Which 2 supplements are non-negotiable after 45 for women? | Dr. Stacy Sims

Dr. Sims frames creatine as a nutrient that has been largely lost from contemporary eating patterns. While it is synthesized in small amounts by the body and obtained from meat, the shift away from organ meats and the overall decline in red meat intake mean most people are now deficient. Unlike collagen and leucine, which can be topped up via a carnivore or high-protein diet, creatine cannot be reliably restored through food alone for the majority. She places it alongside vitamin D as one of the two supplements that transcend individual dietary variability—they are nearly universal needs.

Dr. Sims responds to a common confusion about vitamin D dosing, where people self-prescribe high amounts after noticing subjective drops in HRV during dark months. She strongly advises obtaining a blood test to see where you sit in the normal range. If you are already in the low-normal range, 8,000–10,000 IU daily through the darkest months is a research-backed strategy to maintain adequacy. As spring and summer return, the dose should be reduced. She cautions against the host's anecdotal 20,000–30,000 IU daily regimen, not because it has been proven toxic, but because the long-term toxicity profile of sustained supraphysiological levels hasn't been characterized. The absence of an established upper limit is not a green light for unlimited intake; it reflects a gap in the data.

She argues that modern diets, even those that include some animal products, no longer deliver the creatine levels that the body would obtain from a more ancestral-style diet rich in organ meats and game. As a result, the non-negotiable status applies to women over 45, younger women, and men alike. This represents a shift from case-by-case advice to a blanket, food-system-based necessity. She contrasts this with collagen and leucine, which can often be covered by a diet like carnivore, implying that creatine cannot be reliably met through diet alone for most people.

She notes that even in summer, practical realities—sunscreen use, long sleeves, indoor lifestyles—mean many people fail to synthesize enough vitamin D. This chronic insufficiency, now linked to lean mass preservation, elevates vitamin D from a seasonal, optional add-on to a daily essential. The shift in research means it's not just about preventing rickets or osteoporosis; it directly ties to maintaining functional muscle mass as women age.