Cysteamine Cream for Pigmentation: How It Works & How to Use

Cysteamine cream is a topical depigmenting treatment, usually at 5%, that fades melasma and dark patches by slowing melanin production. It is a short-contact cream: you apply it for 15 minutes to a few hours, then wash it off. Trials show steady fading over about four months, with redness, a strong smell and irritation as the main drawbacks.

Cysteamine has become a popular alternative to hydroquinone for stubborn pigmentation, and you may have seen it recommended for melasma that has not responded to anything else. Here is how it works, how to use it without irritating your skin, how it compares with other brightening actives, and who should skip it.

What is cysteamine?

Cysteamine is a small sulphur-containing molecule that the human body makes naturally when it breaks down the amino acid cysteine. It is present in skin cells and is also used, by mouth, as a medicine for a rare kidney disorder. Dermatologists became interested in it decades ago after noticing it lightened pigment, but early versions were too unstable and smelly to use. Newer stabilised creams made topical use practical.

How does cysteamine fade pigmentation?

Cysteamine works on melanin production in more than one way:

• It slows melanin-making enzymes, including tyrosinase and peroxidase, which turn the amino acid tyrosine into pigment.
• It raises glutathione in skin cells. Glutathione shifts melanin production away from dark brown eumelanin.
• It mops up free radicals, which are part of what keeps pigment cells overactive.

Unlike hydroquinone, cysteamine does not damage or kill melanocytes, the cells that make pigment. This is why it is considered suitable for longer-term use and is less linked to the patchy bluish darkening (ochronosis) seen with long-term hydroquinone misuse.

What does the evidence say?

Cysteamine has a reasonable, though not huge, body of research:

• A placebo-controlled trial in melasma patients found that 5% cysteamine cream used for four months gave a significantly greater reduction in melasma scores than placebo.
• Head-to-head trials against 4% hydroquinone have found it comparable in some studies and slightly less effective in others, with fewer long-term safety concerns.
• Smaller studies suggest it also helps post-inflammatory hyperpigmentation, the dark marks left after acne or rashes.

Results are gradual. Most people need 8 to 16 weeks before the change is obvious, and pigmentation returns if sun protection is skipped.

How do you use cysteamine cream?

Cysteamine is a short-contact treatment, so the routine is different from a serum you leave on:

1. Apply in the evening on clean, completely dry skin. Damp skin increases stinging.
2. Spread a thin layer over the whole affected area, not just the darkest spots, to avoid a halo of lighter skin.
3. Leave it on for 15 minutes to begin with. Your dermatologist may increase this over weeks, up to a few hours, depending on the product and your tolerance.
4. Wash it off with a gentle cleanser and lukewarm water.
5. Moisturise straight after to calm any tightness.
6. Use sunscreen every morning, reapplying when outdoors. Without it, no pigment treatment will hold.

Expect a warm or tingling sensation and some temporary redness during the first two weeks. A sulphur smell is normal and fades after washing.

Cysteamine vs other brightening ingredients

Many routines combine a strong treatment like cysteamine with gentle daily support. Niacinamide works further down the pathway by reducing the transfer of pigment to skin cells, so it complements rather than duplicates cysteamine. If you are deciding between options, our comparison of niacinamide and vitamin C for dark spots is a useful starting point.

Who should avoid cysteamine?

• Pregnant or breastfeeding women: there is not enough safety data. Our guide to pregnancy-safe melasma treatment covers gentler options.
• People with eczema, rosacea or a damaged skin barrier, who are more likely to sting and redden.
• Anyone currently using a strong retinoid or peel, unless a dermatologist is spacing the treatments.
• Undiagnosed patches. Have new or changing dark patches checked first; not every brown mark is melasma.

Can you use cysteamine with other actives?

Yes, with spacing. Keep cysteamine in the evening and avoid using exfoliating acids or retinoids on the same night at first. Niacinamide, hyaluronic acid and a simple moisturiser can be used in the morning or after rinsing the cysteamine off. If your skin gets irritated, pause everything except a moisturiser and sunscreen until it settles, then restart at a shorter contact time.

Why sunscreen decides your results

Melasma is driven by UV, visible light and heat. Even the best depigmenting cream cannot keep up with unprotected daily sun. Use a broad-spectrum SPF 50 every morning, two finger lengths for the face and neck, and reapply when outdoors. Tinted sunscreens add protection from visible light, which matters for deeper Indian skin tones. Read more in our guide to melasma on Indian skin.

Frequently asked questions

How long does cysteamine take to work?

Most people see early fading at 8 weeks and clearer results by 16 weeks of nightly use, provided they use sunscreen daily.

Is cysteamine better than hydroquinone?

Not clearly better, but it is considered safer for longer use because it does not damage pigment cells. Hydroquinone may work slightly faster in some trials.

Can I leave cysteamine on overnight?

No. It is designed as a short-contact treatment. Leaving it on overnight greatly increases irritation.

Why does cysteamine cream smell?

Cysteamine contains sulphur, which gives a smell like boiled eggs. It is harmless and disappears once you wash it off.

Does pigmentation come back after stopping cysteamine?

Melasma is a long-term condition, so it can return, especially with sun exposure. A gentle daily brightening step and strict sunscreen help keep results.