I noticed mine thinning aged 40 ish around the temples and was quite worried.
I immediately started grow gorgeous serum, perfectil hair and nails and nioxin shampoo and conditioner.
Now post-menopause and still have a good head of hair
The shampoo is a topical treatment and contains no special ingredients, so I don't think that is the secret. Do not fall into the trap of associating hair-fall in the shower with net hair loss: You need to keep your scalp clean to allow the follicles to work efficiently, so wash as often as is needed.
Perfectil does work as a good daily supplement for women's health anyway and is pretty cheap, so that was easy enough.
Grow gorgeous is not cheap, but you don't need much. I only use it after washing my hair, as it's so much easier to apply when damp and I only put it on the parting and temples. I have recently switched to the Ordinary version, as it's cheaper and contains more active ingredients. I also purchase the active ingredients myself (Bristol Botanicals/Naturally Thinking) and add a small additional amount with a pipette and funnel. (I did try to formulate my own, but could not get the consistency correct)
I have always taking 1000mg EP oil daily and eat oily fish 1x per week