Understanding EHT Concentration in Sunscreen

Thank you for your question regarding your 50g sunscreen formulation using Ethylhexyl Triazone (EHT) and LipidSoft.

The percentage of an ingredient in a cosmetic formulation typically refers to the weight percentage of the ingredient itself relative to the total weight of the final product.

Therefore, if you want to make a 50g sunscreen with 5% Ethylhexyl Triazone:

• The amount of Ethylhexyl Triazone powder needed is 5% of 50g.
• Calculation: 0.05 * 50g = 2.5g of Ethylhexyl Triazone powder.

Your calculation (0.11g EHT powder + 2.39g LipidSoft = 2.5g solution) seems to be based on dissolving a small amount of EHT in LipidSoft according to its solubility limit, but this 2.5g solution is not 5% of your total 50g formula. It represents only 2.5g out of the 50g total. The percentage of EHT powder in your final 50g formula using your calculation would be (0.11g / 50g) * 100% = 0.22%, which is much lower than your target of 5%.

Regarding dissolving Ethylhexyl Triazone in LipidSoft, the product information states that Ethylhexyl Triazone is soluble up to 4.4% in 100% LipidSoft. This means you can dissolve a maximum of 4.4g of EHT powder in 100g of LipidSoft.

To dissolve the required 2.5g of Ethylhexyl Triazone powder for your 50g formula (at 5% concentration), you would theoretically need approximately (100g LipidSoft / 4.4g EHT) * 2.5g EHT ≈ 56.82g of LipidSoft if LipidSoft is the only solvent used for EHT.

Since your total formula weight is 50g, and you need 2.5g of EHT powder, you only have 47.5g remaining for all other ingredients, including the solvent(s) for EHT. As 47.5g is less than the approximately 56.82g of LipidSoft needed to dissolve 2.5g EHT, it indicates that using only LipidSoft as the solvent for 5% Ethylhexyl Triazone in a 50g formula is not feasible based on its solubility limit.

You may need to consider using a blend of oil phase ingredients that offers higher solubility for Ethylhexyl Triazone (such as OMC, where solubility is up to 14%) or adjust the concentration of Ethylhexyl Triazone in your formula if you intend to use LipidSoft as the primary solvent.

In summary, 5% EHT in a 50g formula means you need 2.5g of EHT powder. Your proposed calculation does not result in 5% EHT in the final 50g product, and dissolving 2.5g of EHT solely in LipidSoft within a 50g formula is not possible due to solubility limitations.