I tried it for about 3 weeks. I don’t have any insulin or glucose issues, I was interested in the potential anti-aging benefits. Started first week at 250mg 2x day and then 500mg 2x day per doc’s recommendation. I had some “gastric distress” towards the end of the first week. I probably wasn’t on it long enough to get any benefit but I never felt quite right when taking it. Stomach a little off and just kind of fatigued. It’s probably useful for someone who is insulin resistant but it wasn’t for me.
You could also check out berberine, it has a similar method of action and is OTC. I tried it too and while it didn’t make me feel off like metformin it didn’t do anything for me so I stopped.
Im surprised that being in the trt forum almost nobody has mentioned that metformin heavily raises shbg. If your shbg is low, this might be a great drug. But if your starting point is an already high shbg, you can start feeling bad as I did. It would be great to know a rule of thumb to increase T while on metformin to balance back the free t.
Metformin is known to elevate SHBG, but it is negligible in most people. And being on TRT decreases SHBG in most people, so it doesn’t usually make much difference. Higher SHBG is considered a marker for longevity, so the medical community likes that side effect.
You are right, it is a longevity marker, but it implies less free t. In my case was more a disaster than negligible. So at least I think it is good to raise awareness in this trt forum were usually not the easiest and common cases are commented.
I did a little poking around in PubMed and found a couple articles that showed an increase in SHBG, but these studies were mostly focused on women, obese men, and/or diabetic men taking insulin treatment. Then I came across this article. It shows a small (~10%) but significant (p<0.009) increase in SHBG in 12 normal men treated with 850mg Metformin twice per day.
Source: Shegem, N.S., Nasir, A.M., Jbour, A.K., Batieha, A.M., El-Khateeb, M.S., and Ajlouni, K.M. (2002). Effects of short term metformin administration on androgens in normal men. Saudi Med J 23, 934-937.