Indeed, injections are slightly safer as estradiol goes directly into the blood and does not need to circulate through the portal vein connecting the intestines to the liver where it triggers a host of changes that tends to increase coagulation. Injections, just like patches, gels, pellets have shown to affect hepatic (liver) markers to a much lesser extent and thus be more appropriate for older people (who are more prone to clotting) although bio-identical estradiol taken orally is still relatively safe, it seems.
In ciswomen, for instance OR even in transwomen, on high doses injections, it has been shown that high doses or levels do not, in general, lead to an increase in the risk of DVT (deep vein thrombosis) or other complications, even in those who are older. The rate of complications is either negligible or very low.
With Delestrogen (estradiol valerate), half-life is around 4-5 days, with levels already significantly decreasing by day 7-8 so usually, individuals feel best injecting every 7 days (5-10 days), keeps things more stable.
