Resveratrol - Cosmetic Science Talk

Resveratrol

I should have a sample of pure Resveratrol arriving mid-week. This is being evaluated as a potential ingredient for a melasma treatment. Has anyone used this ingredient before? I'm interested in determining the correct usage % for skin lightening.
Special interests: anti-aging creams, gels, and serums; sulphate-free shampoos; and therapeutic cosmetics.

Comments

  • Well it looks like 1% and 1% vitamin E (I guess the resveratrol is dissolved in the vitamin E, it's a hydrophobic molecule) from a piece in the Dermatology Times. Interestingly, it has a similar pseudo-estrogenic effect as that possessed by glycyrrhizic acid. 
    Special interests: anti-aging creams, gels, and serums; sulphate-free shampoos; and therapeutic cosmetics.
  • How are you going to evaluate it?
  • edited October 2016
    testers; I will have to evaluate it as a single ingredient of course (I can't avoid the vitamin E though)
    Special interests: anti-aging creams, gels, and serums; sulphate-free shampoos; and therapeutic cosmetics.
  • Trans-Cis Resveratrol

    While researching how to make resveratrol gels and lotions, I read some articles saying that resveratrol preparations aren’t suited to daytime use.  I looked at a few studies.  Studies show that upon exposure to light/UV light, the active/nonpolar trans form of resveratrol converts to the inactive/polar cis form (aka photoisomerization).  In a few hours, most trans-resveratrol [tRes] flips to cis-resveratrol.

    So I’m thinking that tRes, even with sunscreen, isn’t suited to daytime use.  What are your opinions?  Some of the tRes formulas advise using only at nighttime, but it looks like the vast majority of them do not.  Of course it is tRes with all the studies behind it to show that it does anything (when it actually does anything and is not merely label dressing).

    The problem is that I’ve been working on an “anytime” tRes formula per request, but if resveratrol should only be worn away from sunlight, then I need to stipulate that any tRes product needs such an advisement.

    Pterostilbene >>>

    Won’t all the stilbenes be vulnerable to photoisomerization?

    I’m looking into creating a formula with a sort of resveratrol analog, pterostilbene [PS], but there’s not nearly as much information on PS as tRes.

    Has anyone formulated products with PS?  Is it easier to work with than tRes?  I see several patents on PS compounds (ChromaDex, Sabinsa), as well as random bulk suppliers.  I’m wondering if there are some iterations of PS out there that you find better or more resistant to trans/cis isomerization than others?

    I’m not a cosmetic chemist and I’m new to formulating with tRes.



  • Is there any evidence that resveratrol or pterostilbene (photoisomerised or not) have any definable activity in a cosmetic product?
  • T-Resveratrol is a cox 1 inhibitor and thus an anti-inflammatory http://iovs.arvojournals.org/article.aspx?articleid=2378029 ;
    Has also been shown to demonstate bacterioststic activity agaaint p. acnes--https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4257953/----I am sure you can find more if you search.We are currently doing applied research for various applications including a proposed clinical IRB.
  • johnb, yes there is.  It's only the trans forms with all the efficacy studies, though.  Like DRBOB said, you can find lots more. tRes can do a variety of things IFF it's formulated correctly and used correctly.  For instance, its cytotoxic effect on p. acnes is demonstrated in multiple studies.  Now having said that, there's a huge difference between say, how effective it is as used by the average human compared to lab controlled studies on hairless mice!
  • My concern is that the investigative work on resveratrol is directed at pharmaceuticals:
    T-Resveratrol is a cox 1 inhibitor and thus an anti-inflammatory
    its cytotoxic effect on p. acnes is demonstrated in multiple studies
    Even the initial post here states that the intended use is as
    potential ingredient for a melasma treatment.
    Key word there being "treatment".

    References to Dermatology Times are made which emphasises further the medical or potential drug, rather than cosmetic, use of the material.

    All of this is research work and out of the scope of the definition of a cosmetic product.

    I appreciate that Belassi is in Mexico where normal definitions of a cosmetic might not apply but the thread has been resurrected by others - one of whom states:
    I’m not a cosmetic chemist and I’m new to formulating with tRes.



  • #JOHNUB--??????--Cosmetic Ingredient listed as follows and marketed as such. Ingredientingredienthttp://www.paulaschoice.com/cosmetic-ingredient-dictionary/definition/skin-soothing/resveratrol.  
  • I don't doubt that resveratrol may be listed by paulaschoice and that it may be used as a cosmetic ingredient but the uses being advocated in this thread are distinctly referred to medicines and, as such, do not fall within the remit of cosmetic chemistry.


  • @johnb is absolutely right. In Cosmetics all you can essentially say "great anti-oxidant" and then build the claims on diffuse benefits from anti-oxidant activity. Even exploring the Medical benefits is a dead end.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • Retinol, a cosmetic ingredient, followed a similar pathway and hardly ended up in a dead end.
  • edited April 16
    I've been testing a COSMOS formulation using Eve's t-resveratrol. I chose the COSMOS formulation because (a) I wanted to evaluate whether a typical COSMOS formula compared well with a more traditional approach; and (b) I wanted to compare (empirically) the effects of using t-r versus Showa Denko's exotic form of Vitamin C.
     - first I want to say that these are my personal opinions only and I am not a formally qualified chemist -
    1. The COSMOS formulation relied for preservation on a combination of alcohols / glycols, including ethanol at 15%. This is the reason I chose this formula as a vehicle for the trans-resveratrol; it is pretty much impossible to dissolve in anything except ethanol. Therefore the first step was to dissolve the t-r in pure ethanol. To preserve the efficacy of the finished product it was put in airless pump containers. 

    2. The Vitamin C formula is my own design and its intention is to preserve the efficacy of the Vitamin C as long as possible. To this end, it also includes pine bark extract which acts to prevent oxidation of the Vitamin C. However, it should be noted that pycnogenol is also regarded as an active ingedient in that it acts as a lightener. So, at the moment I am unable to compare on a single-ingredient basis as far as the C cream is concerned.

    3. We tested the product using it as a night cream on my wife and myself and other family members, and the wives of friends.

    4. After a couple of weeks we evaluated the results. (Treated area vs untreated area)

    My opinion is that the Vitamin C / pine bark combo had less lightening effect than we wanted - we did notice paler skin in the treated area after about 3 weeks use. The T-R had about the same effect. Noticeable but not wow.
    On the other hand, the C / pine bark combo had a marked effect on skin tone; the skin seemed to become thicker, wrinkles were reduced. On the volar forearm, using it on one area only, produced a demarcation line between relatively smooth and wrinkled skin. We didn't see much of an effect with the T-R. 
    We're in test batch production of the Vitamin C version at the moment, having designed a label, box, and box leaflet.

    Special interests: anti-aging creams, gels, and serums; sulphate-free shampoos; and therapeutic cosmetics.
  • edited April 16
    @DRBOB@VERDIENT.BIZ I actually was contracted to do some work on the NDA for Retinol for Acne. The NDA is still wallowing. In fact, Retinol has the same limitation. There are possible medically supported claims, but you must limit claims to Cosmetic claims. It is in fact, the same exact situation. Trans-retinoic acid aka Tretinoin (Retin-A, Renova) is the prescription post-cursor which fulfills most of the Medical uses at this time.


    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • I agree and went all through this at JNJ. Why go through an NDA with retinol which is a pro-drug and goes to all Trans retinoic acid in vivo?.Same is true for analogs of T-resveratrol as triacetyl analog is stable but is converted back to T-RES in melanocytes. both have cosmetic attributes so why not use them and avoid drug claims.I was at JNJ when they acquired ROC for the very reason we are discussing this.
  • The NDA was in hopes of making Retinol an OTC and hence opening up all markets. I am not a fan of NDA's since (at least for now) the FDA is glacial in approving them.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • Belassi, thank you for your detailed explanation and reporting on your results.  They go toward confirming what I am learning through my formulating attempts with resveratrol [tRes], which is that even with other solvents, tRes functions better with higher ethanol content.  When I hit the right tRes formulation, I also will recommend it for nighttime only.

    Your pine bark/Vitamin C combo is intriguing.  Just spent way too much time learning about different pine bark extracts from different species of trees.  I haven’t had any requests for pine bark in products, but on down the road I might learn how to formulate with it.

    @johnb, because of the way you phrased your initial question, I took it to mean exactly what you asked (“…any definable activity in a cosmetic product?”), as opposed to concerns you later expressed (about efficacy when classified as a cosmetic ingredient).  These two lines of inquiry are worlds apart.

    Why ask for “any definable activity” if you want to restrict the answers to those that can be subsumed only under the definition of a cosmetic?  The repertoire of answers to what is a cosmetic effect is very limited.  If I asked an open-ended question initially and then came back to argue against answers via appended restrictions upon my original question, then I’d get shouted down for presenting a straw man (logical fallacy).

    In any case, I see many cosmetic formulations (advertised only as cosmetic formulations) that indeed have quantifiable/definable pharmacodynamic and pharmacokinetic effects.  It seems to me the most effective cosmetics marketing walks a fine line of luring people in with drug-like promises, without actually making specific claims that would violate the laws.

    Here’s something slightly relevant to the topic of quasi-drug cosmetics.  I’ve had a couple of people ask me about formulating skincare with methyl donors.  I wonder if it’s to become one of those cosmetics marketing buzz phrases.  More importantly, in beginning to research methylation via dermal/transdermal products, it looks totally doable (and I mean beyond the usual B vitamin creams).  It looks like regular glycine betaine/beet sugar extract acts as a transdermal methyl donor.  So it looks with DMAE.  As of now I’ve barely begun to learn how some amino acids (like arginine and lysine) may act transdermally upon methylation pathways.  I’m only at the concept stage of transdermal methylation, so I have a lot to learn.  But I thought it’d be a good concept to hand over to any professional formulators and/or chemists who might be interested.  Of course none of these potential methyl donor ingredients I’m studying so far are new, but focusing upon ingredients as methyl donors in skincare appears novel.  Surely it can be phrased in cosmetics rather than pharmaceutical terms.




  • edited April 21
    @zwapp interesting to note that Paula uses Resveratrol in her sunscreen, maybe not well thought through or perhaps the SPF protects it? Looks like they're using the 1% trick so hard to say how much there's in it but definitely less than 1%.

    @Microformulation why would someone sponsor a NDA for retinol or resveratrol? I'm all for it, but I've heard it's beaucoup pesos and time to get an application through. How many bucks are we talking?
    Tretinoin works, but Retinol has a better dose adjusted efficacy to side-effect profile long term so I actually see Tretinoin as an inferior compound.

    @Belassi have you measured the effect of pine bark on vit c oxidation? Is it demonstrated in literature? Where can I order your cream? Send me a pm if it's available to the US!

    DRBOB@VERDIENT.BIZ Perhaps they would NDA retinol to reduce competition as OTC manufacturing is more expensive? Otherwise I'd think a company that size would look for patentable analogs like with T-resveratrol analogs which they could exclusively market the heck out of, bit risky though if it's not actually superior to the real thing, but that hasn't stopped drug companies in the past.

    My 5 cents on resveratrol: 10% alcohol seems to do OK at solubilizing 1% and it's most stable at pH > 4. Does not play well with Benzoyl Peroxide which coincidentally has a near identical chemical structure. Could be a great option for long term acne prevention as a nurturing BP alternative.
  • @ZinkWell, I was just contracted to provide some Formulation work since I had designed the initial product for the company. I think one issue was the fact that Retinol is difficult to stabilize and the client had done so. I am not sure what the project costs were, but if I had to guess close to 750K.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • Packer also recently found that Pycnogenol extends the lifetime of vitamin C in the body, prolonging its beneficial effects as an antioxidant. 
    There are some other studies but at the moment I am eating breakfast.
    @Zink: Unfortunately we don't supply the USA as yet.
    Special interests: anti-aging creams, gels, and serums; sulphate-free shampoos; and therapeutic cosmetics.
  • #zinc  That is what led to retinyl palmitate analog ;efficacy is similar to retinol and more stable.T-res likely needs a similar analog as triacetyl t-res is more stable and reverts back to T-res in vivo particularly in melanocytes for inhibition of melanogenesis.
  • @Microformulation so would they get a NDA for the patentable? stabilization system retinol combo or make one leading to a monograph? Or to a prescription drug? Could a company block inclusion of retinol in non Rx formulas because they found a way to stabilize it or simple spent the money to prove it has drug like effects, would the FDA even be OK with that? It'd take hundreds of products off the market.

    @Belassi thanks, interesting stuff. If only ascorbic acid didn't break out people with acne more often than not, found any way around that?

    @DRBOB@VERDIENT.BIZ Good example, because retinyl palmitate again has a higher side-effect to efficacy ratio than retinol.
    See the paper "Unoccluded Retinol Penetrates Human Skin In Vivo More Effectively Than Unoccluded Retinyl Palmitate or Retinoic Acid" and then there's concern about phototoxicity which might be unique to the palimate form or just more pressing due to less effective skin penetration and hence higher potential for UV exposure "Photo-induced DNA damage and photocytotoxicity of retinyl palmitate and its photodecomposition products".


  • @zink I have to be purposefully coy, as I have an NDA (the other kind) in place. The gist of it all is that retinol is a difficult material to stabilize and as such it would be difficult to meet the required listed concentrations. Their process (patented) achieved that. If you look at patents, there are hundreds with Cosmetic materials that do not necessarily eliminate others from using them, just not in the "same way" so to speak.

    OTC Products have a much higher burden of proof and testing regarding the final claimed label percentage of the active, a fact which I am sure you are aware. With Retinol, meeting and maintaining this percentage was the real task.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • @Microformulation makes sense, so they would create a stabilized Rx version of Retinol that wouldn't affect the legality of Retinol used in other products. Or if not going the NDA route find a way to market it as a cosmetic with patent protected stabilized Retinol, analogous to Ferulic Acid stabilized Vitamin C serums?

    Must be a challenge to get a 1 year shelf-life and keep retinol degradation under 10% of the label claim; air and UV proof packaging and an anhydrous formula packed with Tocopherol(s) and other fat soluble retinol protective antioxidants (e.g. BHT) could perhaps do it.

    I've have the same issue, I want to optimize for long term stability and present a simple degradation curve to my customers so they know what they can expect when the product is stored out of sunlight at room temperature, even if it degrades more than 10% in a year. Some people might want to use it past the EXP date too, this way they'll at least know how much bang remains.
  • #zink  best way would be to patent a  stabilized form of retinol and its analogs ie retinyl palmitate for cosmetic use and avoid FDA completely.
  • Or a stabilization system that's not too obvious?
  • Or simply use something like RetiStar Stabilized Retinol from BASF in combination with Retinyl Palmitate
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • @MarkBroussard I'm using a similar combination already to help stabilize it, but the addition of .1% Sodium Ascrorbate is interesting.
    Otherwise if you can do a OWO emulsion that can double shelf-life.


  • @Zink + everyone:  Upon even further research, I don’t see how “embedding” tRes in a sunscreen formula will protect the tRes from the trans/cis flip.  The tRes still will be exposed to light, so it still will convert to the cis form.

    The best organic (carbon-based) sunscreens naturally deteriorate with UV exposure/absorbance.  Also, all the sunscreens (including Ti and Zn) absorb some rays from the UV spectrum.  So, even if the tRes were somehow magically encapsulated within tiny sunscreen silos while at the same time mysteriously being active upon the skin from its shrouded sunscreen bubble-sphere, the light rays still would be absorbed by Sunscreens A-Z, thusly reaching the “magically protected” tRes.

    VERY IMPORTANT:  There is sufficient evidence that cRes has some antioxidant properties.  I don’t mean to give the (mistaken) impression that cRes is totally useless.  The problem is that it’s tRes that has most all of the studies behind it concerning its myriad other properties in which I’m interested, as well as the safety studies.  My concern about conserving the trans state is only because comparatively little is known about the cis state effects on skin, not because it is known that cRes is globally inferior.  This is basically a problem of flawed applications research, where people know that tRes will flip to cRes under normal environmental conditions, yet they continue to (mostly) disregard investigation into cRes because it’s easier to piggyback off of existing tRes research.

    @Zink I saw on your glycolic acid thread that you’re formulating sunscreens, so I posted some good (to me) links for you and all there.  The page where a cosmetics chemist debunks sunscreen myths will explain better why a sunscreen won’t prevent photoisomerization of tRes.  (I don’t think it mentions tRes, but it explains sunscreens better than I can, and you can extrapolate from there.)




  • @zwapp has any research been done on the effect of radical chain terminators, e.g. BHT or benzophenone derivatives?

    (since photoisomerisation occurs via a radical mechanism, chain terminators could in principle halt the reaction before it starts)

    also, I'm surprised that photoisomerisation favours the cis form; unless they're macrocyclic or physically constrained in some other way (which resveratrol isn't) the trans form is usually favoured where stilbene-type molecules are concerned
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • @zwapp I think your intuition is wrong and it's more likely that it's protected than not, depends the kinetics of degradation and skin penetration. Here's one study showing how retinol is very well protected in a sunscreen formula exposed to daylight https://www.ncbi.nlm.nih.gov/pubmed/18405792 and this doesn't even account for skin penetration.
    You might not need any protecting factors if it penetrates the skin quickly and deeply enough.

    "photoisomerization yield is reported as a function of 260 nm excitation time. 330 min continuous excitation led to ~60% isomerization yield." https://www.ncbi.nlm.nih.gov/pubmed/21494846 seems to slow to be of much concern in a topical. I also noticed there's a patent describing UV protection of tres.

    At the end of the day you'd have to measure it.




  • @Bill_Toge As is typical of most things, when you isolate a substance (as you know is routinely done for research, pharmaceutical and cosmetics applications, and garnering patents), you see changes in that substance’s behavior.  According to some articles I read, I think *in nature* the trans form is indeed favored because it occurs in glycosylated form.  Then I also read that with various plants, tRes is concentrated in one part of the plant and cRes is concentrated in another part.

    If you’re interested and have the time, you might want to study a book titled Stilbenes: Applications in Chemistry, Life Sciences and Materials Science by Likhtenshtein.  (But I’m not going to study it because it would be spreading myself too thin and most probably too much of it over my head.  I basically need to know if all the stilbenes will present the trans/cis problem.)

    BHT is not an option for the formulation I’ve been working on.  I haven’t looked into it at all and cannot speculate.

    I have now started investigating complexing tRes with some cyclic polysaccharides (HP-β-CD, 2-hydroxypropyl-β-cyclodextrin, in particular), which so far show promising photoprotective properties vis-à-vis tRes.  If you have any suggestions about this, then I would appreciate anything you know.

    Past the basics of some cosmetics chemistry, a lot of formulating stuff is beyond my scope and comprehension.  And I want my formulating hobby to remain a hobby and not turn it into an arm of work (where I’m in research mode often 12-14 hours a day).

    If I wanted to feel confident about making a daytime tRes product, probably I would need the expertise of a few types of chemists for the materials aspect alone, all guided by a cosmetics chemist to formulate necessary ingredients into a photostable, effective, and appealing product.  In lieu of that, I’m simply going to include an advisement for nighttime use (unless I figure out something else).

    By the way, I read that using sucrose esters emulsifiers increases the skin penetration of resveratrol.  I haven’t delved much into that yet, but thought I’d put it out there.

    @Zink Yes, I researched grants and patents before posting here.  For example, I found Tagranat Resveratrol (INCI: resveratrol (and) polymethyl methacrylate (and) tricaprylin).  But remember my original question was about pure (or 98/99%) tRes.  Also remember that my aim was to find out if simple tRes was suitable for daytime wear or not.

    First, I read the abstract to your link about induced isomerization of resveratrol.  It looks to be irrelevant to the sunscreens questions because the wavelength tested was 260 nm, which is UVC range that doesn’t reach earth’s surface.  UVC light is what’s used for germicidal irradiation, and it’s in the range of 100-280 nm.

    Second, I wasn’t talking about retinol.  I was only referring to resveratrol.

    I could be wrong about the photostability of tRes in sunscreen products.  I’m open to being wrong or right.  However, my doubts about sunscreens protecting tRes are not based upon intuition.

    I doubt that sunscreens can prevent the trans/cis flip because (1) there isn’t total/100% blockage or neutralization of UVA and/or UVB light via sunscreens; (2) many sunscreen formulations don’t work well or at all in preventing exposure to UVA light; (3) I think that if tRes were encapsulated in some sunscreen molecules, then the tRes wouldn’t be available for skin delivery (I’m uncertain about #3, but isn’t one reason for sunscreen products’ efficacy due to the fact that they’re formulated to coat and not penetrate the skin?); and (4) it looks like sunscreen ingredients do indeed degrade with exposure to UV light (according to repeated in vitro lab tests that measure actual light filtration across the UV spectrum).  Also, with the inorganic sunscreens, which basically work via a tessellation of molecules, variations in particle size often result in surface breaches that allow for penetration of UV light.  (I think the inorganic sunscreens, in fact, have the most problems with their claims not matching reality—though there are good and effective inorganic formulations out there.)

    No sunscreen product is perfect.  The bottom line is exactly what you said: it would have to be measured.  A sunscreen + tRes formulation would have to be tested in a well-designed (large and expensive) study to determine the level of trans/cis photoisomerization of resveratrol first in the lab and next on human subjects.  Then there would be the difficulties of parsing tRes from cRes effects.

    You also phrased a starting point well, which is could (an appreciable amount of) tRes act upon skin (in significant ways) before it changed to cRes?  But that still leaves the cRes factor.  I’m not finding much in the way of good, reliable cRes skin effects research.

    >>>  It’s not only about whether the tRes remains stable or flips to cRes.  It’s also very much about what the cRes does (or doesn’t do).

    I am satisfied with the research I’ve read showing that tRes rapidly flips to cRes with exposure to UVA and UVB light.  In 40-50 minutes, studies show that anywhere from 80-90% of tRes converts to cRes.  There are fluctuations and variation as always with measurements like this, but looking at relevant studies, you’ll see the conversion is fast.

    Incidentally, I’m a hard sell on studies.  That’s because I’ve had to redesign so many bad ones.

    Not incidentally, formulating tRes with sunscreens (and retinol) was not my inquiry here.  I don’t make sunscreen or retinol products.  So, I’m not so interested in either tRes or retinol with sunscreens.

  • First, I read the abstract to your link about induced isomerization of resveratrol.  It looks to be irrelevant to the sunscreens questions because the wavelength tested was 260 nm, which is UVC range that doesn’t reach earth’s surface.  UVC light is what’s used for germicidal irradiation, and it’s in the range of 100-280 nm.


    "trans-resveratrol has two absorption peaks at 304 nm and 316 nm" right in the UV-B range where sunscreens typically protect the skin very well. UV-A is lower energy too.

    Here's an experiment with trans resveratrol exposed to actual sunlight, it took 2 hours to cause a ~36% conversion, in vivo it'll only be exposed to direct sunlight for a few seconds as it goes through the stratum corneum and since UV-B transmittance of the stratum corneum at these wavelength is only around 10-20%, I highly doubt it will be an issue in a formula with a few SPF points.
    https://www.researchgate.net/publication/23802677_Simple_spectrophotometric_assessment_of_the_trans-cis-resveratrol_ratio_in_aqueous_solutions

    http://www.dnva.no/geomed/solarpdf/Nr_3_Nielsen.pdf

    SPF 15 sunscreen blocks ~95% of UV-B. So 5% gets through, then 15% of that gets through the stratum corneum, then there is absorption by other components in the epidermis etc. Not all sunscreen ingredients degrade significantly either, definitely not mineral sunscreens. Overall this is an easy thing to solve, and I don't think any experiments are warranted.

    Also, you could still use mineral sunscreen actives in a non-sunscreen formula, so this definitely applies. Don't waste your time solving a problem that doesn't need solving.


  • @Zinc Hi I dont mean to jump in out of nowhere, but hey hi! Just reading and thought I could give you some solid info on pine bark extract and oil. Its contains oligemeric proanthocyanidin compounds which as you know are "super antioxidants" property compounds. Its readily available, im a aromatheraphy Essential Oil practitioner. As well as formulater .
    Chow!
  • Also french maritime pinebark is clinicaly shown to contain photoprotective properties against uv rays. Also anti- aging and anti-bacterial. However even topically it can be unsafe for immune system suppresion needs, and as an anti-coagulative sooo...
  • Overall this is an easy thing to solve, and I don't think any experiments are warranted.  Also, you could still use mineral sunscreen actives in a non-sunscreen formula, so this definitely applies. Don't waste your time solving a problem that doesn't need solving.
    @Zink Quite the fiat…  So, when are you going to inform all the researchers working on the problems of photostability with sunscreens and concomitant ingredients that you’ve got the simple answers and all their work is both unnecessary and unnecessarily complicated?  Surely, then, you’ve been published and reviewed extensively with your simple answers, answers that come harder to those of us adhering to the scientific method with all that pesky experimentation?  LOL!

    I’ll start by reminding you again that it was never my query to formulate resveratrol with sunscreens.  I was never working on that problem, so your admonition for me to stop solving the problem is a specious one based upon the logical fallacy of false presupposition.  You are the one who brought up questions about resveratrol + sunscreens.  I merely told you some of my reasons about why I thought a simple tRes + sunscreen combination probably wouldn’t prevent photoisomerization of tRes.  Since you said you are working on sunscreens in another thread, then obviously this would be YOUR problem to solve.

    You dismiss important facts and make erroneous assumptions within your last post.  When I get another minute, I will post some links to relevant information.  Until then, I will correct the record.

    I know a little about sunscreens, because some time ago I considered making sunscreen products.  But as I researched, it wasn’t long before I realized it would be too involved and costly for me to formulate and test sunscreen products safely.  It does not negate what I learned.  My challenge was not only an issue of me not being a cosmetics chemist.  I learned of many challenges and problems in formulating good sunscreens, which are being solved by the expert cosmetics chemists through a lot of trials and learning they do.

    Of course mineral sunscreens, both TiO2 and ZnO, significantly degrade with UV absorption!  They both photo-oxidize.  (Many metals do.)  They both absorb UV rays (not merely reflect).  TiO2 is notorious for generating hydroxyl radicals with exposure to UV light.  Both have been shown to generate other ROS (reactive oxygen species) with exposure to UV light.  ZnO isn’t as photoreactive as TiO2, but ZnO isn’t 100% stable either.

    Photo-oxidants from TiO2 and ZnO will affect (often corrupt) other ingredients in formulation, almost like a chain reaction, as well as photo-oxidants by themselves can have very bad effects on health.  Several types of both TiO2and ZnO formulations have been shown to be genotoxic, the degree of which is dependent upon particle sizes used and which can be attenuated by other formulating factors.

    Micronization of both of these inorganic sunscreens introduces other problems, as well.  One of those problems is that micronization of both Ti and Zn particles decreases UVA protection.  Another is permeation producing toxic side effects.  This is why it’s common to combine larger and smaller particles, as well as to coat both types of particles.

    You dismiss UVA radiation as being “lower energy” as if this fact makes UVA light an unimportant matter in photoprotection and photoisomerization.  Yes, of course the longer-wave UVA light has lower photon energy.  Simple wave physics.  But this lower photon energy doesn’t mean anything about the intensity of UVA light in the wild.

    UVB light is mostly absorbed by the ozone layer.  UVA light is NOT absorbed by the ozone layer.  Of course, the amount of light reaching Earth from Sun depends upon location and season, but generally speaking, of the UV light that penetrates the Earth’s atmosphere, >95% is UVA.  Also, clouds don’t block UVA like they do with UVB, which is why it’s recommended to wear good sunscreens even on cloudy days.

    UVA light penetrates deeper into skin than does UVB light.  UVA light causes a lot of genetic and skin damage, UVA light damage is without the immediate/in situ warning signs of UVB light as it causes its damage.  This is why a person could wear a high and true SPF sunscreen and still acquire much genetic damage, because he wouldn’t be getting signs of sun damage from (imperfectly blocked) UVB, but he would be getting overdosed on UVA.  (UVA is the “silent killer.”  UVB will make the sunburned people seek shelter.)  No doubt this phenomenon is correlated with the high skin cancer rates in USA, which keep rising despite increased use of sunscreens.

    Even if you were right about easy fixes for trans-resveratrol photo-instability, which you are NOT, a 64% level remaining of tRes would not be considered as the tRes being photostable.  I think the standard is that you would need 90% remaining.  A cosmetics chemist will have to check me on the 90%, as I’m going by imprecise memory.  But I know it’s substantially higher than 75%.

    Do you even read the articles you cite?  It says right there in one of your cited articles that tRes photoisomerizes at typical rate of ~8% per minute.  What were you hoping to prove by citing that article, anyway?  (Later I will give good links.)

    And still you ignore the levels of cis-resveratrol.  To use an analogy, the importance of one side of a coin flip cannot be disregarded when looking at coin flips.  This is so basic to the inquiry that for someone to continue disregarding it after multiple reminders of its importance makes it appear as if that someone is uninterested in the matter.

    Most organic sunscreens (especially in USA antiquated formulary) degrade significantly.  This is why it has been big research and development finding photostabilizers to incorporate with the sunscreens.  There are many studies about this.  (Links will follow later.)

    SPFs on labels are notoriously incongruent with actual products’ SPFs.  Also, SPF does not consider UVA light.  And the term “broad spectrum” needs standardization.  Also, skin optics vary somewhat between persons and within person, depending upon present condition of skin/skin barrier, so you cannot say an exact percentage applies to all persons at all times under all conditions.

    No more time, but I will post links later.  I must say that in comparison to your other intelligent posts and lines of inquiry on other threads I have read, I am baffled by your last one here.




  • edited May 11
    @zwapp Yes in case of resveratrol it's fairly clear that we don't need stabilized version for sunscreen formulas, the obvious thing to do to verify this is to test it. If anyone is working on this problem, they should do that verification first. It's not unusual to see scientists missing out on obvious experiments.

    I'm aware of the phototoxicity of TiO2/ZnO, this is why you use silane coating to make extra sure it's not an issue, but even without, there's no real evidence of danger or skin cancer correlation according to SCCP: http://ec.europa.eu/health/ph_risk/committees/sccp/documents/out135_en.pdf ;

    Yes I read the articles I cite, but it's hard to respond to you when you do not cite what you refer to. Why do you think UVA matters for resveratrol when it's absorbance peak in in the UVB range? When the sunlight experiment demonstrated 36% conversion after 2 hours exposed to direct sunlight with no photoprotection, which as I explained would not be the case for in vivo application. If you do the math I'd estimate (again, needs to be measured) that more than 90% would remain in tRes form in vivo with topical application.

    Sorry if I was a bit flippant, I was hoping it would get you to pull out some references! (still hoping ;) )

    @NoHypeCosmetics thx! do share info here or through PM





     
  • @Zink An easier way would be to directly ask for references.  If I have them handy, then I will post for you.  I have learned from your posts and queries, so I would reciprocate where I can.

    At the end, I will begin by posting a paper specifically about rate of trans to cis photoisomerization of trans-resveratrol (tRes), along with a patent paper remarking upon tRes with sunscreens (and instability issues with tRes), and then a very long thesis with sections about tRes.  I don’t mean for you to read the whole thesis!  I hope we can analyze papers in a methodical manner, so I think three at a time is plenty.

    To recap (and correct me if I’m wrong on any point), I have been inquiring about (tRes) in aqueous solutions and how it isomerizes to cis-resveratrol (cRes) upon exposure to light/UV light.  My conclusion is that tRes isomerizes rapidly to cRes.  Your conclusion is that the rate of trans to cis photoisomerization is NOT rapid.  Furthermore, I think it would take more complex formulation to keep tRes active (non-degraded/not isomerized) for daytime use (with or without sunscreens), whereas you think tRes could simply be combined with sunscreens like coated TiO2.  I express concern about the effects of cRes, and you do not.

    NOTE ON RESEARCH AND READING STUDIES >>>   I find a lot of studies from the footnotes of other studies.  This is a traditional way of checking and expanding research.  Many studies I find are beyond my ready intellectual grasp, because they are outside my wheelhouse, as they speak.  I think it’s not just me and that many studies would be difficult for many cosmetics chemists, because there are a lot of highly specialized studies that CosChems need not and really should not bother themselves with.

    Incidentally, at my regular job (where I often must search the literature for our research), we are compartmentalized for good reason.  It is a waste of time and talents to try to be experts on many things, no matter how super intelligent a person is.  It is basically taboo to spend much time on something that is best deferred to another person or department or division.  In this way, we have a more efficient distributed network of brains, so to speak, instead of people getting bogged down in marginalia that is not central to their tasks at hand.  (So, if I were a CosChem, then I would find another chemist who has specialized knowledge about tRes or whatever ingredients I had questions about.  I don’t think CosChems are expected to have overly specialized knowledge about all the behaviors under all conditions of every ingredient they use.  Other scientific domains don’t work that way, anyway.)  By the way, a lot of info about tRes photoisomerization can be inferred from studies mostly about other subjects, but you must be very careful with the inferences.   <<< END OF NOTE

    I inferred from your last post that you think that tRes isn’t photoactive in UVA light.  But it is.  It is even reactive to visible light.

    You asked why I think UVA matters with tRes absorbance peak in UVB range.  I’m not a chromatography or spectroscopy expert either, but I’ll explain the basic gist that I remember.  A substance’s absorbance peak is used to find out the substance’s concentration in a sample or solution.  It’s often used in a process to determine purity of samples.  The absorbance peak of a substance only means that it is the wavelength that is absorbed the best by the substance in the solution.  So that particular wavelength of light (absorbance peak) is used to identify the substance because less light of that particular wavelength will be transmitted because, of course, it’s absorbed more by that substance.  However, just because a substance’s absorbance peak is at x/y/z nanometers/frequency/wavelength does NOT mean it doesn’t absorb or react with light at other wavelengths!

    The paper you cited was mostly about technical aspects of manipulation and measurement, and I think what you did was interpret some results too narrowly and then extrapolated narrow interpretations to wide area where they do not fit.  I did read most of it, but my eyes started to glaze over with the technicalities that weren’t related to tRes in cosmetic formulations or how tRes might photoisomerize in products with everyday wear.

    I did NOT say TiO2 causes skin cancer.  To clarify what I was trying to convey, I think the increasing skin cancer rates with sunscreens are due to the people wearing UVB protection without adequate UVA protection, and they get a false sense of no damage without the UVB overexposure warning signs, which in turn makes them stay in sun too long, which gives them UVA poisoning, which then raises the likelihood of them getting cancers.  It’s not terribly dissimilar to the phenomenon of when people have pain from injuries, then they take painkillers, which deaden the pain/warning signs, during which they overextend themselves, and the overexertion exacerbates their injuries.  The sunscreens and the painkillers don’t cause or increase the insults, yet they allow for them to be more likely to happen.

    Of course the coating helps to keep theTiO2 and ZnO from degrading, which I should have stated more clearly.  The bad effects come from when they do photo-oxidize, and the photo-oxidants/ROS systemically compromise some people.  Systemic effects can follow from ROS generation whether or not the nanoparticles permeate the skin, but of course it is worse with permeation.  And I understand that many people say that the nanoparticles do not permeate live tissue, but the fact is that traces of some of the sunscreen nanoparticles have indeed been found in the systems of people (blood, urine, breast milk) after topical application.  (They’re not eating it!)

    >>>   Now I would like your opinions on materials linked below.  How do you think it compares to the study you posted about spectrophotometric assessment of trans/cis-resveratrol ratios?  More specifically, what do you learn about tRes photoisomerization from your spectro study AND what do you learn from reading these papers I post?

    After your analysis, then please provide links that support your conclusion of tRes NOT rapidly flipping to cRes in light/UV light.  But please no esoteric studies over my brain!  I do keyword searches on papers, and if I hit too many places that are beyond my comprehension, I likely won’t read it.

     

    Resveratrol Photoisomerization

     

    Patent for Possibly Overcoming tRes Instabilities

     

    Drug Uses for tRes + Curcumin – very long; scroll down to Section 1.4 for tRes properties

    Cf. note #69 in long paper.


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