Research

Hormonal

In vitro treatment with eicosapentaenoic acid (EPA) inhibits myotube formation and overrides the stimulatory effects of 17β-estradiol (E2) on myoblast differentiation.

If you are taking hormone replacement therapy (HRT) and considering high-dose fish oil supplements, be aware that they might not work together to build muscle as expected. This lab study suggests that high levels of EPA can actually block the muscle-building benefits of estrogen. Consult your doctor before combining these, especially if muscle maintenance is a primary goal.

ModerateRefutesMEDIUM confidence
Independently, EPA inhibited myoblast differentiation and overrides the stimulatory effect of E2 when used in combination with E2.
Orly Lacham‐Kaplan et al. · International Journal of Molecular Sciences · 2020

Why this rating

The study uses a reliable in-vitro model (C2C12 myoblasts) with rigorous molecular analysis (qPCR, NGS), but lacks in-vivo human validation.

Source

Divergent Regulation of Myotube Formation and Gene Expression by E2 and EPA during In-Vitro Differentiation of C2C12 Myoblasts

Orly Lacham‐Kaplan et al. · International Journal of Molecular Sciences · 2020

DOI 10.3390/ijms21030745

mechanism_onlyCited 11×
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DOI resolved against Crossref · corpus check 2026-06-10

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