Men do it faster, earlier and more than women – lose their hair, that is. In fact, more than half of all men begin balding between the ages of 40 and 49 and, by age 60, two-thirds of men have moderate to extensive hair loss. Even as many as 25 percent of men have already started losing their hair before age 25.

So what makes men the winners when it comes to losing their hair? It usually comes down to hormones and heredity. Here’s what I mean:

Male pattern baldness – also known as androgenetic alopecia – is the most common type of hair loss among men. Hair begins to recede at the front hairline while hair at the crown of the head begins to thin, eventually leaving hair in that familiar U-shape around the sides and back of the head.

The culprit in male pattern baldness is a sex hormone called dihydrotestosterone, or DHT. When elevated levels of DHT are present in a man’s scalp, the hair follicles shrink and hair growth stops. This type of baldness is generally hereditary; however, contrary to popular belief, it’s not inherited solely from your mother’s father. The male pattern baldness gene can be passed down through your mother or father – or both.

Now, if all your male relatives have full heads of hair but you’re still losing yours, you have to look at other potential causes. First, ensure there’s no underlying disease – such as diabetes or thyroid problems – that can cause hair loss. Then, if no illness is involved, here are some other potential culprits:

If you’ve recently undergone surgery, a serious illness or traumatic life event, it could manifest as telogen effluvium, the medical term for hair loss that occurs after a physical or emotional shock to the system. Similarly, if you’re taking certain medications such as antidepressants, anticoagulants, beta blockers, retinoids and NSAIDS, these can contribute to this type of hair loss. So can poor nutrition (think low-protein consumption, iron deficiency or crash dieting). Here’s why:

Each human hair grows about a half-inch per month for two to six years – what’s called the anogen, or growth, phase. The hair rests at that length for a short period – called the telogen phase – then falls out. Soon afterward, a new hair begins growing in its place and the anogen phase begins again. About 85 percent of our hair is in the anogen phase at any given time.

With telogen effluvium, however, stress or some other trauma causes the hair follicles to enter the telogen (resting) phase prematurely. So while it’s normal to lose about 100 hairs a day as part of hair’s natural growth cycle, people with telogen effluvium can lose thousands of hairs a day. The good news, however, is that this is usually a temporary condition and one that resolves on its own.

Alopecia areata is an autoimmune skin disease characterized by hair loss on the scalp as well as other parts of the body. It’s estimated to affect nearly 5 million Americans. It usually starts with one or more small, round and smooth patches on the scalp; how it progresses is different for each individual.

A fungal infection called tinea capitis attacks the hair shafts and follicles of the scalp, eyebrows and eyelashes, causing bare patches of skin in infected areas. The incidence of infection has been reported to be five times greater in boys than girls before puberty, reversing after puberty.

Compulsive twisting and pulling of the hair until it breaks off is called trichotillomania. This condition is estimated to affect up to 10 million Americans, and symptoms usually begin before age 17. It occurs as frequently in boys as in girls during early childhood, but by adulthood only 10 to 20 percent of reported cases are men.

Because there are so many diverse potential causes of hair loss, it’s important to have a thorough, in-person examination by a qualified physician to obtain an accurate diagnosis. Fortunately, there are numerous effective medical and surgical treatments for most of these conditions, as well as state-of-the-art options for hair transplantation and restoration.