[Ifa]

Pharma said:

EHG is said to be active above 0.1% as booster for example for phenoxyethanol. Alone, you’d have to use it well above 1%. Meaning, EHG in a blend like Euxyl 9010 will be limit if sticking to the EU regulation which @PhilGeis mentioned. Given that it’s not too problematic even at 5% or higher (contact allergies are infrequent but we will, most likely, see more in the future due to increasing usage of EHG) and it also acts as emollient and humectant, inclusion at more that just 0.1% seems reasonable. Compared to other, similar compounds, I’d aim at 0.3-0.5% or even more but be careful because higher levels might in some cases interfere with emulsion stability and/or viscosity.

Thank you for your valuable input. 

[Ifa]

Pharma said:

Can and should are two different pairs of shoes. Can = anything you feel happy with and which doesn’t kill the product or the consumer; should = the amount needed to preserve your product sufficiently. Phenoxyethanol has a quite well defined recommended usage level. EHG has too but as a multifunctional booster, you can basically add as much as you want, just don’t go below a minimum.

What would be the ‘minimum’ for EHG?

[Ifa]

Pharma said:

HA is a polymer . High molecular weight HA does gel nicely if used at sufficient levels.

Not knowing what formulation you have makes it impossible to estimate whether or not HA might be enough for the task.

Oh, that’s great! What if it’s used to gel a niacinamide serum? Or say, a stable vitamin C ester?

[Ifa]

Pharma said:

Different in which regard? They aren’t the same chemicals but closely related… see PICTURE.

In the sense, how can I decide when to use 20, 40, 60 or 80?

[Ifa]

Perry said:

@Graillotion - Honestly, each system is different. If your formula has polysorbates in it then parabens are not your best choice. In truth, Kathon works pretty well in a wide range of formulas but then it has a problem of sensitization.  The limiting factor is the particular ingredients used in each unique formula.

Secondly, if a preservative is oil-soluble, can it be solubilised with, say, a polysorbate and used in a water-based formula?

[Ifa]

Perry said:

@Graillotion - Honestly, each system is different. If your formula has polysorbates in it then parabens are not your best choice. In truth, Kathon works pretty well in a wide range of formulas but then it has a problem of sensitization.  The limiting factor is the particular ingredients used in each unique formula.

Why are polysorbates and parabens incompatible? 

[Ifa]

Graillotion said:

Yes, there could be a small subset of consumers that have the perception that PEG is bad. You will always find a group of misguided consumers that will balk at every possible ingredient you might include.  I would balk at the fact you had extracts in your product, which I would consider ‘bug food’.  So you can not please everyone, and in the end you need to make the most stable product you can….which would be 165 based.

Yes you can pair it with Emuligin, if you can bear the sensories.

When you say “bug food”, what do you mean by it? What ingredients fall under this category of ingredients?

[Ifa]

ngarayeva001 said:

I will use a chance to throw my question too as we are lucky to have two experts here. I often combine germall plus and phenonip. The reason being, I buy ingredients from repackagers, and you can’t trust them on storing ingredients properly (I saw things like coconut oil in a ziplock bag and photosensitive materials in a transparent bottle). Also they decant ingredients million times allowing dust and bugs in. So I just assume all ingredients are compromised from day 1. Is there any reason not to do this. I figured there are no overlapping compounds in these two preservative blends so I won’t go over recommended limit. Thank you in advance @PhilGeis and @chemicalmatt

When you say “bug food”, what do you mean by it? What ingredients fall under this category of ingredients?

[Ifa]

luiscuevasii said:

Formaldehide.

We have no restrictions, so, in our country drinking water also contains formaldehide.

Less than 1$/kg, and works like a charm.

Which formaldehyde and at what percentage, specifically?

[Ifa]

ngarayeva001 said:

@emma1985, phenonip is a blend of several parabens and phenoxyethanol and needs heating to reduce possibility of some of the parabens migration to oil phase. It’s generally quite robust. Germall has some limitations: heat sensitive, not allowed under some regulations for applications on large areas, and if I am not wrong there are some limitations for spray products. Germall is great with surfactants (doesn’t mess up viscosity) and in formulations where transparency is important.

1- Can phenonip be used in purely water-based serum? If so, in what manner (since it’s oil-soluble)?
2- If used in a surfactant based system, how can it be (again) incorporated? Into the surfactant or the water-phase? Would it need heating?

TIA.

[Ifa]

Perry said:

DMDM Hydantoin

Do you use it alone or in combination with some other compound/s?

[Ifa]

I also use phenonip (0.5% in heated oil phase and 0.5% in heated water phase) in my emulsions but since it’s oil-soluble, I believe I cannot use it in water-based serums. Am I correct? Any idea on how to work around that?

[Ifa]

Perry said:

Carbomer is added to the water before adding any other ingredient.

Carbomer is generally incompatible with many ingredients, right?

[Ifa]

Sponge said:

ifamuj said:

ngarayeva001 said:

Aristoflex AVC and some very light ester.

Your best ester picks would be?

This is so subjective, it would be hard to say. What are you looking for most in an ester?

Occlusives. Something that would replace a plant oil, butter or wax and prevent trans-epidermal water loss. 

[Ifa]

ngarayeva001 said:

Aristoflex AVC and some very light ester.

Your best ester picks would be?

[Ifa]

ngarayeva001 said:

Re preservative, I was going to say, up it to 1% but then noticed you have another 0.5% in oil phase. The thing is, preservatives must protect water, which is often hard to achieve because some of them tend to migrate to oil phase. So addicting it to oil isn’t very effective strategy. 

Oh, thanks for clarifying! The supplier recommended it to be divided between the oil and water phases, though…

[Ifa]

EVchem said:

you can also always try adding a starch to help with the stickyness, but too much will feel filmy. other than that @ngarayeva001 covered a lot of good suggestions

What sort of starches would be helpful?

[Ifa]

ngarayeva001 said:

HA, pantenol, sorbitol, glycerin, betaine are out. You don’t need that many and pantenol is sticky. I don’t know if allantoin is any effective but you can keep it for claims. Definitely keep sodium lactate. Move urea to waterphase. Introduce lactic acid to buffer the ph (I think 6.2 is ideal for urea). Completely rethink your preservative system. Cut sunflower oil to 10-15%. You don’t need vitamin e, you already have BHT. Centella asiatica… it’s a fluff ingredient. Keep it if you want, but cut to an insignificant amount (less than 0.5%). You don’t really need alcohol there I would say.

Thank you so much! However, I have a few questions:

- What seems to be wrong with the preservative system?
- If I cut sunflower oil to 10-15%, what can I replace the oil phase with to keep the formula consistent and simultaneously prevent the greasy feel? The chosen emulsifier seems to work best at an oil phase of 25-30%. 

[Ifa]

Pharma said:

Phytic acid works at bit better at lower pH than EDTA .

EDTA works for Fe(III) but the instant you add a good antioxidant, you generate Fe(II) whose EDTA complexes dramatically lose stability below pH 4 and attain useless stability at pH 3.

All/most other heavy metals one wants to chelate show similarly poor chelation at such a low pH.

If memory serves me right, gluconic acid is also better at low pH.

BTW do you really need a chelate?

How do you determine whether you need a chelator or not? Doesn’t simply adding water mandate that you add one?

[Ifa]

Perry said:

Your question is too vague to provide a good answer. Whether you can incorporate alcohol or not depends on what is in your formula. 

My moisturisers tend to feel greasy so I wanted to try and see if an alcohol may help to lessen that effect. Here’s an example of the kind of face cream I have formulated in the past:

Water phase:
	Water
4	Propylene glycol
1	Glycerin
3	Sodium lactate
0.2	Disodium EDTA
0.1	Hyaluronic acid
0.1	Solagum AX
0.5	Allantoin
1	Colloidal oatmeal
1	Niacinamide
1	Panthenol
1	Sorbitol
1	Betaine
0.5	Phenonip
Oil phase
4	Montanov 68 (Cetearyl Alcohol (and) Cetearyl Glucoside)
2	Cetyl alcohol
22	Sunflower oil
1	Dimethicone
0.5	Phenonip
0.1	BHT
Cool down
2	Urea
5	Centella asiatica extract
0.5	Vitamin E
0.5	pH adjustment

Please throw some insight on how I can make it feel less greasy.

[Ifa]

ngarayeva001 said:

Speaking of denatured alcohol, I recently found out there could be different materials under this INCI. Does anyone know which types are allowed in the US and EU?

Could you name a few that you are aware of? 

[Ifa]

EVchem said:

It should work fine, EDTA has better solubility with increasing pH. Just test and see if it dissolves. 
 Phytic acid is also a chelator and it will keep your pH very low. I prefer it because it’s more biodegradable than  EDTA

Thanks a tonne! Phytic acid is harder to obtain, though.

[Ifa]

LincsChemist said:

I agree with Perry, it’s hard to beat glycerin - I’ve seen some decent data for Betaine but it was provided by a supplier so it’s to be taken with a pinch of salt. Seems to work quite nicely though and it lowers the tack if you use it in combination with glycerin.

What combo seems to work best for you?

[Ifa]

Hi Perry,

Speaking from an experience point of view, I’ve found hyaluronic acid to be much less non-greasy and much more skin-hydrating in comparison to glycerin. Hyaluronic acid is a natural component of the skin so it blends in better. I think it all comes back to experience. Sure you can use milk all over your face, but using an AHA product seems more convenient. I’m not sure if it’s the right analogy to make here but I hope you get the simple point. People just prefer one over the other based on how the ingredient makes them feel when applied topically. And God knows best. 

[Ifa]

Hi, my name’s Ifa, I’m 21 and I’m from India. Really excited after having joined this forum. I see lots of knowledge, experience and zeal with regards to formulating cosmetic formulae and it makes me so happy. Hoping to have a great time and learn lots of new stuff. Cheers. 

(PS- My background: used to study medicine then quit that to enrol into a few online courses on cosmetic formulation. I’ve received two certifications through that means so far and I also have a 1-year experience in cosmetic formulation. Whoops.)