XY Files Blog

Evidence-based articles on testosterone, men's health, fitness, longevity, and sexual health.

What is the difference between magnesium citrate and magnesium glycinate?

What is the difference between magnesium citrate and magnesium glycinate?

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 22, 2025 · 11 min read

Magnesium citrate is more likely to loosen stools and help constipation, while magnesium glycinate is typically better tolerated and is commonly used for sleep and daily supplementation. Here is the evidence-based breakdown of how citrate and glycinate affect your digestion, sleep, and absorption differently. “Patients often grab the first magnesium bottle they see, not realizing ...

Why do energy drinks make me tired? The crash mechanics and the best cutoff before bed

Why do energy drinks make me tired? The crash mechanics and the best cutoff before bed

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 21, 2025 · 14 min read

Energy drinks can make you tired because caffeine and sugar can create a short-lived spike followed by a “crash,” and caffeine can also disrupt sleep long after the can is empty. If you keep asking “why do energy drinks make me sleepy,” the answer is often a mix of brain chemistry, blood sugar swings, hydration, ...

Moobs or gynecomastia? How to get rid of man boobs with the right diagnosis

Moobs or gynecomastia? How to get rid of man boobs with the right diagnosis

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 21, 2025 · 15 min read

You can get rid of man boobs by first confirming whether you have excess chest fat, true gynecomastia, or a combination, then matching the fix to the cause. The fastest path is usually a smart fat loss plan plus full body strength training, but glandular breast tissue often requires a medical approach. “When a guy ...

Red light therapy for weight loss in men: What the evidence says about rrt and fat loss

Red light therapy for weight loss in men: What the evidence says about rrt and fat loss

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 21, 2025 · 14 min read

Red light therapy for weight loss may reduce waist and body measurements in small human studies, but the evidence is limited and the strongest results come from clinic grade low level laser devices, not typical home panels. If you are considering rrt for weight loss, here is how to separate real data from marketing and ...

Tongkat ali and fadogia agrestis: Do men get a real testosterone boost or extra risk?

Tongkat ali and fadogia agrestis: Do men get a real testosterone boost or extra risk?

Alexander Grant, MD, PhD avatar
Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Nov 20, 2025 · 10 min read

Tongkat ali has human evidence suggesting it can raise testosterone in some men, but fadogia agrestis has no human testosterone studies and a less defined safety profile. If you are considering fadogia agrestis and tongkat ali together, you need to understand what is proven, what is speculation, and where the side effect risk may rise. ...

Can my body use 100 grams meat protein in one sitting for muscle growth?

Can my body use 100 grams meat protein in one sitting for muscle growth?

Bruno Rodriguez, DPT, CSCS avatar
Bruno Rodriguez, DPT, CSCS: Strength, Recovery, and Physical Therapy Expert
Nov 20, 2025 · 9 min read

In a 2023 Cell Reports Medicine study in healthy young men after resistance training, a single 100-gram protein meal supported muscle protein synthesis for longer than a 25-gram dose. In the study conditions, digestion slowed and blood amino acid availability stayed elevated for about 12 hours after 100 grams, compared with a shorter elevation after ...

Getting kicked in the cb: What ball shots really do to your body and how to recover safely

Getting kicked in the cb: What ball shots really do to your body and how to recover safely

Alexander Grant, MD, PhD avatar
Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Nov 20, 2025 · 12 min read

Testicular trauma (getting hit in the groin): what happens, warning signs, and safe recovery A direct blow to the scrotum can cause anything from a painful bruise to internal bleeding or testicular rupture, and the nausea/abdominal pain happens because the testes share nerve pathways with structures near the kidneys from fetal development. Here’s how to ...

What is a bro split workout? The simple weekly plan that still builds size

What is a bro split workout? The simple weekly plan that still builds size

Bruno Rodriguez, DPT, CSCS avatar
Bruno Rodriguez, DPT, CSCS: Strength, Recovery, and Physical Therapy Expert
Nov 20, 2025 · 16 min read

A bro split workout is a weekly training split that trains each major muscle group once per week on separate days. Done right, it is a straightforward way for men to push high session volume, chase a reliable “pump,” and still leave plenty of recovery time between hard sessions. Key takeaways A bro split trains ...

Algae cooking oil: Smart upgrade or just another kitchen trend?

Algae cooking oil: Smart upgrade or just another kitchen trend?

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Nov 20, 2025 · 17 min read

Algae cooking oil is a reasonable upgrade if it replaces butter, coconut oil, or shortening, because its mostly unsaturated, high‑oleic fat profile can lower LDL cholesterol similar to other high‑oleic vegetable oils, and it tolerates high heat with a smoke point around 535°F. Here’s how it actually stacks up against common seed oils in cooking ...

Does nicotine increase testosterone or quietly wreck it?

Does nicotine increase testosterone or quietly wreck it?

Alexander Grant, MD, PhD avatar
Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Nov 20, 2025 · 10 min read

In observational studies, male cigarette smokers average about 15% higher total testosterone and 13% higher free testosterone than non-smokers, likely because nicotine alters liver hormone metabolism and slows testosterone breakdown. That “smoker’s paradox” can still coincide with erectile dysfunction and infertility as smoking damages blood vessels and testosterone-producing Leydig cells, so higher lab numbers don’t ...

Can Vitamin D impact testosterone?

Can Vitamin D impact testosterone?

Susan Carter, MD avatar
Susan Carter, MD: Endocrinologist & Longevity Expert
Oct 28, 2025 · 15 min read

Vitamin D can modestly raise testosterone in men who are truly vitamin D deficient (25-hydroxyvitamin D below 20 ng/mL), likely because the testes contain vitamin D receptors and activation enzymes that may influence Leydig cell testosterone production. Here is how to tell when correcting vitamin D is a meaningful lever. It also explains when low ...

L carnitine benefits for men: What it can and cannot do for fat loss, workouts, and testosterone signaling

L carnitine benefits for men: What it can and cannot do for fat loss, workouts, and testosterone signaling

Alexander Grant, MD, PhD avatar
Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Oct 25, 2025 · 16 min read

L-carnitine can modestly improve endurance style training output and may support sperm motility in selected men, but it is not a guaranteed fat loss or testosterone shortcut. This evidence-based guide breaks down which l carnitine benefits are real, what dose and timeline matter, and how to use it like a structured experiment instead of a ...

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