How to Calculate Ingredient Ratios when formulating skincare?

Calculating skincare ingredients requires a structured approach that considers the components, proportions, and interactions involved in creating effective formulations. This process is crucial to ensure the final product achieves the desired efficacy and adheres to safety standards.

Water as a Base  

Water typically constitutes 55% to 80% of most skincare formulations. It serves as a solvent and carrier, enabling other ingredients to be absorbed effectively into the skin (Moldovan et al., 2017).  

Active Ingredients 

Active ingredients deliver targeted benefits such as hydration, anti-aging effects, or sun protection. For example, formulations might include 3–5% herbal extracts or 15–20% sun-blocking agents like avobenzone (National Academies of Sciences, Engineering, and Medicine 2022).

Emollients and Oils 

Emollients and oils are used to moisturize and soften the skin. Their proportions can vary significantly, with some formulations containing up to 20% oil-based agents (Tomokazu & Hidehiro, 2014).

Formulations are often expressed in mass percentages for simplicity. For instance, in a 100-gram product, a 5% concentration of an active ingredient would equate to 5 grams (Tomokazu & Hidehiro, 2014).

Ingredient Interaction and Stability  

Compatibility Testing  

Evaluating how different ingredients interact is vital. For example, some herbal extracts may enhance or diminish the efficacy of other active ingredients, requiring careful adjustment of their ratios (Panico et al., 2019).

Preservatives and Stabilizers 

These ingredients play a critical role in extending the shelf life of skincare products. Preservative ratios typically range from 0.5% to 1.5%, depending on the water content of the formulation and its susceptibility to microbial growth (Varvaresou et al., 2009).  

The formulation process often involves various adjustments based on results from stability testing and consumer feedback. This ensures the final product meets both efficacy and sensory expectations.

Conclusion

In conclusion, calculating ingredient ratios for skincare formulations requires a precise and methodical approach, and by understanding the roles of key ingredients, conducting compatibility tests, formulators can create effective, and safe skincare products.

References

Moldovan M, Lahmar A, Bogdan C, Părăuan S, Tomuţă I, Crişan M. Formulation and 

evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid. Clujul Med. 2017;90(2):212-219. doi: 10.15386/cjmed-668. Epub 2017 Apr 25. PMID: 28559707; PMCID: PMC5433575.

National Academies of Sciences, Engineering, and Medicine 2022. Review of Fate,

Exposure, and Effects of Sunscreens in Aquatic Environments and Implications

for Sunscreen Usage and Human Health. Washington, DC: The National Academies

Press. https://doi.org/10.17226/26381.

Panico A, Serio F, Bagordo F, Grassi T, Idolo A, DE Giorgi M, Guido M, Congedo M, DE Donno 

A. Skin safety and health prevention: an overview of chemicals in cosmetic products. J Prev Med Hyg. 2019 Mar 29;60(1):E50-E57. doi: 10.15167/2421-4248/jpmh2019.60.1.1080. PMID: 31041411; PMCID: PMC6477564.

Tomokazu, Yoshida., Hidehiro, Nagasawa. (2014). Skin cosmetic composition

Varvaresou, Athanasia & Papageorgiou, Spyridon & Tsirivas, E & Protopapa, Evangelia & 

Kintziou, H & Kefala, Vasiliki & Demetzos, Costas. (2009). Self-preserving cosmetics. International journal of cosmetic science. 31. 163-75. 10.1111/j.1468-2494.2009.00492.x.