The Trouble With “Follow the Science”

"Follow the science" has been a rallying cry on both sides of the aisle since 2020. Often, it means 'do as I say,' even though what is said is diametrically different. How can that be? It seems that the use of the phrase hinges on whether science is a noun or a verb. To better understand the distinction, we need look no further than the recent actions of Secretary Kennedy and FDA Commissioner Makary.

Last week, they overturned two decades of guidance by removing the black box warning on hormone replacement therapy (HRT) for peri- and post-menopausal women. The original warning stemmed from the 2002 Women’s Health Initiative (WHI), a well-designed study that reported a slightly increased risk of breast cancer among women using a combined estrogen-progesterone therapy. Subsequent research reinforced those concerns, and in 2003, the FDA added black box warnings outlining broader risks.

"risks of cardiovascular disease, thromboembolism, breast cancer, and possible dementia without stratifying by age of initiation."  (FDA)

Subsequent study have found the timing of estrogen therapy to flip the script, earlier prescription to a younger cohort than the WHI suggests that HRT reduces all-cause mortality, requiring "a more nuanced interpretation of hormone therapy's benefit-risk balance." Moreover, today's HRT therapy is not confined to systemic treatment, but includes topical use for urinary and sexual symptoms. The new recommendations are tailored to both the type of estrogen product and its systemic or topical use to "reflect risks most relevant to each specific type of hormone therapy product."

A few more nouns (facts)

During the years in which the black box warning was in place, breast cancer incidence rose from 136 to 222 cases per 100,000 women, yet mortality declined. Today, breast cancer behaves more like a chronic illness, with survival improving from 84% in 2002 to 91% now. Cardiovascular disease (CVD) has also become more prevalent in women, due partly to better detection. Still, outcomes remain worse than in men—particularly among post-menopausal women, who experience more than double the 30-day and five-year mortality.

Taken together, these shifts illustrate how scientific conclusions change as new evidence refines earlier assumptions. This evolving pattern of risks helps clarify why reassessing earlier HRT cautions may be scientifically justified.

Science the verb

In speaking about science, it is critical to recognize the underlying scientific "method," taking a hypothesis, carefully building a structure of understanding based on those scientific “nouns,” but accepting that the hypothesis may approach but never become a fact - all remains to varying degrees uncertain. The utility of following the science comes from how well our assembly of the nouns, our narrative, can improve our lives.

In the case of breast cancer, the intervening years allowed for greater investigation of the "signal" heard in the WHI study. That grouping of > 60-year-old post-menopausal women was parsed more finely, looking at younger cohorts as well as those close to the menopausal milestone, the perimenopausal. Simultaneously, science as a verb uncovers nouns regarding earlier diagnostic methods and more efficacious treatment, both impacting the prevalence and survivability of breast cancer.

"When the facts change, I change my mind." - John Maynard Keynes

Although the underlying facts about breast cancer and cardiovascular disease have not fundamentally changed, their relative weight in clinical decision-making has. Improved survivorship and persistent CVD disparities make removing the black box warning a defensible recalibration. Applying the same “abundance of caution” logic that justified the original warning now supports its withdrawal.

There is no need to implicate Big Pharma and Medicine’s evil intent, or to champion an ill-conceived "medical freedom" to explain the change; in this instance, to follow the science is to follow Keynes's adage. A similar dynamic plays out in the long-running debate over fluoride

Fluoride

Here, the noun facts have been clear for over 80 years - the use of fluoride reduces cavities, and too much results in fluorosis. During the interval, our culture and resources have produced new facts to consider. In the 1930s, brushing one's teeth was not a given. Caries was a significant problem, as evidenced by the influx of dental needs among our Armed forces during WWII. The addition of fluoride to commercial products, i.e., toothpaste, as a means of product differentiation and sales-driving began in 1956. The addition of fluoride to our water was more useful in the late 40s and 50s than it is today, when fluoride is more readily available. Reassessing that utility is to follow the science; we needn't implicate evil intent, ignorance, or weak scientific associations.

Vaccines

Vaccines, however, present a very different challenge because individual choices carry collective consequences.

Secretary Kennedy's beliefs on the adverse consequences of vaccines and the use of thimerosal have few, if any, follow the science noun facts to support a strong follow-the-science analysis. Instead, we are presented with more emotive slogans, appealing to a very different analytic belief: nature is good. Slogans and individual stories play on our emotions and tribal affiliations. One of the most critical ways this decision to follow the science is different in this instance is that your medical freedom to choose HRT or fluoride has no direct impact on me. However, when considering infectious diseases, the right to medical freedom must be more closely tied to the attendant responsibility: what you choose has a direct impact on me. 

In the end, “follow the science” will remain an empty exhortation unless we acknowledge that science is a dynamic, iterative process rather than a fixed creed. When we selectively elevate specific facts while dismissing others that are equally well-established, we replace scientific reasoning with ideology dressed in a lab coat. What distinguishes responsible policy from reflexive rhetoric is a willingness to let new evidence reshape old beliefs, and an honesty about when that evidence is thin, contradictory, or nonexistent. The challenge before us is not to choose between science and freedom, but to recognize that both require an informed public capable of discerning data from dogma. If we can manage that, then perhaps the next time we hear “follow the science,” it will signal not a political cudgel but a shared commitment to clarity, humility, and the common good.

Source: Updated Labeling for Menopausal Hormone Therapy JAMA Network Open DOI: 10.1001/jama.2025.22259