Taking this legal supplement is more like using hormone replacement therapy, only without a prescription. Here's the science.
The prohormone era was wild. Over-the-counter supplements converted by your body to produce active hormones? Good times.
Then came the Anabolic Steroid Control Act of 2004. Legitimate companies couldn't sell them anymore. Sure, the gray market existed, but their products were risky: possible liver damage, acne, gyno, hormone imbalances, etc. And of course, they were effectively illegal.
There is, however, one remaining legal prohormone, though you probably don't think of it as one: D Fix ➔ Buy at Biotest.
Why they call vitamin D a vitamin is a mystery. Vitamin D is actually a prohormone and not a vitamin at all. By itself, it has no significant biological activity. Instead, it has to be converted by the body into its active form, the hormone 1,25 dihydroxycholecalciferol.
It’s at that point where vitamin D can do its magic, like bolstering your immune system, your testosterone levels, and even the sex drive of females. You could even call taking vitamin D a form of hormone replacement therapy. And much like other types of HRT, Vitamin D therapy also appears to increase muscle mass.
Body composition studies
A few years ago, nutritionists conducted a study on 163 overweight men and women. They found that subjects with higher levels of vitamin D had more muscle and a lower percentage of fat.
Another paper provided even stronger evidence. It compiled the results of six studies in which men and women took 4,000 IU of vitamin D daily. Across the board, they exhibited more strength in the leg press, chest press, bench press, and other measures of strength.
Now there’s a newer study that further supports Vitamin D’s muscle-building capabilities. Researchers gave healthy participants either 420 IU of vitamin D3 a day or a placebo for a year. When the study was over, the group receiving vitamin D3 increased their lean mass by a little over a pound.
Granted, a good lifter could gain a pound faster than that, but these people gained muscle just by being alive – no resistance training or exercise was involved.
How does vitamin D3 build muscle?
One theory is that vitamin D3 has a suppressive effect on the myostatin gene, and the more you suppress myostatin, the more muscle you grow (up to a point, of course).
Another theory suggests that vitamin D may trigger PGC1-alpha, a key regulator of energy metabolism that spurs the development of new mitochondria. This, in turn, may allow you to train harder and thus foster additional muscle growth.
How much, what kind?
While the study above only gave participants 420 IU a day, it’s both safe and rational to use up to 5000 IU a day, especially if you don't lay out in the sun too often. Even then, many people find it difficult to get their blood levels of D3 up, especially if they'r eover 40.
So, take D Fix ➔ Buy at Biotest. It's made by encapsulating vitamin D3 molecules in solid lipid nanoparticles. The vitamin presents as tiny "beadlets" and is protected from moisture, oxidation, pH, and temperature. The microencapsulated product is stable, water-dispersible, and highly bioavailable – you can actually absorb it. You get 5000 IU of microencapsulated D3 in each tiny softgel of D Fix ➔ Buy at Biotest.
Now, the only way you can know for sure if you have enough 1,25 dihydroxycholecalciferol is to get it tested. A blood value of at least 30 ng/ml is considered okay for basic health, but for fat-burning and muscle-building purposes, shoot for around 70 to 80 ng/ml. Given all the other health benefits of vitamin D, aim for the higher number.
References
- Sun X et al. "Effect of Vitamin D Supplementation on Body Composition and Physical Fitness in Healthy Adults: A Double-Blind, Randomized Controlled Trial." Ann Nutr Metab. 2019;75(4). PubMed: 31801135.
- Siddiqui SM et al. "Dietary intervention with vitamin D, calcium, and whey protein reduced fat mass and increased lean mass in rats." Nutr Res. 2008 Nov;28(11):783-90. PubMed: 19083488.
- Shantavasinkul PC et al. "Vitamin D status is a determinant of skeletal muscle mass in obesity according to body fat percentage." Nutrition. 2015 Jun;31(6):801-6. PubMed: 25933486.
- Tomlinson PB et al. "Effects of vitamin D supplementation on upper and lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis." J Sci Med Sport. 2015 Sep;18(5):575-80. PubMed: 25156880.