How much is too much? How to select the right concentration of cosmetic ...

I hope you've enjoyed part I of this blog post about how to select/ find the right concentration of cosmetic ingredients in each formulation and the golden rule of:

As little as possible

As much as needed

To help you select the right concentration of your cosmetic ingredients and to avoid overdosage of certain ingredients (overdosage is much worse than the underdosage) I'll list the important factors that should be considered when formulating a cosmetic product. Most of these factors are interrelated and interconnected and except for the first factor which should be the alpha and omega of EVERY cosmetic formulation, there is no certain priority in the order of importance of these factors and you may prioritize one factor over the other according to your product concept and brand policy.

1- SAFETY

Without any doubt, safety is the alpha and omega of each cosmetic formulation. It comes before everything else and affects:

• formulation
• manufacturing process
• shelf-life
• packaging
• labeling
• instruction for use

just to name a few factors. Safety should even come prior to efficacy.

In the EU and many other parts of the world who follow EU legislations as a guideline, each cosmetic product should be assessed by a professional and trained safety assessor before entering the market (this includes products that are manufactured outside and are imported to the EU from non-EU countries). Safety assessors are usually toxicologists and evaluate the safety of each product based on:

• the formulation: toxicological data of each single ingredient and the possible interaction between different ingredients in a given formulation
• the packaging
• the shelf-life of the product (based on stability testing results)
• the consumer (baby, adults, elderly?), intact skin, sun damaged skin? etc.
• body parts: apart from the fact that facial skin and eye-contour are more sensitive than the palms of the hands or foot sole, from a toxicological point of view there is a huge difference whether the product is applied over the face, over the body or on the lips (exposure). Another difference (for certain ingredients including most essential oils) is whether the skin would be exposed to sun and UV-radiation or not
• application frequency: is the product applied once per day (such as a night cream) or several times per day (such as a lip balm, a hand cream or a body splash). This affects the exposure of the skin to each ingredient and hence the max. dosage for many ingredients

Do not underestimate (or overestimate?) the safety of "natural" ingredients and think that since you are formulating only and only with plant based and mineral ingredients your product is automatically safe for every application and every cosnumer. Look at the contraindications and possible hazards when using essential oils for example or the carcinogenicity and toxicity of certain plant ingredients: one of the most prominent examples is "alkanna tinctoria" with its amazing colour. It is a very common colourant in natural soaps creating different shades of red to purple. It is considered quite safe in a soap for example but you can not use it in a lip balm or lipstick without safety considerations (it is hepatotoxic and carcinogen).

2- The price

In the mainstream and corporate industry the price is the most important factor after safety. Every cent is important and is considered before a decision is made. Although most of the amazing Indie and artisanal formulators I know are not profit oriented (their main and first purpose is to help people), a business is not a business if it does not throw profit. You may slide the price to the bottom of your list but still you need to consider the price of each ingredient as you decide about its application dosage.

3- The packaging

The packaging not only affects the safety of the product and the exposure rate (there is a difference whether you apply a product from a spray pump or from a jar with your fingertips or from a bottle with a cotton pad), it affects the efficacy of certain ingredients and their minimum required dosage. Consider a certain product being offered in a transparent bottle to one in a wide mouth jar and one in an opaque airless bottle. These products are affected by light, oxygen, moisture and possible external contaminants (wet and dirty finger of the consumer) at different rates and hence the min. required concentration for preservatives and antioxidants would be different for each packaging even for the same product.

All factors remaining the same, there is still a difference whether the product is offered in a 50 ml bottle or a 500 ml bottle. The packaging size affects the duration of the time the product is in use after first opening and again the required dosage of certain ingredients such as preservatives and antioxidants.

Packaging (and the way of application) may as well affect the sensory of the product and hence the min. or max. dosage of certain ingredients. Have you every tried to apply a certain toner formulation from spray bottle vs. a screw cap bottle?

4- The shelf-life

The shelf-life is affected by the packaging and formulation and vice versa. The concentration of preservatives, anti-oxidants and certain active ingredients might vary depending on the shelf-life and period after opening (PAO).

5- The body part

This is not only important because of exposure rate and safety considerations, it affects the sensory of the product. A certain emulsion with high concentrations of butters migh be quite appealing on the foot soles but quite annoying when applied over facial skin.

Another factor to be considered is the possible interaction of certain ingredients with the mucous membrane. Apply a lotion with peppermint oil over your arm or your tired foot soles after a long day standing on high heals and you'll love it, apply the same emulsion around your eyes (DON'T DO THIS) and you'll have a worse reaction than peeling 10 kg onions.

6- Colour,  scent and skin feel

The impact of each ingredient on the colour and scent of the final product is probably the most important factor after product safety.

Consider neem oil for example. As magical as it is, its scent is quite overwhelming. Apply it at a low dosage and you'll profit from the benefits and could be able to mask the scent with your essential oils. Apply it at a higher dosage and you'll have a product that nobody wants to use (no matter how effective it is)

Another example is yucca extract and sunflower lecithin (with a much darker colour compared to soy lecithin). Apply them at a low dosage and they are effective and appealing. Apply them at a high dosage and the colour is a killer.

This is the same for the skin feel of most ingredients (specially oils and butters). Most of them are quite appealing at a certain concentration and in a well-balanced combination but might feel quite sticky and greasy at a higher concentration

7- Stability

Overdosage or underdosage of certain ingredients might affect the stability of your product. Preservatives and emulsifiers have a certain minimum required concentration in each formulation/packaging. Other ingredients (most active ingredients) might not only be unsafe when overdosed, they might kick the stability of the finished product.

Consider these factors when planning a new project and you'll have a safe, stable, effective and appealing product. Send me your comments if there are other factors that I've forgotten to mention.

BeHappy and have fun