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what is the normal size of penis :

1. lenght : 8-18 cm 
2. width : 4-5 cm 
3. circumfrance : 10-12 

how to increase penis size to reach  8 inchs ( 20 cm ) :

- the only medical way to increase penis size effective in wide range is surgical and there is no medication that increase penis size in that range 
- surgeries may increase penis size in range of 5-10 cm to the original size , but its not for sure to reach 20 cm ( 8 inch ) 
- surgical options are :
1. there is a surgical option that may increase you penis size about 4-6 cm by cut out the internal tendons that connect pelvic area to your private area and leave bigger space to penis to increase 
2. there is a plastic surgery that increase penis size by implanting silicon implants in the upper areas of penis goes into the internal area of penis and it increase penis size around 6-8 cm

our advice :

silican implanting surgery would be the most the suitable option for your requests , consult a plastic surgery doctor about those options and its effectivness to your condition 
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