Protein, Creatine, Vitamin D & Beta Alanine | Which Supplements Matter After 40?

Sims explains that resistance training and sprint training create 'a conversation from myokines to the liver.' The myokines tell the liver, 'Hey, these free fatty acids now need to go into the muscle. I don't have to esterify them and store them as visceral fat.' This hormonal cross-talk is the strongest impetus for losing visceral fat. It is more effective than steady-state endurance exercise, which may not be protective if visceral fat is already high. For the biggest bang for your buck, she recommends going in, doing heavy lifting, finishing with sprint intervals, and getting out—a time-efficient, high-impact protocol.

Sims notes that vitamin D works with a timing effect: post-training administration helps reduce hepcidin, thereby allowing better iron uptake. Many female athletes struggle with iron deficiency, and this simple timing strategy can maximize the iron from their diet or supplementation. This is a functional use of vitamin D beyond bone health, leveraging its hormonal interaction with iron metabolism.

Sims shares that recent medical cohorts show active endurance women with 20% body fat yet visceral fat over 100 cm³, accompanied by high LDL, total cholesterol, and A1C. This pattern indicates that the metabolic protection from endurance exercise is insufficient. By identifying visceral fat early, women can intervene with resistance/sprint training and dietary changes before developing insulin resistance and more serious lipid issues in their mid-40s and 50s.

Sims explains that in younger women still in their reproductive years, nitrates actually decrease performance and VO2, while for postmenopausal women they cause vasodilation and confer a benefit. The mechanism is tied to estrogen, which is intimately involved in the nitric oxide cycle responsible for blood vessel control. This means a supplement touted for performance can be counterproductive in one life stage and helpful in another, a distinction that underscores the need for female-specific research and personalized advice.

During a morning conversation with colleagues, Sims reviewed cases where women with long endurance histories looked healthy and had 20% body fat, yet visceral fat exceeded 100 cm³—a threshold for elevated cardiovascular disease risk. Their blood work showed elevated LDL, total cholesterol, and A1C, indicating that endurance was not protective. She urges women 35+ specifically to ask for the visceral fat number and blood work, so they can intervene before developing more serious lipid and insulin issues at 45 or 50.

Sims points out that beyond protein, creatine, beta-alanine, and vitamin D, there is virtually no solid research on supplements for women. She mentions supplements marketed for mitochondrial health or fat mobilization that have only been tested on rats. This leads her to conclude that most supplements are a waste of money for women, though she acknowledges individual variability and the separate category of adaptogens. The emphasis is on the systemic lack of evidence, not just a few bad products.

Sims notes that when someone identifies a problem (like feeling tired) and starts a supplement, they also tend to improve their eating habits. The combined effect makes them feel better, but the supplement may not be the primary cause. This interaction undermines the reliability of anecdotal evidence and explains why many supplements appear to work in isolation.