[zaidjeber]

Simply reduce the concentration of pennyroyal oil, use 0.5% instead of 1.5%. 

[zaidjeber]

Thanks @DRBOB@VERDIENT.BIZ

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@Lainee good suggestion to use Arbutin, thanks 
@Doreen81 the serum is not sticky at all and I apply it at night only. The oiliness starts when I’m not applying the serum (the whole day), it seems that the serum has triggered the excess sebum secretion.
I will try to decrease the glycerin to 5% and dexpanthenol to 1%, but I will keep Vitamin E %, tea tree oil % & BHT %.
Regarding skin darkening, there is no warming effect and again its obvious only when I’m not applying the serum which is during the whole day.
Do you think I should add sunscreen to it? 

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Hello folks 
After trying the formula above I’ve made some changes on some of the ingredients % and added some other ingredients, here is the final formula that I have used to produce the sample:

DI water	80.2
Glycerine	10
PEG-40 HCO	4
D panthenol	2
Vitamin E	1
Xanthan gum	0.6
Allantoin	0.6
Kaffir lime fragrance	0.2
DMDM hydantoin	0.2
Sodium benzoate	0.2
Potassium sorbate	0.2
EDTA	0.2
Tea tree oil	0.2
BHT	0.2
Sodium hyaluronate	0.2
Citric acid	qs

 
I’ve been using this serum now for 3 weeks and some of my friends been using it now for a week or so, now there is good & bad news. The good news that this serum does stop acne formation and soothes the skin.

However, I noticed that my face become oily and the skin appears darker by 1 shade (sometimes I feel its not dark, but rather reddish in color), what was interesting that my friends gave me the same feed back.

Now my questions are:

1. how to stop the oily skin problem? do you think I should include polysorbate-20? does it help? (its similar to PEG-40 HCO)

2. why this serum causing darkening of the skin? is it oxidation or irritation?

Thanks in Advance…

[zaidjeber]

Thanks @DRBOB@VERDIENT.BIZ <span>:smile:</span> -)

[zaidjeber]

@kamalkm thanks

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@DRBOB@VERDIENT.BIZ if the temp is 50 Celsius for 4 weeks, what about RH%?

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I cannot open the video/link!

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It also depends on the clay % in your formula. Its well known that fragrances adsorb to clay, in other words you need to add higher fragrance %

[zaidjeber]

@Lainee use aluminum chlorohydrate 15%

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@Lainee I never heard of AZP/ aluminum zirconium pentachlorohydrate, but i know that aluminium zirconium tetrachlorohydrex gly is being used in deodorants. However, the latter does stain the cloths yellowish and causing stiffening of underarm part of the cloths (in my personal experience).
@Lainee did you face the same problems with AZP? 

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@Chemist79 try adding some xanthan gum, it might work! & lets see what others think about this? 

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@Belassi you are right pH is mostly for water base liquids/ aqueous solutions where the hydrogen ions can be released into the water.

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@DRBOB@VERDIENT.BIZ thank you so much

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@DRBOB@VERDIENT.BIZ what I understood from my readings over the internet that one freeze/ thaw cycle goes like this:
24 hrs freeze at -10C followed by 24 hrs thaw at RT, followed by 24 hrs at 45C, then 24 hrs at RT, so one freeze/ thaw cycle takes 4 days, that means 6 cycles of freeze/ thaw will take 24 days.

Now my questions are:
1. is what I have read is the “ideal” freeze/ thaw cycle? 
2. is what you have suggested is the practical freeze/ thaw cycle that you follow in your practice?

[zaidjeber]

@DRBOB@VERDIENT.BIZ if I may ask, how many hours is one freeze/ thaw cycle?

[zaidjeber]

Thanks @Doreen81 for the clarification and for the patent link  

[zaidjeber]

@Doreen81 Maillard reaction is non-enzymatic reaction (doesn’t need a catalyst), although, high pH accelerates the reaction/ browning discoloration.
Now my question is: do all skin care products that contain Vitamin C do have this browning discoloration effect on the skin or not? if not then why?
 

[zaidjeber]

Shocking to see Neomycin & Corticosteroids as allergens! usually both are API in variety of skin ointments and creams. More shocking its coming from contact dermatitis society! 

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Thanks @Doreen81 <span>:smile:</span>

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@Doreen81 that is why i posted my formula here to get some opinions and insights. Allantoin 1% came from the supplier website “Use level: 0.1% to 2.0%” and vitamin E as Tocopheryl Acetate “Use level: 0.50% to 5.0%”
I’m aware of that discussion and the figure that you have posted there, do you think if I add BHT can help in preventing vitamin E oxidation? 
I wish that @johnb can give us his opinion on that. 

[zaidjeber]

Thanks @Belassi ill use PEG-40 HCO at 3.5% 

[zaidjeber]

I can source these emulsifiers myristic acid, stearic acid, polysorbate 20, ceteareth 25 & PEG-40 HCO. Which do you think is more suitable to use in facial serum and at what percentage? 

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@mikethair my bad, I forget to mention that I only have those ingredients available (have to scout for suitable emulsifier) and I want to package the serum in spray bottle to ease its use. 

[zaidjeber]

@chickenskin I don’t want it to be “shake before use” serum, therefore, ill follow @ozgirl advice to include emulsifier.
Thanks a lot @chickenskin & @ozgirl <span>:smile:</span>