How to get a category of a product

I'm not sure if I can explain this properly, but I have 3 tables

users products categories

and what I'm trying to do is get the category that is attached to a product that is attached to a user. So far I'm only able to get up to the product but I'm not sure how to get the category.

Here is my code

My controller

public function getProduct(User $user)
{
    $products = $user->product;

    return [
        'products' => $products
    ]
}

and here is my User.php

public function products()
{
    return $this->hasMany(Product::class);
}

My Product.php

public function user()
{
    return $this->belongsTo(User::class);
}

public function category()
{
    return $this->belongsTo(Category::class);
}

and my Category.php

public function products()
{
    return $this->hasMany(Product::class);
}