Consists of Propylene Glycol, 1,2-Hexanediol, Hydroxyacetophenone , which are high-efficiency preservatives but gentle, non-irritating to the skin, free of harmful substances, and free of carcinogens. It also has the characteristics of a humectant, helping to retain moisture for the skin, and is not considered a preservative according to the FDA's regulations.
Mild Preserved HD™ (Preservative-Free) consists of Propylene Glycol, 1,2-Hexanediol, Hydroxyacetophenone , which is a high-performance preservative but gentle, does not irritate the skin, does not contain any harmful substances, and is not carcinogenic. It also has the characteristics of a humectant, helping to retain moisture for the skin, and is not considered a preservative according to the requirements of the FDA.
1. Functional benefits for cosmetic chemists
| component |
Key Features |
Legal/Safety Status |
| Propylene Glycol |
Moisturizing, solvent, viscosity adjuster; antibacterial when > 12 % |
CIR guarantees safety up to 50% |
| 1,2-Hexanediol |
Broad spectrum antimicrobial & soft to the touch; low irritation |
Unlimited worldwide use |
| Hydroxyacetophenone |
Antioxidants, reduce irritation & increase preservative efficiency |
Accepted by ECOCERT/COSMOS |
Synergy: Checker-board test shows that the inhibitory HD content is reduced ≥ 4 times when mixed with PG and HAP ⇒ Only ≈ 1 % can pass the Challenge Test (ISO 11930) even without the preservatives specified in Annex V.
2. Antimicrobial efficacy (approximate MIC of the mixture)
| Standard microorganisms |
MIC Ingredients (ppm) |
Recommended formula concentration |
| Staphylococcus aureus |
3000 – 5000 |
0.3 – 0.5 % |
| Escherichia coli |
5000 – 8000 |
0.5 – 0.8 % |
| Pseudomonas aeruginosa |
6000 – 10000 |
0.6 – 1.0 % |
| Candida albicans |
2 500 – 4 000 |
0.25 – 0.4 % |
| Aspergillus brasiliensis |
4000 – 6000 |
0.4 – 0.6 % |
3. Guidelines for use in formulas
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Addition step – Add to aqueous phase or cool to room temperature (< 45 °C) for emulsions.
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pH Formula – Works best at pH 4.5–6.5 but remains effective up to pH 8.
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Clarity – 100% water soluble, does not cloud the sulfate-free shampoo.
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Electrolytes – Tolerate up to 3% NaCl, avoid divalent salts > 5%.
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Effect on viscosity – PG/HD may reduce viscosity; compensate with 0.2–0.3 % xanthan gum or 0.3 % acrylate-C10-30.
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Compatibility – Compatible with all types of surfactants, silicones, natural gums, thickeners, sunscreens, etc.
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Processing – Non-volatile, stainless steel tanks are available, no need to pull the vacuum head of the tank.
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Labeling – Indicate INCI accordingly. Avoid words like “Phenoxyethanol” or “Paraben”.
4. Examples of usage quantities by product type
| Product type |
Volume (% w/w) |
note |
| Micellar water/toner |
0.80 |
Cools down to 5 °C |
| Liquid lotion |
0.90 |
Add < 40 °C, adjust pH 5.5. |
| O/W Cream |
1.00 |
Passed ISO 11930 Criteria B |
| Baby shampoo |
0.75 |
Maintains clarity in SLES 12% + CAPB |
| Wet wipe lotion |
1.20 |
Increased safety against P. aeruginosa |
| Waterless balm (a_w < 0.6) |
0.40 |
Add booster only |
5. Legal & Safety Information
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All three substances have CIR/SCCS reports confirming safety, with no ceiling % limit.
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Not classified as an allergen (HRIPT 200 people, 15% did not experience any symptoms)
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Oral LD₅₀ (rat): PG > 20 g/kg, HD > 5 g/kg, HAP > 5 g/kg.
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REACH compliant, no CMR status or nanoparticles
6. Key selling points
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Complete preservative in one step – no need to mix bacteria/fungi.
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Beautiful label – “No preservatives listed”, suitable for natural/vegan cosmetics
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Highly flexible – Can be used with high water gels, high oil emulsions, cleaning products and wet wipes without losing clarity.
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Gentle on skin – HD C6 chain provides low irritation, HAP helps to soothe the skin.
Usage: For any type of product.
Mixing method: Can withstand heat up to 80 degrees for no more than 5 minutes and can be used in cosmetic formulas with pH 3-8.
Usage rate: 0.5-1.2%
Product characteristics: Clear liquid, colorless or light yellow.
Solubility: Soluble in water.
Storage: Can be stored at room temperature, but close the bottle tightly and keep away from sunlight or heat. The product has a shelf life of at least 2 years.
INCI Name : Propylene Glycol, 1,2-Hexanediol, Hydroxyacetophenone
*Before producing finished cosmetics for sale, formula developers or manufacturers must always perform challenge tests to determine the efficacy and suitability of preservatives for the cosmetic formula before production and sale.*
