Testosterone and hair loss: what actually causes it

When it comes to testosterone and hair loss, it’s a tangled topic. There are different types of testosterone, different types of hair loss, and genetics plays a big part too.

Let’s start by looking at the different types of testosterone, and how they’re linked (or not) to hair loss.

The two types of testosterone

Testosterone circulates in your blood in two states: bound and free. 

Whilst around 98% of your testosterone is bound to certain proteins, just 2-5% of it roams around your body freely.¹ Some of that so-called ‘free T’ then gets converted into dihydrotestosterone (DHT) by an enzyme in your body.² DHT matters here, because it is the androgen most closely linked to hair loss. 

The links between testosterone and hair loss

There’s no real evidence behind the idea that testosterone levels affect hair loss. You might have high testosterone, you might have low, but the amount of testosterone we have is not what determines hair loss. It's how receptive our bodies are to DHT.²

DHT binds itself to the receptors on your hair follicles, which then slowly start to shrink your hair follicles.² Over time, this causes your hair to become thinner and shorter. Eventually this can prevent hair growth altogether.

So to avoid hair loss, we just need to make sure there’s less DHT in our system, right? Well, not quite.

Although DHT is the substance which can lead to hair loss, what really dictates hair loss is the sensitivity of the receptors on your hair follicles. The more receptive they are to DHT, the greater risk you’ll be of hair loss.³

Whether or not your body is receptive to DHT - and therefore prone to hair loss - is largely determined by genetics. It’s why male pattern baldness so often runs in the family.³ If your dad (and his dad) are both bald, it’s more likely that you’ll go bald too. However, that doesn’t mean you’re powerless to prevent it (more on that in the next section).

Still, it’s always a good idea to keep your testosterone levels balanced. It may not be directly linked to hair loss, but healthy testosterone levels have plenty of potential benefits for your health, including:⁴

• Increased energy levels

• Greater muscle mass

• More balanced mood levels

• Better ability to retain information

• Increased concentration levels

Fixing your testosterone levels won’t necessarily prevent hair loss. But there are other ways of doing that.

Not sure whether it's your hormones or your genes? A testosterone blood test will tell you where your levels actually sit, and a clinician can talk you through what is driving your hair loss and what can be done about it.

How to treat hair loss

Genetics may determine your body’s sensitivity towards DHT, but you can do more than simply crossing your fingers and hoping you dodge the bald gene in your family. Here’s how to slow down the production of DHT in your body, and protect your hair at the same time.

Finasteride and minoxidil together

If clinically approved, you can combat hair loss by with two different proven medications: finasteride and minoxidil.³ Each medication is clinically-proven to prevent hair loss, and there's evidence they work better in combination than either does on its own.

Finasteride works by blocking the enzyme in your body which produces DHT. This stops it from binding to your hair follicles and damaging them for good.

Once finasteride is doing its job, minoxidil reactivates those damaged follicles by increasing their supply of blood and nutrients. Over time, this allows your scalp to replace the old, damaged follicles with healthy new ones.

Both finasteride and minoxidil have been shown in clinical trials to improve hair growth. In one trial, minoxidil improved hair growth in roughly 70% of men.⁵ A separate trial reported improvement in 83% of men over two years.⁶

Used together, one comparative study reported a response rate of around 94%.⁷ Both are well-studied treatments with a long track record.

The numan take

Low testosterone does not directly cause hair loss, but it's never a bad idea to keep your testosterone levels in check anyway. Balanced testosterone levels can have a number of other health benefits, including better mood, more energy, and more sexual drive. If you’re worried about hair loss then there are clinically-proven hair loss solutions out there.

References

^{1. Antonio L, Wu FCW, O’Neill TW, Pye SR, Ahern TB, Laurent MR, et al. Low free testosterone is associated with hypogonadal signs and symptoms in men with normal total testosterone. J Clin Endocrinol Metab. 2016;101(7):2647–57}

^{2. Swerdloff RS, Dudley RE, Page ST, Wang C, Salameh WA. Dihydrotestosterone: Biochemistry, physiology, and clinical implications of elevated blood levels. Endocr Rev. 2017;38(3):220–54.}

^{3. Ustuner ET. Cause of androgenic alopecia: crux of the matter: Crux of the matter. Plast Reconstr Surg Glob Open. 2013;1(7):e64.}

^{4. Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, et al. Testosterone Therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–44.}

^{5. Olsen EA, Whiting D, Bergfeld W, Miller J, Hordinsky M, Wanser R, et al. A multicenter, randomized, placebo-controlled, double-blind clinical trial of a novel formulation of 5% minoxidil topical foam versus placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2007;57(5):767–74.}

^{6. McClellan KJ, Markham A. Finasteride: a review of its use in male pattern hair loss. Drugs. 1999;57(1):111–26.}

^{7. Hu R, Xu F, Sheng Y, Qi S, Han Y, Miao Y, et al. Combined treatment with oral finasteride and topical minoxidil in male androgenetic alopecia: a randomized and comparative study in Chinese patients: Efficacy of finasterid & minoxidil in Chinese AGA. Dermatol Ther. 2015;28(5):303–8.}