Vans and Hollister tshirt - sizing for teenage boy

[headinclouds101]

Have been asked to buy the above as a present for boy 15 tallish, muscular build but quite slim.
As far as I can work out the "small" in men's sizes should be okay - but no experience of whether these things come up big or small. Advice from anyone with first hand experience appreciated.

I was forced into Hollister by my teenage daughter over the summer and the combination of young people, murkiness and overpriced handkerchief sized pieces of clothing meant that I had to escape before I bought her anything. However I have two skinny teenage lads, about 5' 11", and I buy them size small in Topman, River Island etc and I would imagine that Hollister probably runs a bit small. As far as I can tell Vans are true to size. Hope that has been of some help.

Have not bought Hollister but a size M from Diesel fits my skinny 11 year old!

My 15 year old son, who would wear a medium from H&M etc is an XL in Superdry and Firetrap.

That's probably no help at all but what I am trying to say is these brands come up extremely small.

My son is a tall slim but muscular 14 year old and a medium in hollister (my almost 10 yr old wears small!!) vans come up small as well I find.
In the US we purchased two age 14-16 vans tshirts for my 14 yr old foolishly not making him try them on, they are far too short for him the small is a nice fit but not much room to grow. The vans 14-16 boys is a nice fit on the younger boy.
So in summary I would size up.

Thanks - I thought they might be small.

KW - how old is your younger boy?

Oh sorry - have just read again - he's not quite 10!

hes almost 10, but is tall for his age and chunkier than ds1, and would usually wear an 11-12.