Itching After using a lotion

Hello! my name is Vanessa, am a biochemist who has taken interest in becoming a cosmetic chemist. I recently made a lotion containing the following ingredients:
•Rose H2O,
•aloe juice,
•Stearic acid,
•glycerin,
•xanthum gum
•sepiwhite,
•L ascorbic,
•E wax,
• co enzyme Q10,
•T resveratrol,
• allatoin,
•EDTA,
• phenoxyethanol
with synthetic fragrance.

I gave 7 of my friends to try it out but 1 people is complaining of itchiness after using the product. Which of these ingredients can cause that. Thank you.

Comments

  • PerryPerry Administrator, Professional Chemist
    One person? Pretty much any of those ingredients.

    But most likely phenoxyethanol, resverstrol, allantoin, rose water, aloe or fragrance. Or maybe your pH is too low.
  • vannevanne Member
    Ok noted. Thank you so much. My final PH was 4.5
  • vannevanne Member
    Hi Perry,

    Thanks for the feedback; so I am thinking of replacing rose water and aloe with just plain distilled water, replace phenoxyethanol , take out Allantoin and resveratrol  and use essential oils as fragrance.

    Also increase pH to 5. What do you think?
  • DoreenDoreen Member
    edited June 2018
    It's also concentration/dose-dependent. People can help you better if you write down the % too. I use phenoxyethanol and allantoin all the time, but I have never experienced itchiness.
    I would rather omit the L-AA, it's very unstable and a potential irritant.
    And ethereal ('essential') oils can be just as irritable as synthetic perfume oils, sometimes even more so.
    Also, your emulsion is very weak on fungi and yeast, with only phenoxy present.

    pH 4.5 is on the low side, probably because of the L-AA.
  • BelassiBelassi Member, PCF student
    How are you getting the stearic acid to combine with water? The formula does not appear to be complete. L-Resveratrol is almost insoluble.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • vannevanne Member
    @Belassi I used t resveratrol (It is liquid) and added at the end of formulation. I add the Stearic acid to the oil phrase
  • vannevanne Member
    @Belassi @Perry @Doreen I forgot to include that I added the following oils: avocado jojoba rosehip neem and sweet almond oil(s)
  • vannevanne Member
    This formed my oil phrase
  • SibechSibech Member, Professional Chemist
    @vanne The T-resveratrol you use in your whitening lotion is from making-cosmetics.com? I presume? in which case it also contains PEG-7 Glyceryl Cocoate and Propylene glycol (not that either of those should be particularly irritating).

    The "emulsifying wax" you use, could you specify which? (some of them contain SLS which can be irritating if left on the skin, even though the concentration is low some people are more susceptible.

    Regarding the ascorbic acid, you would be better off removing it or substituting with a stabilized version (Magnesium Ascorbyl Phosphate for example) as ascorbic acid is extremely unstable and will auto-oxidize into dehydroascorbic acid (with a yucky brown/orange color).

    The percentages used of the potential irritants mentioned would be beneficial to assist.
    Dabbling Formulator — Qualified Cosmetic Safety Assessor — experienced in claim substantiation & EU regulatory affairs.
  • DoreenDoreen Member
    edited June 2018
    @Sibech
    Regarding ascorbic acid. I have experienced orange discoloration due to Maillard reaction, ascorbic acid as reducing sugar -> amino acids in skin. I had orange staining of hands and bed sheets and the smell was typical of that of a cheap self tanner. It was a very concentrated (≥20%) L-AA serum. (The serum itself had no smell and no colour btw)

    Now what still isn't clear to me, and I hope you or anyone else can answer: does the Maillard reaction with L-AA trigger oxidation reactions?
    Maybe it's just psychological, but the discoloration + awful smell didn't feel like it was stimulating collagen synthesis at all. :joy:
    (p.s. I gave up topical L-AA a long time ago) ;)

    @vanne
    Ok, maybe it's best to list all the ingredients + percentage.
    But... neem oil? Yikes! 
  • SibechSibech Member, Professional Chemist
    @doreen When dissolved in water (no stabilizers) the oxidation occurs relatively slowly but after a month or two on the shelf (I had satd. L-AA) then it was suddenly orange/brownish.

    Are you sure it wasn't spray-tan in serum form? (Because dehydroascorbic acid (DHAA) was at least considered for use as a sunless tanner (patent) due to the reductive capacity of DHAA.
    Dabbling Formulator — Qualified Cosmetic Safety Assessor — experienced in claim substantiation & EU regulatory affairs.
  • SibechSibech Member, Professional Chemist
    Come to think of it, there is a chance that the discoloration of the saturated solution was due to complexing with metal ions in the water (it was for pH correction in cooking, not cosmetics).
    Dabbling Formulator — Qualified Cosmetic Safety Assessor — experienced in claim substantiation & EU regulatory affairs.
  • DoreenDoreen Member
    edited June 2018
    @Sibech
    No, there wasn't a self tanner involved. @johnb has helped me with this and concluded that a Maillard reaction has taken place, with L-AA as reducing sugar. I've searched several sites/forums and I see more women complaining about their vitamin C serum (only with L-AA, not a stable ester), whether it's an expensive brand or home made. The same complaints: the staining, the smell. @johnb explained that in these cases it was possible due to the high dose of L-AA (to have the Maillard taken place without heat, or only body warmth).

    So it might not be such a good (temporarily) whitening ingredient after all. :joy:

    p.s. You're right! DHAA as self tanner. I remember! Some brand tried to have it patented.
    But doesn't that mean that in the case of the vitamin C serums triggering Maillard reactions, that somehow there is DHAA present, one way or the other? 

    https://www.reddit.com/r/SkincareAddiction/comments/3t306y/misc_every_vitamin_c_serum_that_i_use_tends_to/

    Hey... I haven't seen this link before. I don't know if this is right, but it looks interesting:

    https://labmuffin.com/vitamin-c-can-stain-skin-avoid/

    @vanne
    I'm sorry for hijacking your post! I'll quit here and start a new thread if I have more!
  • BelassiBelassi Member, PCF student
    (only with L-AA, not a stable ester)
    Even using a very expensive form of Vitamin C, (Aprecier) I was unable to get beyond a 10-week shelf life.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • vannevanne Member
    @Sibech yes I got the t resveratrol from making cosmetics.com and the e wax from brambleberry. com.

    @Doreen no problem, we are all learning ?

    The percentages:

    Rose water:        60.5%
    Aloe :                     5%
    T resveratrol          5%
    allatoin.               0.2%
    Phenoxyethanol    1%
    fragrance.              5 drops
    E wax.                    4%

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