Hydroquinone Cream

Hydroquinone (HQ) is one of the most effective inhibitors of melanogenesis (melanin production). When applied topically, it causes a reversible depigmentation of the skin by blocking the enzyme tyrosinase and reducing melanocyte metabolic processes.

Hydroquinone is used to treat skin hyperpigmentation including:

• Melasma
• Chloasma
• Freckles and age spots (senile lentigines)
• Post-burn hyperpigmentation
• Post-inflammatory hyperpigmentation

Results typically begin to appear after about 4 weeks, with full benefits taking up to 3 months or more.

Hydroquinone produces depigmentation through several mechanisms:

• Blocking the enzyme tyrosinase, preventing melanin formation
• Reducing melanocyte metabolic processes
• Decreasing melanosome production and altering their internal structure
• Increasing the breakdown of melanosomes

To improve effectiveness, hydroquinone can be combined with other ingredients such as tretinoin, glycolic acid, fluocinolone, kojic acid, hydrocortisone, or ascorbic acid.

In Canada, stronger hydroquinone preparations are prescription products. Compounded prescriptions are commonly written at 4%, and prescribers may choose other strengths or combine hydroquinone with tretinoin, fluocinolone, kojic acid, glycolic acid, or hydrocortisone in one cream.

Commercial availability of prescription-strength hydroquinone products in Canada has been limited over the years, which is why many prescriptions come to a compounding pharmacy. The prescription defines the exact strength, combination, and quantity.

Follow your prescription label. General counselling points our pharmacists review:

• Apply a thin layer to the affected areas only — not the surrounding skin
• Many plans use once-daily application, often at night (especially for combinations with tretinoin)
• Avoid the eyes, mouth, and broken skin
• Test a small amount on healthy skin first and watch for 24 hours
• Wash hands after applying
• Daily sunscreen on treated areas is part of the treatment — sun exposure re-darkens the pigment you are trying to fade

Possible side effects include:

• Skin sensitivity or redness
• Drying and flaking
• Allergic reactions (rare)

Precautions:

• Use sunscreen and avoid excessive sun exposure to prevent repigmentation
• Hydroquinone is generally used in treatment courses, not indefinitely — very long continuous use of stronger preparations has been associated with a stubborn darkening called exogenous ochronosis. Follow the course length your prescriber sets and check in before continuing beyond it
• Safety in pregnancy is not well established — use only if directed by your physician

Compounded hydroquinone cream should be refrigerated and kept tightly closed — hydroquinone oxidizes with air and light exposure. Some darkening of the cream over time can occur; if your cream has turned distinctly brown, stop using it and contact the pharmacy — oxidized cream loses effectiveness.

The label carries a beyond-use date shorter than a manufactured product's expiry because the cream is prepared fresh per prescription. Discard after that date.

Price depends on the strength, any combination ingredients, and the quantity prescribed — the pharmacy can quote a specific prescription before it is filled. Coverage varies: some private plans cover compounded dermatology prescriptions and some treat depigmenting therapy as cosmetic, so it is worth having the pharmacy team check your specific plan at the time of filling.

A printable skin-lightening preparations template lists common hydroquinone strengths, combination options (tretinoin, fluocinolone, kojic acid, glycolic acid, hydrocortisone), and directions fields.

For a combination not on the template, call the compounding lab to discuss what can be prepared and the supporting stability considerations.