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InstaNatural Eye Serum

Eye Serum

Restore youthfulness and minimize the appearance of fine lines and wrinkles around the eyes.
Uploaded by: raspberilicious on 12/10/2019

Skim through

Ingredient name what-it-does irr., com. ID-Rating
Aqua solvent
Aloe Barbadensis Leaf Juice soothing, moisturizer/​humectant goodie
Sodium Ascorbyl Phosphate antioxidant, anti-acne goodie
Potassium Cetyl Phosphate emulsifying, surfactant/​cleansing
Glycerin* skin-identical ingredient, moisturizer/​humectant 0, 0 superstar
Limnanthes Alba (Meadowfoam) Seed Oil emollient goodie
Niacinamide cell-communicating ingredient, skin brightening, anti-acne, moisturizer/​humectant superstar
Sodium Hyaluronate* skin-identical ingredient, moisturizer/​humectant 0, 0 goodie
Palmitoyl Tetrapeptide-7 cell-communicating ingredient goodie
Palmitoyl Tripeptide-1 cell-communicating ingredient goodie
Caffeine antioxidant goodie
Ubiquinone antioxidant goodie
Astaxanthin antioxidant goodie
Malus Domestica Fruit Cell Culture Extract goodie
Hesperidin skin brightening, emollient, antioxidant goodie
Rosmarinus Officinalis (Rosemary) Leaf Extract antioxidant, soothing, antimicrobial/​antibacterial goodie
Centella Asiatica Extract soothing, antioxidant, moisturizer/​humectant goodie
Hibiscus Rosa-Sinensis Flower Extract moisturizer/​humectant
Undaria Pinnatifida Cell Culture Extract
Ganoderma Lucidum (Mushroom) Extract
Geranium Maculatum Extract
Passiflora Edulis Flower Extract
Citrus Paradisi (Grapefruit) Peel Oil perfuming icky
Tocopherol* antioxidant 0-3, 0-3 goodie
Xanthan Gum* viscosity controlling
Leuconostoc/Radish Root Ferment Filtrate antimicrobial/​antibacterial, preservative
Pentylene Glycol* solvent, moisturizer/​humectant
Caprylyl Glycol moisturizer/​humectant, emollient
Ethylhexylglycerin preservative
Phenoxyethanol preservative
Butylene Glycol moisturizer/​humectant, solvent 0, 1
Lecithin* emollient, emulsifying goodie
Polysorbate 20 emulsifying 0, 0
Carbomer viscosity controlling 0, 1
Limonene* perfuming, solvent icky

InstaNatural Eye Serum
Ingredients explained

Also-called: Water | What-it-does: solvent

Good 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. 

It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water. 

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Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying. 

One 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. 

Also-called: Aloe Vera | What-it-does: soothing, moisturizer/humectant

Aloe Vera is one of today’s magic plants. It does have some very nice properties indeed, though famous dermatologist Leslie Baumann warns us in her book that most of the evidence is anecdotal and the plant might be a bit overhyped.

What research does confirm about Aloe is that it’s a great moisturizer and has several anti-inflammatory (among others contains salicylates, polysaccharides, magnesium lactate and C-glucosyl chromone) as well as some antibacterial components. It also helps wound healing and skin regeneration in general. All in all definitely a goodie. 

Also-called: Form of Vitamin C, SAP | What-it-does: antioxidant, anti-acne

The sodium salt form of skincare superstar, vitamin C. If you do not know what the big fuss about vitamin C is, you are missing out and you have to click here and read all the geeky details about it.

Pure vitamin C (aka ascorbic acid, AA) is great and all, but its lack of stability is a big challenge for the cosmetics industry. One solution is to create stable derivatives that can be absorbed into the skin, convert there to AA and do all the magic AA is proven to do (which is being an antioxidant, a collagen booster, and a skin brightener).

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SAP (the vit C derivative, not the enterprise software, obvs) is a promising derivative that has great stability up to pH 7. The challenge with it though is skin penetration. Unfortunately, it seems to be limited, or to quote a great article from the Journal of Cosmetic Dermatology "topically applied ascorbyl phosphate salts are, at very best, poorly absorbed in comparison with AA". Regarding conversion to AA, there seems to be no data about it, so we can neither deny nor confirm it.

We have better news regarding the three magic abilities of vitamin C: there is in-vivo (tested on real people) data showing that SAP does have photo-protective (aka antioxidant) properties, though less than pure AA. SAP might also aid collagen boosting; in-vitro (made in the lab) data shows that it works, but is less effective than another vitamin C derivative, called MAP (that seems to be as effective as pure AA). As for skin-brightening, there is a trade publication with in-vivo data showing that SAP can fade brown spots

Another thing SAP might be able to do is to help with acne. A 2005 study showed in vitro (in test tubes) that 1% SAP has a strong antimicrobial activity on evil acne causing P. acnes and it also showed in vivo (on real people) that 5% SAP can strongly improve the inflammatory and non-inflammatory lesions of acne vulgaris. In fact, the results were comparable or even slightly better than with 5% benzoyl peroxide. 

And there is even more regarding SAP and acne. A nice double-blind study from 2009 showed that  5% SAP reduced the inflammatory lesions by 20.14% and 48.82% within 4 and 8 weeks respectively and when combined with 0.2% retinol the results were even better. With this combination treatment, the improvement was 29.28% after 4 weeks and 63.10% after 8 weeks of application. 

Aside from research studies, anecdotal evidence also supports SAP being a promising vitamin C derivative. One of the best-selling (vitamin C) serums in Sephora is the Ole Henriksen Truth Serum, while on Amazon it's the OzNaturals Vitamin C 20 Serum. Another popular choice is the Mad Hippie Vitamin C serum, and all of these contain vitamin C in the form of SAP. 

Overall, we think SAP is a goody!  In terms of anti-aging, it's probably not as effective as pure Ascorbic Acid, but it's totally worth a try. However, if your skin is acne-prone, SAP is your form of Vitamin C and it's a must-try.

A white to beige powder that is described as the golden standard emulsifier for emulsions (oil+water mixtures) that are difficult to stabilize. It is especially popular in sunscreens as it can boost SPF protection and increase the water-resistance of the formula. 

Glycerin* - superstar
Also-called: Glycerol;Glycerin | What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0
  • A natural moisturizer that’s also in our skin
  • A super common, safe, effective and cheap molecule used for more than 50 years
  • Not 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
  • Effective from as low as 3% with even more benefits at higher concentrations up to 20-40% (around 10% is a good usability-effectiveness sweet spot)
  • High-glycerin moisturizers are awesome for treating severely dry skin
Read all the geeky details about Glycerin here >>

Also-called: Meadowfoam Oil | What-it-does: emollient

The emollient plant oil coming from the seeds of the white flowering plant called meadowfoam.  Meadowfoam Oil has a unique fatty acid composition with 95% of it being long chain fatty acids (eicosenoic acid C20:1 - 61%, docosenoic acid C22:1 - 16% and docosadienoic acid C22:2 - 18%) that make the oil extraordinarily stable. It also contains antioxidant components such as vitamin E as well as phytosterols.

Apart from Meadowfoam Oil's crazy stability, the oil is described as non-greasy, rapidly absorbed and having a similar skin feel to more often used jojoba oil. The oil is ideal for products where a soft, smooth, silky feel is required whether it be on skin or hair.

Niacinamide - superstar
Also-called: vitamin B3, nicotinamide | What-it-does: cell-communicating ingredient, skin brightening, anti-acne, moisturizer/humectant
  • A multi-functional skincare superstar with several proven benefits for the skin
  • Great anti-aging, wrinkle smoothing ingredient used at 4-5% concentration
  • Fades brown spots alone or in combination with amino sugar, acetyl glucosamine
  • Increases ceramide synthesis that results in a stronger, healthier skin barrier and better skin hydration
  • Can help to improve several skin conditions including acne, rosacea, and atopic dermatitis
Read all the geeky details about Niacinamide here >>

What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0

It’s the - sodium form - cousin of the famous NMFhyaluronic acid (HA). If HA does not tell you anything we have a super detailed, geeky explanation about it here.  The TL; DR version of HA is that it's a huge polymer (big molecule from repeated subunits) found in the skin that acts as a sponge helping the skin to hold onto water, being plump and elastic. HA is famous for its crazy water holding capacity as it can bind up to 1000 times its own weight in water.

As far as skincare goes, sodium hyaluronate and hyaluronic acid are pretty much the same and the two names are used interchangeably. As cosmetic chemist kindofstephen writes on reddit  "sodium hyaluronate disassociates into hyaluronic acid molecule and a sodium atom in solution". 

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In spite of this, if you search for "hyaluronic acid vs sodium hyaluronate" you will find on multiple places that sodium hyaluronate is smaller and can penetrate the skin better. Chemically, this is definitely not true, as the two forms are almost the same, both are polymers and the subunits can be repeated in both forms as much as you like. (We also checked Prospector for sodium hyaluronate versions actually used in cosmetic products and found that the most common molecular weight was 1.5-1.8 million Da that absolutely counts as high molecular weight).

What seems to be a true difference, though, is that the salt form is more stable, easier to formulate and cheaper so it pops up more often on the ingredient lists. 

If you wanna become a real HA-and-the-skin expert you can read way more about the topic at hyaluronic acid (including penetration-questions, differences between high and low molecular weight versions and a bunch of references to scientific literature).

Also-called: Part of Matrixyl 3000, Pal-GQPR, Previously Palmitoyl Tetrapeptide-3 | What-it-does: cell-communicating ingredient

A four amino acid peptide with the amino sequence of glycine-glutamine-proline-arginine. It is attached to palmitic acid (a fatty acid)  to increase oil solubility and skin penetration. 

It works by reducing the production of the signal moleculeinteleukin-6 (IL-6) which promotes inflammation in the skin and less inflammation means slower degradation of important things (like collagen) that results in younger looking skin for a longer time. 

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It works in synergy with its pal, Palmitoyl Tripeptide-1 in the famous Matrixyl 3000 complex. You can read some more about the famous duo here.

Also-called: Part of Matrixyl 3000, Pal-GHK, Formerly also Palmitoyl Oligopeptide | What-it-does: cell-communicating ingredient

A really famous peptide that is part of Matrixyl 3000, the most sold peptide complex in the word. Before we go and find out what the big deal with Matrixyl 3000 is, let's just focus on Palmitoyl Tripeptide-1 itself for a bit.

It's a small three amino acid (they are the building blocks of all proteins) peptide with the amino sequence of glycine-histidine-lysine, or GHK. GHK is attached to palmitic acid (a fatty acid) to increase oil solubility and skin penetration. 

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The GHK part is the important one as it's a type I collagen fragment. When collagen naturally breaks down in the skin, the resulting peptide fragments signal to the skin that it should get to work and create some nice, new collagen. Adding in collagen fragment peptides, like GHK, might trick the skin into thinking that collagen has broken down and it's time to create some more.

Therefore, Palmitoyl Tripeptide-1 is believed to be able to stimulate collagen production in the skin, and more collagen means fewer wrinkles and younger looking skin. 

In Matrixyl 3000, Palmitoyl Tripeptide-1 is coupled with Palmitoyl Tetrapeptide-7  and the duo works in synergy to reduce wrinkles and give younger looking skin. According to the manufacturer's in-vivo (made on real people) test, applying 3% Matrixyl 3000 twice a day for 2 months resulted in all of the following things:

  • 39.4% reduction in surface occupied by deep wrinkles
  • 32.9% reduction in main wrinkle density
  • 19.9% reduction in main wrinkle average depth
  • 16% improvement in roughness
  • 16.2% in lifting effect
  • 5.5% improvement in elasticity
  • 15.5% improvement in skin tone

Manufacturer results, of course, always have to be taken with a pinch of salt, but if you like peptides, the Matryxil 3000 duo is one of the best-proven and most well-known ones and it's something that is worth trying.

Caffeine - goodie
What-it-does: antioxidant

Hello, our favorite molecule that helps us wake up in the morning and then keeps us going through the day. As a super well-known stimulant from coffee, tea and plenty of other soft drinks, Caffeine needs no introduction. So we will skip right to the part where we talk about what the hell it does in so-so many cosmetic products.

Looking at the research, we were surprised to find how versatile Caffeine is. It is a small, water-loving molecule with pretty good skin penetration abilties. Once in the skin, it has nice antioxidant properties, meaning that it reduces the formation of evil free radicals and it might even be useful in preventing UV-induced skin cancers. 

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A well-known thing about Caffeine is that it improves the microcirculation of the blood vessels. Though conventional wisdom and anecdotal evidence says that this property is helpful for dark under-eye circles and puffy eyes, we have to mention that the double-blind research we have found about a 3% caffeine gel concluded that "the overall efficacy of the selected caffeine gel in reducing puffy eyes was not significantly different from that of its gel base."  But you know, the proof is in the pudding.

Another thing Caffeine is used for in body care products is its anti-cellulite effects. In theory, it can speed up the lipolysis process (the "fat burning"  by our cells) and stimulate the draining lymph system that might lead to the improvement of cellulite. But here again, the evidence that it actually makes a measurable, let alone visible,  improvement on actual human beings is limited (we could find only some animal skin studies or caffeine being combined with other actives). 

Last, but not least, we have to write about caffeine and hair growth. The theory is that it can inhibit the activity of the 5-α-reductase enzyme that plays an important role in hair loss and allows a renewed growth phase of the hair. We have found some recent and promising research to back this up. A 2017 study compared a 0.2% caffeine liquid with a 5% Minoxidil  (an FDA approved active to treat baldness) solution and found that  "a caffeine-based topical liquid should be considered as not inferior to minoxidil 5% solution in men with androgenetic alopecia", or English translation means that the caffeine liquid was pretty much as good as the FDA-approved Minoxidil stuff. Not bad!

Overall, we think that caffeine is a very versatile and biologically active ingredient. Even though some of its effects are more hyped up than backed up, it is still a nice to have on many ingredient lists. 

Ubiquinone - goodie
Also-called: Coenzyme Q10 | What-it-does: antioxidant

Thanks to Nivea, Q10 is a pretty well-known ingredient and the fame and Beiersdorf's (the parent company of Nivea) obsession with it are not for no reason. It's an antioxidant found naturally in human cells where it plays a big role in energy production.

In fact, it's so important for energy production that if taken as an oral supplement it has a caffeine-like effect and if taken at night you will probably not sleep very well (so you should take it in the morning). Q10 supplementation is not a bad idea: it not only gives you energy but research also shows that oral Q10 increases the Q10 level of the skin (of course, it decreases with age like pretty much every good thing in the skin) and may help to reduce wrinkles. If you are not for supplements, dietary sources include fish, spinach, and nuts.

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As for skincare, Q10 comes in the form of a yellow, oil-soluble powder that's shown to absorb into the upper layer of the skin and act there like an awesome antioxidant. It not only has preventative effects but might also be able to reduce the depth of wrinkles, though 0.3% Q10 was used in the study that counts as really high (products containing that much should be very yellow!). 

Astaxanthin - goodie
What-it-does: antioxidant

An oil-loving, red-orange colored pigment that is becoming more and more well-known as a potent antioxidant.

If being an orange-colored pigment reminds you of beta-carotene from carrots, that is no coincidence: astaxanthin also belongs to the chemical group called carotenoids known for giving yellow, orange, or red color to plants. Our guy comes mostly from microalgae, a well-known and often used source is Haematococcus Pluvialis

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So Astaxanthin's main thing is being an antioxidant. You can take it as a supplement or slather it on your skin, it works both ways. A mouse skin study from 2012 found that a liposomal Astaxanthin formula prevented UV‐induced skin damage in multiple ways: UV-induced skin thickening, collagen reduction, and melanin formation were all hindered or prevented when the skin was pretreated with the Astaxanthin formula. 

Another study from 2012 examined the cosmetic benefits of Astaxanthin and found that combining oral supplementation (6mg/day) and topical application for 8 weeks in 30 volunteers showed improvements in skin wrinkle (crow’s feet), age spot size (cheek), elasticity (crow’s feet), skin texture (cheek) and moisture content of the skin (cheek).  If that would not be enough, a 2017 mouse study found our carotenoid molecule to be effective in speeding up wound healing.

Overall, Astaxanthin is an up and coming antioxidant nice to spot on any ingredient list. 

Also-called: PhytoCellTec

We don't have description for this ingredient yet.

Hesperidin - goodie

Hesperidin is an active compound coming from the peel and membranes of citrus fruits. It is a flavonoid with small but promising studies showing antiinflammatory, antioxidant, skin-brightening and skin barrier repairing activities. 

Also-called: Rosemary Leaf Extract | What-it-does: antioxidant, soothing, antimicrobial/antibacterial

The extract coming from the lovely herb, rosemary. It contains lots of chemicals, including flavonoids, phenolic acids, and diterpenes. Its main active is rosmarinic acid, a potent antioxidant, and anti-inflammatory. It has also anti-bacterial, astringent and toning properties. 

The leaves contain a small amount of essential oil (1-2%) with fragrant components, so if you are allergic to fragrance, it might be better to avoid it. 

Also-called: Gotu Kola, Tiger Grass | What-it-does: soothing, antioxidant, moisturizer/humectant

Centella Asiatica - or gotu kola as normal people call it  - has been used in folk medicine for hundreds of years. It’s traditionally used to improve small wounds, burns and scratches and it’s also a well known anti-inflammatory agent for eczema.

Recently science has taken an interest in Gotu Kola as well and it turns out it really has many active compounds with several benefits. Just for hard-core geeks, the main biologically active compounds are pentacyclic triterpenoid saponins called asiaticoside, madecassoside, asiatic and madecassic acid (also called centellosides).

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One of the biological activities of the centellosides is to be able to stimulate GAGs  (glycosaminoglycans - polysaccharides that are part of the liquidy stuff between our skin cells), and especially hyaluronic acid synthesis in our skin. This is probably one of the reasons why Centella Asiatica Extract has nice skin moisturizing properties that was confirmed by a 25 people, four weeks study along with Centella's anti-inflammatory effects.

Madecassoside can also help in burn wound healing through increasing antioxidant activity and enhancing collagen synthesis. Asiaticoside was shown to increase antioxidant levels on rats skin when applied at 0.2%. 

Centella Asiatica also often shows up in products that try to treat cellulite or striae. Of course, it cannot make a miracle but it might have some effect via regulating microcirculation and normalizing the metabolism in the cells of connective tissues. 

Bottom line: Gotu Kola is a great plant ingredient with proven wound healing, anti-inflammatory, and antioxidant properties. Nice to spot on any ingredient list.  

What-it-does: moisturizer/humectant

We don't have description for this ingredient yet.

We don't have description for this ingredient yet.

Also-called: Reishi Mushroom Extract

We don't have description for this ingredient yet.

We don't have description for this ingredient yet.

We don't have description for this ingredient yet.

Also-called: Pink Grapefruit Peel Oil | What-it-does: perfuming

The essential oil coming from the peel of the pink grapefruit. In general, the main component of citrus peel oils is limonene (around 90% for grapefruit peel), a super common fragrant ingredient that makes everything smell nice (but counts as a frequent skin sensitizer). Similar to other essential oils, grapefruit peel has also antibacterial and antifungal acitivity

Other than that, citrus peels contain the problematic compounds called furanocoumarins that make them (mildly) phototoxic. So be careful with grapefruit peel oil, especially if it's in a product for daytime use.  

Tocopherol* - goodie
Also-called: Vitamin E;Tocopherol | What-it-does: antioxidant | Irritancy: 0-3 | Comedogenicity: 0-3
  • Primary fat-soluble antioxidant in our skin
  • Significant photoprotection against UVB rays
  • Vit C + Vit E work in synergy and provide great photoprotection
  • Has emollient properties
  • Easy to formulate, stable and relatively inexpensive
Read all the geeky details about Tocopherol here >>

It's one of the most commonly used thickeners and emulsion stabilizers. If the product is too runny, a little xanthan gum will make it more gel-like. Used alone, it can make the formula sticky and it is a good team player so it is usually combined with other thickeners and so-called rheology modifiers (helper ingredients that adjust the flow and thus the feel of the formula). The typical use level of Xantha Gum is below 1%, it is usually in the 0.1-0.5% range. 

Btw, Xanthan gum is all natural, a chain of sugar molecules (polysaccharide) produced from individual sugar molecules (glucose and sucrose) via fermentation. It’s approved by Ecocert and also used in the food industry (E415). 

Also-called: Fermented Radish Root | What-it-does: antimicrobial/antibacterial, preservative

It's an alternative, natural preservative that comes from radishes fermented with Leuconostoc kimchii, a lactic acid bacteria that has been used to make traditional Korean dish, kimchi. During the fermentation process, a peptide is secreted from the bacteria that has significant antimicrobial properties

It is one of the more promising natural preservatives that can be used even alone (recommended at 2-4%), but it's not as effective as more common alternatives, like parabens or phenoxyethanol

A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent and a broad spectrum antimicrobial. According to manufacturer info, it's also a moisturizer and helps to make the product feel great on the skin. It works synergistically with preservatives and helps to improve water-resistance of sunscreens. 

It’s a handy multi-tasking ingredient that gives the skin a nice, soft feel. At the same time, it also boosts the effectiveness of other preservatives, such as the nowadays super commonly used phenoxyethanol

The blend of these two (caprylyl glycol + phenoxyethanol) is called Optiphen, which not only helps to keep your cosmetics free from nasty things for a long time but also gives a good feel to the finished product. It's a popular duo.

What-it-does: preservative

If you have spotted ethylhexylglycerin on the ingredient list, most probably you will see there also the current IT-preservative, phenoxyethanol. They are good friends because ethylhexylglycerin can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too.

Also, it's an effective deodorant and a medium spreading emollient

What-it-does: preservative

It’s pretty much the current IT-preservative. It’s safe and gentle, but even more importantly, it’s not a feared-by-everyone-mostly-without-scientific-reason paraben.

It’s not something new: it was introduced around 1950 and today it can be used up to 1% worldwide. It can be found in nature - in green tea - but the version used in cosmetics is synthetic. 

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Other than having a good safety profile and being quite gentle to the skin it has some other advantages too. It can be used in many types of formulations as it has great thermal stability (can be heated up to 85°C) and works on a wide range of pH levels (ph 3-10). 

It’s often used together with ethylhexylglycerin as it nicely improves the preservative activity of phenoxyethanol.

What-it-does: moisturizer/humectant, solvent | Irritancy: 0 | Comedogenicity: 1

Butylene glycol, or let’s just call it BG, is a multi-tasking colorless, syrupy liquid. It’s a great pick for creating a nice feeling product.  

BG’s main job is usually to be a solvent for the other ingredients. Other tasks include helping the product to absorb faster and deeper into the skin (penetration enhancer), making the product spread nicely over the skin (slip agent), and attracting water (humectant) into the skin.

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It’s an ingredient whose safety hasn’t been questioned so far by anyone (at least not that we know about). BG is approved by Ecocert and is also used enthusiastically in natural products. BTW, it’s also a food additive. 

Lecithin* - goodie
What-it-does: emollient, emulsifying

A very common ingredient that can be found in all cell membranes. In cosmetics it's quite the multi-tasker: it's an emollient and water-binding ingredient but it's also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes

What-it-does: emulsifying | Irritancy: 0 | Comedogenicity: 0

It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula. 

What-it-does: viscosity controlling | Irritancy: 0 | Comedogenicity: 1

A big molecule created from repeated subunits (a polymer of acrylic acid) that magically converts a liquid into a nice gel formula.  It usually has to be neutralized with a base (such as sodium hydroxide) for the thickening to occur and it creates viscous, clear gels that also feel nice and non-tacky on the skin. No wonder, it is a very popular and common ingredient.

Limonene* - icky
What-it-does: perfuming, solvent, deodorant

A super common and cheap fragrance ingredient. It's in many plants, e.g. rosemary, eucalyptus, lavender, lemongrass, peppermint and it's the main component (about 50-90%) of the peel oil of citrus fruits.

It does smell nice but the problem is that it oxidizes on air exposure and the resulting stuff is not good for the skin. Oxidized limonene can cause allergic contact dermatitis and counts as a frequent skin sensitizer

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Limonene's nr1 function is definitely being a fragrance component, but there are several studies showing that it's also a penetration enhancer, mainly for oil-loving components.

All in all, limonene has some pros and cons, but - especially if your skin is sensitive - the cons probably outweigh the pros.  

You may also want to take a look at...

what‑it‑does solvent
Normal (well kind of - it's purified and deionized) water. Usually the main solvent in cosmetic products. [more]
what‑it‑does soothing | moisturizer/humectant
The famous aloe vera. A great moisturizer and anti-inflammatory ingredient that also helps wound healing and skin regeneration. [more]
what‑it‑does antioxidant | anti-acne
The sodium salt form of skincare superstar, vitamin C. If you do not know what the big fuss about vitamin C is, you are missing out and you have to click here and read all the geeky details about it. Pure vitamin C (aka ascorbic acid, AA) is great and all, but its lack of stability is a big challenge for the cosmetics industry. [more]
what‑it‑does emulsifying | surfactant/cleansing
A white to beige powder that is the golden standard emulsifier for emulsions (oil+water mixtures) that are difficult to stabilize. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
A real oldie but a goodie. Great natural moisturizer and skin-identical ingredient that plays an important role in skin hydration and general skin health. [more]
what‑it‑does emollient
Meadowfoam Oil - An emollient plant that is stable, non-greasy and rapidly absorbed. It gives a soft, smooth, silky skin feel. [more]
what‑it‑does cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant
A multi-functional skincare superstar that has clinically proven anti-aging, skin lightening, anti-inflammatory and barrier repair properties. [more]
what‑it‑does skin-identical ingredient | moisturizer/humectant
irritancy, com. 0, 0
It's the salt form of famous humectant and natural moisturizing factor, hyaluronic acid. It can bind huge amounts of water and it's pretty much the current IT-moisturizer. [more]
what‑it‑does cell-communicating ingredient
The pal of Palmitoyl Tripeptide-1 in Matrixyl 3000. A four amino acid peptide that works by reducing the production of the signal molecule, inteleukin-6 (IL-6) that promotes inflammation in the skin. [more]
what‑it‑does cell-communicating ingredient
A three amino acid peptide that is part of famous peptide duo, Matrixyl 3000. It's a type I collagen fragment that might be able to trick the skin to think that collagen broke down and it's time to create some new one. [more]
what‑it‑does antioxidant
The well-known stimulant from coffee. It has nice antioxidant properties and can improve the microcirculation. Might be helpful for dark circles, puffy eyes, as well as cellulite and hair loss. [more]
what‑it‑does antioxidant
Q10 - an antioxidant found naturally in human cells where it plays an important role in energy production. As for skincare, it works as an awesome antioxidant that might also be able to reduce wrinkle depth. [more]
what‑it‑does antioxidant
An oil-loving, red-orange colored pigment known for being a potent antioxidant. [more]
what‑it‑does skin brightening | emollient | antioxidant
Hesperidin is an active compound coming from the peel and membranes of citrus fruits. It is a flavonoid with small but promising studies showing antiinflammatory, antioxidant, skin-brightening and skin barrier repairing activities.  [more]
what‑it‑does antioxidant | soothing | antimicrobial/antibacterial
Rosemary leaf extract - Its main active is rosmarinic acid, a potent antioxidant, and anti-inflammatory. It has also anti-bacterial, astringent and toning properties. [more]
what‑it‑does soothing | antioxidant | moisturizer/humectant
Centella Asiatica - or gotu kola as normal people call it  - has been used in folk medicine for hundreds of years. It’s traditionally used to improve small wounds, burns and scratches and it’s also a well known anti-inflammatory agent for eczema.Recently science has taken an interest in Gotu Kola as well and it turns out it really has many active compounds with several benefits. [more]
what‑it‑does moisturizer/humectant
what‑it‑does perfuming
The essential oil coming from the peel of the pink grapefruit. Its main component is limonene, a super common fragrant ingredient that makes everything smell nice. [more]
what‑it‑does antioxidant
irritancy, com. 0-3, 0-3
Pure Vitamin E. Great antioxidant that gives significant photoprotection against UVB rays. Works in synergy with Vitamin C. [more]
what‑it‑does viscosity controlling
A super commonly used thickener and emulsion stabilizer. [more]
what‑it‑does antimicrobial/antibacterial | preservative
It's an alternative, natural preservative that comes from radishes fermented with Leuconostoc kimchii, a lactic acid bacteria that has been used to make traditional Korean dish, kimchi. [more]
what‑it‑does solvent | moisturizer/humectant
A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent, and a broad spectrum antimicrobial. [more]
what‑it‑does moisturizer/humectant | emollient
A handy multi-tasking ingredient that gives the skin a nice, soft feel and also boosts the effectiveness of other preservatives. [more]
what‑it‑does preservative
It can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too. [more]
what‑it‑does preservative
Pretty much the current IT-preservative. It’s safe and gentle, and can be used up to 1% worldwide. [more]
what‑it‑does moisturizer/humectant | solvent
irritancy, com. 0, 1
An often used glycol that works as a solvent, humectant, penetration enhancer and also gives a good slip to the products. [more]
what‑it‑does emollient | emulsifying
It's quite the multi-tasker: an emollient and water-binding ingredient but also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes.  [more]
what‑it‑does emulsifying
irritancy, com. 0, 0
It's a common little helper ingredient that helps water and oil to mix together. Also, it can help to increase the solubility of some other ingredients in the formula. 
what‑it‑does viscosity controlling
irritancy, com. 0, 1
A handy white powder that magically converts a liquid into a nice gel formula. [more]
what‑it‑does perfuming | solvent
A super common fragrance ingredient found naturally in many plants including citrus peel oils, rosemary or lavender. It autoxidizes on air exposure and counts as a common skin sensitizer. [more]