If you’ve spent any time in a quality gym, you’ll hear the same guidance and talking points over and over. Success is all about doing the fundamentals well. What are the fundamentals?

Progressive Loading (lift heavier over time)
Don’t Miss Workouts
Eat Like an Adult (eat to reach your goals)
Get your Heart Rate Up Regularly
Sleep Like You Give a Damn

But there’s another piece of the performance puzzle that often gets overlooked and to be honest, it’s probably woth noting that the above list should be worked through first. But, for the sake of needing something to talk about today, let’s dive into hormones, energy, and overall health. Specifically, we’re going to discuss supplementing vitamin D and vitamin K2.

How Vitamin D Supports Testosterone

Vitamin D does far more than support bone health. It plays a meaningful role in hormone regulation, including testosterone production. Inside the testes are specialized cells, which are responsible for making testosterone. These cells have vitamin D receptors, meaning they respond directly to the amount of vitamin D available in the body.

When vitamin D levels are low, testosterone production can be suboptimal. Studies have shown a correlation between healthy vitamin D levels and healthier testosterone levels. While supplementing with vitamin D won’t magically turn anyone into a world-class athlete or get them “jacked and tan”, it can make a meaningful difference in how you look and feel, especially for adults over 40 who are desperately trying to keep all the strength, lean muscle, and energy they can.

Pairing Vitamin K2 With Vitamin D

There’s a good reason you often see vitamin D3 and K2 packaged together. Vitamin D increases calcium absorption, which is great — but only if that calcium ends up in the right places.

Vitamin K2 activates proteins that guide calcium into bones and teeth and away from arteries and soft tissues. In other words, it helps your body use calcium properly. This combination makes vitamin D supplementation more effective and, importantly, safer for long-term use.

Most research supports a practical pairing of:

Vitamin D3: 1,000–5,000 IU
Vitamin K2 (MK-7): 100–200 mcg

This combination supports strong bones, healthy hormone levels, and overall metabolic function — all essential for building and maintaining strength.

What This Means for Your Training

If you’re lifting consistently, managing stress, chasing good sleep, and eating well, your next step is making sure some of your micronutrients are dialed in. Vitamin D and K2 work together to support:

Hormone balance
Recovery
Bone density
Joint resilience
Cardiovascular health

These aren’t “quick fixes,” but they are impactful habits that improve the long game. Which is cool because getting strong takes time.

Should You Supplement?

Whenever clients ask about supplements, my first question is always: is the house in order? Are you already doing a great job of hitting the fundamentals we discussed above:

following a smart program
hitting all your workouts
getting your hear rate up regularly
eating appropriately for your goal(s)
getting in quality sleep

Most of the time, more effort / energy needs to be allocated to those “basic” or fundamental habits first. That being said, once the house is in order supplementation might be useful.

Keep in mind, whenever adding supplements, it’s always smart to check your levels. Vitamin D deficiency is extremely common, especially in adults who work indoors or live in seasonal climates. A simple blood test can tell you where you stand. I would recommend getting your levels checked prior to running out and spending money to fix a problem you might not have.

If you’re low, supplementing with a balanced D3/K2 combo is relatively cheap, easy, and effective … assuming you’re using 3rd-party tested brands (which is a whole other topic).

Want help putting together a plan to help you reach your goals?

Book a Meeting today with one of our coaches and we’ll help you get organized and moving in the right direction.

Hope this helps,

James