Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

Endocare Renewal Retinol Intensive Serum 0.5% Pure Retinol Versus The INKEY List 1% Retinol Serum

Endocare Renewal Retinol Intensive Serum 0.5% Pure Retinol Versus The INKEY List 1% Retinol Serum This anti-aging serum is formulated around Niacinamide and Retinol to soften the look of wrinkles and refine skin texture. This anti-aging serum is formulated aro

Endocare Renewal Retinol Intensive Serum 0.5% Pure Retinol Versus The INKEY List 1% Retinol Serum

This anti-aging serum is formulated around Niacinamide and Retinol to soften the look of wrinkles and refine skin texture.

This anti-aging serum is formulated around Retinol to soften the look of wrinkles and refine skin texture.

What's inside

Key Ingredients

Benefits

Concerns

Ingredients Side-by-side

Cyclopentasiloxane

Caprylyl Methicone

C12-15 Alkyl Benzoate

Undecane

Dimethicone/Vinyl Dimethicone Crosspolymer

Trisiloxane

Dimethyl Isosorbide

PEG-7 Glyceryl Cocoate

Pentylene Glycol

Niacinamide

Tridecane

Sodium Hyaluronate Crosspolymer

PEG-12 Dimethicone

Methyl Methacrylate/Glycol Dimethacrylate Crosspolymer

Bisabolol

Retinol

Hydroxypinacolone Retinoate

Ascorbic Acid

Tocopheryl Acetate

Silica Silylate

Zea Mays Starch

Tetrahexyldecyl Ascorbate

Phenylpropanol

Polysorbate 20

Caprylyl Glycol

Propanediol

Silica

Dimethicone

Propyl Gallate

Disodium EDTA

BHT

Tocopherol

Cyclopentasiloxane, Caprylyl Methicone, C12-15 Alkyl Benzoate, Undecane, Dimethicone/Vinyl Dimethicone Crosspolymer, Trisiloxane, Dimethyl Isosorbide, PEG-7 Glyceryl Cocoate, Pentylene Glycol, Niacinamide, Tridecane, Sodium Hyaluronate Crosspolymer, PEG-12 Dimethicone, Methyl Methacrylate/Glycol Dimethacrylate Crosspolymer, Bisabolol, Retinol, Hydroxypinacolone Retinoate, Ascorbic Acid, Tocopheryl Acetate, Silica Silylate, Zea Mays Starch, Tetrahexyldecyl Ascorbate, Phenylpropanol, Polysorbate 20, Caprylyl Glycol, Propanediol, Silica, Dimethicone, Propyl Gallate, Disodium EDTA, BHT, Tocopherol

Water

Glycerin

Prunus Armeniaca Kernel Oil

Persea Gratissima Oil

Caprylic/Capric Triglyceride

Squalane

Cetearyl Alcohol

Glyceryl Stearate Se

Phenoxyethanol

Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer

Benzyl Alcohol

Phospholipids

Polyacrylate Crosspolymer-6

Glycine Soja Oil

Ethylhexylglycerin

Glycolipids

Dehydroacetic Acid

Polysorbate 60

Sorbitan Isostearate

Trisodium Ethylenediamine Disuccinate

Glycine Soja Sterols

T-Butyl Alcohol

Water, Glycerin, Prunus Armeniaca Kernel Oil, Persea Gratissima Oil, Caprylic/Capric Triglyceride, Squalane, Cetearyl Alcohol, Glyceryl Stearate Se, Retinol, Phenoxyethanol, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Benzyl Alcohol, Phospholipids, Tocopherol, Polyacrylate Crosspolymer-6, Glycine Soja Oil, Ethylhexylglycerin, Glycolipids, Dehydroacetic Acid, Polysorbate 60, Sorbitan Isostearate, Trisodium Ethylenediamine Disuccinate, Glycine Soja Sterols, T-Butyl Alcohol

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Retinol is one of the most studied anti-aging ingredients in skincare (and for good reason!).

It's a form of vitamin A that your skin converts into Retinoic Acid, the active molecule that actually does the work in your cells.

That conversion happens in two steps: your skin first turns Retinol into Retinaldehyde (also called Retinal), then turns Retinaldehyde into Retinoic Acid.

Retinol is converted to biologically active retinoic acid via retinaldehyde by dehydrogenases in a two-step oxidation process.

Each step is a little "upgrade" toward the active form which is part of why Retinol is gentler than prescription Retinoic Acid; your skin does the work gradually. This also explains where Retinol sits in the retinoid family.

Here is the retinoid family ranked roughly by strength: Retinyl Esters (like Retinyl Palmitate) < Retinol < Retinaldehyde < Retinoic Acid.

Retinoid activity increases in that order, while tolerance runs in reverse; retinyl esters are the gentlest and retinoic acid the most irritating.

The more conversion steps an ingredient needs, the gentler (and slower) it tends to be, so Retinol lands in a nice middle spot. It's more effective than the esters, gentler than prescription options.

Once it becomes Retinoic Acid, it binds to receptors inside your cells' nuclei (called RARs and RXRs). These receptor pairs bind to specific DNA motifs called retinoic acid response elements and act like switches that turn certain genes on or off.

In practice, this means a few things happen in a formula. It:

That last two are worth a closer look.

A study that tested Retinol directly (not just prescription Retinoic Acid) found that four weeks of retinol thickened the epidermis and switched on the genes for Collagen I and Collagen III, with more procollagen I and III showing up in the skin. And after twelve weeks, facial wrinkles were visibly reduced.

Retinoids more broadly stimulate the skin's synthesis of hyaluronan and other glycosaminoglycans, part of what gives skin a plumper, more hydrated look over time.

So even the gentler OTC form is doing real structural work (not just sitting on the surface).

It's also worth knowing Retinol isn't only a wrinkle ingredient; it can help with uneven tone, dark spots, rough texture, and the look of pores as well because it speeds up turnover and influences pigment.

The research backs this up as well.

A pooled analysis of six clinical studies found that 0.1% stabilized retinol improved all signs of photoaging versus vehicle as early as week 4 and through 12 weeks, with only a few mild cases of irritation.

Another study comparing concentrations found that 0.3% and 1% Retinol were similarly effective at remodeling photodamaged skin, but 0.3% caused fewer adverse reactions when used daily (a useful reminder that more isn't always better).

Retinol is about tenfold less potent than Retinoic Acid. This is why it works as a gentler, non-prescription option that builds results over time.

Typical concentrations range from 0.1-1%, with 0.1% to 0.3% being a well-supported sweet spot for visible benefits with good tolerability.

One quirk worth mentioning: Retinol is famously unstable.

It's highly sensitive to light and oxygen, and UV exposure breaks it down into a range of degradation products.

Real-world testing bears this out, with retinoid content in some products dropping anywhere from 0% to 80% after six months at room temperature, and even more at higher temperatures.

This is why good formulations lean on opaque, air-tight packaging (think tubes and pumps, not clear jars) and often "encapsulate" the Retinol to shield it.

Signs of oxidation include your product turning yellow or smelling "off". Keeping it somewhere cool and dark, and using it up within a few months of opening helps it stay effective.

The most common side effects are mild and temporary: usually some dryness, redness, or light peeling as your skin adjusts. These tend to settle with consistent and lower-frequency use.

Like all retinoids, Retinol works best with nightly use, a good moisturizer, and daytime sunscreen.

The "ramp up" method works well: start with Retinol once a week to give your skin time to adjust, which keeps irritation low. Slowly add more nights until you reach your goal frequency once your skin feels comfortable.

Retinoids also make your skin more sensitive to the sun in the first few weeks, so wear sunscreen every morning and protect your skin from direct sun while you build up tolerance.

One safety note: topical Retinoids aren't recommended during pregnancy or breastfeeding. Systemic absorption from creams is low but because high oral vitamin A is a known teratogen and topical safety data are limited, most clinicians recommend stopping retinoids when pregnant or trying to conceive.

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

01

Formula cabinet

Ingredients & structured notes

Ingredient index

The Inkey List BakuchiolIngredients explained

  1. 01Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product.
  2. 02It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water.
  3. 03Expand to read more
  4. 04Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying.
  5. 05One more thing: the water used in cosmetics is purified and deionized (it means that almost all of the mineral ions inside it is removed). Like this, the products can stay more stable over time.
  6. 06It seems to us that squalane is in fashion and there is a reason for it. Chemically speaking, it is a saturated (no double bonds) hydrocarbon (a molecule consisting only of carbon and hydrogen), meaning that it's a nice and stable oily liquid with a…
  7. 07It occurs naturally in certain fish and plant oils (e.g. olive), and in the sebum (the oily stuff our skin produces) of the human skin. As f.c. puts it in his awesome blog post, squalane's main things are "emolliency, surface occlusion, and TEWL pre…
  8. 08Another advantage of squalane is that it is pretty much compatible with all skin types and skin conditions. It is excellent for acne-prone skin and safe to use even if you have fungi-related skin issues, like seborrhea or fungal acne.
  9. 09The unsaturated (with double bonds) and hence less stable version of Squalane is Squalene, you can read about it here >>
  10. 10A natural moisturizer that’s also in our skin
  11. 11A super common, safe, effective and cheap molecule used for more than 50 years
  12. 12Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
  13. 13Effective from as low as 3% with even more benefits for dry skin at higher concentrations up to 20-40%
  14. 14High-glycerin moisturizers are awesome for treating severely dry skin
  15. 15Propanediol is a natural alternative for the often used and often bad-mouthed propylene glycol. It's produced sustainably from corn sugar and it's Ecocert approved.
  16. 16It's quite a multi-tasker: can be used to improve skin moisturization, as a solvent, to boost preservative efficacy or to influence the sensory properties of the end formula.
  17. 17An emollient plant oil coming from the Sacha Inchi plant from the Colombian Amazon.
  18. 18Similar to other plant oils, it's loaded with nourishing and moisturizing fatty acids: it's especially rich in α-Linolenic acid (42-49%) and linoleic acid (32-38%) and contains less oleic acid (9-14%). It also contains a decent amount of antioxidant…
  19. 19A clear, colorless, almost odorless oil that spreads nicely and easily and gives a velvet dry skin feel. It is good friends with sunscreen agents and helps to solubilize them. Also, it makes sunscreens feel lighter and spread easier.
  20. 20At first glance, you could think that Bakuchiol is your average plant extract. It is derived from the seeds of Psoralea Corylifolia, aka Babchi, a plant important in Indian and Chinese medicine. The molecule was first isolated in 1973 and several an…
Source · incidecoder.com
02

Product index

Related product references

03

Comparison edit

Read side by side