Those fat-stimulating creams might work for some, but are hard to recommend given how much we still don’t know about them. Fortunately, the second group of topicals are a lot more promising.

Bust-enhancing creams that make use of phytoestrogen provide results by mimicking estrogen in the body. But, what exactly does estrogen have to do with breast development?

To put it simply, the hormone is crucial to breast growth. Without estrogen, along with insulin-like growth factor 1 (IGF-1), the changes typically associated with puberty won’t even occur.

Have you noticed that your bra doesn’t fit the same way throughout the month? That’s due to estrogen as well—when its levels peak during the first two weeks of your cycle, your breasts literally get bigger.

As if trying not to limit itself to stimulating breast growth, the hormone also keeps the skin hydrated. In a way, it shields against the various effects of aging, such as wrinkling and pigmentation.

It’s clear that estrogen is a powerful ally in getting bigger boobs. But, is there any proof that its plant-derived counterparts, the phytoestrogens, can do just as well?

It’s generally accepted among the scientific community that phytoestrogens can be just as effective as estrogen itself, and can compete with synthetically produced compounds.

There’s even growing belief that phytoestrogens should be considered for use as an alternative to conventional hormone replacement therapy (HRT), which has been linked to increased risks for cancer and stroke.

What makes phytoestrogen seem superior to estrogen, however, is that it offers other valuable benefits—such as boosting IGF-1 (which, as we’ve mentioned, is another key factor in breast development).

So at this point, you might be thinking that all creams containing phytoestrogen should work in providing hormonal breast augmentation. Unfortunately, as many have realized firsthand, things aren’t that simple.

Look into phytoestrogen-containing breast enhancement creams and you’ll notice that they don’t all have glowing reviews. In fact, most of these products can be considered average, and some are simply subpar.

Quality matters when it comes to topicals, and it isn’t enough to merely have phytoestrogens. Purity and dose are vital factors that ultimately determine a product’s overall quality and, in turn, its potency.

Creams don’t even have to be approved by the Food and Drug Administration (USFDA) to be sold. Although there are general guidelines in place, there are no guarantees regarding safety and effectiveness.

There’s also the problem with creams being made less pure by their very nature. They typically contain ingredients for moisture and lubrication, as well as for achieving a thicker consistency.

While these may soothe the outer skin, they prevent the active ingredients from effectively (and quickly) going into the deeper layers—this, of course, limits the cream’s capacity to stimulate breast tissue growth.

Some creams do work, particularly those with minimal additives while having high amounts of active ingredients (aka ingredients that supply phytoestrogens).

But, even the “lightest” creams contain things that aren’t that relevant to your quest for a bigger, shapelier bust. That’s why you should probably consider opting for a purer kind of topical—the serum.

Serums, by design, provide high amounts of active ingredients without requiring much time for absorption. These are often water-based, though oil-based serums are still lighter than creams.

Even serums tend to differ in quality, however, as some manufacturers would rather focus on keeping production costs low. Despite that, it’s still safe to say that serums generally work better than creams.

And so, instead of shopping for a bust cream, you should consider moving on to serums. While the latter tend to be a bit more expensive, they do have the advantage being more likely to yield actual, noticeable results.