Can I dread thin or thinning hair? - Dreadlocks FAQ's
If your hair is sparse or thin it is because you have fewer hairs per square inch on your scalp. Did you know that blonds tend to have the thickest, most dense hair while redheads on average have the thinest? Since the number of hairs in a dread determine it's size, those with thinner hair will need to make larger sections so the dreads have the right amount. Your hair density will also vary over different areas on your scalp, so it may be very full or dense in the back and very thin or sparse in the front. The differences can be due to genetics (you've always had fewer hair follicles in that area of your scalp), or they could be due to follicles no longer producing hair. Shampoo residues are one cause of this, check out the residues page for more info. The challenge of sectioning is to try to balance these difference out so your dreads end up roughly the same size. It's not a big deal if they don't end up the same size, it just depends on what you're going for.
That's the question. It's easy to compensate for a hair that is a little sparse, in fact, in many cases dreads tend to hide thinning hair to some degree. However at some point the sections would need to be huge to have enough hair to make a decent dread. If you only have 12-20 dreads they are going to be very sparse and they are going to call attention to the thinness of the hair. If you gather your hair from a 1" square section and the bundle of hair is a bit smaller than the width of a pencil, your hair density in that area of your scalp is about average. If it's less than 1/2 the width of a pencil you may find it challenging to strike a balance between having full looking dreads and having dreads that have enough hair to lock easily.
If it seems to be thinning rapidly I would try to figure out why before moving forward with dreads. Poor nutrition is a likely candidate but it could be other things as well. If it's normal thinning due to age and genetics (thinning may be normal in your family at your age) then you can probably predict what areas are likely to thin the most. You can actually compensate for thinning that hasn't happened yet by making sections in areas that are likely to thin further a little larger. Remember, once hair is dreaded it doesn't shed, so you'll be able to keep every strand that sheds away. =] Of course this isn't going to sustain for ever but if you can enjoy dreads for 5 or 6 years you should!
Actually, dreads will likely have the opposite effect. Most people that switch from using shampoos with residues to our residue free Dread Soap find that their hair is noticeably thicker. This makes sense, because shampoo residues are a primary cause of follicle damage. Another factor you can control is stimulation of the scalp. The Head Honcho works brilliantly for this. You occasionally hear about peoples dreads getting so thin at the roots that they can not hold the weight of a dread and they break. This has a lot to do with the thickness the dreads were to start. Starting dreads with way too little hair in each dread (2/8" sections or something crazy) will quickly lead to problems as the dreads get longer and heavier. This is more common in ethnic hair types since the extra texture makes dreads in sections that small possible. Healthy hair, can hold a very long dread with no problems, as long as there are enough hairs in the dread to support the weight. I don't know what each hair supports on average (think of the force it takes to pop one out), in any case, when you add 800 or so together it's held on pretty durn good.
Even if you're not ready to run off and visit a nutritionist, but you want to keep your hair to grow thicker, longer and faster, I'd consider adding more raw fruits and veggies to your diet. You can also supplement with a combination of vitamins and herbs to assist strong hair growth. I've been taking the Supa Growth Supplement for a while now and I've been really impressed by the results. Every situation is different, but if you give some thought and planning to your sectioning you will likely be able to make gawjus dreads you're really happy with even if you hair is more sparse than average. =]