Last Active


  • On the chemistry: a lot of energy is released in that reaction, so it is not practical to reverse it. Sodium chloride is an extremely stable compound. According to the Wikipedia page, HCl is manufactured on an industrial scale directly from hydroge…
  • What about Hydroxypropyl Cyclodextrin? Would this have any effect in a stick deodorant? (Hydroxypropyl-beta-cyclodextrin is a cyclic polysaccharide that is the deodorant ingredient in Febreeze, which traps VOCs within the ring structure). With resp…
  • Ethanol and IPA reduce the surface tension of water, though I'm not sure the magnitude of effect if you already have surfactants. Or if it'll inhibit soaping in an emulsion. Anecdotally, ethanol or IPA reduces the foaming of a dilute dawn dish dete…
  • Does anyone have bad experiences with ethylhexylglycerin and know it to be the cause? There's another product I know about that caused dermatitis and I suspect it was that ingredient.
  • Found PEG-8 Dimethicone: Another thread:
  • The Farm Bill removed all hemp-derived products, including CBD, from the Controlled Substances Act, which criminalizes the possession of drugs. In essence, this means that CBD is legal if it comes from hemp, but not if it comes from cannabis (mariju…
  • I have lotioncrafter 90% lactic acid. I mixed 5% and 10% solutions by mass of lactate to water. Mixing 5% lactate to water: 2.50g lactate and 47.5g water. With a 90% lactate solution to start with, I mixed 2.778g lactate(90) and 47.222g additional d…
  • Could you source goat milk fat instead of goat milk? Then it would mix easily and you've included the most important part. Could you rehydrate goat milk with water and/or ethanol and then evaporate it out at low heat? Though the ethanol could curdl…
  • That seems like a lot of sodium chloride. Solubility at 25C is only 360g to 1000g water. So 3 lb NaCl to 8.33 lb water (1 gal). Are you trying to saturate a water solution, or are you doing something else like a suspension?
  • (Quote) 
@MurtazaHakim Rereading your ingredients list, I see I misread your concentration: you're using 20% of a 20% solution to give 4% final. Are you formulating an antiseptic handwash?
  • Please thoroughly read the Cosmetic Ingredient Review safety assessments for the ingredients you are using. PR92.pdf from 1993 has the toxicology and animal testing data. You are using two orders of magnitude more Chlorhexidine Digluconate than you …
  • (Quote) 
Oh I'm sorry! 😛 I didn't realize your question wasn't serious. It's hard to tell online...
  • (Quote) 
Most solutions do not need to be iso-osmolar with human blood (~300 mOsm/L). Some should be, such as water-based personal lubricant. Other products could benefit from being iso-osmolar, such as a gentle face wash.My guess is that a …
  • (Quote) 
See this comment by Perry.pH is related to the concentration of H+ (aqueous) ions in solution. They are actually H30+ ions (hydronium ions) because the hydrogen from the solute is too unstable alone. Free Cl- (aq) ions will be equi…
  • @Abdullah Thanks for the link to prior discussion. Looks like buying 10% and diluting to 1% stock would be acceptable.
  • Head & Shoulders has HCl.
  • @Microformulation I really appreciate your advice, but I wish you would elaborate more on why it's a bad idea. Let me try to make your case, because I think I understand where you're coming from. * HCl in a manufacturing setting would be sourcing th…
  • (Quote) If I were in your position, I am sure I would feel 
the same way about another person asking this question—I would have to assume 
they would hurt themself or somebody else. I appreciate the warning, and I admit I am naive, b…
  • (Quote) * HCl is the most efficient acid for pH adjustment and I would like to have HCl and NaOH readily available for their own sake. I like efficiency. * I suspect some are sensitive to citrate in the range ≥0.2% and want the option of eliminatin…
  • @Microformulation thanks for those links!
  • Was the serial dilution test performed on agar plates but the suspension test performed in vials? I see the microbe concentration was equalized to 10 cfu/ml. If on culture plates, could the medium be providing some level of structural protection fr…
  • (Quote) 

Considering citric acid is cheap and you already have it in your formula, have you considered chelating with it? Would have to adjust pH down, but it sounds possible. And IDK how it would fare compared to dEDTA.
  • @Hanson25 I don't know really know anything about surfactant interactions, but the sodium cocoamphoacecate may be it because it's amphoteric and you say the viscosity is changing with pH.…
  • What's your list of INCI ingredients?
  • (On second thought that may actually be the NaBenz)
  • @Abdullah Warning that sodium phytate will probably need more pH adjustment then disodium EDTA. At 0.05% NaPhy, 0.35% NaBenz, I needed 0.20% citrate to get to pH 4.4 from 10.9
  • Thanks Phil and Mark for the advice! 
Btw I just realized my usage of ppm at the top is nonstandard. I thought ppm was on a molar basis (ratio of molecules), but it is conventionally calculated by mass.
  • (Quote) 
Hi again @Abdullah 😆 

I can't answer the chemistry question, but I have found a reference to the fact that each EDTA has their own pH at a standard 5% aqueous solution. They referenced the British Pharmacopoiea, wh…
  • (Quote) 

When I contacted Modernist Pantry, they said that their Xanthan and Konjac produce a transparent solution at 0.5% (though I have not verified it). I think Konjac has a tendency to be somewhat fishy, as I recall some people …
  • (Quote) 

If true I am curious if that sort of inflammation could also be systemically bad for you, like the link between gum disease and heart disease. Skin surface is massive.

Latest Q&A session

Forum Instructions

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

30DaysToBecomeABetterCosmeticChemist_cover (1)