Hi I'm an ex stylist and did a training course in hair science. Silicones are virtually in every cosmetic product hair, skin and even more shockingly in bowel products i.e. anti bloat products

they have many benefits one of the main reasons for their use, is that they are anti foaming agents (which is why if you have a lot of silicone build up it can take several shampoos before one notices significant lather).

Secondly as mentioned above they coat the hair shaft creating a smooth even barrier (keeps cuticles flat and sealed) that holds in and maintains moisture levels leaving a silky feel to the touch whether it be skin or hair. This barrier repels external moisture penetrating the barrier in humid environments which can result in frizz or re-curl of straightened hair (it also has anti-static properties to prevent frizz and dust build up, like when implemented into furniture polish products)

Silicones are non greasy, not oil based and do not weigh the hair down as much giving a cleaner shinier finish that doesn't attract dirt. Some even benefit from anti bacterial/microbial and fungal properties.

To me the biggest disadvantages of silicones are that you get silicone build up. Most people probably do not associate the short term cure of silicones with the mid-long term side effects.

Basically as virtually all products now contain silicones most of which the cheaper bad silicones which are hard enough to wash away as it is and then by topping them up with fresh silicones in the process of trying to wash them away can result in serious build up with in many cases dirt being trapped between the layers of build up. This causes uneven loss in sheen along the hair shaft.

Build up also prevents vital amino acids and proteins found in the shampoos and conditioners to penetrate into the cortex which are to help rebuild the hairs internal strength, increase its elasticity, style retention, and prevent breakage and snapping.

In the case of serious build up on the hair, the hair shaft has reached saturation point silicones no longer sit evenly and smoothly on the hair. It is as if they are holding on for their life like an overcrowded human pyramid, with bits falling away and being replaced every so often but the oldest inner layers have cracked from the constant movement and styling of the hair that it begins crumbling away. Fortunately now there are ex foliating products for hair and scalp which are silicone, paraben and SLS free to get rid of this build up.

So the result is hair that looks brittle and lifeless, most likely has no internal strength left and will likely also break off.

Yes silicones are great but they need to be used in moderation, realistically the should be part of say a maximum 2-4 week treatment/masque and not part of ones daily shampoo/conditioning routine. Always rinse thoroughly.

Too much of a good thing is never good, the same applies for too much protein, amino acids and carbohydrates as going along the damaged hair route purely will surely strengthen your hair but it will becomes so stiff and rigid (also may result in breakage) that it will need softening down with added moisture in-between to get a good balance.

Finally I recommend anyone who has a sensitive scalp, prone to redness, itchiness, dandruff, psoriasis and other similar scalp conditions stay clear of silicone products as they can seriously aggravate the condition.

As I mentioned above the issue of build up has it problems and on the scalp the silicone attaches it self evenly to the scalp and also to any dead keratinized skin which can cause many problems. Resulting in exaggerated padded out clumpy flakes that can become like shards of broken glass against the scalp increasing irritation or heavily increase the moist clog of a psoriasis sufferer by increasing the surface area for the yeast infection to spread.

The scalp needs to therefore be ex foliated which can be hard as there is hair throughout it and rinsed thoroughly to remove all flakes and residue, preferably with a silicone free product so not to increase the build up.

(to "Hairenough") Shower gel will remove superficial oils,dirt without opening the hair cuticle or stripping the hair too much but clean the scalp nicely.

To prevent colour fading anti-oxidants are a good bet, pH Balance of between 4.6-5.5 and up to 6.5 max will keep the scalp and acid mantle nice and healthy, also will keep the cuticle nicely balanced and least likely affect any chemical work done to the hair at the factory i.e. perms, relaxers and colour processing

Products with the least ingredients will generally give you better results in the long term as they conflict less with each other, also as the ingredients tend to separate by molecular weight size as hair dries, this especially noticeable in styling products with lots of ingredients in-particular when silicone is present due to the barrier being formed on the hair the ingredients are either trapped in the cuticle or slide away when sat on top of the silicone coating, giving the appears of a layer of slime or film that coats the hair.

If you are going to use silicone please use in moderation

Wow I think I've chatted way too much for my first thread reply hehehe
tried putting it in layman's terms hope its legible.

NB if anyone actually makes it to the end of this your more than welcome to make a summarized version of my post for clearer reading.

Thanks for reading

Animehair, 24, UK