INCI: Cysteamine Hydrochloride
Antioxidant and melanin degrader, a hydroquinone alternative for stubborn melasma. The main practical downside is a sharp unpleasant odor.
Topical application
BLimited evidence. One RCT or several controlled studies with limitations.
Double-blind RCTs show comparable efficacy to hydroquinone 4% in melasma. Slight stinging on skin but without ochronosis risk.
Cysteamine (Cysteamine Hydrochloride) is a sulfur-containing antioxidant and melanin degrader. A natural coenzyme A metabolite in the human body, used systemically for cystinosis. In dermatology – one of the few hydroquinone alternatives for stubborn melasma and post-acne pigmentation. Mechanism. Cysteamine acts on several levels. Inhibits tyrosinase and peroxidase – key melanogenesis enzymes. Chelates copper, a tyrosinase cofactor. Degrades already-synthesized melanin and disrupts melanosome transfer from melanocytes to keratinocytes. Strong antioxidant via thiol groups. Where applied. 5-7% in creams for treating melasma and post-acne pigmentation. Applied as a 15-minute short contact in the evening, then rinsed – this scheme reduces irritation and unpleasant odor. Course 8-16 weeks. In Spain – Cyspera (original brand from Scientis), available in dermatology clinics. Also Cysteamine Cream from Mediderma, Mesoestetic. Evidence base. Mansouri 2015 RCT: 5% cysteamine vs placebo over 4 months reduced MASI in melasma patients by 50%. Lima 2020 compared cysteamine with 4% hydroquinone – comparable efficacy, better tolerability with cysteamine (no risk of exogenous ochronosis on long-term use). Safety. CIR has not issued a direct evaluation at cosmetic concentrations. Systemic absorption through intact skin is low. Irritation and redness possible in 30-40% of patients in the first 2 weeks, resolving with adaptation. Odor controversy. The main practical limitation is the sharp, unpleasant sulfur-egg odor of the molecule. Manufacturers mask the odor with fragrance and fast-rinse forms, but can't fully eliminate it. Many patients drop therapy due to odor before they see the effect. Pregnancy and lactation – with caution. No direct ban, but during pregnancy azelaic acid is preferred (better-studied safety profile). Cysteamine in this phase is used only if other agents don't work – with dermatologist agreement. Best suited to: stubborn melasma, post-acne pigmentation, hyperpigmentation after laser procedures, patients in whom hydroquinone didn't work or is contraindicated. Not for sensitive skin and low adherence (odor turns people away quickly).
Irritation potential
MediumAllergen risk
LowThe Evigrade extension adds an evidence panel to Wildberries, Goldapple, Letu, iHerb, Sephora and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Cysteamine should be used with caution during pregnancy. Consulting a dermatologist or OB-GYN is advisable.
Cysteamine suits: normal, oily, combination. Use with caution in: sensitive.
Cysteamine has moderate irritation potential. Sensitive skin may show a transient reaction that usually settles with adaptation.
Antioxidant and melanin degrader, a hydroquinone alternative for stubborn melasma.
The INCI name is Cysteamine Hydrochloride. It may also appear as: Cysteamine.
Published: · updated:
Pregnancy
CautionSuitable for
Use with caution