Acne remains one of the commonest diseases to afflict humanity.

If you do online surveys, tea tree oil appears to be

the second most commonly used topical treatment after benzoyl peroxide.

Though crowdsourcing may be a "novel research method

for evaluation of acne treatments,"

before getting too enamored with popular wisdom, you should know

that there's stuff like this circulating on the internet:

the facial application of urine as a home remedy for acne.

Urine therapy advocates cite historical use as proof of its therapeutic potential

as a free cure for many systemic diseases, apparently forgetting

all the godawful, crazy skeletons crowding the closets of medical history.

While recycling what the body intentionally removes

may seem counterintuitive to good health, what about Premarin?

The best argument this author could come up with for putting urine on your face is,

hey, women, after all, swallow pills made from pregnant horse pee.

I'm not exactly following the logic there.

Of course, there's drugs for acne;

there's always drugs, though along with drugs come drug side effects.

Antibiotics that suppress the bacteria that cause acne

are the standard treatment for acne, but are becoming less effective

presumably because of the emergence of antibiotic-resistant strains.

The prevalence of resistant strains has apparently grown rapidly,

such that antibiotics for acne are no longer recommended

just by themselves, with re-evaluations advised every six to eight weeks.

Well, the bacteria do seem to be susceptible

to tea tree oil in a petri dish,

but these kinds of studies were performed with free-floating bacteria,

whereas in pimples the bacteria form what's called a biofilm,

which makes them generally more difficult to eradicate.

The bacteria forms like a glue that plugs up the follicle,

so petri dish studies can only tell you so much.

Even if tea tree oil couldn't kill off the bugs, though,

it has been shown to suppress skin inflammation.

Like if you inflame people's skin with an allergen and then try to calm it down,

tea tree oil did a decent job compared to an over-the-counter ointment

or a moderate potency prescription steroid cream.

So potentially, tea tree oil could help with acne via an antibacterial mechanism

or from an anti-inflammatory standpoint,

but you don't know until you put it to the test.

A 20% tea tree oil gel applied twice a day and a beautiful drop in acne lesions

after one, two, three months. About 24 pimples down to about 11.

They conclude that the study showed that tea tree oil could significantly improve

mild-to-moderate acne, but who can tell me the study's fatal flaw?

Right, there was no control group.

How do we know they wouldn't have healed even faster without it?

In this systematic review of randomized clinical trials on tea tree oil,

their most striking finding is that they could hardly find any.

Given the widespread use of tea tree oil,

this is both disappointing and important to note.

But finally, a randomized, double-blind, placebo-controlled trial

of a 5% topical tea tree oil gel in mild-to-moderate acne.

After six weeks in the tea tree oil group,

a 40% drop in whiteheads and blackheads,

a 40% drop in red and tender acne bumps, and a 47% drop in pus-filled pimples,

compared to comparatively little change in the control group.

Overall, in terms of total lesion count,

the tea tree oil gel was 3.5 times more effective

than placebo, 3.5 times more effective than essentially doing nothing.

But most teens don't do nothing for their pimples.

How does tea tree oil compare to the gold standard, benzoyl peroxide?

We'll find out right now!

Benzoyl peroxide is by far the most popular over-the-counter acne therapy,

despite its side effects.

It can be irritating, causing redness, dryness, peeling, stinging, burning.

However, the prescription option,

the long-term use of topical or oral antibiotics,

is discouraged due to the development and spread of antibiotic resistance.

As a result, attention has turned to non- antibiotic products such as tea tree oil.

The benzoyl peroxide did cause more side effects—

dryness, itching, stinging, redness, burning—but it worked better too,

cutting the number of inflamed pimples by two-thirds within three months

versus only by half in the tea tree oil group,

though the most recent study found them to be more comparable.

Putting all the studies together,

and tea tree oil products not only beat out placebo,

but approximate more standard regimens like benzoyl peroxide

or topical antibiotics, suggesting tea tree oil products

may be an appropriate option for treating mild-to-moderate acne.