For moderate-to-severe psoriasis that topicals and phototherapy can't control, biologics have been genuinely transformative — targeted medicines that switch off specific immune signals rather than blanketing the whole immune system. Here's a clear, science-reviewed look at what biologics (biotherapy) are, how they work, and the safety points that come with them.
Biologics are targeted medicines — usually antibodies — that block one of the overactive immune signals behind psoriasis: TNF-α, IL-23 or IL-17. Given by injection or infusion, they're used for moderate-to-severe psoriasis and psoriatic arthritis when other treatments aren't enough. They're highly effective but not a cure, so they're usually continued long-term. Because they modulate immunity, doctors screen for infections (like TB) and monitor closely — which is why they're strictly specialist-prescribed.
Biologics ("biotherapy") treat moderate-to-severe psoriasis by precisely blocking one overactive immune signal. Psoriasis is driven by pro-inflammatory cytokines — chiefly TNF-α, IL-23 and IL-17. Biologics are antibodies that target one of these: anti-TNF (etanercept, adalimumab, infliximab, certolizumab), IL-23 inhibitors (guselkumab, tildrakizumab, risankizumab) and IL-17 inhibitors (secukinumab, ixekizumab, brodalumab, bimekizumab). They're given by injection or IV infusion (not tablets — they'd be digested), can clear skin dramatically, and also help psoriatic arthritis. They're not a cure and are usually continued long-term. Because they affect immunity, the main concern is infection — so doctors screen for TB and hepatitis, keep vaccines updated, and monitor closely. Always specialist-prescribed.
What Biologics (Biotherapy) Are
"Biologic" refers to how these medicines are made — using living cell systems (biotechnology) rather than simple chemical synthesis. In psoriasis, they're typically antibodies: proteins engineered to lock onto and neutralise one specific immune messenger that's driving the disease. That precision is the point — instead of broadly dampening the whole immune system, a biologic targets a single overactive signal.
They're reserved for moderate-to-severe psoriasis (and psoriatic arthritis) — usually when topicals, phototherapy or other systemic treatments haven't done enough — and are always prescribed and monitored by a specialist.
How Do Biologics Work?
Psoriasis is fuelled by an overactive immune response, in which certain pro-inflammatory messengers (cytokines) are dialled far too high — above all TNF-α, IL-23 and IL-17. Biologics work by blocking one of these targets, quieting the cascade that produces plaques. The main classes are:
- Anti-TNF — e.g. etanercept, adalimumab, infliximab, certolizumab pegol.
- IL-23 inhibitors — guselkumab, tildrakizumab, risankizumab (plus the older IL-12/23 blocker ustekinumab).
- IL-17 inhibitors — secukinumab, ixekizumab, brodalumab, and the newer bimekizumab.
Because they're proteins, biologics can't be taken as tablets — they'd be broken down in the gut — so they're given by injection under the skin or by intravenous infusion, and stored refrigerated. Calming the target pathway clears skin and can also ease the joint symptoms of psoriatic arthritis.
How Well Do They Work?
Biologics can be strikingly effective, and for many people they achieve high levels of clearance — the kind measured as PASI 75, 90 or even 100 (75%, 90% or 100% improvement). But they reduce psoriasis rather than curing it: the underlying tendency remains, which is why psoriasis can return if treatment stops. For that reason they're usually continued long-term as maintenance, with the plan reviewed by your dermatologist over time.
Risks & Safety
Infection risk is the main consideration. Because biologics modulate immune signalling, they can raise susceptibility to some infections — but not all are equal: TNF inhibitors carry more infection risk (including tuberculosis and hepatitis B reactivation), while IL-17 and IL-23 inhibitors tend to have a more favourable profile.
Screening first. Doctors typically screen for latent tuberculosis (and often hepatitis B) before starting — especially important for TNF inhibitors and in regions where TB is common. Newer IL-17/IL-23 agents appear lower-risk, and guidance on routine TB testing for those is evolving; your specialist decides based on the drug and your risk.
Vaccinations. Keep routine vaccines up to date; inactivated vaccines (such as influenza, pneumococcal and COVID-19) are recommended, while live vaccines are generally avoided during treatment — plan these with your doctor, ideally before starting.
Other points. Some classes have specific effects (for example, IL-17 inhibitors can predispose to yeast/candidiasis and warrant caution in inflammatory bowel disease). Report fever or signs of infection promptly. In pregnancy or breastfeeding, biologics are not automatically off-limits — it's an individualized decision, and some (notably certolizumab pegol, which barely crosses the placenta) may be used when treatment is needed. Flag any allergies too. Your dermatologist weighs all of this for you.
What This Means For You
Biologics have reshaped what's possible for moderate-to-severe psoriasis — clearer skin, and relief for psoriatic joints, are realistic goals for many people. But they're specialist-prescribed and monitored, not something to self-select: the screening and follow-up are what keep them safe. If topicals or phototherapy aren't controlling your psoriasis, it's worth asking your dermatologist whether a biologic — or a newer oral targeted treatment — might suit you. This article is here to help you understand the landscape, not to choose for you.
- Targeted antibodies — block one signal: TNF-α, IL-23 or IL-17.
- Injection or infusion — not tablets (proteins are digested).
- Highly effective, not a cure — usually continued long-term.
- Infection is the key risk — TB/hepatitis screening; avoid live vaccines.
- Specialist-only — prescribed, screened and monitored by a dermatologist.
Biologics are targeted medicines that block one overactive immune signal in psoriasis — TNF-α, IL-23 or IL-17. Given by injection or infusion, they can clear skin dramatically and help psoriatic arthritis, but they control rather than cure, so they're usually long-term. The main safety concern is infection (more so with TNF inhibitors), which is why doctors screen for TB and hepatitis, manage vaccinations (avoiding live vaccines) and monitor throughout. Pregnancy isn't an automatic barrier — it's individualized. All of it sits firmly in the hands of a dermatologist.
What we find remarkable about biologics is the shift from "suppress the whole immune system" to "silence one precise signal" — it's targeted medicine at its best, and it's changed lives with severe psoriasis. It's also a firmly clinical space: the value here is understanding your options well enough to have a good conversation with your dermatologist, not picking a molecule. If you're in a TB-endemic area, note how central that screening step is — it's there to keep a powerful treatment safe.
Frequently Asked Questions
What are biologics for psoriasis?
Biologics (biotherapy) are targeted medicines made using living cell systems. They're usually antibodies that precisely block one immune messenger driving psoriasis — rather than broadly suppressing the immune system. Given by injection under the skin or by IV infusion, they're used for moderate-to-severe psoriasis and psoriatic arthritis when other treatments aren't enough, and are prescribed and monitored by a specialist.
How do biologics work for psoriasis?
Psoriasis is driven by overactive pro-inflammatory immune signals — chiefly the cytokines TNF-alpha, IL-23 and IL-17. Biologics are antibodies that block one of these targets: anti-TNF agents (such as etanercept, adalimumab, infliximab, certolizumab), IL-23 inhibitors (guselkumab, tildrakizumab, risankizumab), and IL-17 inhibitors (secukinumab, ixekizumab, brodalumab, bimekizumab). Calming the specific pathway clears plaques and can ease joint symptoms.
Are biologics for psoriasis safe? What are the side effects?
Biologics are generally effective and well-tolerated, but because they modulate immune signalling the main concern is infection risk — and not all are equal (TNF inhibitors carry more infection/TB risk than IL-17 or IL-23 inhibitors). Before starting, doctors typically screen for latent tuberculosis and hepatitis B, keep vaccinations up to date (avoiding live vaccines), and monitor throughout. Report fevers or infections promptly. Your dermatologist weighs the right option for you.
Do you need a TB test before starting biologics?
Screening for latent tuberculosis before starting a biologic has been standard practice, and it's especially important for TNF inhibitors and in regions where TB is common. Newer IL-17 and IL-23 inhibitors appear to carry a lower TB-reactivation risk, and guidance on routine testing for those classes is evolving. Your dermatologist will decide on screening (often including hepatitis B) based on the specific drug and your risk factors.
Can you take biologics during pregnancy?
It's not a blanket "no" — decisions are individualized with a specialist. Some biologics have reassuring data in pregnancy; certolizumab pegol in particular has minimal transfer across the placenta and may be used when treatment is needed. If you're pregnant, breastfeeding or planning a pregnancy, discuss it with your dermatologist and obstetrician so the choice fits your situation.
Boldpurity Science Team
Boldpurity is a clinical skincare brand with in-house cGMP manufacturing in Hyderabad, India, formulating evidence-led skincare for medium-to-deep skin tones. Content is prepared and science-reviewed by the Boldpurity Science Team.
Editorial Process
Articles are drafted from peer-reviewed dermatology literature and clinical guidelines, science-reviewed for accuracy, and kept at an education level. We describe prescription treatments factually, route all decisions to a specialist, correct outdated claims (for example, on TNF-α and on pregnancy), and make no product claims.
Reference Policy
Claims are supported by cited sources (see References), including dermatology guidelines on biologic therapy and current literature on infection risk, screening and vaccination.
Medical Disclaimer
This article is general information, not medical advice, and does not diagnose, treat, or recommend any specific medicine. Biologics are prescription treatments that must be selected, prescribed and monitored by a qualified specialist. Discuss diagnosis, options, benefits and risks — including screening, vaccination and pregnancy — with your dermatologist.
This article is educational, does not diagnose or treat any condition, and does not recommend any specific medicine or product. Biologics are prescription treatments prescribed and monitored by a specialist; drug names are given for information only. Consult a dermatologist about diagnosis, treatment options, screening, vaccination and use in pregnancy or breastfeeding.
- Menter A, et al. Joint AAD–NPF guidelines of care for the management of psoriasis with biologics. J Am Acad Dermatol. 2019.
- DermNet. Biologics for psoriasis. dermnetnz.org.
- National Psoriasis Foundation. Biologics. psoriasis.org.
- Menter A, et al. Drug survival of biologic therapy in a large, disease-based registry of patients with psoriasis (PSOLAR). J Eur Acad Dermatol Venereol. 2016.
