Urea Experiment part 2; Did the pH drift? (Patreon Exclusive 12/23)

taralee
Dec 13, 2023
3 min read

Recap on what Urea is;

Urea is part of the Natural Moisturizing Factors (NMFs). These are chemicals found in your skin that help keep your skin hydrated and moisturized.

Amino acids, hyaluronic acid, sodium PCA, lactic acid, ceramides, fatty acids, phospholipids, glycerin, saccharides, pyrrolidone, carboxylic acid, & triglycerides are all examples of natural moisturizing factors.

Purpose of Experiment;

In the experiment I am taking a look at Urea to figure out how to formulate with it properly because it has a lot of stability issues. For example, the pH likes to raise when using urea in products. So I am trying to figure out how to solve the problem.

Questions I wanted answered with the experiment;

Will the pH of the product increase overtime?
Will the addition of sodium phytate and lactic acid help the pH stability?
Will Urea cause any destabilizing of emulsion?
Does it Smell Odd?

I created 4 different lotion formulas with Urea;

5% Urea Lotion
10% Urea Lotion
5% Urea Lotion w/ Sodium Phytate as a chelating agent & lactic acid to lower the pH
10% Urea Lotion w/ Sodium Phytate as a chelating agent & lactic acid to lower the pH

I divided each formula into two different jars. One jar I put in an incubator at 35°C & the other jar I kept at room temperature 60°F - 70°F. See blog for all the formulas. So in the end I had 4 jars in the incubator and 4 jars kept at room temperature. I have let them sit since July (almost 4 months) So let’s take a look at the results.

Take a look at part 1 blog or video if you haven’t seen or read it.

Experiment Findings for Incubated (35°C) Samples;

Incubated (35°C) 5% Urea Lotion No Sodium Phytate - before pH 5.7

Emulsion - Failed
Smelled funny
Final pH - 7.8

Incubated (35°C) 10% Urea Lotion No Sodium Phytate - before pH 5.7

Emulsion - Failed even more than the 5% Urea (had more separation)
Smelled even more funny than the 5% Urea
Final pH - 8.04

Incubated (35°C) 5% Urea Lotion w/ Sodium Phytate - before pH 4.46

Emulsion - Good - sodium phytate helped with emulsion stability
Didn’t smell weird
Final pH - 8.37

Incubated (35°C) 10% Urea Lotion w/ Sodium Phytate - before pH 5.05

Emulsion - Good - sodium phytate helped with emulsion stability
Didn’t smell weird
Final pH - 8.27 - had a lower pH than the 5% Urea w/ sodium phytate

Experiment Findings for Room Temperature (60°F - 70°F) Samples;

Room Temp 5% Urea Lotion No Sodium Phytate - before pH 5.7

Emulsion - Good
Didn’t smell weird
Final pH - 7.37

Room Temp 10% Urea Lotion No Sodium Phytate - before pH 5.7

Emulsion - Good
Didn’t smell weird
Final pH - 7.7

Room Temp 5% Urea Lotion w/ Sodium Phytate - before pH 4.46

Emulsion - Good
Didn’t smell weird
Final pH - 6.9

Room Temp 10% Urea Lotion w/ Sodium Phytate - before pH 5.7

Emulsion - Good
Didn’t smell weird
Final pH - 6.85

Conclusion;

Products made with Urea will raise in pH over time at room temperature, but will raise even higher in higher temperatures like 40°C (95°F)
Using a chelating agent like sodium phytate will help keep the emulsion stable but won’t help with keeping the pH stable.
More tests need to be conducted for me to share a formula using Urea in a stable way. I have already purchased ingredients to do more tests.

Formula that produced the best results;

Phase A

10% Urea
5% Glycerin
55.45% Distilled water
0.05% Sodium Phytate

Phase B

Phase C

0.5% Liquid Germall Plus
1% Lactic Acid (wasn’t sure how much I needed to lower the pH, but I ended up using only 6 drops to lower the pH, sodium phytate raises the pH so I needed lactic acid to lower the pH)
PH was adjusted to 5.05 before it sat for 5 months.
It was kept at room temperature (60°F - 70°F) with a final pH of 6.85

I definitely plan on making a part 3 to this as I am determined to make a stable formula with Urea. I have some ideas in mind and I already have the ingredients on the way. So I’ll update you all again hopefully soon.