If you go and see any doctors / NCS, they will just recommend you to use Rogaine. If serious cases, they will recommend you to take finasteride but there will be side effects. These are the only 2 FDA-approved treatments. nothing else, so don't bother trying any other magical formulas u read online, just gonna waste your money.
You can purchase rogaines from local sellers on eBay. its 3X cheaper than getting from the pharmacy. usually received within 2-3days. just make sure its from local and have sales track record.
finasteride needs a prescription. as its consumed on daily basis, I do not recommend you getting it online. 1 year supply from KTPH cost me about $300+.
Revita Shampoo and conditioner. Best I have ever tried and still currently using is Revita Anti DHT shampoo and conditioner. after trying many shampoos for many years. this actually show visible improvement and I'm sticking to it. You can get it easily from either Lazada or Shopee. Come in 2 sizes. the big one is more value for money.
Start treatment + using good shampoo early. Once the hair follicle died/closes off, nothing can revive the dead cells. the only solution left will be hair transplant or wear a wig.