As discussed in greater detail in the upcoming second edition of It Starts with the Egg (out in late February, 2019), the supplements to consider taking in the lead up to a frozen embryo transfer are:
- Vitamin D
- Vitamin E
- L-arginine (this is not recommended before egg retrieval however, because it may compromise egg quality, as explained in the book)
- Possibly CoQ10
In 2019, a randomized, placebo-controlled study of women with repeated implantation failure found that supplementing with vitamin E significantly improved lining thickness.[i] An earlier study, involving sixty patients with a thin lining, also found that supplementing with either Vitamin E or L-arginine improved endometrial thickness in about half of patients.[ii]
In that study, the doses used were 600 mg per day for Vitamin E and 6 g per day for L-arginine. Although the women were assigned to receive either vitamin E or L-arginine to compare the effects, it may be even more effective to combine the two supplements, because they work in slightly different ways.
Vitamin E appears to be particularly useful because it boosts cell numbers in the uterine lining and promotes the development of new blood vessels. L-arginine likely works by dilating blood vessels and thereby improving blood flow.
Other than Vitamin E and L-arginine, there is very little evidence for any further supplements. There is a possibility that CoQ10 can improve endometrial thickness, although this is far from certain. One study has reported an increase in endometrial thickness in women taking CoQ10,[iii] but these women had PCOS and were being treated with clomiphene citrate, so it is not clear whether other women would see the same benefit. The study authors suggested that CoQ10 may have improved endometrial thickness by supporting egg development, thereby boosting natural estrogen production.
CoQ10 could also theoretically support lining development more generally by enhancing the function of mitochondria. It has been known since the 1960s that certain cells in the uterine lining suddenly develop so-called “giant mitochondria” at certain stages of the menstrual cycle. This suggests a greater need for energy production in the cells lining the uterus, which could be supported by providing additional CoQ10.
In addition, CoQ10 also plays an important role in regenerating vitamin E back into its active form, so this may be one more way in which CoQ10 could further help lining preparation. Ultimately, however, there is little research confirming that CoQ10 is helpful after egg retrieval and this supplement is therefore a lower priority after egg retrieval.
[i] Hashemi, Z., Sharifi, N., Khani, B., Aghadavod, E., & Asemi, Z. (2019). The effects of vitamin E supplementation on endometrial thickness, and gene expression of vascular endothelial growth factor and inflammatory cytokines among women with implantation failure. The Journal of Maternal-Fetal & Neonatal Medicine, 32(1), 95-102.
[ii] Takasaki, A., Tamura, H., Miwa, I., Taketani, T., Shimamura, K., & Sugino, N. (2010). Endometrial growth and uterine blood flow: a pilot study for improving endometrial thickness in the patients with a thin endometrium. Fertility and sterility, 93(6), 1851-1858.
[iii] El Refaeey, A., Selem, A., & Badawy, A. (2014). Combined coenzyme Q10 and clomiphene citrate for ovulation induction in clomiphene-citrate-resistant polycystic ovary syndrome. Reproductive biomedicine online, 29(1), 119-124.