Hydroquinone 2% vs 4% in Australia: Safety, Access and Results

Hydroquinone has been the gold standard prescription ingredient for fading melasma, sun spots and other forms of stubborn hyperpigmentation for decades. Most medical creams use strengths between 2% and 5%, and guidelines consistently describe it as one of the most effective topical options when it is used short term, with good sun protection and medical supervision.[1–4] In Australia, the two strengths you will hear about most often are hydroquinone 2% and 4%, which differ in intensity, side effects and how you can access them.

This article breaks down how 2% and 4% hydroquinone compare, what the safety data actually says, how access works under Australian regulations, and how these strengths are used in carefully designed routines at services like Prescription Skin. It is general information only and does not replace personalised medical advice.

 

Key takeaways

• Both 2% and 4% hydroquinone can improve melasma and other hyperpigmentation when used for a limited time with strict sun protection.[1–4]
• 4% usually works faster and more strongly but has a higher risk of irritation and needs closer medical supervision.[3–7, 10]
• 2% is milder and often used for maintenance, sensitive skin or as part of combination routines, but results may take longer.[1, 3, 4, 9]
• Serious complications like exogenous ochronosis are rare but are linked to long-term, repeated courses, especially at higher strengths without supervision.[11–13]
• In Australia, hydroquinone up to 2% is classified as a Pharmacy Medicine, while higher strengths like 4% are prescription only, and there are ongoing proposals that may further tighten access.[14, 15]

 

What is hydroquinone and how does it work?

Hydroquinone is a pigment-regulating ingredient that targets the root of dark patches rather than just lightening the surface. It works mainly by blocking tyrosinase, the key enzyme melanocytes use to make melanin pigment.[3, 4] With less tyrosinase activity, less new pigment is produced in the treated areas over time.

Most medical creams use hydroquinone in the 2% to 5% range. These strengths have been demonstrated in clinical trials and guidelines to reduce the severity of melasma and other forms of hyperpigmentation when used at night for several months, in combination with daily high SPF sunscreen.[1–4] It is especially helpful for:

Melasma on the cheeks, forehead and upper lip, hormone-related or sun-induced pigmentation, and post-inflammatory marks after acne or eczema. If you want a deeper dive on the ingredient itself, you can read more in our dedicated hydroquinone ingredient overview and our guides on hyperpigmentation and melasma.

 

Hydroquinone 2% vs 4%: how do they compare for results?

There are many trials of hydroquinone 4% cream for melasma and other dark patches. Studies comparing 4% hydroquinone to placebo or to other lightening creams show clearly better lightening with hydroquinone over about 8 to 12 weeks.[5–8, 16] In one placebo controlled study, almost all patients using 4% hydroquinone had at least partial clearing of their melasma after 12 weeks, compared with about two thirds in the placebo group.[6] Other trials show 4% hydroquinone outperforming kojic acid and ascorbic acid creams, although these can still help and are sometimes used together with hydroquinone.[5, 7, 8]

Guidelines for melasma in general practice note that hydroquinone 2% to 5%, used at night for 2 to 4 months, produces significant improvement in many patients.[1, 2] A narrative review also concludes that creams in the 2% to 5% range are both safe and effective for hyperpigmentation when used as directed.[3, 4]

However, there are very few head to head trials directly comparing 2% versus 4% hydroquinone on their own.

What the available data and expert reviews suggest is:

Effect of strength on results
Higher strengths up to around 4% tend to give faster and more noticeable fading, especially in moderate to severe melasma.[3–7] Lower strengths like 2% can still work, but lightening may be slower and more modest, so they are often used for mild pigment, for maintenance after a stronger course, or as part of combination routines that also include other actives like retinoids, niacinamide or azelaic acid.[1–4, 8, 9]

In one study, 2% hydroquinone was used as a priming step before chemical peels and contributed to overall improvement in melasma, although the peel itself also played a role.[9] Combination gels that include 2% hydroquinone plus glycolic acid or kojic acid have also been shown to improve melasma.[8]

Putting this together in a practical sense:

Hydroquinone 4% is usually chosen when pigment is more stubborn or widespread, such as long standing melasma on the cheeks and forehead. It is often used in a triple combination with a retinoid and a mild steroid, which guidelines describe as first line therapy for many people with melasma.[2, 3, 16]
Hydroquinone 2% may be more suitable for milder or early pigment, for maintenance after a stronger course, or for people whose skin is very sensitive and needs a gentler starting point.[1, 3, 4]

 

Side effects and safety: what does the evidence say?

Like any active medicine, hydroquinone has a benefit side effect trade-off. Common side effects are dose-related and include stinging, redness, dryness and irritation, especially in the first few weeks or if the cream is overused.[3, 4, 10, 13] Concentrations above 4% are more likely to cause irritant dermatitis, which is one reason most medically supervised creams stay at or below that level.[10, 13]

When hydroquinone is used on limited areas of skin, at concentrations up to about 4%, and for a short to medium course, systemic absorption is low and serious internal toxicity has not been shown in humans.[4, 13, 14] Animal data and risk assessments suggest that dermal exposure at therapeutic doses mainly causes local skin effects rather than whole body toxicity.[13, 14]

 

Exogenous ochronosis

The biggest long term concern people read about online is exogenous ochronosis, a blue black, mottled pigmentation that can appear after prolonged use of some lightening creams. Reviews and case series show this is rare, but it is strongly linked to repeated or prolonged courses of hydroquinone, especially at higher strengths and in sunny climates.[11–13]

Reports include people who used 4% hydroquinone daily for years for melasma and later developed gray blue patches that were very difficult to treat.[12] There are also isolated case reports of ochronosis after long-term use of 2% hydroquinone creams, often for seven years or more without medical supervision.[11] Once ochronosis develops, it may only partially improve even with lasers, peels and strict sun protection.[11, 12]

Because of this, expert reviews and guidelines recommend that hydroquinone be used in limited courses, usually for a few months at a time, with breaks in between; is avoided for self-directed, indefinite lightening of large areas such as whole face or body; and is always combined with daily, high-quality sun protection to minimise irritation and rebound pigment.[1–4, 11–15]

 

Other safety questions

Concerns have been raised in the past about possible cancer risk with hydroquinone based on very high-dose animal studies. A detailed safety review concluded that, when used as a thin layer once or twice daily for up to about three months at typical dermatology strengths, hydroquinone has a good safety profile and that real-world adverse reactions are uncommon and mostly mild.[13, 14] Regulatory bodies still keep hydroquinone under close review, which is why access is restricted and use is meant to be supervised.

Hydroquinone is generally avoided during pregnancy and breastfeeding because there is limited high quality safety data, even though significant harm has not been clearly shown in humans.[1–4, 13] Alternatives such as azelaic acid, niacinamide, vitamin C and retinoid free pigment routines may be used instead, depending on your doctor’s advice.

 

How long can you safely use hydroquinone?

Australian and international guidance is fairly consistent here. For melasma, hydroquinone 2% to 5% is usually used once daily at night for about 2 to 4 months, sometimes extended to 3 to 6 months if the skin is coping well and pigment is still improving.[1–4, 16] After that, most clinicians recommend a break, either switching to non hydroquinone maintenance (for example niacinamide, retinoids, ascorbic acid) or cycling hydroquinone on and off under supervision.[1–4, 16]

Regulators have also required warning statements that hydroquinone creams should only be used for a limited period and stopped if there is no improvement after a few months.[14, 15] This is to reduce the risk of ochronosis and unnecessary long term exposure.

 

Access in Australia: 2% vs 4% hydroquinone

In Australia, hydroquinone is treated as a medicine rather than a cosmetic if it claims to lighten pigment by changing how melanin is produced.[14] It is listed in the national Poisons Standard in several schedules:

Hydroquinone creams and lotions for human skin use that contain 2% or less are classified as Schedule 2 Pharmacy Medicines. These can be supplied without a prescription, but only from a pharmacy, with advice from a pharmacist.[14]
Higher strength creams, including 4% hydroquinone, are classified as Schedule 4 Prescription Only Medicines and must be prescribed by a doctor or nurse practitioner.[14, 15]

Recent consultation papers from the Therapeutic Goods Administration have proposed removing the Schedule 2 entry so that all hydroquinone products for skin lightening would become prescription only, reflecting international concern about misuse and safety.[15] At the time of writing, the Schedule 2 entry is still present in the Poisons Standard, but this may change, and individual states and territories can also apply their own rules.[14, 15]

Separately from scheduling, hydroquinone is not allowed in cosmetic products in many regions, and risk assessments recommend that any skin lightening products containing hydroquinone should be regulated and monitored because unregulated products overseas have been found with concentrations up to 9% or more.[14]

In practical terms for patients in Australia:

You may still find 2% hydroquinone creams sold behind the counter in pharmacies, usually marketed for age spots or melasma. These should be used cautiously, on small areas only, and for short periods, following the directions and with pharmacist advice.

For 4% hydroquinone and for customised blends that combine hydroquinone with other actives, you will usually need a prescription from a doctor and a compounding pharmacy to prepare the cream.

 

Who might suit 2% vs 4% hydroquinone?

Every skin is different, so this is general guidance only rather than a rule.

Hydroquinone 2% can be a reasonable choice if you have mild or early hyperpigmentation, for example light sun spots or post inflammatory marks after acne, especially if you are already using other active ingredients like retinoids or ascorbic acid. It is also often used:

As a maintenance step after a stronger course of 4% hydroquinone, to help hold results; for people with very reactive or dry skin, where starting gently is safer; or when you and your clinician want to combine several milder pigment targeting ingredients rather than relying on one strong drug.[1–4, 9, 16]

Hydroquinone 4% is more often chosen when:

Melasma or hyperpigmentation is moderate to severe, long standing, or resistant to milder routines; you have tried 2% hydroquinone plus good sun protection and not had much change; or triple combination therapy (hydroquinone, a retinoid and a mild steroid) is being used for a limited course, consistent with guideline based care.[1–3, 16]

In all cases, careful assessment of your skin tone, pattern of pigment, background conditions like acne or rosacea, and your ability to stick to sun protection is more important than just the number on the tube.

 

How hydroquinone fits into a Prescription Skin routine

At Prescription Skin, hydroquinone is not sold as a stand alone cosmetic. It is used only in prescription strength, personalised formulas where a doctor has assessed your skin photos, history and goals. Many patients are managed through our custom prescription skincare subscription, which can include hydroquinone for a time limited course when it is clinically appropriate.

A typical pigment focused routine might include:

A morning routine anchored by a gentle cleanser, antioxidant serum such as ascorbic acid, a barrier supporting moisturiser with niacinamide and broad spectrum SPF 50 plus.
An evening prescription cream where hydroquinone 2% or 4% is combined with synergistic actives like retinoids, hyaluronic acid and anti inflammatory ingredients, tailored to whether the main concern is melasma, general hyperpigmentation, fine lines and wrinkles or mixed issues like acne plus pigment.

Because the prescription is customised and reviewed regularly, your prescriber can adjust the hydroquinone strength, frequency and duration, introduce “holidays” from hydroquinone, or transition you to non hydroquinone maintenance when it makes sense for long term skin health. Common questions about how this process works are answered in our Frequently Asked Questions.

 

When hydroquinone is not the right choice

Hydroquinone, whether 2% or 4%, is usually avoided or used with extreme caution if you are pregnant or breastfeeding, if you have a history of exogenous ochronosis, if you are seeking whole face or body lightening rather than treating defined patches, or if you are unable to use daily sun protection. In these situations, other ingredients such as azelaic acid, niacinamide, tranexamic acid, vitamin C and retinoids, as well as general routines for acne, rosacea or photoageing, may be safer starting points depending on your clinician’s advice.

If you ever notice new blue gray discolouration, thickening, or caviar like dark papules in areas where you use hydroquinone, you should stop the cream and seek medical review promptly, as this can be an early sign of exogenous ochronosis.[11, 12]

Remember that pigment conditions behave differently in different skin tones and climates. What worked for a friend or an overseas influencer may not be right for you. A supervised, evidence based plan is almost always more effective and safer than experimenting with multiple unregulated lightening products.

 

Medically Reviewed Content

• Written by: The Prescription Skin Editorial Team
• Medically Reviewed by: Dr Mitch Bishop AHPRA Registered Practitioner (MED0002309948)
• Last Updated: November 2025

This content is for informational purposes only and does not constitute medical advice. Treatment is subject to consultation and approval by our Australian-registered doctors.

 

References

1. Doolan BJ. Melasma. Australian Journal of General Practice. 2021;50(12):883–887.
2. Aung T, Elghblawi E, Aung ST. Melasma management in primary care. Australian Journal of General Practice. 2024;53(12 Suppl):S56–S60.
3. González-Molina V, Gatica-Ortega ME, Martínez-Rizo AB, et al. Topical treatments for melasma and their mechanism of action. Journal of Clinical and Aesthetic Dermatology. 2022;15(5).
4. Fabian IM, Kamangar F, Kourosh AS. Topical hydroquinone for hyperpigmentation: a narrative review. Cureus. 2023;15(11).
5. Monteiro RC, Kishore BN, Bhat RM, et al. A comparative study of the efficacy of 4% hydroquinone vs 0.75% kojic acid cream in the treatment of facial melasma. Indian Journal of Dermatology. 2013;58(2):157.
6. Ennes SBP, Paschoalick RC, de Almeida Alchorne MM. A double blind, comparative, placebo controlled study of the efficacy and tolerability of 4% hydroquinone as a depigmenting agent in melasma. Journal of Dermatological Treatment. 2000;11(3):173–179.
7. Haddad AL, Matos LF, Brunstein F, et al. A clinical, prospective, randomized, double blind trial comparing skin whitening complex with hydroquinone vs placebo in the treatment of melasma. International Journal of Dermatology. 2003;42(2):153–157.
8. Espinal Perez LE, Moncada B, Aguilar SR. A double blind randomized trial of 5% ascorbic acid vs 4% hydroquinone in the treatment of melasma. International Journal of Dermatology. 2004;43(8):604–607.
9. Nanda S, Grover C, Reddy BSN. Efficacy of hydroquinone 2% versus tretinoin 0.025% as priming agents before trichloroacetic acid peel in patients with melasma. Dermatologic Surgery. 2004;30(3).
10. DermNet New Zealand. Hydroquinone (bleaching cream). Updated 2023. Available from: https://dermnetnz.org.
11. Bhattar PA, Zawar VP, Godse KV, et al. Exogenous ochronosis. Indian Journal of Dermatology. 2015;60(6):537–543.
12. Qorbani A, Mubasher A, Sarantopoulos GP, et al. Exogenous ochronosis (EO): skin lightening cream induced hyperpigmentation. Autopsy and Case Reports. 2020;10(4):e2020197.
13. Levitt J. The safety of hydroquinone: a dermatologist’s response to the 2006 Federal Register. Journal of the American Academy of Dermatology. 2007;57(5):854–872.
14. Institute of Environmental Science and Research. Health risk assessment: hydroquinone in skin lightening products. ESR; 2024.
15. Therapeutic Goods Administration. Hydroquinone: scheduling decisions and proposed amendments to the Poisons Standard 2020–2025. Therapeutic Goods Administration, Australian Government.
16. Grimes PE, McLaurin CI. New oral and topical approaches for the treatment of melasma. International Journal of Women’s Dermatology. 2019;5(1).

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