I made it using typical Tresemme shampoo.
My dermatologist lurched back with her eyes popping out of her head in shock when I told her that my hair shedding had completely stopped since the last time I saw her which was 3 months prior. I had been on Minoxidil for 9 months and it hadn't done a thing for me but based on her shocked reaction to my recent results.
Make sure that you buy a really good pH meter so that you can measure the amount of vitamin C that you put in your hair. Also don't do more than 2 treatments per week and use a shit load of conditioner (probably daily).
The problem with vitamin C is that its highly acidic and this makes your hair cuticles close up extremely tight making your hair look like you stuck your finger in a light socket sometimes or if you over treat. Conversely if a shampoo is too alkaline then your hair will friz out.
This is the ph meter that I used. I wouldn't use a lesser meter as those are notoriously unreliable.
If you keep the shampoo in between 4.5 and 5.5 then you should be safe. I started using the shampoo at 3.5 and it worked fast but could damage your hair shafts just as quickly.
2 in 1 Temperature pH Monitor Meter Tester Sensor Test Kit 0~14 pH Measure Automatic Calibration BNC Electrode Probe for Hydroponics Aquarium Lab Testing Drinking Water Food pH of Saltwater/seawater https://www.amazon.com/dp/B08SJ7XFBY/ref=cm_sw_r_cp_api_glt_fabc_RYJYNTGH2Y3S4HKQRZC5?_encoding=UTF8&psc=1
I bought this one and I took the ph with my master test kit and it was 7 and this one reading 6.94 and I had to calibrate it with solution before putting in my tank
I have had this monitor for PH for a couple of years.. I have replaced the probe, but I was also able to clean the old one and get it back to reading within .2 with just a soap and water solution. I keep this in and on 24/7. After a certain time, it switches to only getting readings every 10 minutes so it saves on battery life.
https://www.amazon.com/dp/B08SJ7XFBY?psc=1&ref=ppx_yo2ov_dt_b_product_details
As for EC/PPM I use a Truncheon.. I check daily, just cause I am anal... It literally takes less than a minute...