I will typically address the positive, neutral, and negative ingredients in a product through writing. Then, I will do the same for the packaging. At the bottom of each review will be a score summarizing my opinion on said product. Here is the formula that I will use to calculate said score.
- The Total Ingredient Score (TIS) will consist of a Positive Ingredient Score (PIS) and a Negative Ingredient Score (NIS).
- The PIS will be given an arbitrary number (out of ten) by me, because positive ingredients work together to benefit the skin. Combined with the fact that because much effort is required to repair and protect the skin, it would be unrealistic of me to give individualized and separate scores to each positive ingredient.
- The NIS on the other hand, can be more easily individualized because one negative ingredient will harm the skin no matter what. Furthermore, it requires far less effort for an ingredient to damage the skin. Therefore, each Negative Ingredient (NS) will subtract a single point (out of ten), multiplied by the amount present, which will be represented by an Magnitude of Harm Score (MHS):
- A score of three will mean that HIGH amounts of an ingredient are present.
- A score of two will mean that MODERATE amounts of an ingredient are present.
- A score of one will mean that LOW amounts of an ingredient are present.
- After both quantities (the PIS and NIS) have been calculated, the NIS will be subtracted from the PIS, which will result in the Total Ingredient Score (TIS).
- Now, the Total Packaging Score (TPS) will be given a number (out of three), based on the following conditions:
- A score of three will mean that either PUMP or TUBE packaging is employed.
- A score of two will mean that DROPPER packaging is employed.
- A score one will mean that JAR packaging is employed.
- Then, the TPS will be multiplied by the Weighted Packaging Constant (WPC) which will ALWAYS be 1/3. This will transform the WPS to the Weighted Total Packaging Score (WTPS).
- Then, the TIS will be multiplied by the Weighted Ingredient Constant (WIC) which will ALWAYS be 2/3. This will transform the WIS to the Weighted Total Ingredient Score (WTIS).
- Then, the WTIS will be added to the WTPS for the Final Score (FS).
- Then, the FS which will be multiplied by 100%, resulting in the Percentage Score (PS).
- Then, depending on whether or not the product contains water, the PS will be multiplied by either 1.0 (water) or .75 (no water) since aqueous formulations are almost always more effective at delivery ingredients into the skin than non-aqueous formulations. The explanation of this is covered in the relevant Ideal Routine post.
- Finally, the resulting Alpha Score (AS) is summarized by the following table:
- 100% > A+ > 97%, 97% > A > 93%, 93 > A- > 90%
- 90% > B+ > 87%, 87% > B > 83%, 83 > B- > 80%
- 80% > C+ > 77%, 77% > C > 73%, 73 > C- > 70%
- 70% > D+ > 67%, 67% > D > 63%, 63 > D- > 60%
- 60% > F+ > 57%, 57% > F> 53%, 53 > F-
Let’s do an example, just so everything is clear.
- A product is given a PIS of 9/10.
- The ingredients are air-sensitive.
- There are 2 negative ingredients.
- One is present in MODERATE amounts.
- The other is present in LOW amounts.
- The product employs DROPPER packaging.
- The product does NOT contain water.
Here is the math:
PS = [[[PIS – [(NI1 x MHS1) + (NI2 x MHS2)]] x WIC] + [TPS x WPC]] x 100%
PS = [[[PIS – [(1/10 x 2/3) + (1/10 x 1/3)]] x WIC] + [2/3 x 1/3]] x 100%
PS = [[[PIS – [2/30 + 1/30]] x WIC] + [2/3 x 1/3]] x 100%
PS = [[[9/10 – 3/30] x 2/3] + 2/9] x 100%
PS = [[[27/30 – 3/30] x 2/3] + 2/9] x 100%
PS = [[24/30 x 2/3] + 2/9] x 100%
PS = [48/90 + 20/90] x 100%
PS = 68/90 x 100%
PS = .755 x 100%
PS = 75.5% x .75
PS = 56.7%
AS = F
Please note that there will be exceptions to these rules. For example, if a product packaged in a jar doesn’t contain any ingredients that are air-sensitive, but does utilize preservatives, then the TWPS would automatically be given full marks. Furthermore, if the purpose and focus of a product is barrier protection, rather than ingredient penetration, then the (no water) penalty would automatically negated, regardless of whether or not the product actually contains water.
As you can see by my score formula, negative ingredients, improper packaging, and a lack of water can seriously hurt an otherwise excellent formulation a great deal. It’s because, like I said above, that it’s a lot easier to hurt or damage your skin, than to repair or maintain it. Think of the skin as a giant well-oiled machine. It’s massive and works independently. The good ingredients serve as the parts necessary to maintain the machine, such as quality oil for the cogs and quality wires for the cables. The bad ingredients serve as poor quality oils and cogs that over time, will weaken the machine’s ability to produce effective products. Furthermore, the machine itself will begin to deteriorate more rapidly. Poor packaging translates to squashed and trodden boxes of wires that otherwise would have been pristine. Now they are bent out of shape and/or have begun to rust due to premature exposure to the air. Therefore, the machine would need replacements more frequently than if these wires had arrived and remained in good condition. Finally, a lack of water is like not having a fast enough truck to deliver the the boxes. Keep in mind that this is a metaphor, not an exact comparison.
Finally, keep in mind that there are several limitations to ingredient-based product reviews.
One, is that I can only evaluate the amounts present based on how high or low its position is on the ingredient list. So when I say that “high amounts” of an ingredient are present, that could actually translate to 10% or 1% present. There’s no way to know for sure.
Two, is that I can’t tell how deeply a product will penetrate into the skin. Yes, I can make evaluations based on an ingredient’s chemical properties, vehicle type, and known penetration enhancers present, but still they are just approximations. Furthermore, different skin types will have varying levels of epidermal and dermal thicknesses, which in turn will affect penetration and efficacy.
For a detailed discussion of the relationships between price, quality, and quantity, click here.
Make sure to check the “Ingredient Profiles (IPs)” page for more information on specific ingredients.
Hello! I’m actually about to start a blog soon and was looking for the best way to do product reviews. What’s your source or reference for the product review rubric? Thanks! 🙂
I’m not sure I really understand your question. Is there something specific about my rubric that’s confusing?
But I’ll try to answer your questions as best as I can… There were not sources or references. I just made this rubric up as I saw fit.
Please let me know if you need further assistance.