AMH - is this normal?

J💋

When I was 25 at the end of 2020 I had my AMH tested. The result of that test was 4.66. Since then I have done 4 medicated IUI cycles each producing 1-3 mature follicles at the time of trigger. A few weeks ago I am now 27 and I had my AMH tested again in preparation for IVF and it is 6.02. Is this normal for it to increase? Could supplements and vitamins have caused an increase? I thought if anything it would’ve decreased.