Thoughts on this serum

Hi Randy, 

This serum is ludicrously expensive but my skin is temperamental and I find this formula very settling. What are your thoughts on it? The stability of green tea always concerns me. 


  • Looks like a great product with many different actives, but I wonder what the whole INCI list is. I don't see any solvents to keep the actives suspended. According Paula's Choice Daucus Carota extract may be irritating, I found some studies certain extracts may contain Limonene, but I'm not sure what the exact composition of Daucus Carota Extract is.
  • edited March 2017
    Fancy seeing you here Peter! :) Presuming you are my same friend from Reddit! 

    I have been really scratching my head over this product for a long time as it really suits my skin which can be tricky to please but the formula looks peculiar. It looks like an incomplete INCI list but this is all the ingredients on the bottle too which concerns me (where the heck is water?!) At first I thought it was lacking in preservatives but over on the Cosmetic Science forum they observed that the combination of the sodium salicylate/gluconolactone may work in a similar way to benzoate/gluconolactone (e.g Geogard Ultra.) Plus it has leucidal but that is a weak preservative. The gluconolactone is a chelator so hopefully that would work to bind any metal ions in the green tea but I'm no cosmetic chemist! 

    I love green tea as an ingredients but am concerned over how unstable it tends to be. I fear putting a serum on my face which may have oxidised. Hopefully my concerns are unfounded! 

  • edited March 2017
    Yep, I'm the same person ;-)

    Well to me it looks like an incomplete inci list, or it's not listed according the official inci rules. Most of the extracts and actives are powders, so considering the site says it's a gel, there must be water or some other solvent. It's possible that the Green Tea extract in reality is water + green tea extract for example... also >10% Sodium Hyaluronate is quite uncommon, it could be a solution..

    Stability is a difficult subject, I've never found much reliable information on ingredient stability. Only some studies on ascorbic acid, niacinamide and resveratrol in different bases, but not so much about the stability of finished formulations. Some companies (like TO or PC) claim their products are stable in dropper bottles and tubes, others (uncover skincare) claim they only remain stable in airless packaging stored in a fridge. But to be honest, I don't know the truth, airless packaging is better, but is it necessary, for some ingredients perhaps....
  • edited March 2017
    Yes, there is undoubtedly water in the serum, its a light watery gel texture. I'm unsure of how they get around INCI regulations? 

    I am of the opinion that airless pumps are the absolute best way forward (if not utterly essential.) There are a few labs (like those of Ultrasun and Environ) who employ such incredibly stringent and high tech manufacturing techniques that, with their use of airfree technology, are able to not add preservatives and still pass batch testing perfectly. I like to keep absolutely everything in the fridge. If you look on sites that sell individual ingredients and actives for cosmetic crafting and read the storage instructions you realise that many actives have the potential to degrade rapidly unless kept at 4/5 degrees C. Peptides and growth factors are extremely sensitive to heat. I also often wonder how retailers store such products. I would like to hope they are refrigerated and not sat on shelves in warm warehouses for months. I think the doctor from Uncover is being very realistic and honest and I appreciate businesses like that. 

    I've seen a few studies about the degradation of green tea which suggest it's rather unstable unless encapsulated. Its hard to know what to think. This is a product I like but wish I could replace if you know what I mean! Its about pH 4.6 which my skin enjoys and high enough to avoid the Niacinamide hydrolysing to Niacin. 
  • But there is a possibility that its best to store a separate ingredient at 4/5 degrees, but a formulated product not. Companies add stabilizers, and well according Paula's Choice, a very low temperature may mess up that stabilized formula. So I really wonder if keeping cooler is always better. Uncover Skincare did mention they wanted to formulate a product with green tea, but didn't manage to stabilize it completely, even when encapsulated. But an airless pump is best.
  • edited March 2017
    From my understanding, sometimes very low temps can cause an emulsion to seperate but I've never had that issue with my trusted products. I have seen it with a few less well-formulated products where the oil and water part ways when kept in the fridge! It's pretty gross. I guess a happy medium would be to store your products in a wine chiller between 8-10 degrees, at least in hot summer weather.

    On the Skinactives website they instruct that certain of their serums and creams with growth factors and peptides must be kept refrigerated. I spoke to another Dr/formulator who said certain actives lose their potency fairly rapidly unless kept cool. Again though, it was mainly the growth factors and peptides, stuff like Matrixyl. Also traditional L-Ascorbic Acid products, it tends to slow the oxidisation when they are kept cool I believe. 

    I am very particular about not keeping anything longer than 6 months personally and always feel some piece of mind from refrigeration. You do have to wonder with some products which may have sat on a shelf for a long time, or been shipped to you in the summer heat... could some actives already be corrupted and useless? Products are batch tested for mould/bacteria but they rarely test them to see if their actives are still potent after a while. I think some manufacturers are not honest about this. Many people don't want the hassle of buying products they have to keep in the fridge or throw away after a few months rather than 2 years. 

  • I want to keep my products in a fridge as well, at about 10 degrees. In the summer months it can be over 35 degrees here, and I don't believe such high temperatures in a humid bathroom are beneficial for the active ingredients. But I do wonder why Paula's Choice says its bad to store the products in a fridge, see this beauty blog with tips from Paula, on their FAQ for the 15% vitamin C, and their Dont's on the UK page. They really say a refrigerator reduces the lifespan and stability of a formulated product. It's confusing because Uncover Skincare even stores the product in the distribution center in a refrigerator and advice to store the moisturizer in the fridge when you receive it at home, but it could also be a marketing trick, letting people think the products are very potent and thus need a refrigerator.
  • edited March 2017
    Fridges tend to sit at around 2-4 degrees. Wine chillers go from about 4 degrees to 18 degrees or so. You just have to look at the spec as they are more humid than fridges but some are adjustable (if its too dry the cork on the wine dries out. Regular fridges tend to continually remove the humidity.) I kept my products in a wine chiller for about seven years but it recently went kaput so I invested in a very nice, ultra stable-temperatured catering fridge (it goes from 2-12 degrees) with digital control. Initially I was concerned there could be a problem but nothing seems to have changed or separated in any way. I chose to keep it at 5 degrees to keep my peptides happy and but also I enjoy the feeling of cool products! 8-12 degrees would probably be suitable for most products, colder for peptides etc.

    I came across those warnings too about not keeping products in the fridge so asked a few formulators and Drs behind skincare products and came to the conclusion it was fine. Digging deeper the only thing I could find to suggest there was issue with this was the potential for an emulsion to break down in cold temperatures i.e water, oil and silicones can separate from each other and then you get unhomogenized layers in the product which would of course be an issue. I have seen this occur with cheap products years ago and the result is the oil floats to the top, so you press the pump and just oily mess comes out. Now, of course, I am presuming that an emulsion breaking down would be an obviously visible problem, perhaps a chemist would disagree! I very much doubt the actives would lose their potency per sey.

    Perhaps it would be interesting to pose the question to Uncover and show them the PC formulas? Perhaps, from a formulating point of view, those particular formulas would be more prone to separating due to the heavy silicone bases or types of emulsifiers used? Also, seeing as they were all tested at room temperature, PC don't know how the cold could potentially effect them so would rather customers didn't take the risk and then complain and want refunds? I often take PC advice with a pinch of salt. For example, there are a lot of filters in her sunscreens you and I wouldn't want to use on our skin but she states they are good.

    I would be very interested in what Dr Jetske Ultee had to say seeing as she suggests the refrigerator route. Perhaps she has a specific temperature in mind to those of us with cosmetic fridges/wine chillers and are able to very accurately control it? My biggest concern would be a separation which would cause the UV filters in sunscreen to not be distributed evenly but clearly Dr Ultee trusts her emulsions and doesn't see this as being a problem. Perhaps the PC formulas are not as stable in cold temps. 

    If you get any info please let me know Peter and  I'll increase the temperature of my fridge a few degrees if so! :) 

  • @RandyS

    What do you think? Is it better to store a cosmetic product in the refrigerator to decrease degradation of actives? Why does Paula's Choice say you should never store a product in the refrigerator because it can degrade the actives, while other companies like Skinactives and Uncover Skincare do advice to store products in the fridge?
  • @RandyS

    I like to know your stand on temperature and stability testing of products.

    Should we store our skincare in the refrigerator?

    This summer in Sydney, it hit 45°C or 113℉  breaking 121 year summer heat record :(

  • For the most part we agree with Paula's assessments. This one, however, doesn't quite make sense to me. In my professional experience, low temperature storage (but not freezing!) can extend shelf life. 

    I can imagine some special formulas MAY have stability problems at very low temps but for the vast majority of products I can't see why it would pose a problem. If Paula has data to share on this I'd love to see it. 
  • Thank you @RandyS :) That makes me feel a lot more confident about using my little fridge! 
    I wonder if Paula's silicone heavy formulas are prone to separation? Saying that I've kept her products refrigerated and have seen no discernible changes in the formulas, though I know the eye test isn't always the most scientific one.

    By the way, what are your thoughts on the serum posted in my first comment? Thank you! 
  • It is expensive but if you like the way the product makes your skin feel and you can afford it then it seems fine. 
  • edited March 2017
    Thank you very much @RandyS
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