How Not to Go Bald

Losing your hair as you age is a concern for many men, and some women. Baldness isn’t a health problem and it won’t shorten your life, so it’s perhaps a little off-topic for this blog. But if you can find a treatment that’s cheap, easy, harmless, and effective, isn’t it worth giving it a shot? Today I turned 31, so I took a look at the evidence on Rogaine.

A shaggy surprise

Rogaine is the brand name for a drug called minoxidil. In 1979 it was approved as a treatment for high blood pressure. Increased hair growth came as a surprising side effect that set off years of legal disputes over the rights to a treatment that would be a lot more profitable than a blood pressure medication.

Doctors quickly started prescribing minoxidil off-label for hair growth. In 1988 Rogaine finally hit the market as a 2% topical solution for male hair loss. Later studies showed that it also worked for women and that a 5% solution worked better than 2%. A lack of serious side effects eventually led to its approval as an over-the-counter drug.

Supportive science

A meta-analysis found that a 2% solution of minoxidil caused growth of an additional 8 hairs per square centimeter in men and 12 hairs per square centimeter in women. A 5% solution gave men an extra 15 hairs per square centimeter (no results were reported for women at this concentration).

But did the effect last? Men in the 2% solution group had slightly less hair after five years of treatment than at the one-year mark, but still more hair than when they started. The worst side effect observed was itchiness, which was much less common in the 2% solution group.

Busting Rogaine myths

There are myths to be busted about Rogaine. I’ve heard people say things like “Rogaine won’t make your hair grow back, it will just prevent further hair loss.” But that’s not entirely true.

If you are completely bald, it’s true that Rogaine won’t bring your hair back. And if a receding hairline is your primary concern, the product probably won’t bring back hair in areas where it’s completely gone. These studies focused on top-of-the-head replenishment. A rule of thumb I’ve heard (without direct evidence, but it’s consistent with these studies) is that once a patch of your head has turned shiny and hairless, it’s too late for Rogaine to make a difference. But if there’s a part of your head that has some hairs, just not as many as used to be there, it’s very likely Rogaine will bring back at least some of them.

The asymmetric eyebrow experiment

Some people have become so enthused about Rogaine’s effectiveness that they’ve run some bizarre experiments. A side effect I didn’t mention before is excessive hair growth in places where the solution drips down accidentally. Of course, it might not make sense to say that excessive hair growth is a ‘side effect’ of a drug intended to cause hair growth.

Anyway, one study tested whether rubbing 2% minoxidil lotion on people’s eyebrows would make their eyebrows grow more. They had people randomly rub different lotions on each of their eyebrows — with one of the lotions being a placebo and the other the real deal. It worked as expected. The test subjects spent 16 weeks walking around with asymmetrical eyebrows. I hope they were well compensated. Two other studies (summarized in this review) found similar results for eyebrows.

Yet another experiment (summarized in the same review) tested whether a 3% minoxidil lotion would enhance beard growth. Again, it did.

These studies are very high quality, so we can be confident that the effect was real. People don’t normally drip medicine all over their heads, so it’s unlikely that the control group (or control eyebrow) was exposed to the drug or a similar hair-inducing substance. This is very different from nutrition experiments, in which it’s nearly impossible to keep track of what people eat. And the outcomes happen fast. The researchers simply wait a few months and count the number of hairs in a square-centimeter patch of scalp. That’s much faster than tracking whether a drug reduces heart attacks or causes death. Outcomes like those are so rare, and influenced by so many other factors, that it takes much larger, longer studies to collect a strong signal.

Attain your mane

Rogaine, then, turns out to be very effective. You can buy products containing the generic version, minoxidil, just about anywhere at very low cost. And while a resplendent head of hair isn’t going to help me live to 115, I see no reason not to try it out. Maybe by my next birthday I’ll look like Chewbacca.

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