Do you think using a hair thickening shampoo can help with beard growth?

Nope. Your beard is what it is.

The best way to have it come in thicker is a good close shave every day.

I second the daily shave.

There was an article that states that there’s no medical proof that daily shaving will help promote faster growth/more thicker hair.

I agree on it because I also tried shaving daily, but there’s still not enough beard

Some people don’t have much beard. A full blooded American Indian has almost no beard. It’s in their genetics.

^Yes. It’s genetic… Mine grows like a weed, but my half brother doesn’t even have to shave… His mother is of American Indian /Puerto Rican ancestry. He also looks younger than me, although he is almost 20 years my senior. ..

Amish men smear cow shit on their beards acting as a fertiliser to enhance growth.
Cute that they combine the past with horticulture…back to the fuchsia

Try exfoliating your skin. This means scrubbing to remove any dead skin, and open pores. Aside from that, there is nothing else to try that I can think of.
Even if so called thickening products worked, the most they can claim to do is puff up hair which is already there. None of them can start new growth.

I hope the whiskers aren’t too big a deal for you. Some men just don’t grow much of a crop ever. I had one brother in the Navy, struggling to get something to grow, my other brother was told to shave off his moustache when he was a high school freshman.
Neither is more macho than the other.

Since hair-thickening products don’t actually….you know….thicken hair, I can’t imagine their doing anything to improve someone’s….um….....beardiosity….