Testosterone 101

Everything you need to know about testosterone, backed by the latest research. We turn complex topics like diagnosis, dosing, delivery methods, and lab results into simple, practical insights. Understand TRT benefits and risks, maintain estradiol balance, and spot drug interactions - all grounded in evidence, not hype.

Start here

The essentials for testosterone 101 — then explore the latest posts below.

Got “Normal” testosterone on Function Health but still feel off? How to interpret results and plan next steps.

Got “Normal” testosterone on Function Health but still feel off? How to interpret results and plan next steps.

Dr. Susan Carter, MD avatar
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Feb 09, 2026 · 11 min read

A testosterone result can be “normal” and still feel off because testosterone deficiency is diagnosed by symptoms plus consistently low morning total testosterone on repeat testing (often around ~300 ng/dL), and total testosterone can look adequate while free testosterone is low when SHBG is elevated. Here’s how to decide when a repeat draw matters, which ...

Testosterone and the Dietary Guidelines for Americans: What men should actually do

Testosterone and the Dietary Guidelines for Americans: What men should actually do

Dr. Susan Carter, MD avatar
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Jan 21, 2026 · 11 min read

The phrase “testosterone dietary guidelines americans” sounds like a niche search query. But it reflects a real shift: more men are looking to federal nutrition guidance for answers about hormone health. The Dietary Guidelines for Americans (DGA) doesn’t set testosterone targets, but its focus on weight and cardiometabolic health overlaps with factors associated with testosterone ...

Athlete biomarker testing for longevity: The lab numbers that keep men performing longer

Athlete biomarker testing for longevity: The lab numbers that keep men performing longer

Dr. Susan Carter, MD avatar
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Jan 19, 2026 · 11 min read

For longevity-focused men who train, repeating key labs—especially HbA1c (a ~3‑month average of blood sugar) and ApoB (the number of atherogenic particles that can enter artery walls)—can reveal early metabolic drift and cardiovascular risk before performance drops or disease shows up. Pair those with iron, inflammation, and hormone/recovery markers to build a “healthspan dashboard” that ...

Does creatine increase testosterone? The science on muscle fuel and male hormones

Does creatine increase testosterone? The science on muscle fuel and male hormones

Dr. Alexander Grant, MD, PhD avatar
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Jan 11, 2026 · 10 min read

Creatine monohydrate does not significantly increase total or free testosterone in healthy men in controlled studies, because it works by boosting cellular energy (ATP recycling) rather than directly stimulating the endocrine system. It may still help you train harder and see temporary workout-related hormone spikes—and a single 2009 rugby study reporting higher DHT (a potent ...

9 foods that fight hot flashes: A tactical guide for men

9 foods that fight hot flashes: A tactical guide for men

Dr. Alexander Grant, MD, PhD avatar
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Jan 07, 2026 · 11 min read

In men with severe hypogonadism or on androgen deprivation therapy, hot flashes occur when falling testosterone disrupts the hypothalamic “set point,” triggering norepinephrine surges that drive rapid skin vasodilation and sweating—pathways diet can help calm by reducing neuro-inflammation and autonomic stress. If you’re among the up to 80% of men on ADT who experience these ...

Special OfferLab panels included: $300/year free for all members