If you have some experience with formulating, you must have come across formulations that turn brown over time. They are especially evident with lotions and creams, but can also be seen in other kinds of formulations. These happen primarily due to natural materials like butters, oils, essential oils, herbs, etc. There are a few tweaks you can make to your formula to prevent this from happening, or at the very least mitigate its effects.
1. Switch to a more stable variant
If you have a natural oil with a short shelf-life, like Grape seed oil, you can switch to something more stable like jojoba, or better yet, a natural ester like Coco Caprylate/Caprate.
2. Add antioxidant protection for unstable products
Oxidation is the death of all-natural oils! Eventually, all-natural oils degrade – some faster than others. Your job as a formulator is to delay that deterioration during the shelf life of your oils. The addition of anti-oxidants like Mixed Tocopherol (the most potent kind of tocopherol. It is also naturally derived) can save your formula from an early onset of deterioration. Don’t be tempted to add too much though – too much of a good thing in this case is a bad thing. Derivatives like tocopherol acetate cannot protect your formula.
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Another alternative mixed tocopherol is Rosemary CO2 extract. This is a super anti-oxidant and a little goes a long way. It is also naturally derived with an exceptional purity level.
3. Protect Water and oil Soluble Actives that Oxidize, Yellow and Brown over time
Water-Soluble Actives: Certain actives tend to oxidize from exposure to the air. Actives like Kojic acid, etc. Use Activ-Shield (INCI: Sodium Metabisulfite) to protect those actives at no more than 0.2%. At 0.2% or less in cosmetics, when used as a preservative, the CIR considers Sodium Metabisulfite as GRAS (Generally Regarded As Safe). This is also effective with vitamin C derivatives that tend to degrade with accompanying discolouration under certain conditions.
Oil-Soluble Actives: Active Lipid-Shield is a powerful synthetic antioxidant that protects actives from yellowing and oxidizing. It also helps protect the skin from oxidative damage and signs of photoaging. Add Active-Shield Pro to your formula if you need consistency and stability with photo-sensitive actives. Actives like Retinyl Palmitate, Symwhite, etc
Activ-Shield is best for water-soluble actives, and Active Lipid-Shield is best for oil-soluble actives.
4. Protect From Metal Ion Interference
If your water is not deionized, it may contain ions even if it is free from microbial contamination. Metal ions present in water, as well as botanical extracts, can interfere with other ingredients, including your preservative system! This can make your formulation unstable. If you use any kind of filtered water that is not deionized, or if you have botanical actives present in your formula, I recommend you add a chelating agent. Chelating agents are raw materials that bind themselves to metal ions and prevent them from interfering with the function and performance of formulas. Unless a raw material says otherwise, add it. EDTA is just right for that. If you want a raw material with a more sustainable profile, go for Sodium Phytate – a natural and biodegradable alternative.
5. Protect products in transparent packaging
The best way to protect your product from light is to use dark packaging. However, even with materials that do not readily degrade on exposure to sunlight, they could eventually deteriorate. UV rays can be harsh on both living and non-living things! So, the rule is simple, to keep your product from degrading when used in transparent packaging, add a raw material that protects it from UV rays. Tinoquard Q is one such raw material that is ideal for formulas in transparent packaging.
6. Protect your formula from a drastic drift in pH
It is unknown to many formulators, that the final pH your formula was adjusted to is not usually the pH it has at the end of its shelf life. A formulation pH is dynamic, and can be influenced by the features of your formula; some more so than others. The addition of what is known as a buffer can keep your formula’s pH in check. For example, Sodium Citrate will help keep your formula’s pH stable between 3.0 – 6.2. Another, Sodium Lactate, is effective between 3.5 – 10.0. If you want a tighter restriction, play with Sodium Citrate.
7. Combine different protective measures
Based on what your formula needs, you can combine any of the above solutions to prevent deterioration over time and maximize the shelf life of your formulas. It is still your responsibility to test your formulation – every formula is different. As someone once said “It should…” is not the same as “it does”; something may look good in theory but, the results come out different! Truly, every formula is different, so every formula should be checked for stability. See our simple guide below. Conduct a careful study of all ingredients in your formula and make educated decisions.
- In the presence of a natural extract, add EDTA or sodium phytate.
- In the presence of natural oil, add mixed tocopherol or Rosemary CO2 (oleoresin) extract.
- If your product’s packaging is transparent, add Tinoguard Q
- If you have an unstable ingredient, add Activ-Shield
- If your formula is particularly sensitive to a pH drift, add Sodium Citrate
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