Topical Steroid Potency Chart: How to Choose the Right Strength and Avoid Skin Damage

Using the wrong strength of topical steroid can ruin your skin-thin it out, stretch it, turn it red, or even trigger a rebound flare. Yet most people don’t know what strength they’re using, or why it matters. It’s not about going stronger for faster results. It’s about matching the right potency to the right skin, the right area, and the right duration. A potency chart isn’t just a doctor’s reference-it’s your safety guide.

What Does Steroid Potency Even Mean?

Topical steroids aren’t all the same. One cream might be 100 times stronger than another, even if they both say "hydrocortisone." Potency refers to how powerfully the steroid reduces inflammation and suppresses the immune response in your skin. Higher potency means faster relief-but also higher risk of damage if used wrong.

The U.S. FDA classifies topical steroids into seven classes, from Class I (superpotent) to Class VII (least potent). Class I includes drugs like clobetasol propionate (Temovate) and halobetasol (Ultravate). These are used for thick, stubborn plaques-like severe psoriasis on elbows or knees. Class VII is your over-the-counter hydrocortisone (0.1%-2.5%), safe for short-term use on mild rashes or insect bites.

But potency isn’t just about the name on the tube. Three things change how strong a steroid really is:

• Molecular structure (60% of potency): Some steroid molecules bind more tightly to skin receptors.
• Concentration (25%): A 0.05% cream is stronger than a 0.01% cream of the same drug.
• Base formulation (15%): Ointments trap moisture and absorb deeper than creams. A hydrocortisone ointment can be nearly twice as effective as the cream version.

That’s why two products with the same active ingredient can behave differently. For example, Elocon (mometasone furoate) is 25% stronger than Advantan (methylprednisolone aceponate), even though both are classified as moderate potency. You can’t guess-you need the chart.

Why Potency Charts Reduce Side Effects by Over Half

Using a high-potency steroid on your face? That’s a common mistake. The skin there is thin, sensitive, and absorbs more. Studies show applying Class IV or higher steroids to the face increases the risk of skin thinning, visible blood vessels (telangiectasia), and acne by four times.

But here’s the fix: when doctors use potency charts, side effects drop by 58%. Why? Because they match the right strength to the right place.

• Face, eyelids, genitals: Stick to Class VI or VII-hydrocortisone 1% or 2.5%. Never use Class I-III here.
• Body (arms, legs, torso): Mild to moderate (Class IV-V) works for eczema flares. Use for 1-2 weeks max.
• Thick skin (palms, soles, scalp): You can use Class II-III for up to 3 weeks if needed for psoriasis or severe eczema.

And don’t forget the body site trick: skin folds (armpits, groin, under breasts) absorb steroids faster. So if you’re using a Class IV steroid on your inner elbow, it’s acting like a Class III on your forearm. That’s why Australia’s Skin Health Institute recommends dropping down one potency class when applying to skin folds.

How Long Is Too Long?

It’s not just strength-it’s time. Even the right steroid can hurt you if you use it too long.

Here’s what the guidelines say:

• Class I (superpotent): Never use more than 2-3 weeks straight. Long-term use can cause adrenal suppression, especially in kids.
• Class II-III (high to moderate): Limit to 3-4 weeks. After that, switch to a moisturizer or non-steroidal option.
• Class IV-V (moderate): Can be used for up to 8-12 weeks if needed, but only under supervision.
• Class VI-VII (mild): Safe for longer use-some people use hydrocortisone 1% twice weekly as maintenance for eczema.

That’s why the American Academy of Family Physicians says: no ultra-high-potency steroids for more than three weeks. Ever. The evidence is clear: beyond that, the risks outweigh the benefits.

And kids? They’re even more vulnerable. Children have thinner skin and a higher surface-area-to-weight ratio. A dose that’s safe for an adult can cause hormonal disruption in a child. The American Academy of Pediatrics says to cut adult doses by 50-75% and never use anything stronger than Class V for more than 14 days in children under 12.

The Fingertip Unit: How Much to Use (And Why Most People Use Too Much)

You don’t need a thick layer. In fact, using too much is one of the biggest reasons people get side effects.

One fingertip unit (FTU) is the amount of cream or ointment squeezed from a tube from the first crease of your index finger to the tip. That’s about 0.5 grams. One FTU covers an area equal to two adult hands (palms and fingers).

Here’s how many FTUs you need:

• One adult hand: 1 FTU
• One arm (front and back): 3 FTUs
• One leg: 6 FTUs
• Entire back: 8 FTUs

Studies show 35% of patients use 2-3 times the recommended amount. That doesn’t make it work faster-it just increases absorption and raises your risk of skin thinning, stretch marks, and even systemic effects like adrenal suppression.

What About Facial Eczema and Psoriasis?

Facial eczema affects about one in three people with atopic dermatitis. It’s tempting to grab your strongest steroid-but that’s the worst move.

Research shows using mild steroids (Class VI-VII) on the face reduces skin atrophy risk by 65% compared to moderate ones. So if you have red, flaky skin around your eyes or cheeks, stick to hydrocortisone 1% or 2.5% for no more than 7-10 days. After that, switch to a ceramide moisturizer or a non-steroidal option like crisaborole (Eucrisa).

For scalp psoriasis? You can use Class II-III, but only as a solution or foam. Ointments are too greasy. Betamethasone dipropionate (Diprosone) foam is a common choice-used once daily for up to 4 weeks.

And if you’re treating plaque psoriasis on your elbows or knees? Superpotent steroids (Class I) can clear 90% of plaques in 4 weeks. But you must use them in short bursts-no more than 2-3 weeks-then switch to a maintenance plan with tar, calcipotriene, or phototherapy.

What the Charts Don’t Tell You

Potency charts are helpful-but they’re not perfect. They assume your skin barrier is intact. But if you have broken, cracked, or oozing skin-like in a severe eczema flare-your absorption rate jumps by 40-50%. That means a Class IV steroid on broken skin can act like a Class II.

That’s why some patients develop side effects even when they follow the chart. If your skin is damaged, use the lowest potency possible and focus on healing the barrier first with emollients. Then add steroid only if inflammation doesn’t improve in 3-5 days.

Also, newer formulations are changing the game. Hydrocortisone valerate 0.2% foam (Westcort) is 35% more absorbable than the old cream version-even though the concentration hasn’t changed. The FDA approved it in 2021, but many potency charts still list it as "mild." That’s a gap. Always check the product’s prescribing information, not just the chart.

What Patients Are Saying

On Reddit’s r/eczema community, 63% of users say they don’t know if their steroid is "moderate" or "potent." One person wrote: "I was using Eumovate on my face for months because I thought it was mild. My skin got so thin, I could see veins through it. I didn’t realize it was Class IV until my dermatologist called me out."

Another said: "Knowing my Daivobet was Class II helped me understand why my doctor only gave me a 4-week supply. I used it exactly as told-and my plaques cleared without damage."

But the numbers don’t lie: 29% of people using Class I steroids for more than 3 weeks report skin thinning. 12% using Class II-III for over 3 months develop visible blood vessels. These aren’t rare. They’re predictable.

How to Use the Chart Right

Here’s your simple action plan:

1. Identify your skin condition: Is it eczema, psoriasis, contact dermatitis?
2. Check the body site: Face? Genitals? Hands? Thicker skin?
3. Match the potency: Use the lowest class that works. Start low.
4. Use the FTU method: One FTU per two palm-sized areas.
5. Set a timer: No more than 2 weeks for strong steroids. 4 weeks for moderate. 3 months max for mild.
6. Switch to moisturizer: Once inflammation is down, stop the steroid. Use emollients daily.

If you’re unsure, ask your pharmacist or dermatologist: "What class is this steroid?" They’re trained to know. Don’t guess.

The Future: Smarter Charts

The next wave isn’t paper charts. It’s digital tools that adjust recommendations based on your age, skin condition, and past response. The American Academy of Dermatology’s updated tool now uses AI to suggest potency based on 15 factors-including whether you’ve used steroids before, how much skin is affected, and your skin type.

Even more exciting: wearable sensors that measure transepidermal water loss (TEWL) in real time. If your skin barrier is weak, the app could auto-recommend a lower potency. Pilot programs are already testing this in Australia and the U.S.

But for now, the best tool you have is the chart-and your awareness. Use it right, and you get relief without damage. Use it wrong, and you risk years of skin problems.