Will Selsun Blue Help Pass a Hair Follicle Test? Where the Rumor Comes From and What It Can Really Do
Old Style Aloe Toxin Rid, sold direct by TestClear. Read our how-to before you buy.
Ad: we may earn a commission if you buy through this link. Information only, not medical or legal advice. Tampering with a drug test can be illegal and usually counts as a refusal. The only sure way to pass is to not use.
Selsun Blue has been passed around drug test forums for years as a cheap drugstore fix for a hair follicle test. The short answer is no: there is no evidence that Selsun Blue helps you pass a hair test. It is an anti-dandruff shampoo built to treat flaky, itchy skin on the scalp, and a hair test measures drug that is locked inside the hair strand, not anything sitting on the scalp. This page explains where the rumor started, what the active ingredient does, what using a lot of it can do to your hair, and what is more useful to do first. We may earn a commission if you buy through our links.
The quick verdict
Selsun Blue is a fine product for dandruff. It is not a drug test product, its maker has never claimed it affects drug tests, and no study shows it lowers drug levels in hair. Washing with it several times a day won't change what is inside the cortex of hair that has already grown out of your scalp. The only sure way to pass a hair test is not using during the window the test covers, which is roughly the last 90 days for a standard head hair sample.
Where the Selsun Blue rumor comes from
The idea goes back to early internet forums, long before today's detox shampoos were widely sold. A few things helped it spread:
- It is cheap and everywhere. Any drugstore or grocery store has it, which makes it an easy thing to try with a test a few days away.
- It is a "medicated" shampoo. The word medicated sounds strong, and people assumed a stronger shampoo must clean deeper.
- Selenium sounds technical. Some posts claimed selenium "binds" to drugs or "strips" them out of hair. There is no published evidence for that.
- Survivor stories. Someone used Selsun Blue, passed, and posted about it. Nobody posts the full picture: how much they used, when they last used, the test panel, or whether they would have passed anyway. Light or infrequent use can test negative with no shampoo at all.
Forum threads from that era also mixed in rumors about hair tests for urine-style "masking," which doesn't apply to hair at all. A hair sample is cut, washed by the lab and analyzed. There is nothing for a shampoo to mask.
What Selsun Blue actually is
The classic Selsun Blue formulas use selenium sulfide as the active ingredient, typically at 1 percent in the over-the-counter versions. Stronger selenium sulfide shampoos and lotions, around 2.5 percent, are sold by prescription. Some products under the brand use other dandruff ingredients, so read the label on the bottle you have.
Selenium sulfide is an antifungal and anti-dandruff agent. It works mainly on the skin of the scalp. It slows down the overgrowth of a yeast called Malassezia that lives on most people's skin and plays a role in dandruff and seborrheic dermatitis, and it slows the rapid turnover of skin cells that produces flakes. Doctors also use selenium sulfide for a fungal skin condition called tinea versicolor. None of those jobs involve the inside of the hair shaft.
Why a dandruff shampoo can't reach what a hair test measures
When you use a drug, small amounts reach the hair follicle through the bloodstream and become part of the hair as it forms under the skin. Sweat and oil can add some on the surface too. As the hair grows out, those compounds are trapped inside the cortex, the dense core of the strand under the protective cuticle.
At the lab, technicians wash the hair sample before testing specifically to remove surface material, such as smoke, residue and hair products. Then they break down the hair and screen it, usually by immunoassay, against cutoff levels. Anything that screens positive is confirmed with a more precise method such as mass spectrometry. A shampoo works on the surface for a few minutes. The lab's own wash already targets that surface. What decides the result is what is left inside, and Selsun Blue is not designed to get there.
What heavy Selsun Blue use can do to your hair
Used as directed, usually a couple of times a week, selenium sulfide shampoo is safe for most people. Using it many times a day for a week to try to beat a test is different. Known side effects from product labels and medical references include:
- Dry or oily hair and scalp, and a rough, straw-like feel when it is overused.
- Hair discoloration, especially on blond, gray, white or chemically treated hair. Rinsing well helps reduce this.
- Scalp irritation, burning or itching, which gets more likely the more often you wash and the longer you leave it on.
- Unusual hair shedding has been reported in some people.
- Eye irritation if it runs into your eyes.
Labels also say not to use it on broken or inflamed skin. If you were already scrubbing your scalp with other products, it is easy to end up with a raw, stinging scalp and nothing to show for it.
Selsun Blue compared with detox shampoos
| Product | What it is made for | What the seller claims about hair tests | Independent proof it beats a hair test |
|---|---|---|---|
| Selsun Blue | Dandruff and seborrheic dermatitis | Nothing; it isn't marketed for drug tests | None |
| Old Style Aloe Toxin Rid | Deep-cleansing hair shampoo sold for people facing hair tests | Sold as a hair test cleansing shampoo with a multi-day schedule | None |
| Zydot Ultra Clean | One-time cleansing shampoo kit used on test day | Sold as a hair test cleansing product | None |
| Regular clarifying shampoo | Removing product buildup and hard-water film | Nothing | None |
The honest summary is that none of these has published, independent proof. The difference is that detox shampoos are at least designed and sold for this situation, with directions built around it, while Selsun Blue simply isn't.
Ad: we may earn a commission if you buy through this link. Information only, not medical or legal advice. Tampering with a drug test can be illegal and usually counts as a refusal. The only sure way to pass is to not use.
Where Old Style Aloe Toxin Rid fits
If you are looking at shampoos because of a hair test, the product most guides name is Old Style Aloe Toxin Rid, sold by TestClear. Here is what the seller presents, and where the evidence stops.
- What TestClear claims: a deep-cleansing shampoo that removes buildup, residue, chlorine and minerals from hair.
- Maker's directions: wash with regular shampoo first, then apply Old Style Aloe Toxin Rid to damp hair, massage into the scalp and roots, leave it on for 10 to 15 minutes and rinse with lukewarm water.
- Schedule: daily washes over several days before a test, more often if time is short, often paired with Zydot Ultra Clean on test day.
- What isn't proven: no independent published study shows it beats a hair follicle test, and reviews are anecdotes.
You can see Old Style Aloe Toxin Rid at TestClear, and our Aloe Toxin Rid shampoo review and how-to guide covers the directions, wash schedules and honest limits in detail.
A better first step: test yourself
Before spending money on any shampoo, find out whether you would actually test positive. A home hair follicle test kit sends a hair sample to a lab and gives you a result before the real test. If it comes back negative, you don't need to do anything to your hair. If it comes back positive, you know where you stand and how much time you may need. Our guide to the best hair follicle drug test kits explains how they work, and how long it takes to pass a hair follicle test walks through the 90-day window and hair growth math.
Other drugstore products people ask about
Selsun Blue isn't the only bottle with a reputation. Head and Shoulders, Neutrogena T/Sal, Nizoral, Suave clarifying, dish soap and laundry detergent all show up in the same threads. The pattern is the same: none is made for drug tests, none has evidence behind it, and the harsher ones (dish soap and detergent) can badly irritate your scalp. If your hair is dry or damaged, our page on Macujo method hair damage covers how stripping routines affect hair and how to recover.
Should you use Selsun Blue at all?
If you have dandruff, sure. It is a common, well-understood dandruff treatment. Follow the label, rinse well and condition the ends if your hair feels dry. Just don't count on it for a drug test, and don't stack it with other harsh products in the days before a collection.
Our sourcing
Information on selenium sulfide comes from standard drug references and over-the-counter product labeling. Hair testing steps reflect published laboratory practice for washing, screening and confirmation. Old Style Aloe Toxin Rid claims and directions come from TestClear's product page. We haven't tested any shampoo on real samples and we don't publish testimonials. See our editorial methodology.
Tests this page does not apply to
Do not use any shampoo or product mentioned here for DOT-regulated tests (truck drivers, CDL holders, rail, transit, pipeline, maritime), FAA aviation testing, federal employee programs, military testing, or court, probation and parole testing. Tampering with those programs can count as a refusal and may be illegal.
Disclaimer and support
Informational only, not medical or legal advice. Tampering with a drug test may be illegal and can count as a refusal or failed test. The only guaranteed way to pass is abstinence. Free, confidential help is available 24/7 from the SAMHSA National Helpline at 1-800-662-4357, and you can call or text 988 if you're in crisis.
Questions people ask
Does Selsun Blue help you pass a hair follicle test?
There's no evidence it does. Selsun Blue is a dandruff shampoo that works on the scalp's skin. Hair tests measure drug locked inside the hair strand, and labs wash samples to remove surface material before testing.
What is the active ingredient in Selsun Blue?
The classic formulas use selenium sulfide, usually 1 percent in over-the-counter versions. It is an antifungal and anti-dandruff agent. Some products under the brand use other active ingredients, so check your bottle.
Can Selsun Blue damage hair if I use it a lot?
Overuse can dry or irritate the scalp, make hair feel rough, and discolor light, gray or chemically treated hair. Some people report extra shedding. Use it as the label directs.
Is Selsun Blue better than a detox shampoo for a hair test?
Neither has independent proof of beating a hair test. Detox shampoos such as Old Style Aloe Toxin Rid are at least designed and sold for this situation; Selsun Blue isn't marketed for drug tests at all.
What should I do first if I have a hair test coming up?
Take a home hair follicle test so you know where you stand, and check exactly which test and panel your employer uses. The only sure way to pass is abstinence.
Can I use Selsun Blue for a DOT or court test?
No. Don't use any product to try to affect DOT, FAA, federal, military, court, probation or parole tests. Tampering can count as a refusal and may be illegal.
Ad: we may earn a commission if you buy through this link. Information only, not medical or legal advice. Tampering with a drug test can be illegal and usually counts as a refusal. The only sure way to pass is to not use.
No product can promise you a pass, and the only certain way is to not use. Tampering with a drug test can be illegal and is usually treated as a refusal. We never help anyone beat DOT, federal, safety-sensitive, or court-ordered tests. If substance use is getting on top of you, call the free, confidential SAMHSA National Helpline on 1-800-662-4357 (24/7, English and Spanish), or call or text 988 in a crisis. Source: samhsa.gov.