Severe hair loss at very young age.

Nothing to do with thyroid. You may be suffering from androgenic alopecia which is also called as pattern baldness. The hairs start reducing in density at the crown (top) and also the hairline starts refeeding  from the front. This is usually progressive throughout life unless treated. This is usually accompanied by severe dandruff which we call seborrhoea. The FDA approved treatment for this condition is a lotion and tablets. There is no other alternative. No oil or cream will magically work because the hairs are getting miniaturised  and eventually disappearing due to the hormonal effects on the hair roots. Please call me or  contact me with photos using online consult option for proper examination and treatment. Do not start treatment without consulting. I can give guidance and then you can continue treatment on your own.