Biofreeze Recipe

Hydration and thickening

Sanitize work surfaces and utensils. In a heat-safe beaker, combine 50 ml distilled water and glycerin. Sprinkle carbomer slowly into the water-glycerin while stirring with a spatula to avoid clumping. Allow carbomer to fully hydrate for 10–15 minutes until a slightly thickened, uniform slurry forms.

In a separate sanitized bowl, measure 1 cup pure aloe vera gel. Gently warm the aloe (to about 30–35°C / 86–95°F) in a warm water bath if it is very cool, then slowly fold the hydrated carbomer slurry into the aloe gel while stirring to distribute evenly. The mixture should begin to thicken further.

Dissolving menthol

Place menthol crystals in a small glass beaker and add 1–2 teaspoons of warmed (not boiling) fraction of the aloe/carbo-mer mix or a small amount of ethanol (95%) up to 5 ml to help dissolve crystals. Stir until crystals fully dissolve and produce a clear solution. If using ethanol, ensure final product volatility is acceptable and that you account for it in labeling.

Once menthol is dissolved, add camphor (if using a solid form, dissolve similarly) and mix until homogenous. Add the dissolved menthol-camphor solution into the main aloe/carbomer base while stirring slowly to avoid aeration. Mix for 2–3 minutes until evenly distributed.

Add eucalyptus and wintergreen essential oils dropwise, stirring between additions. These are optional and primarily for aroma; if skin sensitivity is a concern, omit or reduce quantity.

Neutralize and preserve

Check the viscosity: carbomer gel needs neutralization to reach full viscosity. Add TEA dropwise (or 10% NaOH solution) while stirring and monitor the gel; the mixture will thicken as pH rises. Aim for a final pH of ~5.5–6.5. Add TEA slowly — total around 0.5 tsp but add incrementally and check pH.

Once pH is adjusted, add phenoxyethanol and potassium sorbate (if using) and mix thoroughly to ensure even distribution of preservatives. These protect the product against microbial growth. If you used ethanol earlier, note its preservative contribution but do not rely on it as sole preservative.

Add 4 drops vitamin E oil and stir gently to incorporate. Allow the gel to rest for 10–15 minutes to eliminate small air bubbles and to let fragrance settle.

Perform a quick patch test on a small area of skin (inside wrist) to confirm no irritation. Label the product with ingredients and a note: 'External use only. Avoid contact with eyes. Do not apply to broken or sensitive skin. Keep out of reach of children.'

Fill sterile tubes or pump bottles using a sanitized funnel or dispensing pump. Leave headspace to allow for dispensing. Seal and store in a cool, dark place. Best used within 6–12 months if proper preservative is used; refrigerate for longer shelf life if desired.