Goa powder—also known as araroba powder—is a botanical preparation historically used on stubborn skin plaques. Its activity comes from chrysarobin, a natural anthracene derivative that calms overactive skin cell turnover. Today, pure Goa powder is uncommon outside specialist or historical contexts; modern dermatology favors the synthetic analog anthralin (dithranol), which delivers similar effects with standardized strength and better control. If you’ve heard of “short-contact therapy” for psoriasis, that approach was built around anthralin, and it can still help localized plaques on elbows, knees, or the scalp. This guide explains what Goa powder is, how it works, where it fits now, practical application steps, typical concentrations and schedules, and the safety issues you must weigh—especially irritation and staining. You’ll also see an evidence check so you can discuss options confidently with your dermatologist.
Quick Overview
- Helps slow plaque growth on localized psoriasis; modern care prefers anthralin over crude Goa powder.
- Biggest drawback is skin and fabric staining plus predictable irritation during early weeks.
- Typical short-contact anthralin: 0.1–1% applied daily for 5–30 minutes, then washed off.
- Avoid unsupervised use on face, genitals, or flexures; seek medical guidance in pregnancy or for children.
Table of Contents
- What is Goa powder?
- Does it work for psoriasis?
- How to use it correctly
- How much and how often?
- Risks and who should avoid
- What the evidence says today
What is Goa powder?
Goa powder (araroba powder) is a crude plant material historically obtained from the heartwood of South American trees that concentrate chrysarobin. Chrysarobin belongs to the anthracene family, a chemical class that interacts with skin cell proliferation and inflammation. In dermatology’s early days, pharmacists mixed Goa powder into ointments and pastes to treat chronic scaly plaques. Those mixtures varied from batch to batch, and they stained everything they touched. As laboratory chemistry advanced, anthralin (also called dithranol) was synthesized to deliver a consistent, measurable effect similar to Goa powder’s active ingredients but with predictable strength. That shift—away from crude botanical powder and toward a standardized drug—marked an important safety and quality milestone.
Mechanistically, anthracene derivatives reduce keratinocyte hyperproliferation (the “too-fast” skin growth that creates thick plaques). They also have local anti-inflammatory effects. Because the effect is local and mostly confined to where the ointment sits, these agents are aimed at limited-area disease rather than widespread psoriasis. They’re also not a fit for thin or delicate skin sites (face, genitals, or body folds) because irritation is common in those areas.
Where does Goa powder fit now? You’ll rarely find it on a modern prescription because pharmacists and guidelines prefer anthralin formulations made to pharmacopoeial specifications. Some heritage or compounded preparations still reference chrysarobin, but they’re niche and typically reserved for dermatologist-directed use. For most people reading about Goa powder online, the practical take-away is this: the up-to-date, controlled way to harness the same mechanism is anthralin cream, ointment, or paste used in short-contact regimens. If you’re thinking about “Goa powder” because of historical recommendations or a traditional remedy, plan to discuss anthralin instead—your clinician can tailor the strength and exposure time to minimize irritation while maintaining benefit.
Finally, Goa powder is not a dietary supplement and should never be ingested. Its role—historically and today—is topical and targeted. If a product markets “Goa powder” as an oral herb or general tonic, that’s a red flag: stick to topical use under qualified guidance.
Does it work for psoriasis?
For thick, localized plaques, anthracene-based therapy can be effective. Historically, chrysarobin from Goa powder helped soften and flatten plaques that resisted other options. Modern practice, however, anchors on anthralin because it’s standardized, studied, and easier to dose precisely. In comparative terms, anthralin isn’t your first-line topical—that position belongs to corticosteroids and vitamin D analogs for most patients—but it remains a viable option when common agents fall short or when you want to rotate away from steroids.
What kind of improvement is realistic? On clearly defined, localized plaques (elbows, knees, shins), regular anthralin use can reduce thickness and scaling over several weeks. The effect is most reliable when you combine it with supportive care: daily emollients to reduce scale, keratolytics (like salicylic acid on non-sensitive sites) to enhance penetration, and careful protection of surrounding healthy skin. Expect a “conditioning” period where mild irritation and browning of the treated plaque occur; that’s part of the known response, not necessarily a failure or allergy. Most protocols intentionally use short, controlled exposures at higher concentration (short-contact therapy) to strike a balance between efficacy and tolerability.
How does it compare with other topicals? Anthralin’s practical disadvantages—staining of skin and clothing, bathroom cleanup, and the learning curve—mean many clinicians try simpler regimens first. Yet for patients who prefer steroid-sparing options or who respond incompletely to vitamin D analogs or retinoids, anthralin can still deliver. It’s also a reasonable rotational agent to reduce long-term steroid use on body plaques. For scalp disease, properly formulated anthralin lotions can help, though staining of hair and towels can be a barrier.
Crucially, these benefits apply to controlled anthralin formulations rather than raw Goa powder. If you encounter a product that lists “Goa powder” without standardized strength, it’s hard to predict performance or side-effects. That uncertainty is why modern sources recommend anthralin with defined concentrations and clear directions for exposure and removal, ideally under a clinician’s guidance.
How to use it correctly
Because irritation and staining are predictable, technique matters as much as the tube you choose. Here’s a practical, step-by-step approach adapted from contemporary anthralin use:
- Choose the right areas. Reserve therapy for thick plaques on robust skin (elbows, knees, outer arms, shins). Avoid the face, groin, genitals, and body folds. Do not apply to excoriated or infected skin.
- Prepare the skin. After a warm shower, gently remove loose scale (don’t pick) and pat dry. If advised by your clinician, apply a keratolytic first on non-sensitive sites to help penetration.
- Protect the surroundings. Rub a thin ring of petrolatum around, not on, the plaque margins. This “fence” reduces spillover irritation.
- Glove up and apply a thin film. With disposable gloves, spread a pea-sized amount over the plaque—enough to coat, not cake. Close the tube promptly to limit oxidation.
- Use short-contact timing. Start low and go slow. A common on-label pattern is 0.1–1% anthralin once daily for 5 minutes on day one, then rinse off completely with lukewarm water and mild cleanser. If well tolerated, increase the contact time by 5 minutes each day (or every few days) up to 20–30 minutes. Some regimens use about 20–60 minutes once daily at 1% or higher under specialist direction. Your clinician may adjust the cadence for your skin and schedule.
- Rinse methodically. Wash hands, skin, and any splashes on sink or tiles immediately. Cool to lukewarm water helps reduce staining. Pat dry with older, dark towels.
- Moisturize after. Apply a bland emollient to support the skin barrier and comfort.
- Color expectations. Treated plaques often turn brownish during active therapy. That color shift is expected and can persist for days to weeks after you stop. It fades as skin renews.
- Clothing and linens. Wear dark garments over treated areas. Use older pillowcases or towels for scalp applications.
- When to pause. If you develop sharp pain, blistering, spreading redness beyond the “fence,” or symptoms of infection (ooze, crust, fever), stop and contact your clinician. Many people experience mild, transient burning; severe reactions are not the goal and warrant reassessment.
This same approach describes how historical chrysarobin ointments from Goa powder were used, but standardized anthralin makes the process more predictable. If a dermatologist prescribes a chrysarobin-based compound for a very specific plaque, they’ll provide explicit instructions; follow that plan rather than self-modifying concentrations or exposure times.
How much and how often?
Modern default: short-contact anthralin (dithranol) on localized plaques.
- Strength: commonly 0.1–1%; some regimens titrate higher for brief exposures on very thick plaques, supervised by a specialist.
- Frequency: once daily on treatment days; some people use it 5–7 days/week during an induction phase, then reduce frequency for maintenance or rotate to other topicals.
- Contact time: begin at 5 minutes, adding 5-minute steps as tolerated to a usual target of 20–30 minutes (some protocols extend to 60 minutes on robust skin).
- Course length: reassess after 2–4 weeks; many users continue 6–12 weeks to consolidate gains before transitioning to maintenance.
Scalp patterns: lotions or pastes designed for scalp use can follow the same contact-time logic. Protect the hairline and ears with petrolatum and plan extra cleanup time; product can stain hair and cotton towels.
Combination strategies: anthralin can be paired with a vitamin D analog in the morning and used alone at night (or vice versa). Combination with topical steroids is sometimes used in rotations to manage irritation and limit steroid exposure. Your clinician will individualize the sequence; do not layer agents simultaneously unless instructed.
Children and adolescents: under dermatology supervision, short-contact anthralin up to 1% can be used on selected plaques. The same caveats apply—avoid sensitive areas, start with very brief exposures, and prioritize emollients. Family training on application and cleanup improves adherence and safety.
Historical Goa powder (chrysarobin) strengths: older texts describe chrysarobin in ointment bases at low single-digit percentages for chronic plaques. Because these products are uncommon today and variation is high, dosing should be physician-directed only. For almost all readers, anthralin provides the safer, standardized way to access this mechanism.
Not for these sites: avoid face, genitals, body folds, and any area with fragile skin. Do not apply to inflamed eczema, open fissures, or infected plaques. Avoid mucous membranes.
Practical quantities: as a rule of thumb, a “fingertip unit” (the amount squeezed from the tube from fingertip to first crease) covers roughly 2 adult handprints of skin. Most people need small amounts per session because treatment targets discrete plaques.
When to stop or switch: if plaques remain unchanged after 2–4 weeks despite appropriate escalation, or if irritation limits progress, it’s reasonable to pivot to alternative topicals, phototherapy, or systemic options. Your clinician can also reframe the plan as a rotational therapy—anthralin during flares, steroid or vitamin D analogs for maintenance.
Risks and who should avoid
Irritant dermatitis is expected, up to a point. Warmth, tingling, and a browning of the plaque are common transient effects. Escalate contact time only if those sensations remain mild and confined to the treated area. If sharp pain, blistering, or spreading redness occur, stop and get advice; it may be overtreatment or, less commonly, allergic contact dermatitis.
Staining is universal. Anthracene derivatives oxidize and stain skin, nails, hair, clothing, bedding, bathroom fixtures, and even plastic gloves. The discoloration on skin fades with turnover; fabrics and grout may not recover fully. Plan dark clothing and mindful cleanup to lower frustration.
Sensitive sites are off-limits. Avoid application to the face, genitals, or body folds. The stratum corneum is thin there and far more prone to irritation and possible erosions. Likewise, avoid use on acutely inflamed eczema or broken skin.
Eyes and mucosa: keep away from eyelids, lips, nostrils, and any mucous membrane. If accidental exposure happens, rinse generously with water and seek care if burning persists.
Children and pregnancy: pediatric use is acceptable when supervised and limited to appropriate plaques with short contact and low strengths. In pregnancy or while breastfeeding, discuss risks and benefits with a clinician first. Although systemic absorption from brief, small-area use is minimal, conservative practice favors alternatives with less mess and irritation.
Photos and phototherapy: anthralin is not a photosensitizer like psoralen, but irritated skin can feel more reactive to UV. If you’re in a phototherapy program, coordinate timing with your clinic; they may ask you to avoid anthralin on treatment mornings or to shield recently treated areas.
Allergy and rare concerns: allergic contact dermatitis can mimic “too much irritation”—a clinician can help distinguish them. Historically, chrysarobin (the active in Goa powder) showed tumor-promotion activity in mouse skin experiments at high, prolonged exposures; this supports the modern emphasis on controlled duration, limited areas, and clinician-directed therapy, and it’s another reason unsupervised use of crude Goa powder has fallen out of favor.
Drug interactions: because this is topical and locally acting, classic drug–drug interactions are rare. Focus instead on sequence and spacing with other topicals to avoid compounding irritation: for example, on nights you use anthralin, skip other potential irritants (strong retinoids, high-strength salicylic acid) on the same spot.
When not to use: do not ingest; do not apply to widespread skin; do not continue if you develop signs of infection on treated plaques. People with limited mobility or visual impairment may need caregiver help to avoid accidental spread to healthy skin and household surfaces.
What the evidence says today
Dermatology guidelines continue to list anthralin among viable topical options for mild-to-moderate plaque psoriasis, emphasizing its role as part of combination or rotational therapy rather than a default first-line agent. Contemporary reviews summarize why: it works for the right plaques, but it’s messy and predictably irritating, and patients often prefer cleaner, once-daily steroid or vitamin D analog regimens. Still, for steroid-sparing goals, localized thick plaques, or rotational strategies to reduce long-term steroid exposure, anthralin remains relevant.
Short-contact therapy is the modern standard, reflecting decades of clinical evolution from the earlier Goa powder era. Short, daily exposures at controlled strengths (typically 0.1–1%, titrated by tolerance) help flatten plaques while limiting collateral irritation. Pediatric recommendations allow its use—again, with short contact, limited sites, and caregiver education—because systemic absorption is negligible and the main risks are local and manageable.
Historically, chrysarobin from Goa powder helped catalyze this whole therapeutic path. Over time, however, concerns about batch variability, irritant strength, staining, and laboratory observations of tumor-promotion in mice pushed clinical practice toward the standardized, synthetic analog anthralin. That’s why you’ll seldom see “Goa powder” listed in modern formularies even though it seeded an enduring approach.
Where does this leave you if you’re deciding among topicals? If your plaques are localized and thick, and if you’re comfortable with some mess and a learning curve, a time-limited anthralin plan can still be worth trying—especially when other agents underperform. If your disease is widespread or involves sensitive sites, other modalities (vitamin D analogs, topical steroids, calcineurin inhibitors for folds, phototherapy) usually rise to the top. The best outcomes typically come from a tailored regimen with clear instructions, set expectations about irritation and staining, and scheduled follow-up to tweak timing, strength, or combinations.
Bottom line: Goa powder itself belongs to dermatology’s past; its legacy lives on in anthralin short-contact therapy. When used thoughtfully as part of a broader plan, that legacy can still make a tangible difference on stubborn plaques.
References
- Topical Therapies in Psoriasis 2017 (Review)
- Joint AAD–NPF Guidelines of care for the management and treatment of psoriasis with topical therapy and alternative medicine modalities for psoriasis severity measures 2021 (Guideline)
- Recommendations for Management of Childhood Psoriasis 2021 (Guideline)
- Mechanism of mouse skin tumor promotion by chrysarobin 1985 (Seminal/Mechanistic)
- Psoriasis and Treatment: Past, Present and Future Aspects 2020 (Review)
Disclaimer
This article provides general educational information about Goa powder, chrysarobin, and anthralin as topical therapies for psoriasis. It is not medical advice and does not replace a consultation with a qualified health professional who can evaluate your specific condition, medications, and risks. Do not start, stop, or change any treatment without personalized guidance. If you develop severe irritation, signs of infection, or unexpected symptoms, seek medical care promptly.
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