Optiphen Plus Preservative

• INCI Name: Phenoxyethanol (and) Caprylyl Glycol (and) Sorbic Acid
• Common Name: Optiphen Plus
• Appearance: Clear, light yellow to dark yellow liquid
• Odour: Mild, faint characteristic
• Usage Level: 0.75–1.5% of total formulation weight
• Recommended Standard Usage Rate: 1.0–1.2% for most applications
• Optimal pH Range: 6.0 or below — CRITICAL; efficacy of sorbic acid component drops significantly above pH 6.0
• Maximum pH for effective use: 6.0
• Solubility: Soluble in water and in oil/water systems; disperses readily in most cosmetic formulations
• Phase Addition: Any phase — can be added to oil phase, water phase, or at cool-down; most commonly added at cool-down below 40°C
• Temperature Stability: Stable up to 80°C — can be added to hot phases if needed; cool-down addition below 40°C preferred to preserve full activity
• Paraben-free: Yes
• Formaldehyde-free: Yes
• Formaldehyde-releasing: No
• Suitable for: Rinse-off and leave-on formulations
• Suitable for: Aqueous, emulsion, surfactant-based, and gel formulations
• Shelf Life: 2 years from manufacture in sealed storage
• Storage: Store sealed in a cool, dark place away from heat and direct sunlight

HOW IT WORKS — THE THREE-COMPONENT SYSTEM

Optiphen Plus achieves broad-spectrum protection through three complementary active components working synergistically:

Phenoxyethanol (the primary antibacterial)
Phenoxyethanol is a glycol ether with strong bactericidal activity. It disrupts bacterial cell membranes, preventing growth and killing existing bacteria. It is effective against a broad range of gram-positive and gram-negative bacteria including Staphylococcus aureus and Pseudomonas aeruginosa — two of the most common and serious cosmetic contaminants. Phenoxyethanol's activity is relatively pH-independent, providing reliable antibacterial protection across a wide formulation range.

Caprylyl Glycol (the booster and skin conditioning agent)
Caprylyl Glycol is a multifunctional ingredient — it acts as both a preservative booster and a cosmetic emollient. As a preservative booster, it enhances the activity of phenoxyethanol and sorbic acid through membrane disruption effects and by disrupting microbial cell function. As a skin conditioning agent, it contributes a smooth, non-greasy skin feel — making it a beneficial addition beyond its preservative function. It also has some antifungal activity in its own right.

Sorbic Acid (the antifungal)
Sorbic acid is a naturally occurring organic acid (found in berries of the Sorbus aucuparia tree) with proven antifungal and anti-yeast activity. It works by inhibiting fungal enzyme systems involved in energy metabolism. Critically, sorbic acid is only active in its undissociated (protonated) form, which only occurs at pH below 6.0. Above pH 6.0 (particularly above pH 6.5), sorbic acid becomes largely dissociated and loses most of its antifungal efficacy. This is the defining constraint of Optiphen Plus — it must be used in formulations at pH 6.0 or below to achieve the full broad-spectrum claim.

The result: Phenoxyethanol handles bacteria; sorbic acid handles yeast and mould; caprylyl glycol boosts both and contributes skin feel. Together at 0.75–1.5%, they provide comprehensive broad-spectrum protection sufficient for most cosmetic formulation applications.

USAGE RATES BY FORMULATION TYPE

Face and body lotions and creams (O/W emulsions)

• Rate: 1.0–1.2%
• pH requirement: Adjust to 5.0–5.5 for optimal skin compatibility and preservative efficacy
• Notes: The most common application; full broad-spectrum protection at 1% in well-formulated pH 5.0–5.5 lotions

Facial serums and toners (water-based)

• Rate: 0.75–1.0%
• pH requirement: 4.5–5.5 typical for serums; ideal for sorbic acid activity
• Notes: Ensure complete dispersion — stir thoroughly in aqueous formulations with low emulsifier content

Shampoos and conditioners

• Rate: 1.0–1.5%
• pH requirement: Shampoos typically pH 5.0–6.0; rinse-off application; upper end of usage rate recommended
• Notes: Can be added at any production phase; ensure uniform dispersion throughout

Body washes and facial cleansers

• Rate: 1.0–1.2%
• pH requirement: 5.0–6.0
• Notes: Effective in surfactant-rich formulations; caprylyl glycol aids dispersion

Gels (carbomer, hydroxyethylcellulose, xanthan gum)

• Rate: 0.75–1.0%
• pH requirement: Note that many carbomer gels are formulated at pH 6.0–7.0 — if your gel must be above pH 6.0, consider alternative preservative systems (e.g., Optiphen, Germaben, or Euxyl PE 9010)
• Notes: Stir thoroughly for uniform dispersion in gel systems

Bath and body oils (anhydrous)

• Rate: Not required for purely anhydrous formulations — preservatives are only needed where water is present
• Notes: If your oil formulation could be contaminated by water during use (e.g., used in the shower), consider preservation at 0.5–0.75%

Baby products

• Rate: 0.75–1.0%
• pH requirement: 5.5–6.0 for baby skin compatibility
• Notes: Optiphen Plus is accepted in most baby product formulations at the lower usage rate; check with your regulatory consultant for specific baby product claims

Eye creams and eye gels

• Rate: 0.75–1.0%
• Notes: Suitable for periocular formulations at lower usage rates; patch testing essential

Micellar water and makeup remover

• Rate: 0.75–1.0%
• pH requirement: Adjust to 5.5–6.0

Dry shampoos and anhydrous powders

• Rate: Not required — no water present means no microbial growth risk

• Broad-spectrum protection — active against bacteria (including gram-positive and gram-negative), yeast, and mould at recommended usage rates; true broad-spectrum single-component system
• Paraben-free — meets consumer and certification body requirements for paraben-free claims
• Formaldehyde-free and non-formaldehyde-releasing — suitable for clean beauty, natural, and organic-positioned product ranges; does not generate formaldehyde as a degradation product
• Three-component synergistic system — phenoxyethanol (bacteria), sorbic acid (fungi/yeast), and caprylyl glycol (booster + skin conditioning) working together
• Can be added at any production phase — flexibility in manufacturing; oil phase, water phase, or cool-down addition all acceptable; cool-down below 40°C preferred for maximum activity retention
• Effective as a standalone preservative — no need to blend with additional preservatives in most standard formulations
• Also functions well alongside other preservatives — can be used at lower rates in combination systems if desired
• Skin conditioning co-benefit from caprylyl glycol component — contributes smooth skin feel rather than being purely a functional chemical
• Wide formulation compatibility — suitable for rinse-off and leave-on, aqueous and emulsion, surfactant-based and gel formulations
• Widely accepted globally — recognised by cosmetic formulators, regulatory bodies, and natural beauty certification organisations

PRODUCT SAFETY

• For cosmetic use only — not for internal consumption
• Cosmetic grade preservative — safe for use in finished cosmetic products at 0.75–1.5% usage rates
• Contains Phenoxyethanol — EU Cosmetics Regulation limits phenoxyethanol to 1.0% in finished products for most applications; 0.4% in products for children under 3 years (nappy area); always check current regulatory limits for your target market
• Avoid contact with eyes in undiluted form; if contact occurs rinse thoroughly with water for several minutes and seek medical advice if irritation persists
• Skin sensitisation potential at high undiluted concentrations — handle with care; wear gloves when handling neat preservative
• In finished formulations at 0.75–1.5%, well-tolerated by most skin types
• Keep out of reach of children
• Store sealed in a cool, dark location away from heat and direct sunlight — heat and UV exposure can degrade sorbic acid content
• Not for use in purely anhydrous (water-free) formulations — preservatives are not required in anhydrous systems and add unnecessary cost

Always perform preservative efficacy testing (challenge testing) on finished formulations before commercial product launch.

CRITICAL pH GUIDANCE

pH management is the most important formulation consideration when using Optiphen Plus. Here is what you need to know:

Why pH matters for Optiphen Plus:
The sorbic acid component — responsible for antifungal and anti-yeast protection — is only active in its undissociated (acid) form. At pH 6.0 or below, approximately 40–50% of sorbic acid is in the active undissociated form. Above pH 6.0, the proportion drops rapidly. At pH 7.0, less than 5% is in the active form. Without active sorbic acid, Optiphen Plus loses its antifungal coverage and becomes primarily antibacterial only — not truly broad-spectrum.

Practical pH targets by formulation type:

• Leave-on facial products: pH 4.5–5.5 (optimal for both skin and preservative)
• Leave-on body products: pH 5.0–6.0
• Rinse-off products (shampoo, body wash): pH 5.0–6.0
• Maximum pH for Optiphen Plus efficacy: 6.0

How to check and adjust pH:
Use a calibrated pH meter — not pH strips, which are insufficiently accurate for cosmetic formulation. Check pH after all ingredients including the preservative are incorporated and the formulation is at room temperature. To lower pH (make more acidic): add Citric Acid solution (dissolve citric acid in distilled water at 10–50% and add dropwise). To raise pH if needed: add Sodium Hydroxide solution (dilute NaOH in distilled water and add dropwise). Re-check pH after each addition.

If your formulation must be above pH 6.0:
Optiphen Plus is not the correct preservative for formulations with a required pH above 6.0 (for example, some conditioners formulated at pH 6.5–7.0). In this case, consider Optiphen (Phenoxyethanol and Caprylyl Glycol — without sorbic acid, effective to pH 8.0), Germaben II, Euxyl PE 9010, or other preservative systems suited to higher pH ranges.

What is the INCI name for Optiphen Plus?
The correct INCI name is Phenoxyethanol (and) Caprylyl Glycol (and) Sorbic Acid. All three components must be individually listed on your finished cosmetic product ingredient label in this exact INCI form.

What is the correct usage rate for Optiphen Plus?
The recommended usage range is 0.75–1.5% of total formulation weight. For most standard creams, lotions, and shampoos, 1.0–1.2% is the standard starting point. Use the lower end of the range (0.75–1.0%) for rinse-off products and formulations with a naturally hostile environment for microbes. Use the upper end (1.2–1.5%) for products with high water activity, products intended for challenged environments (pump bottles, wide-mouth jars), or when additional assurance is required. Always confirm efficacy with challenge testing at your chosen rate.

Can I add Optiphen Plus to hot formulations?
Optiphen Plus is stable to approximately 80°C, so it can technically be added to hot phases. However, cool-down addition below 40°C is recommended best practice — adding at cool-down minimises any thermal degradation of the sorbic acid component, maximises efficacy, and avoids potential evaporation of phenoxyethanol from hot formulations. In practice, if your manufacturing process requires it, addition at up to 80°C is acceptable.

Why is pH so critical for Optiphen Plus?
The sorbic acid component of Optiphen Plus is only antimicrobially active in its undissociated (protonated) form, which only exists in significant quantities at pH 6.0 or below. Above pH 6.0, sorbic acid becomes dissociated and loses most of its antifungal efficacy. Without active sorbic acid, Optiphen Plus cannot claim full broad-spectrum protection — it would only provide antibacterial coverage from phenoxyethanol. Always formulate and pH-adjust to 6.0 or below when using Optiphen Plus.

Is Optiphen Plus suitable for natural or organic certified products?
Optiphen Plus is not derived from natural sources — it is a synthetic preservative system. It is paraben-free and formaldehyde-free, which satisfies most clean beauty consumer expectations. However, it does not meet the requirements of strict natural/organic certification standards such as COSMOS, Natrue, or certified organic Australian standards, which require naturally derived preservation systems. If your product requires a certified natural/organic preservative, alternatives such as Leucidal Liquid SF, rosemary extract combined with Vitamin E, or other certified-natural systems may be more appropriate. For the majority of Australian natural beauty brands that are "natural-positioned" without formal certification, Optiphen Plus is widely used and accepted.

Can I use Optiphen Plus in baby products?
Optiphen Plus can be used in baby products at the lower end of the usage range (0.75–1.0%). However, current EU Cosmetics Regulation limits phenoxyethanol to 0.4% in products specifically intended for children under 3 years applied to the nappy area. If formulating for the Australian market without EU export intentions, Australian TGA and AICIS guidelines apply — check current requirements. For baby products generally, staying at 0.75–1.0% total Optiphen Plus is prudent, and performing preservative efficacy testing is strongly recommended.

Do I need to blend Optiphen Plus with other preservatives?
Not for most standard formulations. Optiphen Plus is designed and marketed as an effective standalone preservative system at 0.75–1.5%. It provides genuine broad-spectrum coverage (bacteria, yeast, mould) without blending when used at the correct pH and usage rate. However, for particularly challenging formulations (high water activity, minimal emulsifiers, unusual actives, or very long intended shelf life) some formulators choose to blend at lower rates with complementary preservatives. If blending, reduce Optiphen Plus to 0.5–0.75% and add a compatible co-preservative such as sodium benzoate or potassium sorbate.