Why is knowing the exact concentration (0.3%) of estriol useful for users?
Knowing that M4 contains 0.3% estriol is useful because it tells you the product is using a specific, low-dose strength of a less potent estrogen. That helps put the product in context.
At Alloy, we chose estriol because it’s weaker than estradiol but still effective for skin concerns like dryness, thinning, moisture loss, and reduced elasticity. So when you see 0.3%, it helps you understand that this is meant to work locally on the skin, not like systemic hormone therapy. It also helps explain why safety comes up so often in the research and education around topical estriol.
That low-dose context matters even more because in our M4 study, estradiol and estriol levels did not increase over 12 weeks. So the exact concentration gives users a clearer picture of both strength and why estriol was chosen in the first place.
If you want the fuller science, our skin science page and M4 product page are the best places to read more.
M4 Face Cream Rx
Estriol
$150.00
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