How can 2 pills be the exact same size but one is 2mg and one is 5mg?

[Moonlight85]

I have got Adaflex for my son (melatonin) for his awful sleeping habits. The 2mg pill wasn't enough so we have been moved to 5mg.
But the 5mg pill looks exactly the same size, width, height etc as the 2 mg. (Even though it has 5 imprinted on each pilI) I also looked up online and they have the exact same dimensions.
How is this possible for a pill that is supposed to be more than twice the dosage of the 2mg?
I also have him the 5mg last night and it didn't work as well as I had hoped.

@MollyButton and @myfavouritemutant my levo tablets change size every now and then. Last time I was given the big 25mg and tiny 100mg, and accidentally took my first dose the wrong way round. 2x100mg and 1 x25 instead of 2x25mg and 1x100mg. First thing dopiness. I do think that’s poor packaging!

Colour and size is determined by a lot of factors. Regulatory requirements limit the colour and ingredients. Colour is mostly determined by cost and marketing. The colour of a drug can also change around the world depending on the meaning of colours in a country. Most are white as most organic compounds are white.

Best explanation so far!

But really, OP, you should realise that you could not possibly see or take a pill that weighs only 2mg.

A milligram is a thousandth of a gram.
Let’s say your pill weighs a gram.
The 2mg pill is 2 parts active ingredient and 998 parts filler.
The 5mg pill is 5 parts active ingredient and 995 parts filler.
In brands where they are different sizes for different strengths it’s just to give a visual clue to avoid mixing them up.