide-38, Palmitoyl Tetrapeptide-7, Glyceryl Caprylate, Lactic Acid/Glycolic Acid Copolymer, Polyvinyl Alcohol, Phenylpropanol, Copper Palmitoyl Heptapeptide-14, Heptapeptide-15 Palmitate, Potassium Sorbate, Xanthan Gum

1,2-Hexanediol

Nicotiana Benthamiana Hexapeptide-40 Sh-Oligopeptide-1

N-Prolyl Palmitoyl Tripeptide-56 Acetate

Sh-Oligopeptide-1

Sh-Oligopeptide-2

Sh-Polypeptide-1

Sh-Polypeptide-11

Sh-Polypeptide-9

Acetyl Glutamine

Copper Tripeptide-1

Raphanus Sativus Root Extract

Bacillus/Folic Acid Ferment Filtrate Extract

Hydroxyacetophenone

Disodium Acetyl Glucosamine Phosphate

Sodium Glucuronate

Sodium Phytate

Magnesium Sulfate

Hydroxyethylcellulose

Lecithin

Maltodextrin

Propanediol

Pentylene Glycol

Water, Glycerin, 1,2-Hexanediol, Nicotiana Benthamiana Hexapeptide-40 Sh-Oligopeptide-1, N-Prolyl Palmitoyl Tripeptide-56 Acetate, Sh-Oligopeptide-1, Sh-Oligopeptide-2, Sh-Polypeptide-1, Sh-Polypeptide-11, Sh-Polypeptide-9, Acetyl Hexapeptide-8, Acetyl Glutamine, Copper Tripeptide-1, Raphanus Sativus Root Extract, Bacillus/Folic Acid Ferment Filtrate Extract, Hydroxyacetophenone, Disodium Acetyl Glucosamine Phosphate, Sodium Glucuronate, Sodium Hyaluronate, Sodium Phytate, Magnesium Sulfate, Hydroxyethylcellulose, Lecithin, Citric Acid, Maltodextrin, Propanediol, Butylene Glycol, Pentylene Glycol, Ethylhexylglycerin, Caprylyl Glycol, Phenoxyethanol

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Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Acetyl Hexapeptide-8 (also known as Argireline) is a synthetic hexapeptide that is often called a "topical Botox alternative".

It works by mimicking how Botox relaxes muscles; it interferes with the signaling process that tells your facial muscles to contract. This can help soften expression lines like forehead wrinkles or crow's feet over time.

The comparison to Botox does have limits because the molecule is water-loving and relatively large.

Acetyl Hexapeptide-8 has a hard time absorbing deeply enough through the skin's outer barrier to actually reach the muscles.

So whether it truly works the way Botox does at a biological level is still up for debate, but early clinical outcomes are fairly encouraging.

A 12 week human study of a multi-ingredient regimen containing this ingredient saw:

While some studies have observed improvements in wrinkle appearance, it is important to note that more consistent results are seen in multi-ingredient formulations (vs just Acetyl Hexapeptide-8 alone).

Some research studies also used higher concentrations (up to 10%) while this ingredient is usually found in concentrations up to 0.005% in leave-on formulations.

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.

Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.

Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.

Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.

Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.

However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.

Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:

The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.

Topically, glycerin does several things at once:

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.

In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.

Interestingly, the size of the molecule affects its behavior:

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.

You'll typically see concentrations between 0.1-2% for this ingredient.

Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!

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