They're equally fast: julia> @btime fact_prod(10000) 7.833 μs (0 allocations: 0 bytes) julia> @btime fact_loop(10000) 7.908 μs (0 allocations:

They're equally fast: julia> @btime fact_prod(10000) 7.833 μs (0 allocations: 0 bytes) julia> @btime fact_loop(10000) 7.908 μs (0 allocations: 0 bytes)