Don't waste money with "magic potions" ! There are very very few chances to solve the problem. If your service history is good and you changed oil and filters with good ones and in proper time, chances drop to ZERO. Possibly a lifter is damaged or the cylindered itself is damaged. Either way, some concentrated oil derivate will not make miracles, especially when the problem is clear at cold starting.
My advice is to investigate the lifters and replace the "sick" ones.
You may have another solution, but first tell us what oil and filter you use.